Circulating Pump settings

Wearb

I replaced the circulation pump on this which was the main reason for the visit. Just got a call to say rads are slow to heat. I used an A rated 5M pump and set it to auto. I expect I need to use a different setting? 26kw boiler with 5 single and 5 double rads and DHW. No zones or trvs.
Pump has cp1 and 2, pp1 and 2 and 3 speed options.
Any one know which setting I should use. Perhaps pp1 at 2 speed?

John.G

Wearb wrote: »

I replaced the circulation pump on this which was the main reason for the visit. Just got a call to say rads are slow to heat. I used an A rated 5M pump and set it to auto. I expect I need to use a different setting? 26kw boiler with 5 single and 5 double rads and DHW. No zones or trvs.
Pump has cp1 and 2, pp1 and 2 and 3 speed options.
Any one know which setting I should use. Perhaps pp1 at 2 speed?

What make pump/model?. and what did it replace ( what speed setting was this on ?)

Wearb

John.G wrote: »

What make pump/model?. and what did it replace ( what speed setting was this on ?)

Old one set at 2. Pic of box from new one.

agusta

Was there any slight leak in the old pump valves

Wearb

agusta wrote: »

Was there any slight leak in the old pump valves

Not until I closed them. I only had 1" valves with me (3/4" on it), so I need to go back and change them ...if the weep hasn't stopped by then. I will change them anyway sooner or later.



How would you set up the A rated pump? I know that no plumbers around here does the calculations. They just buy the stocked pump, which is always a 5M and set it at two for a medium sized house, 3 if bigger and turn it back one if it's noisy.

---

Just found the PDF for the pump that I put on it.
http://www.sanbrafyffe.ie/pdfs/specifications/tucson-a.pdf

Wearb

Even more details on the pump here.

http://media.brintex.com/Occurrence/174/Brochure/4729/brochure.pdf

John.G

Wearb wrote: »

Old one set at 2. Pic of box from new one.

As far as I can interpret the pump curves, PP1 will operate between 2M & 1M and PP2 between 4.5M and 2.25M.....I don't think that you can set PP1 or PP2 on any particular "speed". I would suggest PP2 and see how that goes. If the rads are still slow to heat then change to FP2 which will try and maintain a constant 4.5M...if all else fails you can go to constant speed iii (ii is probably a little low as it corresponds to a 3.2M pump).
I installed a Wilo Pico Yonis 1-6 a few weeks ago and settled on a PP setting of 4.0M which gives a flow rate of 12LPM @ 3M head with all rads and coil full on which gives a 20 Kw boiler a temperature rise of ~ 22/24C. I have 6 double rads & 4 singles.

agusta

its annoying not having the pump valves,i probably would have fitted a 6m pump and put it on constant speed 2.
With the 5m pump, i would have put it on constant speed 3.If the house was zoned and thermostatic valves id have set it on pp2.Tested heating and see how rads heated etc.Having said that my knowledge of pump curves is limited.

John.G

Wearb wrote: »

Not until I closed them. I only had 1" valves with me (3/4" on it), so I need to go back and change them ...if the weep hasn't stopped by then. I will change them anyway sooner or later.



How would you set up the A rated pump? I know that no plumbers around here does the calculations. They just buy the stocked pump, which is always a 5M and set it at two for a medium sized house, 3 if bigger and turn it back one if it's noisy.

---

Just found the PDF for the pump that I put on it.
http://www.sanbrafyffe.ie/pdfs/specifications/tucson-a.pdf

I did mine in the following manner (but I have all the time in the world to play around with the settings) I measured the boiler deltaT with everything opened up fully with the old pump in service and then just tried different PP settings until I got the same DeltaT with the Wilo. The higher you set the PP the higher the flow rate for any given condition. If I was in the trade and in a hurry I would be inclined to use the CP rather than the PP settings and if available set it at between 3.5M and 4.5M. or just go to the tried and trusted fixed speed setting of 2 or 3.

Wearb

John.G wrote: »

As far as I can interpret the pump curves, PP1 will operate between 2M & 1M and PP2 between 4.5M and 2.25M.....I don't think that you can set PP1 or PP2 on any particular "speed". I would suggest PP2 and see how that goes. If the rads are still slow to heat then change to FP2 which will try and maintain a constant 4.5M...if all else fails you can go to constant speed iii (ii is probably a little low as it corresponds to a 3.2M pump).
I installed a Wilo Pico Yonis 1-6 a few weeks ago and settled on a PP setting of 4.0M which gives a flow rate of 12LPM @ 3M head with all rads and coil full on which gives a 20 Kw boiler a temperature rise of ~ 22/24C. I have 6 double rads & 4 singles.

