Air Source Heat Pumps

[Deleted User]

Uclan wrote: »

I have a cheap Chinese made ASHP installed by my builder 3 years ago which I am trying to update for a better model i.e. Mitsubishi etc. I have had quotes from several companies. Two of which are supposedly Ecodan registered installers. The prices they have quoted seem a lot for what they are offering. Not one of the companies have offered a solution to my problem which is a lack of heating to the system. The hot water to the tank is fine but the radiators do not get hot enough to warm the house unless the 6kw immersion kicks in also. The HP is linked into an ACV SLME SMART 300L. tank which is supposedly compatible with heat pumps. The tank is twice the price of the heat pump. One of the companies has suggested ripping out this tank and replacing it with a Kingspan. The house is approximately 180m2 with up to standard insulation throughout. The system heats 15 various oversized radiators. We are off the gas grid so the only alternative is oil or lpg. I would appreciate any input regarding finding a compatible good quality HP fitted at a reasonable price by a knowledgable company with a good warranty. Both quotes I have recieved have asked for money up front before completion of work. The way these companies seem to work reminds me of the double glazing industry in the eighties. I would be especially interested of any input regarding the compatibility and the quality of the ACV tank.

A few questions spring to mind...

What are the quotes?

No location given so can't recommend an I installer I have used.

Have you done calcs to check to see if the the sizes of the existing rads are correct?

Size/bore of existing piprwork?

Funds may well be required up front as Mits as I remember don't do credit facilities. You should not have to pay up front for labour/plumbing work.

The packaged kingspan tank has all the control systems attached to it for a quick install but as long as any tank has the correct size of coil and connections it can be used with the Mits control systems.

Suggest finding a local MCS company with a solid grounding in heating/plumbing and not a national as you say... There are cowboys in every walk of life.

Uclan

Thanks for the prompt reply. I'm in N.Wales. The radiators seem adequate enough. When the system first went on the heating seemed to work but the DHW didn't stay hot for long. I got someone in to repipe the tank. Now there's enough hot water but the radiators lose their heat very quickly. He said that the pipework to the radiators is undersized-10mm. There doesn't seem a flow problem as when the immersion is on the radiators keep their heat and become warm within minutes. Most of the warmth is in the top of the radiators. I've asked this HP installer to return to check my system but he is reluctant as there is no name make on the heat pump. It is supposedly a 11.7kw unit but looks too small to be that. I have it set at 47c at the moment. When it comes on if the heating is set it drops quickly to 30c and never seems to recover until the CH is switched off. It then takes about an hour to recover back to 47c depending on the weather. The immersion only kicks in alongside the heat pump if the temperature drops to around zero. I don't understand why one of the quotes involved replacing the ACV tank. If you look on you-tube there is an 8minute clip of an installation in Cheltenham of A MITSI. and when the camera films the set up of the tank, low and behold its an AVC SMART tank. One quote was for 8000 just to replace the unit and the other was for nearly 11000 to replace the tank and unit.

[Deleted User]

Uclan wrote: »

Thanks for the prompt reply. I'm in N.Wales. The radiators seem adequate enough. When the system first went on the heating seemed to work but the DHW didn't stay hot for long. I got someone in to repipe the tank. Now there's enough hot water but the radiators lose their heat very quickly. He said that the pipework to the radiators is undersized-10mm. There doesn't seem a flow problem as when the immersion is on the radiators keep their heat and become warm within minutes. Most of the warmth is in the top of the radiators. I've asked this HP installer to return to check my system but he is reluctant as there is no name make on the heat pump. It is supposedly a 11.7kw unit but looks too small to be that. I have it set at 47c at the moment. When it comes on if the heating is set it drops quickly to 30c and never seems to recover until the CH is switched off. It then takes about an hour to recover back to 47c depending on the weather. The immersion only kicks in alongside the heat pump if the temperature drops to around zero. I don't understand why one of the quotes involved replacing the ACV tank. If you look on you-tube there is an 8minute clip of an installation in Cheltenham of A MITSI. and when the camera films the set up of the tank, low and behold its an AVC SMART tank. One quote was for 8000 just to replace the unit and the other was for nearly 11000 to replace the tank and unit.

Other end of the country i'm afraid so can't recomend an installer.

Is it 14kw Ecodan that is being quoted for?

andrewlato

Uclan wrote: »

Thanks for the prompt reply. I'm in N.Wales. The radiators seem adequate enough. When the system first went on the heating seemed to work but the DHW didn't stay hot for long. I got someone in to repipe the tank. Now there's enough hot water but the radiators lose their heat very quickly. He said that the pipework to the radiators is undersized-10mm. There doesn't seem a flow problem as when the immersion is on the radiators keep their heat and become warm within minutes. Most of the warmth is in the top of the radiators. I've asked this HP installer to return to check my system but he is reluctant as there is no name make on the heat pump. It is supposedly a 11.7kw unit but looks too small to be that. I have it set at 47c at the moment. When it comes on if the heating is set it drops quickly to 30c and never seems to recover until the CH is switched off. It then takes about an hour to recover back to 47c depending on the weather. The immersion only kicks in alongside the heat pump if the temperature drops to around zero. I don't understand why one of the quotes involved replacing the ACV tank. If you look on you-tube there is an 8minute clip of an installation in Cheltenham of A MITSI. and when the camera films the set up of the tank, low and behold its an AVC SMART tank. One quote was for 8000 just to replace the unit and the other was for nearly 11000 to replace the tank and unit.

