Heat Pumps - post here.

Condenser · 20-11-2012 11:06pm

hugo29 wrote: »

is there any way to determine what depth boreholes are. we have geothermal system but we dont seem to be getting a decent temp in from them

It will depend what the drill crew find when drilling. They should be checking the cuttings from the bore to check what type of ground they're in. A good rule of thumb is 50W per linear meter of pipe. What you're actually trying to do is cover the cooling capacity of the heat pump. The cooling capacity is the heating capacity minus the electrical load so if you had a 10kw heat pump with a 2kw electrical load you would have an 8kw cooling capacity. 8000W divided by 50W equals 160, so about 160m of bore would be required in this case.

If you're close to the above then your pipework could be too small. Your pump might not have enough pumping head. Was your borehole grouted? Are there filters in the line? Did it ever work right? Does it gradually drop and drop in temperature?

Also if you needed more than 120m and its all in one bore then that'll be a contributing factor. The pumping capacity required increases the deeper you drill and unlikely that the pump would be sized for that and the fluid would circulate slower. If drilling deeper than 120m it should be split in two. Below that is only suitable in commercial situations.

hugo29 · 21-11-2012 11:05am

engineermike wrote: »

As sheff has proposed this information is accurate - however if your not reading optimum temp differential at the pump computer (flow and return at the energy / loop - ground loop), there may be an issue with undersizing.
The manufacture of the pump & the KW of the unit (model no. also).
Distance from bore hole to inspection chamber and return to the pump.
Last time you had the unit serviced ?
These details would be helpful to provide an accurate answer of your probable issue.
Rgds,
Mike F

thanks guys, i am slowly going mad here

heat pump and bore holes were fitted in feb 2009

Model is Alpha Innotec, 14 kw

distance from bore hole to chamber approx 3m, distance to heat pump from chamber is approx 20m

bore holes were to be 100m each but that is debateable

they hit rock, limestone by the looks of the shavings at the time, no water found, holes were not grouted (did not know at time they should have been)

piping was 1 and half inch I think

system has never been right I think, and all I seem to get is muppets talking rubbish when i try to get it sorted, original plumber is gone bust which is a good thing really,

Condenser · 21-11-2012 12:10pm

hugo29 wrote: »

thanks guys, i am slowly going mad here

heat pump and bore holes were fitted in feb 2009

Model is Alpha Innotec, 14 kw

distance from bore hole to chamber approx 3m, distance to heat pump from chamber is approx 20m

bore holes were to be 100m each but that is debateable

they hit rock, limestone by the looks of the shavings at the time, no water found, holes were not grouted (did not know at time they should have been)

piping was 1 and half inch I think

system has never been right I think, and all I seem to get is muppets talking rubbish when i try to get it sorted, original plumber is gone bust which is a good thing really,

Theres your problem. Pipes are floating in mid air. You have no thermal contact. You need to get the bores grouted and then you should be fine. And make sure its done with a proper thermal grout.

hugo29 · 21-11-2012 12:18pm

Condenser wrote: »

Theres your problem. Pipes are floating in mid air. You have no thermal contact. You need to get the bores grouted and then you should be fine. And make sure its done with a proper thermal grout.

ok thanks, next question,
1. who does thermal grout,
2. how much does it cost and
3. before hand is there any way I can stick camera down hole to see if it needs to be grouted for the whole depth, no point in grouting if dont need to

Condenser · 21-11-2012 1:19pm

hugo29 wrote: »

ok thanks, next question,
1. who does thermal grout,
2. how much does it cost and
3. before hand is there any way I can stick camera down hole to see if it needs to be grouted for the whole depth, no point in grouting if dont need to

Its a kind of how long is a piece of string question. You can calculate the volume of the bore to get an approximate volume of how much you need but cavities and fissures in the rock can affect this. Cost depends on who does it and finding someone is not an easy thing to do. Most drillers claim to do it but very few have the proper equipment. It should be grouted top to bottom regardless. You can get away with it if its sitting in moving water but you said yours is not.

hugo29 · 21-11-2012 1:22pm

Condenser wrote: »