Do you mean change to Cp2? It doesn’t have a Fp setting.

John.G

Wearb wrote: »

Do you mean change to Cp2? It doesn’t have a Fp setting.

Sorry, yes, I meant constant pressure.

Wearb

John.G wrote: »

I did mine in the following manner (but I have all the time in the world to play around with the settings) I measured the boiler deltaT with everything opened up fully with the old pump in service and then just tried different PP settings until I got the same DeltaT with the Wilo. The higher you set the PP the higher the flow rate for any given condition. If I was in the trade and in a hurry I would be inclined to use the CP rather than the PP settings and if available set it at between 3.5M and 4.5M. or just go to the tried and trusted fixed speed setting of 2 or 3.

I suppose that you realise that the original pump would most likely not have been sized correctly either. It would have been fitted as I described above.

Plumbers around here will tell you -correctly- that they’ve been doing it like that for years without problems.
And I suppose that in the average domestic system it does work out fine.

I only once fitted an A rated pump once before and that was for a plumber that couldn’t get around to it. That was set to auto and I didn’t hear if it caused problems.

I just wondered if there was a rule of thumb guide for those new pumps. I did read that one of the settings shouldn’t be used with zones or trvs.

anthonyos

System may need balancing or there is a possibility that there was issues before you arrived. Heatmercants do an own brand pump that is 7 metre head.i have been a plumber for many years and have never got in to sizing and that crack and have never had any problems

anthonyos

Was the old one seized

Wearb

anthonyos wrote: »

.i have been a plumber for many years and have never got in to sizing and that crack and have never had any problems

Domestic heating systems fairly tolerant of of the variation in pumps and the merchants stock the ones that have proven to work.

System may need balancing or there is a possibility that there was issues before you arrived. Heatmercants do an own brand pump that is 7 metre head

It wasn't fully seized. There was a little heat coming through the pump, but from putting my hand on both sides of it, the output from the pump was way too low. It was eventually tripping the Hi limit.



I wouldn't be surprised if the system needed balancing. When I was there the coil valve was fully open, but I suspect that it was tampered with by the customer when the pump went.



Is the Heatmerchants one digital and if so, what is the usual setting for them?

Wearb

John.G wrote: »

Sorry, yes, I meant constant pressure.

Something that I forgot to add and has come back to me now. I noticed that on auto the pump was using about 20W, something that at the time struck me as too little in a house 40 hours without heat. however I left it at auto, assuming that the A rated pump was way more efficient than my own ancient 80W one.

John.G

Wearb wrote: »

I suppose that you realise that the original pump would most likely not have been sized correctly either. It would have been fitted as I described above.

Plumbers around here will tell you -correctly- that they’ve been doing it like that for years without problems.
And I suppose that in the average domestic system it does work out fine.

I only once fitted an A rated pump once before and that was for a plumber that couldn’t get around to it. That was set to auto and I didn’t hear if it caused problems.

I just wondered if there was a rule of thumb guide for those new pumps. I did read that one of the settings shouldn’t be used with zones or trvs.

Because there are/were "only" 3 speed settings in the old pumps then whatever setting was selected it wouldn,t be perfect so the tendency was to oversize and run it at speed 2 or if more rads added to the system run at speed 3.
The A rated pumps are supposed to give the best of all worlds, ~~ 2 to 3 times more efficient under all conditions with additional further savings if properly set up on PP control, sufficient head to satisfy full heating needs and then modulation as zones/TRVs shut down as lower head required then = lower power, my old Salmson ran at a constant 46 watts (speed 2) but was/is still in perfect condition after 18 years and if/when the Wilo expires then I will re install it. I do see a reduction of 2/3 watts as TRvs shut down and ~ 5 watts if cylinder coil only in service. It is recommended to use CP for underfloor heating as the head required is supposedly more constant than with rads.

corkgsxr

Tuscan pumps are ****. Sorry.

I've tried various. Stuck to grundfos after a few years. And I've no issues with pumps anymore

Wearb

corkgsxr wrote: »

Tuscan pumps are ****. Sorry.

