I don't know if this is a heat pump installer-specific issue, to be honest, as my experience with a lot of the skilled trades is that they will quite often say anything to get out of having to do things properly. They often get away with it too, because most of the general public don't know how things are meant to be.

We experienced this multiple times when we moved into our new flat a couple of years back, even with the most simple things.

For example, we had some missing bits of trim around some of our windows. The tradies sent out to look at it tried to act like they were just cosmetic, but I personally reached out to the window suppliers and they made it clear that the trim pieces were necessary to avoid water ingress, and that their warranty would not be valid without them in place.

The builders also failed to follow the building regs when installing the MEV system, with the kitchen vent left unconnected, and no vent at all put in the utility room. Again, the building services engineer who came out to look at it acted like it was completely normal until I started quoting chapter and verse in the building standards (and then followed up with emails from the local building standards to confirm my reading of the information).

When it came to the heating system, however, there were so many more levels to it.

Every fault had to be exhaustively documented and described before they would do anything more than turn up, look at the system (without actually touching it, just looking at it from a distance), and declare that it's all working as expected.

Zone thermostats connected to the wrong zone valves? "Ahh, no, there's controls on it to make sure it's not overheating." Yeah. I know. They're called thermostats. And they're connected to the wrong valves.

Zone thermostats fitted without floor temperature sensors? "Ahh, no, they were definitely specced, so we fitted them. Did you fiddle with the stat somehow?" Yeah, mate. I fiddled. I took a look at the back plate and found that there was no floor temperature sensor ever fitted.

Whole system is ruinously expensive to run (for an 'energy-efficient flat', anyway) and incapable of providing ample hot water when the heating is needed? "Ahh, well, it's heat pumps, innit? Everyone knows they don't really work. But that was what they designed. Nuffin' I can do, mate. Just buy some fan heaters."

Fortunately, I have an engineering background, and a willingness to research any problem I encounter until I'm absolutely certain of what the problem actually is and all their attempts to brush me off or to pretend like the issues weren't real failed miserably. Our neighbours, however, didn't have my background.

In one instance, an elderly neighbour complained that their heating wasn't working at all (it 'worked' to a level, but couldn't warm the flat above about 20C in even marginal weather). The engineer who came out 'tightened' the inlet air duct on the Heat pump hot water tank and told them straight to their face that that would help. They had no real choice but to accept their word on it, but of course it didn't change a thing. Even now, that neighbour is almost entirely reliant on plug-in fan heaters for their heating.

In another instance, the tank was frequently venting through the pressure relief valve, and the resident raised the issue of 'frequent rushing water sounds' from the unit. Again, an engineer turned up, looked at it from a distance and proclaimed it all good. "It'll just be the condensate drain." Only when the amount of released water resulted in significant damp and mould issues was it actually fixed.

Another neighbour moved in to find a system that didn't work at all. The system was unpressurised, and the filling loop had been removed entirely. Despite this, the engineer who'd gone in to look at it had proclaimed it "Working, it's just not cold enough yet for the heating to come on."

I've done what I can to explain to our neighbours exactly what they should report to the builder if they want things fixed because the sad fact is that any issue like "It's cold", "It's expensive" or "It's not working" will invariably lead to zero investigation from the trades involved, and they'll instead try to blame the resident for using it wrong, or not understanding.

The elderly resident from earlier, shortly after they moved in, had found that their flat couldn't go much above 20C and so as a test, they set all their thermostats to 30C so that they could be sure that the heating was on in all areas. They weren't trying to get the property to 30C. They just wanted something more than 20C. But the engineers called out to look at her problems just focused on the 30C thing. "Oh no," they said, "It's not designed to go to 30C. That'll never work." Completely ignoring the fact that it is designed to maintain 21C at -4C OAT and shouldn't be struggling to manage 20C at +5C OAT.

And that's even before I try to count up all the occasions where neighbours were told their systems had been properly calibrated and that they shouldn't touch it, only for me to go in and to find that they were often underpressure, with pumps in the wrong mode, with wrongly connected or inoperable zone valves, and seemingly randomly chosen temperatures and completely unbalanced manifolds.

Genuinely infuriating to see.

I moved to a new build 18 months ago with a 2 year warranty period.  The builder has completely ignored any requests for remedial action.

• Oversized heat pump
• Contaminated underfloor as a result of no biocide being added
• Failure of the expansion vessel.

Going through a protracted legal battle is of little point and not worth the stress.

I was asked to help a lady who had an Ideal heat pump installed under the ECO4 scheme.  She asked for help, because the lounge thermometer was reporting 28C.  I suspected that the three step installation process had not been followed.  

I rang the Deal help desk and reported the symptoms.  He responded immediately "The installer hasn't run the three step installation process.  This comes up a lot."  I ran the process, which took all of 5 minutes.  Suddenly, the room thermostat and weather compensation started doing their job.

Don’t know if this is relevant to this thread, but my ASHP installation was reviewed by MCS as part of an installer audit

As far as I could tell, the MCS chap just looked at the state of the pipe work inside and out (took 20 mins mind you).

Not once was I asked if the system a) did its job b) met the design criteria c) what parameters the system was running under d) saved us money e) am I happy with it. As it happens, a) yes it does b) yes it did c) won’t bore with numbers d) yes it is e) very

But I do have very neat pipework