Its a kind of how long is a piece of string question. You can calculate the volume of the bore to get an approximate volume of how much you need but cavities and fissures in the rock can affect this. Cost depends on who does it and finding someone is not an easy thing to do. Most drillers claim to do it but very few have the proper equipment. It should be grouted top to bottom regardless. You can get away with it if its sitting in moving water but you said yours is not.

ok, can anyone recommend a company that they have experience with,

There is some water in bore hole but its stagnant i think and its a long way down

engineermike · 21-11-2012 4:38pm

Just a couple of points to consider also,
- The thermal grouting / bentonite is only going to lend itself in the order of a very small percentile of the efficiency.
- Depth of bore hole is more likely the latent issue.
Alpha innoTec 14.7 kW Heat Pump Mode SWC140s - Spec. is 2x no. 115m bore holes (max 10 m from manifold - although this relates to the circulation pump & the running time / cost to keep that pump over worked if it is).
Your pipe sizing sounds correct @ inch & half / '120m Double U-Probe 32mm PE 100 SDR 11 Pipe (x2)

The depth they achieved water in the bore holes sounds like the possible issue - less water / ground loop conductivity surface - thermal transfer surface - would adversely affect your Delta T.
A third ground loop would have amended this issue.
I'll P/m details so you can provide details to a competent engineer that will diagnose & repair.
mike F

hugo29 · 21-11-2012 4:49pm

engineermike wrote: »

Just a couple of points to consider also,
- The thermal grouting / bentonite is only going to lend itself in the order of a very small percentile of the efficiency.
- Depth of bore hole is more likely the latent issue.
Alpha innoTec 14.7 kW Heat Pump Mode SWC140s - Spec. is 2x no. 115m bore holes (max 10 m from manifold - although this relates to the circulation pump & the running time / cost to keep that pump over worked if it is).
Your pipe sizing sounds correct @ inch & half / '120m Double U-Probe 32mm PE 100 SDR 11 Pipe (x2)

The depth they achieved water in the bore holes sounds like the possible issue - less water / ground loop conductivity surface - thermal transfer surface - would adversely affect your Delta T.
A third ground loop would have amended this issue.
I'll P/m details so you can provide details to a competent engineer that will diagnose & repair.
mike F

mike thanks for all that but you lost me a little, piping yes you are correct (blue have pic if required), bore holes if memory serves me correct were 100m each but i would have my doubts that they are even that

by 10m to manifold I presume you mean the external manifold and the distance to this from the boreholes, so at 3m I am fine

are you saying that a third loop in each of the boreholes is the best way to go, rather than grouting or both

when you say p/m details what does that mean

engineermike · 21-11-2012 5:06pm

hugo29 wrote: »

mike thanks for all that but you lost me a little, piping yes you are correct (blue have pic if required), bore holes if memory serves me correct were 100m each but i would have my doubts that they are even that

by 10m to manifold I presume you mean the external manifold and the distance to this from the boreholes, so at 3m I am fine

are you saying that a third loop in each of the boreholes is the best way to go, rather than grouting or both

when you say p/m details what does that mean

Its seems to be a combination of factors - but if your saying they unlikely achieved 100m depth in the bore & Alpha spec. says 115m, then your missing at the very least 1m per ground loop of surface contact area between the pipe and water source. Thats got to have an affect on the delta T.
What depth they achieved water at, again a contributing factor, lowering the surface area (Thermal conductivity area) in each ground loop.
Diagnosing the issue correctly is a must before a resolution / fix could be proposed.
Bentonite / thermal grouting, again a contributing factor - ( > %)
3rd loop / bore - is a 'possible' resolution, but better to diagnose the problem correctly first & then propose solutions to the issue.