I've tried various. Stuck to grundfos after a few years. And I've no issues with pumps anymore

Fingers crossed so.

John.G

Wearb wrote: »

Something that I forgot to add and has come back to me now. I noticed that on auto the pump was using about 20W, something that at the time struck me as too little in a house 40 hours without heat. however I left it at auto, assuming that the A rated pump was way more efficient than my own ancient 80W one.

It will be interesting to see the wattage if/when you change to PP2 or CP2 or constant speed 3.

Wearb

John.G wrote: »

It will be interesting to see the wattage if/when you change to PP2 or CP2 or constant speed 3.

I did run through them before settling on auto. I remember that pp2 was about 40w

John.G

Wearb wrote: »

I did run through them before settling on auto. I remember that pp2 was about 40w

That's a pretty hefty power draw, I would have expected that on a CP2 setting, it should certainly satisfy the rads/cyl coil requirements.

Wearb

John.G wrote: »

That's a pretty hefty power draw, I would have expected that on a CP2 setting, it should certainly satisfy the rads/cyl coil requirements.

I wouldn’t be 100% certain that it was pp2, but thought it was. When I saw the low consumption on auto, I just cycled through the other settings to see how auto compared and then returned it to auto.

I don’t think these pumps modulate down as the temperature on return rises? Since trying to understand all the settings on this I have read of ones that do this.

John.G

Wearb wrote: »

I wouldn’t be 100% certain that it was pp2, but thought it was. When I saw the low consumption on auto, I just cycled through the other settings to see how auto compared and then returned it to auto.

I don’t think these pumps modulate down as the temperature on return rises? Since trying to understand all the settings on this I have read of ones that do this.

It could have been PP2, as you increase the PP setting the power consumption gets closer to the same CP setting and the opening/closing of zone valves has a much bigger effect on the power consumption as the slope of the PP curve gets steeper with increasing PP. I would venture that if you opened/closed the coil balancing valve (if not zoned) that you could see ~ 5W difference if on PP4.5

Re the Auto setting power consumption of 20W, I would have thought that (20W) would have given quite reasonable circulation through the rads etc even though I know that each house heating circuit is different, your system, 5D+5S rads isn't hughly different from mine, 6D+4S, power consumption ~ 20W on PP4.0 all rads and cylinder coil are performing fine with no balancing of either, I suppose that's what makes these pumps so interesting in their reaction to different systems and may even highlight some abnormal restrictions?, I think some pumps actually display the flow rate which would be extremely helpful.

No, these pumps don't modulate on temperature.

I will revert later to your post re the HM pump.

John.G

Wearb wrote: »

Domestic heating systems fairly tolerant of of the variation in pumps and the merchants stock the ones that have proven to work.




It wasn't fully seized. There was a little heat coming through the pump, but from putting my hand on both sides of it, the output from the pump was way too low. It was eventually tripping the Hi limit.



I wouldn't be surprised if the system needed balancing. When I was there the coil valve was fully open, but I suspect that it was tampered with by the customer when the pump went.



Is the Heatmerchants one digital and if so, what is the usual setting for them?

The HM 4-7 is I think a re badged DAB Evosta 4-7. It has 6 PP settings and 3 constant speed settings but no CP settings. Of the 6 PP settings, setting 5 &6 are probably the most applicable, PP5 is 3.8M to 1.9M & PP6 is 5.0M to 2.5M. The three constant speeds are (1) 4.2M, (2) 5.5M & (3) 7.0M.

I would suggest either PP6 or constant speed 2.

http://www.heatmerchants.ie/v4/581ae913-e1fb-435e-a88b-ded312da5b38/uploads/HM%20PROflyer.pdf

Wearb

John.G wrote: »

The HM 4-7 is I think a re badged DAB Evosta 4-7. It has 6 PP settings and 3 constant speed settings but no CP settings. Of the 6 PP settings, setting 5 &6 are probably the most applicable, PP5 is 3.8M to 1.9M & PP6 is 5.0M to 2.5M. The three constant speeds are (1) 4.2M, (2) 5.5M & (3) 7.0M.

I would suggest either PP6 or constant speed 2.

http://www.heatmerchants.ie/v4/581ae913-e1fb-435e-a88b-ded312da5b38/uploads/HM%20PROflyer.pdf

Coincidentally I was just looking at the pdf for that dab pump before lunch. Perhaps it’s well ranked in a google search.

