Circulating Pump settings

Wearb · 09-12-2018 09:03PM

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 · 09-12-2018 11:29PM

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 · 09-12-2018 11:43PM

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 · 19-12-2018 08:51PM

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 · 19-12-2018 09:17PM

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 ðŸ€”

John.G · 20-12-2018 04:31PM

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 · 20-12-2018 07:02PM

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 · 21-12-2018 11:07AM

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 · 22-12-2018 12:05PM

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 · 22-12-2018 05:38PM

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 · 22-12-2018 05:51PM

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 · 15-07-2019 03:51PM

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 · 15-07-2019 05:06PM

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 · 15-07-2019 05:21PM

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 · 15-07-2019 05:31PM

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 · 15-07-2019 05:47PM

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 · 15-07-2019 06:15PM

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 · 15-07-2019 06:32PM

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 · 18-07-2019 09:23PM

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.

Circulating Pump settings

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