P/m ( private message) - info. sent.
rgds,
Mike F.

sheff the ref · 21-11-2012 7:33pm

I suggest that the first thing you do is try and measure the borehole depth

hugo29 · 22-11-2012 11:43am

sheff the ref wrote: »

I suggest that the first thing you do is try and measure the borehole depth

other than tossing the plumber who installed system in begining into it, has anyone a simple method to measure

badgerhowlin · 22-11-2012 11:49am

who ever bored the whole should have it on record.

hugo29 · 22-11-2012 12:10pm

badgerhowlin wrote: »

who ever bored the whole should have it on record.

i doubt it very much, the plumber owned the well drilling rig, could always try i suppose

badgerhowlin · 22-11-2012 12:19pm

Only other thing is get a LONG LONG LONG rope with a heavy weight and drop it down the hole.

sheff the ref · 22-11-2012 8:04pm

Get a long enough clothes line rope and tie a heavy weight to the end of it and basically let it down until it reaches the bottom. I did it once with a Water Well. I think I used a piece of Angle Iron I found that had a hole in it, and tied the rope to that.

hugo29 wrote: »

other than tossing the plumber who installed system in begining into it, has anyone a simple method to measure

sheff the ref · 25-11-2012 12:46pm

I am a teacher myself so I have a fair idea of the usage of oil within a school. Basically the school is mainly heated between the hours of 8am and 2pm and the heat goes to radiators. I have taught in something like 30 schools between day to day subbing and everything and not one school that I have taught in has had underfloor heating. Basically for an Oil Boiler, Oil is the consumable. For a Heatpump, electricity is the consumable and there is a significant difference between Night Rate electricity and Day Rate electricity and consequently it costs less to heat by night. When I worked in the area of Geothermal, the theoretical plan was that the bulk of the heating of the underfloor concrete slab would take place by night on the lower rate of electricity.

Any heating done by day would be timed and would essentially be top up heating of the underfloor slab. Obviously on freezing cold days, there would be exceptions and more heating would be required on the day meter. In a school because of the radiators, all the work would need be done on the day rate electricity so basically I could not see it being viable unless you can do maths to prove otherwise. You have also to factor in the amount of heat that escapes from schools through external doors being open at break time etc. when children enter and leave the building.

Nowadays there is a Weather Dependent Controller that calls in the heatpump based on an outside temperature drop. Something I would like to know is, how does this impact on the use of the night meter because if on any given day (unlikely as it is) the night temperature happens to be warmer than the day temperature, then the bulk of the work will be done by day on day rate electricity.

cwboy wrote: »

Thanks for the replies.

I am based in Carlow. The school is reasonably well insulated but doors would be open at breaktime leading to heat losses. With grant aided funding, would we be foolish to ignore a way to rid ourselves of oil? The oil bill is around seven thousand a year. The installer reckons we can elimate 80% of this with the heat pumps.

Are the photo voltaic panels good enough yet to really help with the electricity burden?

sheff the ref · 25-11-2012 6:11pm

Just wondering how your costs have worked out between. I am seriously considering an Alpha Innotec model with borehole.

My demand would probably be above 6kw and no more than 8kw. Are there any pricelists available online from the various companies???

The Hurricane wrote: »

Hi Sunnymeade

Hope I can help Ive had Geothermal installed for 3 years in august this year house is 3000 sq ft built house in 2006 well insulated etc. I have an Alpha Innotech 12 kw Heat pump with boreholes as opposed to ground loops. My esb bill for last year April - April was €1470 total including light all esb house usage I used 5316 night units and 7448 day units. Last February I installed a motorosied valve at the pipe entrance to all the manifolds as there was a slight leak somewhere so the heat pump was coming on during the day when none of the room stats were calling for heat. Since I have done this and fitted a timer operating the heat pump only on nightsaver electricity 11pm -7pm. It has been great im delighted since we had the coldest winter in ages it actually worked really well. Some rooms especially with a lot of glazing just never reach the set roomstat temperature. The garage door is a wooden one wish I had put in a proper PVC sealed door ( doing it this summer) and this affects the utility which is next door to it.

Basically in the first year we moved in we got high ESB bills and I complained to the plumber he kept fobbing me off saying it was normal and the high esb bills would calm down once house dried out etc and all his customers got high winter bills I got sick of him ( hes since gone bust) and contacted Powertech to check the system out for peace of mind. His work and plumbing was perfect but he had the heatpump starting up 3 times an hour with the compressor working doing absolutely nothing which was using up units during the day and of no benefit energy or heatwise.

My advice is get the system checked out by the manufacturer and fit a timer so it only comes on during the nightsaver hours and maybe a motorosied valve depending on your system.