Here is where I’m trying to get to with all my reading (and I think that to a large extent you have answered it). Most houses I visit are roughly the same size and either bungalows or dormers. Most have 3 zones and or trvs. I would like to be able to know what the most appropriate pump settings are for those houses.
I think that I’m slowly getting there. To be more accurate I just need to get my gathered information together and work out the max velocity for the pipework, head per meter, length, fittings etc. I may never get around to this and just stick to the tried and trusted 5,6 or 7m pump.

John.G

Wearb wrote: »

Coincidentally I was just looking at the pdf for that dab pump before lunch. Perhaps it’s well ranked in a google search.

Here is where I’m trying to get to with all my reading (and I think that to a large extent you have answered it). Most houses I visit are roughly the same size and either bungalows or dormers. Most have 3 zones and or trvs. I would like to be able to know what the most appropriate pump settings are for those houses.
I think that I’m slowly getting there. To be more accurate I just need to get my gathered information together and work out the max velocity for the pipework, head per meter, length, fittings etc. I may never get around to this and just stick to the tried and trusted 5,6 or 7m pump.

You may find the attached link of interest: http://www.tasonline.co.za/toolbox/pipe/velfirc.htm

You can quickly calculate pipe velocities,dynamic head,friction loss, and orifice sizing.
rem (approx) 1/2"qual pex ID=11.3MM. 3/4"qual pex ID=16.7MM & 3/4" copper ID=19.0MM. I cant find a bit of 1/2" copper pipe just now to measure its ID.

Wearb

John.G wrote: »

You may find the attached link of interest: http://www.tasonline.co.za/toolbox/pipe/velfirc.htm

You can quickly calculate pipe velocities,dynamic head,friction loss, and orifice sizing.
rem (approx) 1/2"qual pex ID=11.3MM. 3/4"qual pex ID=16.7MM & 3/4" copper ID=19.0MM. I cant find a bit of 1/2" copper pipe just now to measure its ID.

Thanks. Just had a look. How do I get flow rate?

John.G

Wearb wrote: »

Thanks. Just had a look. How do I get flow rate?

You have to input the flow rate, the pipe diameter, the pipe length and the material, the formula will then give you the friction loss. you would need to know the flow rates in the different pipes before and after they branch off to the rads or whatever....not a easy task, you would have to draw a line diagram from and to the boiler to the various rad tails etc and input the flowrates etc etc. I only posted it from a interest point of view really as it shows you the dramatic effect on the friction losses that using small bore pipework has which means higher pump heads required etc but as you say yourself just go for a 5 or 6 M pump, set it to a fairly high PP of 4.5 to 6 if available, if not, just put it to constant speed 2 or 3 and away you go, I think that some of these smart pumps now have so many bells and whistles that they can confuse the basics but no matter how clever or not they are then all of them will have the traditional 3 speed setting to fall back on as you can't be sitting there all day when you could be making a few bob on another job.

Wearb

John.G wrote: »

You may find the attached link of interest: http://www.tasonline.co.za/toolbox/pipe/velfirc.htm

You can quickly calculate pipe velocities,dynamic head,friction loss, and orifice sizing.
rem (approx) 1/2"qual pex ID=11.3MM. 3/4"qual pex ID=16.7MM & 3/4" copper ID=19.0MM. I cant find a bit of 1/2" copper pipe just now to measure its ID.

I have been working on this and It seems that modern houses with each rad plumbed individually back to the hotpress (in 1/2" pex) manifolds require a a larger pump than those with the old way of plumbing. The manifolds use a lot more piping.

John.G

Wearb wrote: »

I have been working on this and It seems that modern houses with each rad plumbed individually back to the hotpress (in 1/2" pex) manifolds require a a larger pump than those with the old way of plumbing. The manifolds use a lot more piping.

They do but I would think that the 3 or 4; 1/2" parallel circuits would have less of a pipe friction loss than than 2 X 3/4 ins headers with 1/2" short rad tails.

Wearb

John.G wrote: »

They do but I would think that the 3 or 4; 1/2" parallel circuits would have less of a pipe friction loss than than 2 X 3/4 ins headers with 1/2" short rad tails.

