Whining Combi Boiler until hot water tap comes on

paul.super.mario

I have a problem with the boiler in my house that I have just moved into. From the beginning, it has made a high pitch whining sound when the heating is on which only goes off when the hot water tap is on. When the tap is off again, it takes a few moments and then the noise starts again! I have no experience with boilers but someone suggested bleeding the radiators to release trapped air which I did and hasn't solved the problem. Before I bought the house, I asked for seler to get the boiler and central heating inspected (just to ensure it was ok) and they got someone out who issued a gas safety certificate. I have tried to contact this plumber to get his opinion but he doesn't return any voicemail messages! Does anyone know what might be wrong with my boiler, the noise is waking us up early in the morning and slowly driving us mad

escapee

We had this with our boiler when it was newly installed. It could be air in the feed to the boiler - in this case you would need a non return valve fitting to the cold water inlet feeding the boiler.

However, the most probable cause and one that should be ruled out first is a 'dead-leg' which is a length of pipework which was capped off when the boiler was installed (it probably fed the old tank or feed cistern).

It could be an easy or hard job to fix, depending on where the dead-leg is situated, if you can locate it, the solution would simply be a case of loosening the screw cap slightly until all of the air has dissipated.

If you can't find it, then chances are it will be hidden under the floorboards somewhere! Try to locate an old airing cupboard or take a look in the loft to see if you see any exposed pipes which are capped off.

This usually happens when the mains water is switched off for any period and would have to be done every time the mains feed has been isolated.

escapee

Another possible way of removing the air, would be to turn ALL of your hot and cold taps on for a short period (a few minutes), in the kitchen, bathroom and toilet if you have a sink in there too.

If this is the case you will probably hear the air escaping as it is forced out by the water pressure.

paul.super.mario

escapee wrote: »

We had this with our boiler when it was newly installed. It could be air in the feed to the boiler - in this case you would need a non return valve fitting to the cold water inlet feeding the boiler.

However, the most probable cause and one that should be ruled out first is a 'dead-leg' which is a length of pipework which was capped off when the boiler was installed (it probably fed the old tank or feed cistern).

It could be an easy or hard job to fix, depending on where the dead-leg is situated, if you can locate it, the solution would simply be a case of loosening the screw cap slightly until all of the air has dissipated.

If you can't find it, then chances are it will be hidden under the floorboards somewhere! Try to locate an old airing cupboard or take a look in the loft to see if you see any exposed pipes which are capped off.

This usually happens when the mains water is switched off for any period and would have to be done every time the mains feed has been isolated.

Thanks very much for the advice. I will try to seek out this dead leg and see if I can get the air out. Hopefully it is not too difficult to find. I will be going into the attic sometime soon to look at the insulation so will see what I can find up there.

paul.super.mario

escapee wrote: »

Another possible way of removing the air, would be to turn ALL of your hot and cold taps on for a short period (a few minutes), in the kitchen, bathroom and toilet if you have a sink in there too.

If this is the case you will probably hear the air escaping as it is forced out by the water pressure.

I gave this a go but unfortunately as soon as I turned off the taps again it started up. Oh well, but thanks so much fo the advice

Seronera

Make and model of boiler is always useful to know. A whine could be a hydraulic or a combustion noise,depending on model.Either way you probably need somebody who knows what they are doing to diagnose it and hopefully rectify it.

southcoastrgi

escapee wrote: »

We had this with our boiler when it was newly installed. It could be air in the feed to the boiler - in this case you would need a non return valve fitting to the cold water inlet feeding the boiler.

However, the most probable cause and one that should be ruled out first is a 'dead-leg' which is a length of pipework which was capped off when the boiler was installed (it probably fed the old tank or feed cistern).

It could be an easy or hard job to fix, depending on where the dead-leg is situated, if you can locate it, the solution would simply be a case of loosening the screw cap slightly until all of the air has dissipated.

If you can't find it, then chances are it will be hidden under the floorboards somewhere! Try to locate an old airing cupboard or take a look in the loft to see if you see any exposed pipes which are capped off.

This usually happens when the mains water is switched off for any period and would have to be done every time the mains feed has been isolated.

none of this will solve your problem & the first paragraph is total nonsense

paul.super.mario

southcoastrgi wrote: »

none of this will solve your problem & the first paragraph is total nonsense

Ok well if you know that much, sounds like you know a lot so can diagnose youself. Its a Remeha Avanta Plus 28c - Any helpful tips?

southcoastrgi

do you have thermostatic rad valves ? does the noise go away if you open them up ?
when was it last serviced ?

unclebulgaria

Remeha Avanta are a very quiet boiler so any small noises will be easily heard. Whining is usually a faulty non return valve or possibly the gas valve. As southcoastrgi has stated try turning down/up your radiator thermostats to check if its one of them starting to chatter. You could also try turning down your incoming mains water pressure at the stop !!!! and seeing if that makes a difference. If it does it either the non return valve on the hydraulic unit or the non return valve on the filling loop.
Of course if its the gas valve whining don't mess with that get a qualified engineer in to fix it.