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Andrew Smith
Andrew Smith, Home Appliance Technician
Category: Appliance
Satisfied Customers: 3768
Experience:  Gas cooker specialist
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have a greenstar camray 25/32. Not kicking in when heat demanded.Low

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have a greenstar camray 25/32. Not kicking in when heat demanded.Low system pressure when happened.Pressure restored. internal expansion vessel full, should it be ? airlock. Help appreciated.Marck
***** ***** : Can you confirm what the expansion vessel is full of?

just heavy, used to be empty, assume it is water ?

***** ***** : The expansion vessel should have water and a balloon inside
***** ***** : The balloon acts as a cushion of air against the expansion of the water when heated
***** ***** : Has the boiler overheated and just needs resetting?

I understand, just seems a lot heavier than before, almost full.


have reset it before, but no change

***** ***** : If there was a problem with the expansion vessel then the PRV would discharge every heat cycle
***** ***** : Has the PRV been discharging?

boiler kicks in when boiler pump switched on manually and heats water fine, but pump/boiler do not kick in when heat demanded by heat store.temp drops below setpoint


what do you mean by that?

***** ***** : Did you lose your pressuer outside or do you have a leak?

is taht the automatic vent on top of cylinder?, that often splutters a bit

***** ***** : No, a discharge pipe outside - a 15mm copper pipe through the wall?

runs straight into drain, not noticed it discharging


last topped it up 3 months ago, no loss of pressure since then

***** ***** : ok, thats good then
***** ***** : How do you turn on the pump manually?

have a control panel that regulates heating input from solar panels as well. Allows me to switch boiler pump on.

***** ***** : Ok, the motorised valve opens which the fires the boiler - is it in the airing cupboard?

no, next to boiler

***** ***** : When you turn the heating on only does the valve move at all?

valves are controlled separately. boiler responds (or should do) to drop in temperature in heat store, not heating demand in house.


if there is an airlock, how could taht be released, or should the automatic vent at the top heat store deal with that

***** ***** : The auto airvent should sort that and also you can bleed the pump

is that straightforward ?

***** ***** : Just the screw in the centre, if you slacken it and put a bowl under then run it for 10 minutes it will let the air out
***** ***** : I thought your boiler had overheated, but if that was the case then it would not fire at all, but you can make the boiler fire by turning the pump on
***** ***** : It is pointing to a fault with the thermal store thermistor not calling for heat

thank you for your time an deffort

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