Hot water turns off heating.

[Kammx41966]

Hi a strange thing is happening to my Baxi 105 E boiler. If the heating is on running fine and we put a hot tap on the heating turns of and hot water comes out. If nothing is using the boiler and we put a hot tap on and then the heating the heating won't work until the hot tap is turned off. HELP Please. Many thanks for any replies.

 

[bernardgreen]

Sounds like a normal combi boiler.

When hot water is required the boiler puts as much heat as it can into heating the water leaving no heat to supply the heating system.

 

[Kammx41966]

So what your saying is if the heating is up to temperature maybe the hot water would work?.

 

[bernardgreen]

No what I said was that heating hot water takes precedent over heating the house.

 

[ChrisJP]

Hi a strange thing is happening to my Baxi 105 E boiler. If the heating is on running fine and we put a hot tap on the heating turns of and hot water comes out. If nothing is using the boiler and we put a hot tap on and then the heating the heating won't work until the hot tap is turned off. HELP Please. Many thanks for any replies.

As bernardgreen has said, this is how combi boilers work.
In answer to your question "So what your saying is if the heating is up to temperature maybe the hot water would work?" - this implies that your hot water doesn't work when the central heating is on - but this is not what you said in your initial posting.
In your initial question you described a situation where HW always works - taking precedence over the central heating whenever there is a demand for hot water. This is normal combi boiler operation.

 

[Kammx41966]

Thanks but its the first time this has ever happened. Always had both services from our combo boiler.

 

[bernardgreen]

Thanks but its the first time this has ever happened.

Possible reason is the temperature of incoming water supply is colder and this colder water requires all the available heat from the boiler

 

[ChrisJP]

Are you perhaps running hot water for longer periods than you used to? For example you've got a new shower, or somone is showering for longer?
When you run hot water for hand washing or just into a basin, the central heating will go off, but not for long enough for the radiators to cool down much. It's only when hot water is running for an extended period that the radiators have time to get cold.
Alternatively if you haven't got a combi boiler and instead have a gravity fed system from a header tank, then it's possible that a motorised valve has failed.

 

[gas112]

A baxi 105e working correctly will not give you heating whilst a hot tap is turned on it is either not both at same time
If it has a faulty divertor valve and you run a bath say for 20 minutes then some of rads may still get heat , but that is a fault condition

 

[stem]

its the first time this has ever happened.

Most people usually don't notice it. If the radiators are already hot, they don't tend to cool down that much in the short period of time hot water is being used.

So, has anything changed? Does someone who previously had a 2 minute shower now run a full bath instead that takes longer? are there several members of the household showering consecutively? but even then the radiators would come back on for the in-between period.

 

[Kammx41966]

Maybe after 18 years its the first time ive ever noticed it.

 

[Kammx41966]

A baxi 105e working correctly will not give you heating whilst a hot tap is turned on it is either not both at same time
If it has a faulty divertor valve and you run a bath say for 20 minutes then some of rads may still get heat , but that is a fault condition

Would only 1 service working IE heat or water be a sign of a faulty valve?.

 

[Stuckinarut]

Thanks but its the first time this has ever happened. Always had both services from our combo boiler.

Are you sure it’s a combi boiler?

 

[gas112]

Would only 1 service working IE heat or water be a sign of a faulty valve?.

you mean at a time , no its a sign that its working exactly as it should