Manifold plumbing pipe routing problem

[Nickfromwales]

16 minutes ago, TerryE said:

My concern is that few plumbers are at your level of sophistication

You know the way to a mans heart 

[divorcingjack]

Hi chaps, 

 

I haven't caught up with all the replies yet, but just wanted to upload my shoddy drawing to illustrate the problem. Hopefully, this makes some sort of sense - I will try to add explanatory notes as well. 

 

As I mentioned, there are a couple of internal doorframes in the way and a large slider in the playroom, which leaves us very tight for space and almost impossible to separate the H/C. The other problem is that the section outlined in red is single storey, and the large kitchen/living is double height. So, the joint between the utility and the kitchen is actually a roof, filled with insulation. We have already had to put a load of MVHR pipes in here, so I'm very twitchy about adding more and losing even more space for the insulation. 

 

The location for a potential second manifold would be the big cupboard which backs onto the two bathrooms - we would run a 22mm H/C feed through the ceiling from the boiler to here, with a 10mm hot return as suggested by Nick. I have put dimensions around the wall runs so you can see the lengths of run we're talking about. 

 

Have to go now - commuting. I'll catch up at lunchtime with questions. Thanks a huge amount for all your help. 

[TerryE]

Sounds to me like you've got a plan ?

[divorcingjack]

Righto, commuting again  The plan with the 10mm return to a secondary manifold in the big cupboard makes perfect sense, pump on a timer. We’ll shortly have a second baby in the house, so occupancy will be much higher for a year or so. 

 

The calcs for insulated pipe also were very helpful, but given that the hot and cold supply will be running in conduit through the single storey ceiling, should we leave the hot uninsulated and use the losses to mitigate the missing insulation, insulating once we come down from the ceiling into the cupboard? 

 

Thanks again everyone, priceless advice as always. 

 

Dj 

[TerryE]

1 hour ago, divorcingjack said:

should we leave the hot uninsulated and use the losses to mitigate the missing insulation,

 

IMO, we can get a bit too paranoid about this. If you pack something loose around the pipe insulation such as wool insulation or even rockwool, then the difference in local U value will be fairly small.  OK, you might lose the few W along the pipe, but it's also leaking waste heat so it will probably be a wash. The odd few W here and there isn't going to matter, so long as there isn't a material thermal break which is causing a cold spot near the condensing temperature.  In this case if you insulate the pipework and any gaps around the pipework, then I doubt that you would be able to detect any difference in surface temperature with an IR thermometer.