Your ESB usage is incredibly high either your heatpump is sized wrong for the energy demand of your house given its size or the heatpump settings are not set to come on at night when you can farm in cheap electricity.

Hope this helps you as I had those high bills for a few months and how I discovered it was monitoring the esb over a 12 and 24 hour period.

hugo29 · 26-11-2012 12:03pm

sheff the ref wrote: »

Just wondering how your costs have worked out between. I am seriously considering an Alpha Innotec model with borehole.

My demand would probably be above 6kw and no more than 8kw. Are there any pricelists available online from the various companies???

if anyone is speaking to someone about alpha innotec pumps ask them what setting should be used for heating curve, got various answers from various people

Condenser · 27-11-2012 12:10am

hugo29 wrote: »

if anyone is speaking to someone about alpha innotec pumps ask them what setting should be used for heating curve, got various answers from various people

It will depend on the insulation level of your house and the design of your underfloor so if the installer hasn't set it you can play around so it matches the room temp you require at the various outside temps. You just need a thermometer to measure your inside temp. If you have stats then the heat curve would need to be set up completely differently than if you were running off weather compensation alone.

hugo29 · 27-11-2012 12:46am

Condenser wrote: »

It will depend on the insulation level of your house and the design of your underfloor so if the installer hasn't set it you can play around so it matches the room temp you require at the various outside temps. You just need a thermometer to measure your inside temp. If you have stats then the heat curve would need to be set up completely differently than if you were running off weather compensation alone.

Have stats so what do I do

Condenser · 27-11-2012 10:47am

hugo29 wrote: »

Have stats so what do I do

Do you have a buffer tank? You need to have a buffer if you have stats so you maintain constant flow across the condenser no matter how many thermostats are open or your COP will be affected.
If you do have a buffer give me some info on the insulation level of the house and the highest set stat. If you don't have a buffer give me some info on the insulation level of the house and the temp of the flow and return when all stats are open. Then remove all actuators. Don't run the HP with stats and no buffer you will have a serious effect on its efficiency and life span.

Juantorena · 29-11-2012 5:58pm

Condenser wrote: »

It will depend on the insulation level of your house and the design of your underfloor so if the installer hasn't set it you can play around so it matches the room temp you require at the various outside temps. You just need a thermometer to measure your inside temp. If you have stats then the heat curve would need to be set up completely differently than if you were running off weather compensation alone.

Hmmm...could you expand on this a little please? I have no stats, am on weather comp. What/how many readings would I need to take and where? How would they then feed into the heating curve setting?

Thanks.

Condenser · 29-11-2012 7:19pm

Juantorena wrote: »

Hmmm...could you expand on this a little please? I have no stats, am on weather comp. What/how many readings would I need to take and where? How would they then feed into the heating curve setting?

Thanks.

Your house should really not have anymore than 1C difference wherever you go if your installation is good. Just wander around the house with thermometer to confirm the average temp. Then it depends on the unit you have, some have predesignated heat curves and some have fully adjustable curves. The later is better. Somewhere along the curve your outside temp will match the current return temp. If the house temp required matches this current temp then you're fairly on point, if its higher the heat curve is too high and if its lower the heat curve is too low. Its hard to give figures because if I install a better ufh system than you my heat curve will be lower. Similar story with insulation.

Juantorena · 30-11-2012 12:26am

Condenser wrote: »

Your house should really not have anymore than 1C difference wherever you go if your installation is good. Just wander around the house with thermometer to confirm the average temp. Then it depends on the unit you have, some have predesignated heat curves and some have fully adjustable curves. The later is better. Somewhere along the curve your outside temp will match the current return temp. If the house temp required matches this current temp then you're fairly on point, if its higher the heat curve is too high and if its lower the heat curve is too low. Its hard to give figures because if I install a better ufh system than you my heat curve will be lower. Similar story with insulation.

Ok thanks Condenser.

Should I have a plot from which I can read these points? The manager allows me change the curve in specific point form (from recollection say 0.6, 0.7, 0.8, etc) but I'm not getting an X and Y axis type read out.

Thanks for your help.

Condenser · 30-11-2012 9:44am

Juantorena wrote: »

Ok thanks Condenser.

