In a way I’m glad the water heating shows this up. As least then its not something beyond the plant room, but perhaps having a bigger LLH further exaggerates what was going on before.
Builder said the installer has been radio silent though said he was monitoring house temps over the weekend. Am sure them going down didn’t give him opportunity to say he’d fixed it lol.
Another odd thing. I still get the metallic bang in one of the living rooms on an Eskimo rad. And thats happened during a hot water cycle when the zone is shut. I know that would seem a smaller issue amongst all this, but any ideas what it could be? I think its the non TRV side of the rad…
I do run that to the bare min, 1 cycle a day for an hour. If no one has a shower etc, it will sit lowest 44C, so fine for using.
probes show 45C on pipework flow into plant room from ASHP into LLH, 34C top left of LLH and 34c just before 2 port valves - heating/water tank.
so no wonder thats struggled.
would seem secondary pump is now buggered
With that drop its clear that very little hot water is getting from the primary into the secondary so either pump problem or piping problem. Has he plumbed the LLH back to front eg with primary and secondary going in opposite directions. That would cause all sorts of interesting effects none of which are good.
It beggars belief that the installer didn't check this before he left. Id be tempted to lock the door next time!
I do run that to the bare min, 1 cycle a day for an hour. If no one has a shower etc, it will sit lowest 44C, so fine for using.
probes show 45C on pipework flow into plant room from ASHP into LLH, 34C top left of LLH and 34c just before 2 port valves - heating/water tank.
so no wonder thats struggled.
would seem secondary pump is now buggered
With that drop its clear that very little hot water is getting from the primary into the secondary so either pump problem or piping problem. Has he plumbed the LLH back to front eg with primary and secondary going in opposite directions. That would cause all sorts of interesting effects none of which are good.
It beggars belief that the installer didn't check this before he left. Id be tempted to lock the door next time!
This is what the specialist thought but looked at the specs of the tank and it has no baffles which he said would mean you can’t really pipe it wrong. All the labels are on the front, no arrows this time. I tried to get my phone round the back but couldn’t see anything.
I was shocked he left so quickly. Either he realised it was buggered so rather than be there any longer thought he’d chip off or something has ramped down after he left.
He did place the flow probe and probe thats just before the heating zones next to each other. I wonder if he thought the one just before zones was actually the return and was happy that there was a lovely delta and not however something completely wrong lol. I thought I was going a bit mad when saw them next to each other but theyre definately on the pipe work that runs above the 3 zone valves and just under the hot water valve so they can’t be a return.
Let me know if I am bonkers though have attached a photo. However the black probe temp is very close in temp to another that’s top left of the LLH (so the flow after the LLW).
Can’t believe Im boosting hot water again this morning, thats 3 times since got home yesterday.
Photo shows the heat drop after the LLH and secondary pump. Black probe just before 2 port valves. White probe flow the ASHP. This is just a joke. Flow sett shows 20L/min. This is on a hot water cycle.
I still get the metallic bang in one of the living rooms on an Eskimo rad. And thats happened during a hot water cycle when the zone is shut. I know that would seem a smaller issue amongst all this, but any ideas what it could be?
Thermal contraction of the radiator as it cools? Aluminium has approximately twice the thermal expansion coefficient of steel.
I still get the metallic bang in one of the living rooms on an Eskimo rad. And thats happened during a hot water cycle when the zone is shut. I know that would seem a smaller issue amongst all this, but any ideas what it could be?
Thermal contraction of the radiator as it cools? Aluminium has approximately twice the thermal expansion coefficient of steel.
could be but why is it just one that does it?
assume these installers have dine anything you could wrong lol. I wonder if something is up with the valves either side.
his is what the specialist thought but looked at the specs of the tank and it has no baffles which he said would mean you can’t really pipe it wrong.
You might not be able to, but your installer definitely could. If you swap flow and return either on the primary side or the secondary side then basically the primary and secondary pumps are acting in opposition. Exactly what happens is anyone's guess but most likely water circulates round each loop more or less separately with lots of flow vertically through the LLH rather than horizontally, with much reduced heat transfer from primary to secondary. Here is an illustration (drawn for a buffer but same idea for an LLH, albeit more turbulance in the middle
Let me know if I am bonkers though have attached a photo. However the black probe temp is very close in temp to another that’s top left of the LLH (so the flow after the LLW
Your not bonkers but I cant actually see whats going on (which may be part of the problem! so I cant comment on whether you are right or not.
TBH there is absolutely NOTHING complex or mysterious about any of this stuff at all, other than your installers seemingly inexhaustible capability to screw up. All you need to do is generate heat (the heat pump) and transport it to where its needed (the pipework and water therein). Heat cant get lost (conservation of energy), it can only be dissipated, and it will only move from hot to cold (other than in the heat pump of course)..
his is what the specialist thought but looked at the specs of the tank and it has no baffles which he said would mean you can’t really pipe it wrong.