You would think so, but when you put it into the calculator it comes up with a huge figure. When you consider that each individual rad (and probably 10 or 12 of them) has 2 pipes returning to the hotpress. That is a lot of piping on lets say a 200M bungalow.

John.G

Wearb wrote: »

You would think so, but when you put it into the calculator it comes up with a huge figure. When you consider that each individual rad (and probably 10 or 12 of them) has 2 pipes returning to the hotpress. That is a lot of piping on lets say a 200M bungalow.

OK then if you had 12 rads, each with a total run of 20M of 1/2" pipework and each emitting 2.0 KW with a deltaT of 15C. By calc the flow rate through each one is ~ 1.9 LPM and the pipe friction loss is 0.29M but because the 12 rads have parallel circuits then the total head required is still only 0.29M so for those 12 rads you still only need a 0.29M head for a flow rate of 22.8 LPM to overcome the pipe friction losses, the flow rate is cumulative but the head is not. Now if you assume another 0.29M head loss through each rad and valve fittings then the total head loss is 0.58M, add another 20% for pipe fittings losses and you need a total of 0.7M head for a flow rate of 22.8 LPM with a total of 12 rads.

There are bigger losses in the 3/4" supply& return pipes as some of these must carry the full flow rate of 22.8 LPM. these losses are then added to the above to arrive at the final pump head required to give that flow rate. Maybe 1"
pipes are fitted or should be which would then give a reasonably low total head requirement.

Wearb

John.G wrote: »

OK then if you had 12 rads, each with a total run of 20M of 1/2" pipework and each emitting 2.0 KW with a deltaT of 15C. By calc the flow rate through each one is ~ 1.9 LPM and the pipe friction loss is 0.29M but because the 12 rads have parallel circuits then the total head required is still only 0.29M so for those 12 rads you still only need a 0.29M head for a flow rate of 22.8 LPM to overcome the pipe friction losses, the flow rate is cumulative but the head is not. Now if you assume another 0.29M head loss through each rad and valve fittings then the total head loss is 0.58M, add another 20% for pipe fittings losses and you need a total of 0.7M head for a flow rate of 22.8 LPM with a total of 12 rads.

There are bigger losses in the 3/4" supply& return pipes as some of these must carry the full flow rate of 22.8 LPM. these losses are then added to the above to arrive at the final pump head required to give that flow rate. Maybe 1"
pipes are fitted or should be which would then give a reasonably low total head requirement.

I was just about to ask about the total head on that parallel setup. I guessed it wasn’t cumulative because otherwise it would require over 20m pump.

John.G

Wearb wrote: »

I replaced the circulation pump on this which was the main reason for the visit. Just got a call to say rads are slow to heat. I used an A rated 5M pump and set it to auto. I expect I need to use a different setting? 26kw boiler with 5 single and 5 double rads and DHW. No zones or trvs.
Pump has cp1 and 2, pp1 and 2 and 3 speed options.
Any one know which setting I should use. Perhaps pp1 at 2 speed?

Just to be clear on the above re "Just got a call to say rads are slow to heat", what setting did you finally settle for and what are/were the watts?.

Wearb

John.G wrote: »

Just to be clear on the above re "Just got a call to say rads are slow to heat", what setting did you finally settle for and what are/were the watts?.

CP 2 about 40 w ......I think 🀔

John.G

Wearb wrote: »

CP 2 about 40 w ......I think ��

I reckon if you were on Auto, it would have corresponded to a PP setting of 3M, using CP setting there are still reasonable savings to be had especially where zoning is used as the pump efficiency is still very high at the reduced flows/speed

I have attached some light reading for the Christmas period!!. re Auto (adapt).

Wearb

John.G wrote: »

I reckon if you were on Auto, it would have corresponded to a PP setting of 3M, using CP setting there are still reasonable savings to be had especially where zoning is used as the pump efficiency is still very high at the reduced flows/speed

I have attached some light reading for the Christmas period!!. re Auto (adapt).

I have just read it and will need to do so a few more times to understand all or most of it. Are they suggesting that it takes time to bed-in on auto?

The one that I installed was on a manifold system without any TRV's or controlled zones. That's why I went for CP rather than PP. That is after changing from auto. It might have been nice to have left it on auto for longer to see how it would have worked out.

John.G

Wearb wrote: »

I have just read it and will need to do so a few more times to understand all or most of it. Are they suggesting that it takes time to bed-in on auto?