Hi Uclan

Theres nothing wrong with your tank and it should be left where it is. Most likely piping is wrong (connections not the size of it)or a set up between your sensors(DHW and CH) and 3/4way valve. Have you got any data (heating performance) of your unit? Yo seem to have quite large house for the size of unit.If your HP was a main brand there's good chance it would cover required KW of your house but 'chinese' drop in performance hugely when temp goes down, so maybe it's coping only(before immersion kicks in) with one DHW or CH and not both at the same time? Can you tell me - with temp outside at around 10deg- would you get enough DHW and warm house?

Installers want to replace things to fit what they want to fit not what you need, typical unprofessional , rip off approach.
For 800pounds you can get separate ASHP for your DHW, and then just change your CH unit , makes you system as simple as poss. You should get change left in you pocket from 4k for both . I know it's an extra tank but should (in the future)the system ever go wrong most plumbers with half a brain can get things fixed.

nande2000

Uclan wrote: »

I have a cheap Chinese made ASHP installed by my builder 3 years ago which I am trying to update for a better model i.e. Mitsubishi etc. I have had quotes from several companies. Two of which are supposedly Ecodan registered installers. The prices they have quoted seem a lot for what they are offering. Not one of the companies have offered a solution to my problem which is a lack of heating to the system. The hot water to the tank is fine but the radiators do not get hot enough to warm the house unless the 6kw immersion kicks in also. The HP is linked into an ACV SLME SMART 300L. tank which is supposedly compatible with heat pumps. The tank is twice the price of the heat pump. One of the companies has suggested ripping out this tank and replacing it with a Kingspan. The house is approximately 180m2 with up to standard insulation throughout. The system heats 15 various oversized radiators. We are off the gas grid so the only alternative is oil or lpg. I would appreciate any input regarding finding a compatible good quality HP fitted at a reasonable price by a knowledgable company with a good warranty. Both quotes I have recieved have asked for money up front before completion of work. The way these companies seem to work reminds me of the double glazing industry in the eighties. I would be especially interested of any input regarding the compatibility and the quality of the ACV tank.

"Raine or Shine" in Wrexham fitted my Ecodan and i'm more than happy to recommend them. If you want more details I can PM you.

Uclan

They were quotes for an Ecodan 14kw. As for the data it can be found on the Wharf Pumbing site. If you look back to this site on page 3 you will see their explanation of how good their heat pump is. As far as I know they are still supplying the same or a similar model. Mine is supposedly a 11.5kw.
As for heating at 10c I never have the ch on at that temp as its a waste of electric because the radiators do not keep their heat as the HP drops to 30c and then takes an age to recover once the heating has clicked off.
I would be very interested to hear about your raine and shine installation Nande. Thanks.
I have tried to reply to TiredGeek but I have been blocked for some reason. I am also not being allowed web access to that HP company you recommended.

andrewlato

Hi again,
With reference to my previous thread i have more data on how HP performed.
I've collected some data after fitting sub-meter on HP circuit(no immersion heater connected). We had some various temps so it's good for us see how S1200 coped(or not coped).
I have 7 rads fitted with a total output of 10175W(at delta50deg-manufacturers data). They are oversized by around 20%(calculated heat requirement for gas/oil boiler was around 8.5KW).The total volume of water in the system is 155ltrs (rads,pipes and buffer).
I have disconnected immersion heater so my data is purely for HP and circulation pump(CP). The CP is using 72W in 3rd gear. The HP+CP power input comes to 2.9KW regardless of temp(tested at range from 1deg-8deg) and is significantly more than Trianco claims in their manual. Being non-inverter type i just dont understand why (according to Trianco manual) the power input varies between 2.35-3.05 kw)? But anyway-back to numbers:
I have insulated all the external pipes now so heat loss is minimal.

1. I set temp on the programmer at 50deg with 7deg outside and it took around 1h to recover temp in buffer from 33 to 50deg. It looks like HP is able to produce 10kw at 7deg. Temp in the house around 21deg. It works for about 1h and cools down for 2h.

2. I set temp at 50deg with 1deg outside and pump will work all the time because it cannot reach 50deg.It is still using around 3kw per h but cannot produce 10kw that radiators are able to emit. I lowered temp to 47 and it was also struggling to reaching it.This is the point where pump is going all the time and your bills are getting out of hand.

