Out of interest, does anyone have an idea why in the hottest performing room, turning the rads down (basically closing down the lock shield equivalent via the Drayton pre-setting balance key which is under the TRV head) - would make the room warmer?  My assumption would be it would reduce the flow to the Eskimo rads in that room, thus allowing other rads further along the zone to have more heat (e.g the other living room).

My only thought is that perhaps at the Grant ASHP side, the pump speed in the ASHP itself is set too high, and reducing the flow to the rads allows more heat loss from them? (keep in mind my knowledge is trite on this stuff).  This room is the first in order from the ASHP.  The Eskimo rads themselves – water capacity wise are tiny.

Struggling to balance the 2 rooms and hallway essentially.

Current flow temp with WC is 32.5C (at 7C it would be 35C exactly)

2 rooms are:

Living 1 (currently around 1C cooler than other):

2x 1451x400mm Eskimo rads (both set at max 6/6 on balancing + TRV max)

(with doors closed) Room sits at around 20C, just a bit too cool and off balance with other

With doors open to hall and other living room - 19.5C

The hallway is cooler than the living rooms (as suspect the heat just pushing upstairs via stairs to landing)

Living 2 (hottest, around 1C warmer than other - previously this was worse performing room before rad upsize):

1x 1694x400 Eskimo rad (set at 2/6 on balancing + TRV max)

1x 963x400 Eskimo rad (set at 4/6 on balancing + TRV max)

Room easily hits 21C, with doors open to hall and other living room - 19.5-20C

To summarise where I am currently:

1) Have to ensure upstairs zone is running, otherwise ASHP cycles and downstairs doesn't get to temp at all, stuck at 19C

2) Have to close down the radiators in Living 2 as overheats

3) Living 1 not quite to temp

4) Upstairs:

3/4 bedrooms - balancing at 2/6 + TRV at 2 - these are all off atm from what I can tell

4th bedroom (office) - balancing at 6/6 + TRV at Max - it's hitting 22C right now, so I'll dial that down…

2 front bedrooms - 19.5C - that's getting too warm, rear bedroom (not office) - 18.5C - perfect

4) Once balance Living 1 and 2, need to reduce the flow temp of ASHP via the WC to avoid overheating and upstairs overheating

Downstairs is proving to be a real headache with the hall and Living 1 under performing against Living 2.

Plus having to run upstairs to avoid cycling causes that zone to overheat where ideally wouldn't want the heat other than my office.

My only thought is I will actually need to use TRVs if rooms just have such different needs/overheat v others in zones.  I know that's not best practice other than bedrooms and rooms where sunlight can cause a big effect (living rooms do suffer from that).

@crimson 

In answer to the question no, unless the lockshield is behaving oddly which will wouldn't rule out.  Does turning it back up reduce the temperature or was this response a one off.

Posted by: @jamespa

↑

@crimson 

In answer to the question no, unless the lockshield is behaving oddly which will wouldn't rule out.  Does turning it back up reduce the temperature or was this response a one off.

It seems opening them back up does reduce the temperature.  Which makes me wonder if the rate at which the water passing through is too fast?  Certainly if I change the secondary pump in my plant room to 2/3 instead of 1/3, you can really HEAR the water rushing through the rads that are dialled down.

I do recall the heat specialist when he came that he was trialling and erroring different 2nd pump speed and ASHP pump speeds to see where the least cycling occurred, I wonder if at some point the plumbers have just put the Grant ASHP back to max, hence me now oddly running at slowest 2nd pump speed, whereas before I would run at 2/3.

Update on this.  It irked me that the plant room pump had to be on 1/3 not 2/3 so reached out to plumber and asked if the Grant ASHP speed had changed at DIM switch.  Bit of photos and talking through it I now can change that (didn't want to without them giving go ahead).  For some reason it was on minimum at the ASHP side, level 1 of 3.  So now I've upped that to 2/3 will see how downstairs gets on.  That may be a reason one room performed better than the other and suspect I'll have to re-balance etc against that.

