microbore c.h. systems

[patagonia]

We recently made an offer for a bungalow which has been exended and has two c.h. systems, the old part a pressurised system with normal sized pipes to the rads and the new part a microbore system, which we hadn't noticed but was pointed out by a builder friend who inspected the property for us. There are 2 boilers, one in the loft and one in the garage, neither condensing, and two cylinders. Our builder has warned us off a microbore system as he says they always block up eventually and there is no way of cleaning them out. There is no rad in the kitchen; only a kickspace which is defunct - I don't like them anyway - and no rad in the hall, where there is a grill from an obsolete warm air system, so we would need to install them. Our builder says we should replace the pipes to the normal half inch (or whatever the mm equivalent is), which wd mean bringing them down the walls as the floors are all solid.

Do you agree that microbore systems are a no-no and would lead to problems. We have had more than enough with our system here and don't want to have it all decorated and then have problems.

Advice appreciated.

 

[mikej2005]

Do you agree that microbore systems are a no-no and would lead to problems.

8mm microbore is perhaps a bit on the small side, but I don't see any problem with using 10mm microbore in a CH system, provided that system is treated properly and not neglected.

I guess an old microbore system that has not been looked after or well maintained could give you problems, however.

I replaced my entire central heating system last year and part of it is a combination of 22mm copper tubing, with 10mm microbore to the radiators - microbore is a very convenient material to work with, as it's far easier to bend than 15mm tube and it's also possible to minimise joints, because it's available on large rolls.

 

[patagonia]

Thanks for that. So what is it made of then? The microbore tube was in two different sizes. I guess some was 8mm and some was 10mm. I didn't realise you could mix 22mm copper with microbore. I wouldn't know what was in the solid floor. As this area is mostly tiled in rather nice terracotta tiles, it would be a nightmare to replace so one would have to bring it down the walls and box in.

 

[patagonia]

P.S. What do you mean by looked after and well maintained? What should have been done? I think the microbore system is about l5 yrs old and my impression is that they don't have it serviced on a regular basis.

 

[mikej2005]

Thanks for that. So what is it made of then?

Copper, although you can get narrow-bore plastic tubing too. The copper microbore is far easier to bend round corners and awkward angles than 15mm copper tube, but it has a tendency to kink rather easily so must be handled with care.

I didn't realise you could mix 22mm copper with microbore.

It's fairly common for a boiler to have a 22mm send and return. In my case, these run the length of the house, with 10mm microbore coming off via manifolds or T's and feeding the radiators. You can only extend so far with 10mm though - longer runs may need to be run in 15mm for at least part of the way.

I wouldn't know what was in the solid floor. As this area is mostly tiled in rather nice terracotta tiles, it would be a nightmare to replace so one would have to bring it down the walls and box in.

Running pipe down the corner of a room is common when you've got solid floors and saves a lot of mess and hassle. It also means the pipes are more accessible if ever there's a problem. In my previous house, this was done in white plastic conduit, which was either painted the same colour as the walls in an effort to blend in, or just left white. It is possible to chase pipework into walls, however you need to leave room for expansion or you risk the plaster cracking with the temperature changes.

 

[mikej2005]

If all the pipework and radiators get nice and hot as expected and the boiler seems to work OK, then you may not have anything to worry about.

If you were going to add new radiators, then flushing the whole system through with a suitable cleaner first would be sensible though.

 

[patagonia]

Thanks, but you haven't answered my question as to how it should have been looked after and maintained.