combi boiler on a single pipe system.

[doitmyself]

A one pipe system is only 70% efficient.

Where did you get that from; and how do you measure efficiency?

 

[cygnet]

From Vaillant a few years ago now, a customer wanted to keep the one pipe system, I wouldn't do the job but a few years later i did a service on the boiler, she complained that the gas bills hadn't come down at all

 

[doitmyself]

One pipe systems are still used on commercial installations, where every penny counts. I can't see finance directors being very happy with systems which are only 70% efficient.

Most of the heat output of a boiler is used to heat the house - apart from a small amount lost from pipes in unheated parts, e.g under the floor. So if 5% is lost there is still 95% left to heat the house. The boiler may be only 70% efficient - or less if it's very old - but that has nothing to do with the piping system.

 

[AWheating]

Fitted a WB combi to one 5 years ago and it's worked great. Just balance the system well and it should be fine. Use full flow trv's if needed.

 

[turboera]

Just an update.
I have had a combi fitted to the one pipe system. It works very well. It always did with the old boiler. The one thing I miss with the combi is the warm airing cupboard but I will get used to it