The one that I installed was on a manifold system without any TRV's or controlled zones. That's why I went for CP rather than PP. That is after changing from auto. It might have been nice to have left it on auto for longer to see how it would have worked out.

I won't pretend that I fully understand the Auto Adapt but I do get the gist of it.
No matter how clever it is it is still a compromise like the PP setting but in a properly installed heating system probably has big benefits.
Most installations that you and others will be doing will be replacing fixed speed pumps, as quite a lot of these will have been "over headed" then some customers will complain about slower warm up times with even a properly configured A rated pump so you are inclined to set them to high heads to keep the customer happy vs a completely new installation where there is no comparison to make.

Re Auto Adapt, yes it looks like its continuously bedding in/adapting.
The CP setting you choose was probably the correct one, a lower setting would probably have done but the Tucson has only two settings, 4.5M & 2M, the 2M would IMO be pretty useless in a whole house heating scene.

The Wilo has incremental 0.1M settings from 0.5 to 6M heads available in all modes except the 3 fixed speeds, here are a few readings I took over the past few weeks.

Rads+cyl coil (cold start) : PP4 (4m head) 24/27W CP4 (4M head) 26W
Rads+cyl coil (fully hot house) : PP4 (4m head) 16/18W CP4 (4M head) 20W

Rads only (cold start) : PP4 (4m head) 21/23W CP4 (4M head) 24W
Rads only(fully hot house) : PP4 (4m head) 14/18W CP4 (4M head) 19W

cyl coil only (hot or cold) : PP4 (4m head) 16W CP4 (4M head) 22W

ONE rad only i/s full open.:PP4 (4m head) 10W CP4 (4M head) 20W

Should also have said that the Tucson on Auto gave a reasonable result as at 20W it would/should have been circulating ~ 80% of the flow at 4.5M head if it was producing a 3M head (on auto)
It would be informative if any readers with these A rated pumps posted their settings.

Wearb

John.G wrote: »

I won't pretend that I fully understand the Auto Adapt but I do get the gist of it.
No matter how clever it is it is still a compromise like the PP setting but in a properly installed heating system probably has big benefits.
Most installations that you and others will be doing will be replacing fixed speed pumps, as quite a lot of these will have been "over headed" then some customers will complain about slower warm up times with even a properly configured A rated pump so you are inclined to set them to high heads to keep the customer happy vs a completely new installation where there is no comparison to make.

Re Auto Adapt, yes it looks like its continuously bedding in/adapting.
The CP setting you choose was probably the correct one, a lower setting would probably have done but the Tucson has only two settings, 4.5M & 2M, the 2M would IMO be pretty useless in a whole house heating scene.

The Wilo has incremental 0.1M settings from 0.5 to 6M heads available in all modes except the 3 fixed speeds, here are a few readings I took over the past few weeks.

Rads+cyl coil (cold start) : PP4 (4m head) 24/27W CP4 (4M head) 26W
Rads+cyl coil (fully hot house) : PP4 (4m head) 16/18W CP4 (4M head) 20W

Rads only (cold start) : PP4 (4m head) 21/23W CP4 (4M head) 24W
Rads only(fully hot house) : PP4 (4m head) 14/18W CP4 (4M head) 19W

cyl coil only (hot or cold) : PP4 (4m head) 16W CP4 (4M head) 22W

ONE rad only i/s full open.:PP4 (4m head) 10W CP4 (4M head) 20W

Should also have said that the Tucson on Auto gave a reasonable result as at 20W it would/should have been circulating ~ 80% of the flow at 4.5M head if it was producing a 3M head (on auto)
It would be informative if any readers with these A rated pumps posted their settings.

Very interesting to have those figures John. I can see that CP is very close to the constant setting. After reading down the list, I was surprised to see 20w usage with only 1 rad.

Auto and PP would seem to give the best performance on the correct system and (as you say) one that hadn't already created high expectations from the exaggerated performance of an oversized pump.



I would have liked to have had a go at different settings on my installation. The customer would have been able to follow my instructions over the phone. However, the pump is installed at the back of the modular unit and would mean removing and replacing screws every time.


Seeing as the only changes the pump can make is to it's speed and the only sensor is pressure, do you understand how it differentiates between CP and PP?

John.G

Wearb wrote: »

Very interesting to have those figures John. I can see that CP is very close to the constant setting. After reading down the list, I was surprised to see 20w usage with only 1 rad.