You might not be able to, but your installer definitely could. If you swap flow and return either on the primary side or the secondary side then basically the primary and secondary pumps are acting in opposition. Exactly what happens is anyone's guess but most likely water circulates round each loop more or less separately with lots of flow vertically through the LLH rather than horizontally, with much reduced heat transfer from primary to secondary. Here is an illustration (drawn for a buffer but same idea for an LLH, albeit more turbulance in the middle
Let me know if I am bonkers though have attached a photo. However the black probe temp is very close in temp to another that’s top left of the LLH (so the flow after the LLW
Your not bonkers but I cant actually see whats going on (which may be part of the problem! so I cant comment on whether you are right or not.
TBH there is absolutely NOTHING complex or mysterious about any of this stuff at all, other than your installers seemingly inexhaustible capability to screw up. All you need to do is generate heat (the heat pump) and transport it to where its needed (the pipework and water therein). Heat cant get lost (conservation of energy), it can only be dissipated, and it will only move from hot to cold (other than in the heat pump of course)..
Thankfully they haven't done the incorrect diagram, I can at least tell that.
The small one had different port positions, and even arrows on it, they got that wrong (we're talking literally a red arrow right to left, a blue arrow left to right…).
I've told the architect (running the project) that I want the builders to sack the installers now. It's a tough thing to say but I can't risk this any longer. I honestly had in back of my mind that Sunday I'd return to a leak or something.
The list of blunders is considerable:
2023:
December: Temps capped at 14C
2024:
Late Jan: Installers realised LLH back to front - fixed - temps hit 18C
Feb/March: New calcs confirmed incorrect rad sizing
October: Rads upsized. Horizontal Eskimos double height. Vertical Eskimo tripled width Stelrads K1 > K2 - temps capped 18.5-20C (downstairs WC worse temp, living rooms not to temp)
2025:
July: Specialist hired by builder attends and tries enforced nightmode with Grant at 60% power, cycling slightly reduced. Also tried heat dump and different primary/secondary pump speeds to reduce cycling. States volumiser on return required due to low volume on demand, not LLH
September 15th: Site meeting: Installers state water volume is issue (due to Eskimos), causing the short cycling. Suggest 50L LLH - will not go for volumiser as state voids Grant warranty, need a LLH
November 5th: 5-6L LLH replaced with 50L LLH - temps capped 18.5-20C, no change, temps seem to slide downwards trend
Installer indicates primary circulating pump in Grant ASHP is faulty. Installer states didn’t think water volume was issue but 50L install not for nothing due to low Eskimo volume seen when draining rads
November 7th: Pump replaced - Temps still capped at 18.5-20C, no change, temps keep sliding
November 9th: Temps have dropped and no hot water
Other Installer issues:
Not providing rad selection / sending entire Stelrad catalog along with heat calcs (which turned out wrong) to me to pick rads (I had no experience of this at the time)
Ended up me having to suggest Eskimos as no movement from installers to pick ground front floor zone rads, installers confirm they'll work
Leak in kitchen ceiling
Pipe widths wrong for Eskimos (I queried, they said were good - at install, they were wrong)
Eskimo ordering issue - (Eskimo order system failed, but installer didn't seem to clock no order) - late install
Calcs wrong
Utility floor flood due to air cap left off LLH
WC rad install delayed due to an installer breaking something
Asked me to measure space in pump room (when attended site and measured themselves) - and tried to get me to pick a new LLH
Installers left upstairs and UFH zones manually open at 50L LLH install, I clocked it before DWH sent 50C to UFH zone
Thankfully they haven't done the incorrect diagram, I can at least tell that.
So what have they done 'cos its got to be serious to get what you measure. Faulty secondary pump? Valve left closed? Fitted a bypass loop? The heat, if its generated, and water if its pumped, has to go somewhere, there is no mystery possible by the laws of thermodynamics!
This post was modified 3 weeks ago 2 times by JamesPa
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
Thankfully they haven't done the incorrect diagram, I can at least tell that.
So what have they done 'cos its got to be serious to get what you measure. Faulty secondary pump? Valve left closed? Fitted a bypass loop? The heat, if its generated, and water if its pumped, has to go somewhere, there is no mystery possible by the laws of thermodynamics!
i should find out tomorrow.
they’ve offered to come today but I’ve told builder need to speak to architect. Basically I don’t want them here anymore but will get architects advice
Builder told me the installer thinks there’s air in the coil?
Builder told me the installer thinks there’s air in the coil?
How would that explain the temp difference across the LLH which you measure? More likely the air is in his head!
Lol I've no idea, hence me not wanting them here anymore.
The final straw was him saying he didn't think water volume was the issue. That to me said, they agreed to do work - suggested it within a meeting, nay sayed the actual advice, and then upon seeing it not work, tried to say they never suggested it. It reeks of blame gaming. That plus leaving the zones open.
God knows what else is wrong in that pump room now, I dread to think.
But I think I've come to terms with them not coming back and having someone else come in and just try having a 2 port volumiser. I'm asking the builder employ the specialist/or he gets specialist to instruct another installer what to do.
I think having the current installers out the game, will allow for more level headed and systematic diagnosing to happen.
