Glow worm Compact - Water only hot when heater is on

[SDR]

Hi all,

I have just bought my first house and am currently doing some DIY renovations over the next week before I move in. I noticed yesterday that when the central heating (radiators) are turned off I can only get luke-warm water out of the taps. If I turn the heat on the tap water becomes scorching hot.

Any thoughts? I am OK at many DIY tasks around the house, but heating is not one of them I'm afraid.

I have a Glow Worm Compact combi boiler.

Thanks in advance
Seth

 

[gblades]

I am no boiler expert but this is normally causes by a faulty rubber diafram. The water flow out of the hot tap moves the diafram which signals the boiler to ignite and also diverts the water so it doesnt try and heat the radiators every time you want hot water.

It can be other things but the diafram is the most common culprit.

 

[kevplumb]

compact dont have a diaphram its a motorised diverter

worth checking if its working tho as you will get same prob

 

[assured heating]

compact dont have a diaphram its a motorised diverter

worth checking if its working tho as you will get same prob

Compact has a diaphram on the hot water flow witch! I think thatwhat he meant

 

[kevplumb]

i stand corrected sir

was thinking if the flow switch the boiler wouldn't fire at all

 

[SDR]

Many thanks everyone. I guess I should just call in the service guy.

 

[Agile]

compact dont have a diaphram its a motorised diverter

worth checking if its working tho as you will get same prob

Compact has a diaphram on the hot water flow witch! I think that what he meant

No, he did not!

He thought it had a traditional diverter valve of the Gianonni type because he said that it also diverted the flow away from the rads.

Its easy to check the DHW flow witch. Turn off CH and see if boiler fires up when tap on.

If so then suspect the diverter valve motor. Gland may have leaked and spoilt the motor.

Tony