glow worm 30ci pressure loss

[vision]

boiler is losing pressure and holding at 0.5 bar which doesn't allow the system to run, have been topping up nearly daily have checked all pipework with no visible leaks, if it was leaking it would flood the house, went to top it up opened the inlet valve but seems no water getting into the system???? need to get a shower so any ideas i'm at a loss.

 

[corgiman]

no it probably wouldnot flood the house as you dont need to loose a lot to depressurize a system, quite a bit to fill it though but it aint emptying is it

when the boiler is running does the pressure go up?

 

[vision]

yes pressure increases, have checked all joints and found no leaks or signs of water damage, have tried to boost the system pressure but now no cws entering the system what do you think?

 

[bster]

Is the safety valve dripping etc (the pipe that goes to the outside (or it should!).

 

[vision]

no have checked all that, was hoping it was that so it would be simple but hey ho.

 

[Gasguru]

The earlier blue filling valves are prone to shearing off inside - hence opening the valve has no effect (cheap part to replace)

or

your mains pressure is low. This boiler uses a reduced pressure zone (RPZ) valve to comply with the water regulations. The mains water pressure must be significantly higher than the 1 bar fill pressure in order to top up the boiler. If this is the problem try later on when the street pressure may be higher.

The RPZ valve can also leak under fault conditions (as its supposed to do). Check under the left hand side of the boiler for any dripping from the small brass circular device.


If you can't get the pressure back up - it may be worth pumping up the expansion vessel (only give it 20 pumps with a standard cylcle pump). This may be sufficient to raise the water pressure to get the boiler going for now.

 

[bster]

people have mentioned split heat exchangers that allow the water to run to drain through the condensate. better engage with one of the pros for further info though.

isolation of the boiler will rule out system leaks if no drop overnight this will isolate problem to your boiler.

what pressure is the boiler reaching during operation after topping up to normal pressure?

 

[Gasguru]

The 30ci is standard efficiency so no condensate.