Should I have a plot from which I can read these points? The manager allows me change the curve in specific point form (from recollection say 0.6, 0.7, 0.8, etc) but I'm not getting an X and Y axis type read out.

Thanks for your help.

Its hard to say as most manufacturers have their own version but it sounds like yours should have a graph in the manual that matches those points. What type of machine is it.

Juantorena · 30-11-2012 10:15am

Condenser wrote: »

Its hard to say as most manufacturers have their own version but it sounds like yours should have a graph in the manual that matches those points. What type of machine is it.

It's a Remko.

Can't get my hands on our manual but found this on line - go to page 7 http://www.remko.de/download/archiv/Bedienungsanleitungen/Neue_Energien/Inverter-Waermepumpen/GB/Alt/CMF-CMT80-150-Kurzanleitung_GB-V02.pdf

I'm seeing flow temperature plotted against outside temp. Not sure what determines which heat curve and how internal temperature readings might feed into it...

Condenser · 30-11-2012 4:04pm

Juantorena wrote: »

It's a Remko.

Can't get my hands on our manual but found this on line - go to page 7 http://www.remko.de/download/archiv/Bedienungsanleitungen/Neue_Energien/Inverter-Waermepumpen/GB/Alt/CMF-CMT80-150-Kurzanleitung_GB-V02.pdf

I'm seeing flow temperature plotted against outside temp. Not sure what determines which heat curve and how internal temperature readings might feed into it...

Flow temp is a bad way to run your heat curve as it is not indicative of floor temp. A undersized pump or a blocked filter can affect your flow temp. Return temp gives you an actual indication of floor temp so weather comp should always react to return temp. Going from the graph you would need to be 0.3,0.4,0.5. Impossible to tell exactly where without matching the room temp to the set temp. But the fact its flow temp will mean it might not be very accurate.

Juantorena · 30-11-2012 5:58pm

Condenser wrote: »

Flow temp is a bad way to run your heat curve as it is not indicative of floor temp. A undersized pump or a blocked filter can affect your flow temp. Return temp gives you an actual indication of floor temp so weather comp should always react to return temp. Going from the graph you would need to be 0.3,0.4,0.5. Impossible to tell exactly where without matching the room temp to the set temp. But the fact its flow temp will mean it might not be very accurate.

So should I be taking room temperature readings and comparing them to the 'desired temp' setting in the manager - if there is a difference I alter the curve setting until the two temps converge? And I presume external temp has a bearing on this too?

Sorry for the questions but never got my head around this system.

Condenser · 30-11-2012 6:06pm

Juantorena wrote: »

So should I be taking room temperature readings and comparing them to the 'desired temp' setting in the manager - if there is a difference I alter the curve setting until the two temps converge? And I presume external temp has a bearing on this too?

Sorry for the questions but never got my head around this system.

Exactly. With the preset curves you have, the manufacturer has made an assumption as to what flow temp will be required at various outside temps in order to achieve the room temp you require. So you just need to match the current temp to the desired temp. I don't like the fact its based on flow temp however and don't think it will be very accurate.

Juantorena · 30-11-2012 6:09pm

Condenser wrote: »

Exactly. With the preset curves you have, the manufacturer has made an assumption as to what flow temp will be required at various outside temps in order to achieve the room temp you require. So you just need to match the current temp to the desired temp. I don't like the fact its based on flow temp however and don't think it will be very accurate.

Appreciate your responses Condenser, will stop wrecking your head now whilst I do some tests.

Thanks.

brophis · 11-12-2012 11:56pm

Got my Ecodan 8.5kW air to water heat pump installed last week. Working out round €3 a day so far to run in this weather. House still drying and unoccupied and haven't fine tuned the system yet so looking good. Solar air heating not running yet. House is 2800 sq ft timberframe with 75mm concrete screed downstairs and 45mm liquid screed upstairs. Ufh is toasty. Would recommend big time. The screed holds the heat beautifully and gradually releases heat.

sheff the ref · 12-12-2012 12:32am

How much was that heatpump?

brophis · 12-12-2012 7:23am

sheff the ref wrote: »

How much was that heatpump?

