…so that turned out a valve was closed in plant room which was the rear bedrooms. The amount of errors is really getting to me.

off the back of that it seemed downstairs picked up too. Will see over night if temp is better in morning too. Very difficult to get a system settled like this

@crimson one tends to assume basic issues like air and valve not open have been checked by the installers..... if there's a section of your bill called "commissioning", don't pay it.....

Posted by: @iancalderbank

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@crimson one tends to assume basic issues like air and valve not open have been checked by the installers..... if there's a section of your bill called "commissioning", don't pay it.....

Even if there is no itemised section titled commissioning, I would suggest applying a deduction to the overall bill, since the system was not left functioning correctly, so subsequently had not been correctly commissioned.

In the past I have withheld a percentage of the final payment until all work has been completed to my satisfaction. More people should possibly do so, which may encourage the installers to do their job correctly.

Very much so. I’ve complained to architect who acts as design manager for project and certifies each months fees. Definately at point of wanting some money off. No offense to those here, knowing this much about ASHP was never a plan of mine and that’s become purely just not from it not working as expected (though undoubtably been a hugely beneficial learning! And good to know for future). When you undertake a project like this you don’t expect to need to get into every microdetail of everything but plumbing/heating seems to have certainly become one.

I do hope the thread though randomly becomes useful for someone else.

@crimson My experience too. I never considered going online to discuss the performance of my gas central heating. It generally just worked - like my car , I didn't need to become a mechanic to drive it. But I too have, unwittingly, found myself having to learn more about ASHP's then I ever imagined necessary or possible. It's a measure of how crap so many ASHP heating system designers and installers are and how far off the pumps themselves are from being proper consumer products.

Mike

Plumbers returned.

External lagging upgraded (removed valve handles to be screwed back on when needed so no gaps in lagging also).  And plant room fully lagged.

Also adjusted some balancing (I've been working today, something about at the manifold 1 litre or something or other - caught me at a busy time - will message him to ask what exactly it was) as found no air in all but 1 downstairs rad so that's eliminated as an issue.

Early days as yet, but already can see the temp top left of LLH to just before heating zone is a closer match (before it was losing up to 4-5c).  Also temps coming in from outside seem higher upon first glance.

Photos attached

Old example temp from 1 week ago v new at LLH/just before heating zone:

Top right of LLH (flow coming in from ASHP):

• Old - 42c
• New - 44.9c

Top left of LLH (flow to heating):

• Old - 43.1c
• New - 45.1c

Just before heating zones:

• Old - 38.6c - 4.5c drop
• New - 46.1c (1C higher than top left of LLH but I guess closer)

Note the WC is 50C at peak on ASHP settings atm hence above 40C.

Using an Excel sheet from these forums 'WC ready reckoner' - apologies can't recall which thread got it from.   At 7C outside, with my WC settings in the sheet, the ASHP should run at 46.43C

And totally forgot to add, the 4th temp probe that sits in one of the living rooms is showing 21.2C atm.  I can't recall seeing that at this time of day and to me that's a good temperature.

Obviously time will tell over next few days how this is.

Other changes suggested by them:

Keep downstairs a constant temp, no setback at all.  Will try that.

I'm also looking at removing the second hot water run (1pm-2pm), leaving just 3-4am.  As I haven't seen the temp reported on the tank at any less than 44C in the day.  I'll see if this affects our hot water etc but could see it hit 50C after 35 minutes today on the second run, which meant it wasn't doing the heating for almost half an hour which is a waste in my eyes.

…and would also appear changed the ASHP settings, one I know:

2102 - is now 52.5C up from 50C

So the WC would imply run at 48C at 7C outside.

Quite a jump, not sure why gone in straight up and bumped that setting higher than 50C

@crimson this is great news. 😀 Those little temperature probes are very handy, accuracy is probably +/-1degC. They certainly help with understanding what heat is going where.  I find the temperature on the primary side into my LLH reads between 1 & 2degC lower than the Grant controller tells me the LWT is. That's a combination of the Grant controller having only a 1degC display accuracy and the digital thermostat accuracy. Once all is running well, and you are reaching target indoor zone temperatures, (the pipe insulation will certainty help), you can try lowering the maximum LWT parameter setting 2102 to see if you can get away with the system flow temperature a little lower than 50degC.

My system was designed and sized for 50degC flow from a 13kW Aerona in an average EPC C detached house, but it does the job at 45degC unless the outdoor temperature drops well below zero. I have a 10kW Aerona due to DNO issues with the capacity of the supply to the house, fuse rating, meter tail sizing, etc., so the issue is more with the ASHP sizing than the LWT. There's a cosy log burner as secondary heating to make up any shortfall.

PS: I think the Grant WC ready reckoner may have been me

PPS: I'll send your plumbers a bag of black nylon cables ties with my compliments 😉

Posted by: @crimson

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so the WC would imply run at 48C at 7C outside.

so thats quite a hot running temperature for 7C. even more so if there's been replacement of or new radiators, UFH etc .

The lower you can get it running, the more efficient it'll be. 

See if you can reduce these weather comp numbers down, until you can find the point at which your house no longer stays warm, then go back up a smidgen.

HW would be better run during the afternoon (say 3-4pm) rather than overnight, as it's when the LWT is highest so you want the warmest external air you can. Although this might depend on your usage - if you use most HW in the morning, you want to ensure you have enough.

The 'wasting half an hour' thing is an issue with Grants - it's the hottest water you're losing too, if the LWT is 55C during the HW phase. I listen for when my HW has hit the target (I can hear the HP "turning off") and then just go and hit the 'advance' button on the HW timer - which switches the HP back to CH mode (or rather, ends the DHW cycle early). I'm hoping this is something the new Grant controller (or Homely) is smart enough to do. It's a very obvious improvement.

Yeah, I had actually changed 2102 from 50 to 45C for a few days and didn't notice any difference in the downstairs temp before (maybe .1-.2C temp when would get up in morning).  So once I give this a few days I'll keep playing.

Hopefully this is the start of it getting somewhere better, will report back tomorrow how it goes overnight.

I'll be happy if I can get downstairs to a comfortable 21C as a starting point to then adjust from.  Having it barely hit that in a day has been annoying.

Got to say, I'd kill for a smart app interface for the system and the heat misers combined.  Going into the Grant panel is painful, but I guess once get it right should just walk away and forget it.