3. I set temp at 45deg with 1deg outside and it would get there but house gets only about 19deg.The time it took for water temp to recover from 23deg to 45deg is 1h 20min. It cools down after about 1h50min and HP comes on again.It uses 4kwh

4. I set temp at 47deg with 2 deg outside, i get 20deg in the house, it takes 1h25mins to recover buffer temp from 27to 47deg. It gets quite quickly to 43 deg then it struggles a bit but gets there in the end. Uses 4.2kwh in process.

I've worked out that when temp outside is above 3deg and you set water temp at or below 50deg the HP will use an acceptable 29kwh per 24h costing me below 3pounds(on E7) a day for heating alone. One 24h period it's gone up to 48.7kwh!!!(due to low ambient temp at night and too high water temp set on programmer) The issue here is HP not being able to produce required heat output at low ambient temp and by trying to achieve required temp will stay on all the time until user changes settings or temp outside improves. This is very costly!!!
From the heating performance graph (Trianco manual) you can work out that s1200 is not a true 12kw HP(by European Norm). It should be tested and COP measured at -7/35 ,2/35 deg, and 7/35 deg like main brands are. HP apparently has 12kw at 20deg- that is useless info if you using HP for heating only-you are not gonna use it for heating when temp outside is 20deg. Trianco claims to be 'World leading heating engineers" - why wouldnt they test their product to EN like all the others?

Im yet to see it working at below 0deg temp.Im interested about defrost mode-how much the performance will drop -lets say -at -5. I have not yet connected immersion heater( will be connected through E7- to protect myself from huge bills). I just dont want HP to get 'lazy' and work off the back up.It will also make it a bit harder to work out what HP is really worth in terms of KW(should it use immersion-that is) . Im thinking of installing Heat Meter on pipes and the true COP will then be known- it's just the cost of it-around 150quid...
Now we are told that cold weather is coming so i should get a chance of testing it further. And i shall let you know about the outcome...
So far my bills between 28/dec and 12/jan that is 15days cost me 62pounds for all electrics that includes occasional heater coming on when newborn has a bath. The prices im paying are 12.6p day, 4.73p night and 23p standing charge.These prices will go up at next top up in line with current Sparks Energy Prepayment tariff.
Above data shows that you really need to monitor your HP in order to understand how it works and set it up according to your needs.
Thanks for reading.
Andre

zeupater

andrewlato wrote: »

.... I've worked out that when temp outside is above 3deg and you set water temp at or below 50deg the HP will use an acceptable 29kwh per 24h costing me below 3pounds(on E7) a day for heating alone. One 24h period it's gone up to 48.7kwh!!!(due to low ambient temp at night and too high water temp set on programmer) The issue here is HP not being able to produce required heat output at low ambient temp and by trying to achieve required temp will stay on all the time until user changes settings or temp outside improves. This is very costly!!! ...

Hi

If you're running the system at 29kWh/day and the cost is under £3 on E7 it's likely that you've used the wrong tariff (daytime tier2 ?) or you seriously need to change energy provider .... E7 should not cost anywhere near 10p/kWh ...

"This is very costly!!! " may not be as quite as bad as you have calculated ! ....

HTH
Z

Cardew

zeupater wrote: »

Hi

If you're running the system at 29kWh/day and the cost is under £3 on E7 it's likely that you've used the wrong tariff (daytime tier2 ?) or you seriously need to change energy provider .... E7 should not cost anywhere near 10p/kWh ...

"This is very costly!!! " may not be as quite as bad as you have calculated ! ....

HTH
Z

He stated:

The prices im paying are 12.6p day, 4.73p night and 23p standing charge.

No Tier 2 prices he pays a daily standing charge

If the 29kWh for the HP was split evenly on a ratio of 17:7 by my arithmetic it would cost £2.58 + £0.40 + 23p so £3.21 a day. So he appears to use slightly more during the 7 hours E7 period.

In my area(Midlands) I can't find a cheaper E7 tariff than the OP quotes

andrewlato

zeupater wrote: »

Hi

If you're running the system at 29kWh/day and the cost is under £3 on E7 it's likely that you've used the wrong tariff (daytime tier2 ?) or you seriously need to change energy provider .... E7 should not cost anywhere near 10p/kWh ...

"This is very costly!!! " may not be as quite as bad as you have calculated ! ....

HTH
Z

Hi Zeupater

Sorry, but you misunderstood- the prices im paying on E7 are 12.6day and 4.73p night. The way i calculated 3pounds a day cost of heating is:
29kwh x 7h(E7)/24h= 8.5kwh on E7-rate 2 x4.73p = 40p
29kwh x17h(remaining h in a 24h period)/24h=20.5kwh (on rate 1) x 12.6p= 2.58 pounds
Total for day 2.98quid plus standing charge
Hope that makes sense