Praying it suddenly causes enough of a change that this journey is over lol.

Plumber attended today and "balanced" upstairs radiators, didn't check any temperatures or anything, just a case of closing down those closest to ASHP gradually with those furthest away opened up.  Guess basic principle there but not checking the delta across the rad and actual effect seemed to be due to lack of time for the attendance.

This was done on the lock shields themselves, tried to explain that Drayton have a balancing key but plumber said not a good idea - heavily suspect he wasn't aware of the feature and thought I was limiting the TRV or something, oh well.

So currently I'm keeping upstairs zone open by having the heat miser panel set high, Grant ASHP is on medium speed, plant room is on speed 2/3, have tried 3/3 also.  Conclusion: barely any actual heating cycles happening in those conditions.  Downstairs is stuck around 19.5-20C.  It's just a smidge off.  If upstairs isn't open - the ASHP doesn't run at all on these ASHP speed/pump room speeds.

I think I'll revert back to the ASHP on speed 1 (minimum) and plant room back on 1/3.  Then just close upstairs more and work more on balancing.  At least under those conditions I had one room to temperature downstairs rather than none.

The other option would be to up the weather curve a degree or 2 to try and push downstairs up, and have upstairs basically off.  It's not like it's running that often anyway, I think a smart meter might be good here to understand actual money cost of different scenarios rather than chasing a curve.

Overall still a very frustrating system that's 1C off me not having to think about it.

@toodles - I recall you spent a considerable amount of time balancing your property.
Wondered if you had any tips?

I've managed to now get the house heating quite well, without relying on upstairs running alongside downstairs (in fact I think that zone rarely turns on - office sits at 20C, bedrooms 19-19.5C) with a combination of:

• Balancing downstairs
• Upping the internal side pump speed from 1/3 to 2/3
• Upping the min temp (went from 29.5C/30C to 32C – at 10C outside that's a flow temp rise of 33.8C to 35.5C)

Currently I get:

• Living 2 - 20.5-21C (20.5C is fine for us as soon as we sit in it it reaches over 21C)
• Living 1 - 19.5-20C (this feels a bit off)
• Hall - 19.5C (am fine with that)

My goal is to get the 2 rooms in balance then dial back the flow temp as much as possible.  This is as other zones when they do call for heat can quickly overheat (having to use TRVs upstairs along with the plumbers closing down the lock shields somewhat).

The challenge I have is though it's 0.5-1.5C difference between the living rooms – one feels a bit cooler.  Suspect the material of the room plays a difference (one is carpeted with less of an open layout due to furniture – the other is wood flooring and more open layout).  So probably ideal world need the wood floor room to just be warmer than the carpeted one (if that makes sense).

What I've done so far is without so much as checking which radiators heat first (very difficult with the cycles tbh and room layout – plus me being based upstairs working). – I've been approaching it as how the plumbers did with upstairs, closing down the rads "closest" to the ASHP and keeping those furthest away fully open.  I've done that using the Drayton balancing key as that lets me have number levels that I can check back on.  This so far has been the biggest improvement in getting temperatures up.

Living 2 is closest to the ASHP so suspect that also factors into why it heats up a bit more.

One issue I do find, the further I close a rad down with the internal pump at speed 2/3 – the more audible the water rushing is (and family have commented - I can never win!). In my head next action would be to further close down the warmer Living 2 rads - but conversely that means it will be quite "noisy".

Just wondered if you had any insight

@crimson Hello Crimson, yes I did spend a fair amount of time balancing the radiators; the details may be found in a guide I published in RHH.

https://renewableheatinghub.co.uk/how-to-balance-radiators-the-role-of-the-lockshield-valve

I have very little knowledge of the Drayton valves bit IIRC, they are designed to do the balancing without fussing with the lockshield valve themselves so I am uncertain how this affects implementation of my method. I can’t help feeling that a good starting point would still be with all valves fully open and the pump working at a moderate flow temperature - then start moderating things from there. Please let us know how things proceed, there is also a method on the net from Heat Geeks I’m told but I know not if it is similar to my own or different. Whatever method you choose, take your time - you will need it. (A benefit of being retired in my case!) Regards, Toodles.