About €3600 ex VAT. The main bulk of the heating system cost is in everything else which is common to most systems. Eg. Taking into account extra ancillary equipment for the heat pump it was bout €3200 ex VAT more than an oil option.

sheff the ref · 12-12-2012 11:12pm

That €3200 would not buy much oil in fairness. We havent really had that much of a cold period of late to test that air to water system. Even though we have had frost, I doubt if the temperatures have been much below zero if at all in a lot of places. Let us know if the temperatures dip if there is much impact on the bill. Have you anything else providing heat to the house, or any significant solar and passive gain which might have contributed to less use of the heatpump?

brophis wrote: »

About €3600 ex VAT. The main bulk of the heating system cost is in everything else which is common to most systems. Eg. Taking into account extra ancillary equipment for the heat pump it was bout €3200 ex VAT more than an oil option.

brophis · 13-12-2012 8:28am

sheff the ref wrote: »

That €3200 would not buy much oil in fairness. We havent really had that much of a cold period of late to test that air to water system. Even though we have had frost, I doubt if the temperatures have been much below zero if at all in a lot of places. Let us know if the temperatures dip if there is much impact on the bill. Have you anything else providing heat to the house, or any significant solar and passive gain which might have contributed to less use of the heatpump?

Worst I've monitored so far is -4 and the heat pump didn't seem too bothered which was kinda cool to see. Playing around with running the heat pump on a schedule or always on demand at present. Have mixed results so the jury's still out on that one.
Some decent solar gain to living spaces which did reduce usage over the two or three days of sun. No other heat source till solar is commissioned and connected to the hrv.

sunnymeade01 · 20-12-2012 5:52pm

Stay well clear on Thermia heatpumps as they have issued a Safety Warning

Safety warning on Thermia Heat pumps - see the national consumer agency

I told them there was a problem 3 years ago and they fobbed me off

2 houses have went on fire because of the heatpump

muffler · 20-12-2012 6:04pm

@ sunnymeade01 - please post a link to where this info is available officially

sunnymeade01 · 20-12-2012 6:07pm

http://www.nca.ie/index.jsp?p=103&n=127&a=966

muffler · 20-12-2012 6:46pm

sunnymeade01 wrote: »

http://www.nca.ie/index.jsp?p=103&n=127&a=966

Good stuff. Thanks

sheff the ref · 20-12-2012 9:10pm

I had intended having the heatpump in a plant room off the Utility Room. Fire is something I did not consider. I think the heatpump will need to be in the Garage after hearing that.

sunnymeade01 wrote: »

Stay well clear on Thermia heatpumps as they have issued a Safety Warning

Safety warning on Thermia Heat pumps - see the national consumer agency

I told them there was a problem 3 years ago and they fobbed me off

2 houses have went on fire because of the heatpump

steloide · 02-03-2013 12:56am

Hi all, I'm dealing with heatlink in tullamore. Iv had my thermia atria in for about 4 years now and have had problems from day 1. The ground floor piping was laid very bad to start with (corners were cut, cold spots were left. Forever.) Our first christmas in the house (the winter before the hard ones) our esb bill was over €1200 for 2 months. We took a loan out for that one. The pump was running 24/7. There has been 4 soft-start replaced. A thermostat at the fan unit had been placed in the wrong spot so the pump thought it was cold all the time so it pumped heat around my house 24/7 but there was no heat cos the soft-start had blown but it keep pumping and pumping.............
So the soft-start was replaced and a couple of months later it blew again. (I dont notice for about 4-5 days till the heat starts dropping). That was also replaced and some computer readings were taken and i was told they were "off the chart" but the machine was reset and all should be ok. A while later that soft start blows "DEJA VU". That was replaced with a much bigger one, that blew the same week, a wire is now bridging something at the front of it and it has been fine since. The circulating pump seized in the mean time and the most recent is the compressor chugging like a tractor. To make matters worse i cant afford a lawyer, I also pretty sure my warranty is up soon. And im sure this post is in the wrong place. SORRY IF IT IS. Is there anyone out there that can help my please I dont know what to do this is obviously not normal.

