I bought a Heat Pump

Reed_Richards

AFAIK it is perfectly possible to insulate a pitched roof to the same standard as the floor in a loft.  It's more expensive, but if your rooms-in-roof were well-built you don't have anything to worry about.   

akwexavante

However, I'm now being told that room-in-roof insulation may not be included despite the council website stipulating otherwise, without which I don't believe it would be worth it at all. As a guess 50% of our upstairs ceilings are vaulted room-in-roof, which is probably where all our heat is going. 

At the time of my surveys, i was told that each grant would only pay for ONE item.  I could have either an ASHP or solar panels or insulation.   I was told insulation included either loft or cavity wall, but did not include room in roof slopes.

My 1st grant (Spend up to £10K) was via my local council, the 2nd grant (Spend up to £30K) was via my county council (TWO VERY DIFFERENT POTS OF MONEY).  Qualifying for the first didn't disqualify me from the second.

For the 1st grant, i went for the ASHP.  My room in roof slopes to rooms were not insulated and i was still very happy indeed with the ASHP heating system.

For the 2nd grant, i went for the Solar Panels.

There will be a third grant shortly where i'll explore what i can qualify for, not convinced my cavity wall insulation is complete, or it has settled so much there could be gaps etc. A possibility, maybe!

I insulated my room in roof slopes myself (roughly 30mtrs), so the process was labour free, it took me a leisurely two weeks to complete, and the materials cost me £650.00.  However, i haven't had the slopes re-plastered yet (other works to do yet before i need a plasterer to do all of it together).

Take up has been low, probably because people are generally scarred of something that's new and "Is it really free? What's the catch, will this bite me later on?" worries folks, and nobody likes change nor the disruption it may cause.

I can see more grants over the next couple of years, so go for what you can, one at a time.  Get your room in roof slopes done in whatever way you choose to do so yourself, and i know it's worth it.

My previous owner's annual (Propane and Electric) bill was over £1900 (two ladies, pre price hike) a year.  My last electric bill estimates my next 12-month bill to be less than £680, (one chap on his own, though).

Doing the room in roof insulation isn't difficult and the tools required are not expensive and most people have the tools required already.  I had to buy a simple stapler! But i could have managed without it, though.  The most expensive tool which i already have would have been a battery drill if i had to buy one.

I could argue that a new heating system (ASHP), Solar Panels and insulation has cost me just £650! What an absolute bargain, a no-brainer!

Oh! I forgot to add that in fact i also sold my 2yr old Valiant boiler on Farcebooks marketplace for £300 so my £650 spend was actually only £350.

henrik777

Harvs94 said:

Supposedly once the insulation is installed they would carry out a heat loss survey to determine the size of the radiators that would need replacing. 

Hopefully they're deciding on the heat pump size at this point too 

Reed_Richards

A rare example of heat pump humour (source https://xkcd.com/2790/ )

grahamm

Hi, thanks for pointing me to this thread. Unfortunately there doesn't seem to be a way of searching this thread alone

A little background (sorry for the length of this): 

I've just had an LG Heat Pump installed and I'm trying to optimise the performance.

To start with, the Pump was actually working *too* well and room temperatures were getting up to 24 degrees. I tried using the AI controlls on the LG Therma V R32 Monoblock controller in steps, but even when it had got down to -5 (I'm not sure what this actually means) the rooms were still too warm.

I contacted the installer who suggested that I set the Thermostat to 22 degrees which did help solve the problem, although he'd previously advised against it, because it was ineffecient and would cause the system to cycle too much (which is, apparently, not a good thing).

I've now adjusted the Weather Compensation Curve on the controller down from 49 to 47, but I'm still getting a room temperature of 23 degrees (the thermostat is now set to 24 degrees)

My energy supplier (Good Energy) have said they're participating in the Demand Flexibility Scheme where, if I reduce my power consumption for an hour at certain peak times, I'll get a credit to my account (they're apparently passing on 85% of the full amount)

In the month since I switched the pump on, I used 400KWh of electricity which the installer said is about right, but he also wasn't sure that "turning off" the pump (by setting the thermostat lower) is a good move as the pump would then have to ramp up to a higher level afterwards.

So what I need to do is to compare two days, one where I run the system as normal, the other where I turn it off for an hour to simulate the DFS and see what the results are.

Problem is, I don't know how to calculate the COP and figure out how efficiently the system is working.

Any comments or advice would be very welcome

akwexavante

Just a thought, are you getting room temperature and LWT (leaving water temperature) mixed up? Your reference to - 5 would suggest that you have adjusted the LWT to 5 below the default perhaps. If you set the desired room temp to a temperature you want at the room stat the ashp shouldn't heat up the room above that. Is the room stat in the same room as the room you say gets too warm?

