MJNewton

<Stands up> We live in an estate - a Persimmon one in fact - and love it here. <Sits down to a reassuring ripple of clapping from the amassed circle of new friends, and nods of acceptance now that I've finally been able to say such a thing out loud> Joking aside, having spent many years renovating various Victorian properties and developed skills, knowledge and experience of pretty much every aspect (including, unexpectedly, building construction photography which found its way into the Haynes Victorian House Manual!) we never expected to end up in a new build (or rather 3 years old at the time). However, an estate agent suggested we had a look round even just to rule such a property out so we did and something just felt 'right' to both of us when we did. We bought it and 14 years on have absolutely no regrets. Indeed, I can easily see us staying another 14 as it suits us (small family now) perfectly. Perhaps we've been lucky with having the show home but the house is very well built. Having extended it and retrofitted MVHR I've seen almost every last inch of the building fabric - inside and out - and the build quality is absolutely fine. I'm a fussy bugger too - non-aligned screw heads are all that's required to keep me awake at night. Compared to every single one of the older properties we've renovated it is world's apart. People say 'They don't make them like they used to' and all I can say is 'Thank God for that!'. It performs well and is an absolute dream to work on. It turns out things can be built square after all. We're not overlooked, although others are so of course not all plots are the same, and we've always had great neighbours so again maybe we've been lucky in that respect too (currently a vet one side and dentist the other so I want you to imagine a family photo hanging up in the hall showing our gleaming white smiles, even on the cat! 😂). For those that can't understand our choice I wonder what the alternative is that is being compared with? Presumably the same general location and cost, otherwise does any such comparison make any sense?

It should be the same matting on all joins - both surface and upstands etc. For the upstands and wall abutment our roofer put down some pre-formed bends (of rigid fibreglass?) too but I think that was as an alternative to wooden angle fillets that you might normally see. I don't know if there's a benefit to this (e.g. more gradual angle transition) or whether it was just quicker/easier for him (probably the latter knowing him).

Yeah, all good as far as I know! It's been down five years now (where does the time go?!).

For what it's worth, my BCO didn't ask for anything.

I was just going to say that even if it was counter intuitive you'd soon get used to it, but yes - it is exactly the sort of thing that keeps me awake at night in the planning stages!!

Perhaps a little on the short side? More seriously, might there be benefit in hanging it on the other side so as to match the machine opening itself? Probably doesn't matter much either way, but I'm just thinking of it might have you a little more space when loading/unloading.

Put the heating on max and watch what happens. The pressure increase without expansion capacity will happen without having to wait too long.

Does the PRV outlet show any signs of passing?

As the water heats and expands in the sealed system it'll increase in pressure and cause the PRV to open. This loss of water will result in pressure loss once cooled.

So, you've found the issue. From what you've written it sounds like you're still looking though?

Yes - completely agree. Furthermore, if it stops further ingress of water that can only be a good thing whilst the decision is made what to do next.

Yes, entirely normal. After about 1/2-3/4 turns most LSVs are for all intents and propose fully open. Because of this only small adjustments should/can be made.

Flow should be the hottest, and Return coolest. How that correlates to the TRV and LSV depends on which way round they have been fitted. TRVs used to be directional - and hence would be located at the Flow end - but these days non chattering valve inserts are generally used thus making them bidirectional. Whether new or old you will have to work out which way round each of yours are by measuring the temperatures as you have been doing. Not that it matters too much for balancing - it will always be the LSV that you will be adjusting regardless which end of the radiator it has been put.

Whilst MVHR might help with heat-related 'stuffiness', it won't do much for the heat itself. The combination of the low heat capacity of air and the relatively low flow rates means it is not a good solution.

Yeah, bought one about a year ago. Still haven't used it!!

That sort of thing doesn't bother me. It HAUNTS me!! 😂

Looks lovely - well done. Perfect time of year to be completing a room like that!

If you do run the MVHR (I would - find it great for drying washing so the dehumidfying effect is definitely there) keep the filters in place. They protect the heat exchanger from becoming fouled up.

Yeah, and suggests there's something wrong with the figures (or something external that is skewing them).

If the calculation focuses on how much the supply temperature has risen it doesn't consider where the source of that heat comes from, or rather assumes it is all from heat transferred from the extracted air. The reality is that some heat may have come from the air surrounding the box itself, the contribution of which will be greater with a poorly insulated unit than a well insulated one. Similarly with one that leaks air compared to one that is airtight. Hence poor units get 'rewarded' (as in appear better) than better ones using such a calculation. If you take an alternative approach that isn't based on supply temperature but factors in exhaust temperature (i.e. it views the unit from the opposite direction in terms of heat transfer), then that same heat leakage that artificially increases the supply temperature is picked up by the increase in exhaust temperature and results in a decrease in calculated efficiency. Thus poor units now get 'punished' for any leakage that exists.

I was going to comment on that actually as I am not quite sure how that has happened. The temperature sensors haven't been swapped round have they?

Forgive me sounding so negative but if you take the simple ( Supply - Intake ) / ( Extract - Intake ) calculation method that gives ( 13.4 - 12.1 ) / ( 14.4 - 12.1 ) = 57% which isn't all that high? Better than 0% of course so heat is being recovered, but it's not really in the ball park (85%+) that is realistically achievable with these units.

In our case whilst we wanted it low profile we weren't after flush (there's nearly a brick height drop on the outside anyway so benefits would be limited). I think we've got around 10-15mm above finished floor level. It might be technically slightly less actually given the finishing strip over the edge of the wooden flooring. I do remember being worried about threshold height and at what point would it be too high. Part of the subsequent thought process was to become better informed through first-hand experience so I set about measuring existing door threshold heights - which had never caused any issue - and couldn't believe how high some of them were! I suppose your brain unconsciously deals with that sort of thing. Bit different between a front door and a wide glass opening to the garden of course but it did remind me not to worry too much about such things. I still did though.

I seem to recall our sliders had a gap of 10mm all round. They did remark that it was one of the squarest openings they'd ever measured so may well have taken a tighter tolerance than usual!

It looks great. and very neat! The sort of thing deserving of a perspex lid and internal lights... 😆 As mentioned above though it does seem rather on the small side, or am I being tricked by the perspective? Maximising contact time in the HEX is what's important; it doesn't matter how big the unit itself is. You will likely find that as your air flows increase the efficiency will drop - there's only a certain amount of transfer capacity available. You mentioned about sourcing fans; what are you using at the moment and are they representative flow-wise of what you are ultimately seeking?