@toodles - it seems I failed to reply to this when thought I had. Thanks for all this info. So far I now have living rooms within 0.4C of each other thanks to your tips which is amazing!

At the moment I’m purely experimenting with plant room pump speeds and the actual flow temp via the WC to get temperatures where I want them.

One thing that keeps coming up, the installer keeps saying worth having the highest temp at 45C. Not sure why as the whole system is designed to 40C at -3C ambient. Frustratingly tomorrow it will be -3C here and I’m away the day for work so will need to rely on the other half to tell me what temperatures the rooms are at (plus her terrible habit of opening external doors and leaving them open for ages doesn’t give great results)

Should a flow temp ever exceed the designed? Is there some offset I’m not aware of or is this just a case of installer running “hot” to keep me off his back?

Current the weather curve I have this at is 40C at -3C, min flow 31.5C, max ambient 17C.  That puts 7C ambient at 35.75 and -2C which should be at 39.5C flow which I believe temps will get down to today.

The living rooms (due to a setback i have between 10pm and 4:30am) are at 19-19.5C 8:30am this morning, so not hitting 21C.

@crimson That’s fine and I’m glad it is proving fruitful for you now. I’ve no experience with your pump (mine’s a Daikin) but I suspect there are many things in common when it comes to flow, control amd the likes. I have homely controlling mine and according to Homely, the max. flow temp. is 45 degrees C and the minimum is 35 degrees. However, I find that in present cold conditions, the pump sometimes runs at approx. 47 degrees for a while and certainly drops below 35 at other times. As long as you have WC switched on and you use whatever method you have to set the slope or curve for the range of temperatures set up then I doubt that the max setting of the leaving water temperature is too critical - as long as the pump can go high enough to keep you at the temperatures to which you have become accustomed! 😉 Someone with a similar unit to yours may be able to advise on this aspect though. Glad to be of help in some small way though. Regards, Toodles.

So unfortunately with a cold snap of 2C down to -3C, the living rooms are around 18C.  Supremely frustrating as hoped this was resolved.

Am letting builder/architect and installer know.  Not sure why the Eskimo zones are struggling, they've more than doubled output with the size upgrade from last year and seeing similar temperatures.  I suspect a combination of cycling and defrost cycles is impacting this.  Or yet again the calculations are so far off for the downstairs zone that we're still undersized…

Posted by: @crimson

↑

Should a flow temp ever exceed the designed? Is there some offset I’m not aware of or is this just a case of installer running “hot” to keep me off his back?

Noting your most recent post it's perhaps worth commenting on the question you asked earlier.

The answer is a definite maybe.  Designs are based on fairly simple theory which doesn't always translate precisely into practice in the more complex world.  So a bit of give and take is to be expected.  If you have to bump up the flow temperature to achieve the desired house temp then that might just be how it is.  Of course it may alternatively point at a fault or sub-optimal arrangement somewhere.  Either way it's probably best to try it as you will definitely learn something.

Of course it's warming up soon!

Thanks @jamespa 

I've upped max flow temp to 42C. It didn’t have that big an effect and temps were around 4C plus today. So I went round and rebled rads, towel rads had a bit in. What’s odd is the small Eskimo when bleeding either side - neither noise of air nor water  comes out! Not seen that before. I can hear water rushing at TRV side and it is warm. Have reached out to plumber but no answer yet.

Something my other half said was there’s been some odd noises in the Eskimo rads.  Really loud clicking TRV side that seems to move around them at times. Wonder if something is up which may explain such a big drop. Tonight temps back to 19-20C after the bleed but for life of me no water coming out nor air noise on that small Eskimo rad.

Room temps up could just be no defrost cycles hampering stuff now though.