Auto and PP would seem to give the best performance on the correct system and (as you say) one that hadn't already created high expectations from the exaggerated performance of an oversized pump.



I would have liked to have had a go at different settings on my installation. The customer would have been able to follow my instructions over the phone. However, the pump is installed at the back of the modular unit and would mean removing and replacing screws every time.


Seeing as the only changes the pump can make is to it's speed and the only sensor is pressure, do you understand how it differentiates between CP and PP?

They are pretty smart because the don't measure the head, they just derive it or calculate it from the absorbed power.
For example take a system that requires 4M to deliver 25LPM then if you set the CP setting to 4M the pump should see ~ 34W....which means the pump is pumping 25 LPM @ 4M head & 48% efficiency. Now, say that you shut off a number of rads until a 4M head will give a flow rate of 12.5 LPM, the pump should see ~ 22W....which means the pump is pumping 12.5 LPM @ 4M head & 36% efficiency. Taking this case which is ~ mine with everything opened up IE the flow rate is 12.5 LPM @ 4M AND you then change over to PP mode. The pump is now looking at a demand "curve" which starts at 0 lpm @ 2M head and finishes at 25LPM at 4M.The pump will speed up until it sees 22W and then because there is only one spot on this curve where the proportional demand(power) will match the actual power the pump speed will modulate down until it reaches this equilibrium which in one of my cases is as low as 15W = 10.5LPM @ 3M head & 33.5% efficiency. Now it may not work exactly as I think but its certainly along those lines.
If, a system flowed 25 LPM @ 4M on CP mode and you then change to PP setting then the pump speed will not change (or the head & flowrate) until the TRvs start to close in or manual shut off or whatever and the proportional effect begins to kick in.......again because the PP curve is 0LPM=2M and 25LPM=4M.
In your Tucson case I think you said you didnt see much difference between the CP & PP modes (40W both) and the above is the reason IMO, the actual flow was at the top of the curve ~ 22LPM @ 4.5M, if you were to shut off some of the rads in PP mode then you should see the watts/flow/head decreasing.

I didn't pick these efficiencies out of thin air, you can get a good feel for them by playing around with this Grundfos link.

https://product-selection.grundfos.com/catalogue.product%20families.q%26h%20alpha3.html?custid=GPI&familycode=ALPHA3&flow=0&head=0&lang=ENU&qcid=484848372&time=1545495087091

The reason for a pump power of 20W with one rad is because at a 4M head the rad is probably flowing ~ 2 LPM with a very poor pump efficiency of ~ 5 or 6%.

Wearb

That’s a lot of very informative information John. You have really put your pump through it’s paces with great information gleaned. Thanks for sharing.

I will read this again when I have the Tucson pump curves in front of me

John.G

Wearb wrote: »

That’s a lot of very informative information John. You have really put your pump through it’s paces with great information gleaned. Thanks for sharing.

I will read this again when I have the Tucson pump curves in front of me

Didn't want to start a new thread but the following is interesting, I went to start up my Wilo Yonos Pico 6M pump yesterday around midday but found it wouldn't start, the ambient temperature was ~ 20c but the Firebird Heatpac enclosure where the pump is installed was 36/38C (sun shining directly on it) as measured with a digital thermometer.
The user's manual states -10C to 40C as the operating conditions so I presumed that this was preventing the pump from starting as it did start when the enclosure temperature fell to ~ 32C. I rang Wilo (Dublin) and they were of the opinion that it was indeed this high enclosure temperature was/is the problem. While discussing with them I did say that the pump just didn,t run but on reflection (but didn't mention this to them) I am surprised that it didn't flag a error code as one of these codes, E30 states "Fault: Excessive temperature of module" Cause: Module Interior too warm".
I will keep a good eye on it when running under normal conditions as I'm not entirely convinced of the pump's health in the absence of any fault code.

Wearb

John.G wrote: »

Didn't want to start a new thread but the following is interesting, I went to start up my Wilo Yonos Pico 6M pump yesterday around midday but found it wouldn't start, the ambient temperature was ~ 20c but the Firebird Heatpac enclosure where the pump is installed was 36/38C (sun shining directly on it) as measured with a digital thermometer.
The user's manual states -10C to 40C as the operating conditions so I presumed that this was preventing the pump from starting as it did start when the enclosure temperature fell to ~ 32C. I rang Wilo (Dublin) and they were of the opinion that it was indeed this high enclosure temperature was/is the problem. While discussing with them I did say that the pump just didn,t run but on reflection (but didn't mention this to them) I am surprised that it didn't flag a error code as one of these codes, E30 states "Fault: Excessive temperature of module" Cause: Module Interior too warm".
I will keep a good eye on it when running under normal conditions as I'm not entirely convinced of the pump's health in the absence of any fault code.

