Intermittent hot water

canyouhelp

Hi

This question will probably show up my lack of knowledge of how boilers work, so apologies...

I have recently had a loft conversion, which has involved adding a new radiator to the system. It doesn't have a bathroom so no other water pipes have been added.

However since the radiator was added, my hot water has been intermittent. It heats up and then goes back down to lukewarm before starting up again. It makes it difficult to do the washing up as when the sink is full it's not really hot enough.

I can't see how the extra radiator would be causing this problem, but it was literally just from that day that it has happened. It happens if the heating is on or off.

Could it be the new radiator, or is it just a coincidence to do with the boiler?

Any thoughts appreciated!

macman

Make and model of your boiler would help. Combi or conventional boiler? Since the CH and DHW are on separate circuits, it's not likely to be connected.
What do you mean by 'it heats up and goes back down again'? I assume from this that you have a combi boiler, and the DHW flow is going from hot to cold and then hot again? In which case a faulty divertor valve is possibly the problem.
Have you bled the new rad in the loft since it was commissioned?

canyouhelp

Thanks

It's a Biasi Combi boiler. It's pretty reliable and has been checked over recently.
I haven't bled the loft radiator no, it was only put in a couple of weeks ago.
Yes, the hot water is heating up, going lukewarm, then heating up again.
the heating seems fine so perhaps it's just an unlucky coincidence?

diywhynot

canyouhelp wrote: »

Thanks

It's a Biasi Combi boiler. It's pretty reliable and has been checked over recently.
I haven't bled the loft radiator no, it was only put in a couple of weeks ago.
Yes, the hot water is heating up, going lukewarm, then heating up again.
the heating seems fine so perhaps it's just an unlucky coincidence?

By 'checked over' do you mean serviced by a RGI?

canyouhelp

diywhynot wrote: »

By 'checked over' do you mean serviced by a RGI?

Yes, about 3 months ago

stebiz

Does it happen when you have the central heating off. We've just moved into another property whilst we get a loft conversion and renovation done on ours and it happens here. We couldn't even run a bath. Then my wife suggested turning the central heating off and hey presto running constant hot water.

canyouhelp

thanks, happens when it is on or off

diywhynot

canyouhelp wrote: »

Yes, about 3 months ago

Call for a repair.

canyouhelp

diywhynot wrote: »

Call for a repair.

Thanks for that... my question isn't about whether I should call someone out, it's whether it could possibly be connected to the extra radiator, in which case I will get the building firm back in rather than calling my regular heating engineer.

Ruski

Is the hot water 'cycling' i.e. hot, cold, hot, cold, hot, cold - or does it just go luke warm once then constantly hot??

canyouhelp

Ruski wrote: »

Is the hot water 'cycling' i.e. hot, cold, hot, cold, hot, cold - or does it just go luke warm once then constantly hot??

Cycling hot and cold- I have to keep stepping in and out of the shower!
I have tried to look at what the boiler is doing when i put the hot tap on, the flame is going out and then re-igniting