Glow Worm Compact 75e help with hot water please?

[hartleyinteriors8]

I have a Glow Worm Compact 75e, over the past couple of weeks we have been experiencing a problem where when the hot water taps or shower is turned on, the boiler doesn't always ignite to heat the water. The indicator light next to the tap symbol on the boiler comes on to show that it is sensing the water flow however the boiler ignition doesn't come on. I had a plumber around yesterday to look at this problem and he fitted a new 'diaphram' (small rubber disc) inside the part with the pin controlling the domestic hot water micro switch as he thought this had worn and was causing the problem. However this is still occuring. The system has been bled and the pressure checked. The heating part seems to be operating normally.

I wonder if I replaced the domestic hot water switch with the replacement one with three cables whether this would solve my problem?

Can anyone help please? I noticed namsag had commented on a post a number of years ago for a Glow Worm Compact 100e.

Thank you!

It's just been suggested by Glow Worm support that it could be the thermistor? Would this cause an intermittent problem or would I simply never get hot water?

 

[hartleyinteriors8]

Just to add further to this, Glow Worm have suggested the micro switch is working correctly as if there was a fault with this the hot water demand LED wouldn't illuminate.

They have also suggested that it could be the thermistor? Would this give me an intermittent problem as I am experiencing? On asking Glow Worm this they said that would depend on it's 'resistant reading'? Also they said if it wasn't that it could be the diverter valve sticking - I cannot see this on the parts list in the manual.

Does anyone have any thoughts please?

 

[hartleyinteriors8]

Does anyone have any ideas? I notice some people have responded to Glow Worm issues in the past?

Thank you.

 

[kevindgas]

the thermistors can be a problem on these.
but i wonder if scale could be a problem as well as it has worked ok for several years presumably without a descale.
the boiler would overheat if scaled up as it wouldn't be able to get the water away fast enough.

 

[mickyg]

Glowworm are correct, the light indicates the microswitch is activated. If the heating is working then I'd be looking at the thermistor of possibly the diverter valve is faulty. The diverter head can be removed to check operation without the need for draining. The pin in the diverter body should be able to be pushed down and spring back(it will be hard) the pin in the motor head should react to changes in demand.

 

[hartleyinteriors8]

Thank you for that.

It hasn't been descaled as far as I know. So if scale had built up the heating would work normally but every now and then the water wouldn't heat up? And if it was the thermistor, would that too cause an intermittent problem or would I simply never get hot water?