Leaky CH system, condensation

[Andrew Haylett]

Friends have a house with two problems. First is a leaky CH system. The system, which is pressurised and driven off an 8-yo Vokera boiler, loses water pressure quite rapidly over a period of a few days, falling from c. 1.5 to 0.1 or so. Plumber is not sure where the leak is, suggests that replacing the pressure vessel may help, also suggests replacing entire boiler ("8 years is near end of life span, can't get the parts, modern condensing ones are much better", &c.) We aren't sure that even replacing the boiler will fix the problem. Question: is there any technique for tracing leaks, or are they better off putting some sort of sealing agent in the system and seeing if it helps?

Second problem is excessive water in the atmosphere in the house; they have to use crystal-based water collectors to contain the problem. What can be done to mitigate the problem? Expensive survey ended up recommending either running the CH system for longer each day (!) or adding cavity wall insulation (only the house doesn't have cavity walls...) Any better suggestions?

thanks, Andrew.

[Andy Hall]

It might.

Favourite places for the water to escape are from the pressure relief valve and around the stems of radiator valves. It has to be going somewhere.

It probably wouldn't unless the water is escaping inside the boiler and being boiled off.

There are such things as leak sealers which may work. Leak tracing is laborious but may be the only way.

1) Ventilation. If the whole place is sealed up tight with no air flow (or not enough) then with uninsulated walls, they will be cold and condensation is inevitable. 2) Insulate the walls

3) Use dehumidifier - electric one.

Raising the temperature using the CH temporarily helps but is an expensive solution given what they have.

[John]

It sounds like the damp is due to the leak from the CH. Cure that and the second problem will reduce if not disapear.

Leak sealer may work but could be masking a problem. I had a similar minor leak in a house. Finally found it when I disturbed a radiator for decorating and a pipe fitting came apart under the bedroom floor. Once that was repaired, the system held pressure. It may be a sod of a job, but it's better to solve the problem not the symptom.

John

[John Stumbles]

section "system pressure dropping"

[Ed Sirett]

Much useful half answers in the Sealedch and Boiler Choice FAQs.

[Andrew Haylett]

Many thanks for the useful comments and helpful links - some avenues to explore there.

Andrew.