Help with heating

clairecymru

We have an intermittent problem (every 2-3 days) in that once our heating has been on for about 45 mins - an hour it becomes REALLY noisy. It sounds like there is a motorbike in the house. The only cure is to either turn the heating off, or turn every radiator in the house up to full blast.

We have a homecare package with British gas and have called them out about it twice but each time they cannot replicate the problem and have said we have a really energy efficient boiler in excellent condition (about four years old).

Does anyone have an idea what is wrong and what can be done about the noise. It's so loud even the neighbours have commented on it!

TheCyclingProgrammer

Sounds like it could be water hammer.

nofoollikeold

As you'll appreciate, its impossible to be certain without being there when it happens. However I'd consider one of the following:

1. The automatic bypass valve (if fitted) could be faulty. This valve should only operate once there is no other flow through the circuit, for example when all radiators are closed because their thermostatic valves have reached the set temperature. You might test for this by turning on the hot water system the next time it happens. If water can circulate through the hot water cylinder's coil, the automatic bypass should shut as its no longer needed.

2. One or more cheap or faulty thermostatic radiator valves. While in theory most can be fitted on either the flow or return pipes to a radiator, certainly I've known the cheap ones make an appalling noise on the return pipe, and sometimes make an awful noise whatever pipe they are on. You could try shutting each radiator off in turn once the noise starts, and see if one makes a difference, but it could be more than one playing up.

3. A fault with the two port or three port motorised valve which could be "bouncing" open and closed sending shocks through the pipework. Depending how handy you are it might be worth taking the head of the valve (the central heating one if you have two x two port valves) and manually setting the valve to central heating.

southcoastrgi

What's the make & model of your boiler?