I suppose it depends on the safety features of the pump, but once while testing a boiler for nuisance firevalve trips, I measured modular cabinate temperature and from memory often found it higher than that. I probably posted the info in boards, but not sure of that. Just check that the cabinate is vented as designed. It might have been at an even higher temperature earlier.

John.G

Wearb wrote: »

I suppose it depends on the safety features of the pump, but once while testing a boiler for nuisance firevalve trips, I measured modular cabinate temperature and from memory often found it higher than that. I probably posted the info in boards, but not sure of that. Just check that the cabinate is vented as designed. It might have been at an even higher temperature earlier.

I have just ran the burner+circ pump to the hot water cylinder coil for the past hour or so, flow/return temps 75C/62C, enclosure temp 35/40C, "plastic" module/motor temperature 45C/52C with no problem for pump stop/starting so a bit strange to say the least, even in winter and even though I've the pump installed on the boiler return I would expect that plastic module to be well in excess of 40C because of its close proximity to the pump body. I will have to keep a very good eye on this, as I stated previously, I find it hard to believe that IF temperature protection has operated that it doesn't flag a error code as this pump has error codes for all sort of faults.

Wearb

John.G wrote: »

I have just ran the burner+circ pump to the hot water cylinder coil for the past hour or so, flow/return temps 75C/62C, enclosure temp 35/40C, "plastic" module/motor temperature 45C/52C with no problem for pump stop/starting so a bit strange to say the least, even in winter and even though I've the pump installed on the boiler return I would expect that plastic module to be well in excess of 40C because of its close proximity to the pump body. I will have to keep a very good eye on this, as I stated previously, I find it hard to believe that IF temperature protection has operated that it doesn't flag a error code as this pump has error codes for all sort of faults.

Did you check L&N at the pump during its non run period?

John.G

Wearb wrote: »

Did you check L&N at the pump during its non run period?

Yes, I did and even ran a separate supply to the pump, I also changed the plug top and checked that I was getting L(238V) & N at the other end of the quick connect end, the pump was certainly getting power as you would hear a click when plugging in but nothing else, you also hear this click under normal operating conditions.

Wearb

John.G wrote: »

Yes, I did and even ran a separate supply to the pump, I also changed the plug top and checked that I was getting L(238V) & N at the other end of the quick connect end, the pump was certainly getting power as you would hear a click when plugging in but nothing else, you also hear this click under normal operating conditions.

Does sound like internal protection then, though absence of error code is puzzling. As you said that ambient cut off temperature suggested in MI's seems too low anyway.
Could be a sign of impending problematic electronics in the pump.

I will watch this space.

John.G

Wearb wrote: »

Does sound like internal protection then, though absence of error code is puzzling. As you said that ambient cut off temperature suggested in MI's seems too low anyway.
Could be a sign of impending problematic electronics in the pump.

I will watch this space.

"Could be a sign of impending problematic electronics in the pump."

That's my reasoning as well.....so maybe back to a real pump, my 18 year old Salmson.
It doesn't actually state the above -10C/40c as cut off points, I think that just refers to the normal operating range, the electronic box in any of these pumps
must be running at somewhere between the enclosure temperature and the flow or return temp, depending on where the pump is installed.

John.G

Wearb wrote: »

That’s a lot of very informative information John. You have really put your pump through it’s paces with great information gleaned. Thanks for sharing.

I will read this again when I have the Tucson pump curves in front of me

Came across pump curves for a UPS selectric which would be I think the same as the one you replaced, incidentally PC:0717 on that pump face plate means it was manufactured in week 17 of year 2007 so your customer had got a good run out of it.
You said it had been running on speed 2 so I just took 3 readings from the pump curves (UPS attachment) at that speed as the pump had to be operatring somewhere on that curve so I took what I thought would be reasonably representative of that installation and you can see from the spreadsheet what the head/flow the Tucson should be running at if PP2 were selected.