How big is your home? How many rooms? Is it adequately insulated? With the weather still mild at mo, 400kw is a lot. So far this month I've used 160kw to heat a 2 bed end terraced house.

Have you balanced the rads in all your rooms so that they warm up evenly together? Then turn the trv's to set temps in each room.?

Reed_Richards

I need to ask some questions:

Are you heating with radiators, or underfloor heating, or a mixture of both?
Are you using the LG controller to control your temperature, or do you have a third party controller?
Are you trying to use just Weather Compensation without any explicit temperature control (which would be why your thermostat was initially set higher than the temperature you wanted but then reduced on the advice of your installer when that didn't work)?
Is the LG controller set to Water or Air + Water?
Was you heat pump installed to MCS standards?  If so, it should have been set up for a maximum output water temperature at some particular outside temperature.  Do you know what these parameters are?

I can't attach documents on this forum but if you look down the page here: https://forum.buildhub.org.uk/topic/6385-lg-therma-v-mono-block-air-source-heat-pump/page/11/ I have split the Product and Installation Manual into three parts and posted each part.  This gives much more detailed information on the Therma V controls.

My heat pump would not at all mind being off for an hour.  But if you eventually get your Weather Compensation really finely tuned then it might take a while to get your house back up to temperature afterwards.      

grahamm

akwexavante said:

Just a thought, are you getting room temperature and LWT (leaving water temperature) mixed up? Your reference to - 5 would suggest that you have adjusted the LWT to 5 below the default perhaps. If you set the desired room temp to a temperature you want at the room stat the ashp shouldn't heat up the room above that. Is the room stat in the same room as the room you say gets too warm?

How big is your home? How many rooms? Is it adequately insulated? With the weather still mild at mo, 400kw is a lot. So far this month I've used 160kw to heat a 2 bed end terraced house.

Have you balanced the rads in all your rooms so that they warm up evenly together? Then turn the trv's to set temps in each room.?

The house is a 3 bed mid-terrace (built around 1900) and it's got cavity wall insulation and 300mm of loft insulation.

The ASHP is supposed to be running fully in Weather Compensation mode, I only started using the Thermostat because the temperature was getting too high, however the installer said that I should normally set the Thermostat to eg 24 degrees and leave the TRVs fully open because the system is designed to keep the house at about 21 degrees, so the stat and TRVs wouldn't have any effect.

I've tried reducing the Temperature curve by a couple of points, but the rooms are still getting up to 23 degrees, so I may need to lower it further.

PS the -5 is an adjustment on the AI mode which is supposed to tweak the setting down a bit, but it wasn't having much effect.

grahamm

Reed_Richards said:

I need to ask some questions:

Are you heating with radiators, or underfloor heating, or a mixture of both?
Are you using the LG controller to control your temperature, or do you have a third party controller?
Are you trying to use just Weather Compensation without any explicit temperature control (which would be why your thermostat was initially set higher than the temperature you wanted but then reduced on the advice of your installer when that didn't work)?
Is the LG controller set to Water or Air + Water?
Was you heat pump installed to MCS standards?  If so, it should have been set up for a maximum output water temperature at some particular outside temperature.  Do you know what these parameters are?

I can't attach documents on this forum but if you look down the page here: https://forum.buildhub.org.uk/topic/6385-lg-therma-v-mono-block-air-source-heat-pump/page/11/ I have split the Product and Installation Manual into three parts and posted each part.  This gives much more detailed information on the Therma V controls.

My heat pump would not at all mind being off for an hour.  But if you eventually get your Weather Compensation really finely tuned then it might take a while to get your house back up to temperature afterwards.      

The house (3 bed mid terrace with cavity insulation and 300mm loft insulation) is being heated by radiators.

From what the installer said, the LG controller should be working in AI Mode with Weather Compensation, so it provides heat according to the outside temperature based on a figure they calculated for heat loss from the house.

I only used the Thermostat to stop the rooms overheating. Now I've tweaked the Temperature Curve down a couple of points down from a target Temperature of 49 degrees to 47, I reset the stat to 24 degrees to stop it switching the ASHP off, but the rooms are still getting to 23 degrees, so I'm trying dropping it another couple of points to 45 over the weekend.

The controller is set to Water only.

I'm not sure what standards the pump was set up to or what the parameters are (or where to find them), unless they're the ones for the Target Temperature I mentioned above.

Hope this helps clarify things.

akwexavante

For me the installer is wrong. A room stat is for you to set a temperature that's comfortable for you and 24 is very high and clearly it's uncomfortable for you too! So ignore the installer and set it to a lower temp and wait a couple of days for things to settle. If it's then too warm lower it a tad further or increase it if you feel like it's too cold. 
Again the TRV's are for you to adjust to suit yourself. I prefer a warm bathroom so my trv in that room is set at max, whereas I like a cool bedroom so that trv is set at 2 and so on throughout the house.