Pressure problem on Glow Worm 38 CXI

[petetobin]

For the last couple of mornings, my boiler hasn't fired up in the morning because the pressure has been below 0.6 Bar and I have needed to open the water inlet to increase the pressure above 1 Bar to make the boiler operate. Today, I opened the inlet for less than 30 seconds and closed it once the boiler fired up, I couldn't see the exact pressure as it didn't show on the display. However, as the boiler heated up i realised that the pressure was now flashing at 3.0 Bar even though the inlet tap was definitely switched off. After a while the pressure dropped and it is now about 2.0 Bar when I switch the heating off.

I am not sure where the PRV is but i have noticed a smallish amount of water below the far left of the boiler. I also noted that quite a bit of water was coming out of there as I was topping up the boiler. From reading previous advice, it sounds like an Expansion Chamber issue rather than a leak in the system so I have called out the Boiler Engineer under our warranty. I assume this was the right thing to do? A leak would be a nightmare as we have limestone tiling so I don't even want to think about that for now!

 

[petetobin]

Just found where the PRV outlet is and it looks like it dumped a load of water today when the pressure hit 3 Bar. System is now operating ok, is it safe to keep the system running until the repair man comes on Wednesday?

 

[RaRa]

definitely sounds like the expansion vessel needs re-pressurising or changing.

Should be fine to use till an engineer gets there, as long as the water being discharged is not damaging anything

 

[petetobin]

definitely sounds like the expansion vessel needs re-pressurising or changing.

Should be fine to use till an engineer gets there, as long as the water being discharged is not damaging anything

Thanks for your help. Only thing that's confusing me is that when the PRV kicked in, it dumped a load of water but the heating carried on operating but at a reduced pressure. I thought the PRV was meant to take the pressure down to about 0.5 Bar? The heating is currently off at the thermostat and the reading says 1.3 Bar.

 

[RaRa]

The valve will release water to bring the pressure back to a safe level. The boiler will continue to operate but as the water cools the pressure will go down too. when it is cold it will have dropped to around 0.5 bar and your boiler won't fire