My Glow Worm 30ci no hot water

[missjo]

My Glow Worm 30ci will only produce hot water for about 3 mins & then goes completely cold. A mechanic came out & replaced a pressure valve as the pressure kept dropping & then going too high. Now pressure ok, but problem persists! Central heating fine, but hot water still plays up when central heating on & boiler lit. Cannot think of an explanation. Sometimes water works ok for a bit longer & makes it difficult for me to convince the mechanic of the problem... Help!! It is driving me mad and I need a shower!

 

[Agile]

Much as I would love to help you, unfortunately your description and the terms you use make it difficult for me to guess at what is wrong.

Can you try to explain a little more carefully?

Have you been to Ojo ?

Tony

 

[missjo]

Hi Tony

Thanks for your speedy response!

Sorry, I don't really know much about boilers, so I'm not sure what you need to know...
This is what happens when I try to run a bath for example.
When c/h is off & hot water is turned on, the boiler will fire up & hot water will come out of the tap for about 3 mins & then the water goes totally cold (& boiler flame goes out).
When c/h is on (the boiler is lit to begin with), hot water will come out of the tap for about 3 mins & then go totally cold (& boiler flame is still lit & c/h still on).
The pressure is fine now at all times.

Does this make any sense???
Please tell me what you need to know...

thanks! Jo

 

[gas4you]

When the water goes cold, is the boiler still registering a HW demand on the front panel?

 

[Agile]

Hi Tony

When c/h is on (the boiler is lit to begin with), hot water will come out of the tap for about 3 mins & then go totally cold (& boiler flame is still lit & c/h still on).

thanks! Jo

Are you saying that the CH is on and keeping the radiators hot for say 30-40 minutes when the hot tap is on?

Are you sure the hot water is really hot for as long as three minutes?

Could you time it a few gos to see what the average really is ( in seconds )?

Tony