Judith

No, not definitely. It wouldn't have cost much extra if we'd had it with the Genvex though. Not much extra to install, maybe much extra to run.

My short list of companies is so far: Genvex, Zehnder, BPC, Daikin, Vaillant, but still at a very early stage of research.

Heat calcs are 6kW (don't forget we were building in the 1990s), so the 4kW in the duct heaters was a deliberate undersizing. We don't need to heat all the rooms in the winter, and we have a lot of solar gain in the south.

I'll try and get more pics and more info.

Well that's interesting. It would take someone who knew what they were doing to decommission the heat pump in the Genvex, then hopefully it would no longer blow fuses. Do you know of any make of heating-cooling heat pump that could run inline with it?

Yes, yes he did, definitely. My mistake.

Thanks, but I don't think so. It functioned for years, no fuse ever went. Then last autumn we tried switching it on and it just wouldn't come on. I think it probably has reached the end of its life after about 24 years, and we need a new machine. I wonder what brands are on the market.

The capacitor cost about £30 to import from Germany. But despite the brand new capacitor, the same thing is happening again. The instant the machine is switched on, a fuse blows, a real one inside. They are very cheap but fiddly to put in. A sparks told us that it probably means the condenser itself is gone. We could have it degassed and removed, but then we would need a new condenser, which would be a different kind and wouldn't fit in the box. Maybe someone could do it, but not a DiY job.

There are three duct heaters. One does the basement lounge, and that's 2 kW. with a grid at floor level. Another at 1 kW does the kitchen-diner and the other at 1 kW the bedrooms, those all into the ceiling MVHR. They're on 3 programmable thermostatic controllers. We might replace them as well, as they are prone to cutting out unnecessarily and hard to reset. We could DIY that replacement or get a local sparks to do it. We are very upset about the Genvex failing BTW as it would have been repairable were it not that the CFC refrigerant is no longer legal (for good reason of course but we like to keep stuff running).

So that's 24 years, not 4. We have electric duct heaters in the ducts. No wet heating.

Installed 1999.

I will try to see. It was someone sent by Joule who fitted it, after the original person who set the machine up couldn't understand why it wasn't working properly (although he had gone through the steps in the manual and signed them off). There's a complication in who is ultimately responsible. Our contract was with a medium-sized electrical contractor who fitted the PV roof and the iBoost. But they bought the Joule from a smaller heat pump specialist company. They were all very nice people and we trusted them to get the teething troubles ironed out. But now the heat pump specialists, who never knew much about the Joule in the first place, have pulled out of air-source and are doing ground-source HPs only. The senior guy from the electrical contractor, who has tried the most to understand what is wrong, has given up on trying to get any info out of Joule. I probably need to contact him again, but they will charge full-whack even for a non-emergency call-out, so I am trying to understand as much as possible by myself beforehand. With the help of people here, much appreciated.

Thank you. As far as I can see at the moment it is not heating up at all on HP only. But I need to take some time to understand the programming system in the manual, to understand when it is meant to be coming on. I might be able to do that tomorrow.

Hi all. Our old Genvex 400 MVHR with heat pump has almost certainly given up the ghost. A capacitor was obviously no longer working, we replaced it (took ages to get it imported from Germany), but a fuse blows every time the machine is switched on. We understand that probably means the condenser is faulty, and it cannot be worked on because the CFC in it is no longer legal. So we are resigned to buying a new MVHR with heat pump for our space heating, this time I think with the "comfort cooling" option. All the ducting is still in place to re-use. What brands are on the market that we should consider? I see that Genvex is still available, but perhaps there are more choices now? Many thanks.