Cavanjack · 02-03-2013 9:47am

I've a question on heat pumps that I've never heard anyone mention. Do they become less efficent over time due to wearing parts the same as an engine does? Will they still run as good after 10 years as they do on day 1.

al2009 · 02-03-2013 4:10pm

Steloide

document all calls, work done, repairs and failures, log phone calls and times, who you spoke with and action taken.

contact Thermia directly, give them copies of the above documents, and ask for suggestions, the issues with the underfloor they will not be able to help with, that is solely the installer.

I would also recommend contacting the small claims court, see if you can get some remedy, it is very low cost.

Condenser · 02-03-2013 5:00pm

Cavanjack wrote: »

I've a question on heat pumps that I've never heard anyone mention. Do they become less efficent over time due to wearing parts the same as an engine does? Will they still run as good after 10 years as they do on day 1.

If they are run at low temperature then they should keep a stable efficiency but if they are consistently ran to high temp for long periods of time i.e in heating mode, then the compressor will become compromised and start to draw more power. As with everything with heat pumps, if the initial design is right they'll serve you well.

brophis · 02-03-2013 10:27pm

Condenser wrote: »

If they are run at low temperature then they should keep a stable efficiency but if they are consistently ran to high temp for long periods of time i.e in heating mode, then the compressor will become compromised and start to draw more power. As with everything with heat pumps, if the initial design is right they'll serve you well.

On that note, I've been playing with lowering the flow temperature of my ASHP and found the power usage reduces nicely but the heat pump naturally has to run longer. I'll eventually reach a point where the heat pump would have to run non stop to keep the house warm I imagine. Would it be preferable to run 24/7 at as low a flow temp as possible or run warmer for say 12 hours?

Condenser · 02-03-2013 11:09pm

brophis wrote: »

On that note, I've been playing with lowering the flow temperature of my ASHP and found the power usage reduces nicely but the heat pump naturally has to run longer. I'll eventually reach a point where the heat pump would have to run non stop to keep the house warm I imagine. Would it be preferable to run 24/7 at as low a flow temp as possible or run warmer for say 12 hours?

Depends on how much power you're saving and how long extra it runs. Whats your energy consumption per day as opposed to what it was (don't use an owl meter or similar they're crap).
To avail of most of the savings from running at lower temp your system would need to be designed (same energy output from lower temp water) towards that on day one but very few are.

brophis · 02-03-2013 11:19pm

Condenser wrote: »

Depends on how much power you're saving and how long extra it runs. Whats your energy consumption per day as opposed to what it was (don't use an owl meter or similar they're crap).
To avail of most of the savings from running at lower temp your system would need to be designed (same energy output from lower temp water) towards that on day one but very few are.

Haven't got figures for full day yet as still testing various settings. Averages are coming in bout 25% less, maybe less. I was wondering more so from a maintenance point of view if running longer would be worse than running at a higher temp.

Condenser · 02-03-2013 11:55pm

brophis wrote: »

Haven't got figures for full day yet as still testing various settings. Averages are coming in bout 25% less, maybe less. I was wondering more so from a maintenance point of view if running longer would be worse than running at a higher temp.

No, like all motors, compressors prefer clocking up hours rather than operating in a start stop cycle and they much prefer low temp as higher temps means higher pressures and a harder lifetime for the motor.

Even if the result of your test is close (you should save money despite the extra hours) you should still run at low temp for the sake of longevity of the equipment.

steloide · 03-03-2013 9:41am

al2009 wrote: »

Steloide

document all calls, work done, repairs and failures, log phone calls and times, who you spoke with and action taken.

contact Thermia directly, give them copies of the above documents, and ask for suggestions, the issues with the underfloor they will not be able to help with, that is solely the installer.

I would also recommend contacting the small claims court, see if you can get some remedy, it is very low cost.

Thanks for all that but unfortunately i have only start to log calls and callouts about the more recent problems, nothing from the past (but i can dig phone records) as far as who called and what they did that would be just from memory. I'll get in contact with the small claims ,see what they have to say. Thanks for all your input.

sheff the ref · 03-03-2013 1:06pm

A bad install possibly with an undersized collector and an undersized heatpump for the size of the house.

I know of one heatpump in a 3200 square foot house that in the real cold year, 2010, January to December had total ESB bills of €1200 euro.

Heat Pumps - post here.

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