Baxi Combi Boiler Pressure Issues

[Nothingdoing]

Hi All,

My first time posting on this site, however am hoping that someone might be able to assist with an issue we are having with our boiler.

For the last 3 weeks we have been having to repressurise the system as it was losing around 1 bar every 8 hours, which was resulting in an E118 code on the boiler.

We've had a couple gas engineers look at the boiler, and all have said it is fine and the issue is a leak in the system.

We have also had 3 plumbers around, none of whom could find a leaking valve, so have indicated it is likely we have an under floor leak happening.

Finally we have had a specialist leak detection service out, who believe that they have found the leak under one of the raditators and so we are going to get a plumber in to pull up that section of flooring and fix.

So far looking like everything is going to be working again.

However...

When the specialist leak detection service came they drained the entire system to pump gas through the system to check for possible leaks, and then afterwards repressurised it.

Since then the system has been sitting on 2.3 bar pressure steadily, and now we have the opposite problem as when the heating is on the pressure rapidly rises to 3 bar, the PRV seems to activate and the boiler shuts off and has an E119 code (high pressure).

I was wondering whether it might be possible that the low pressure issue is actually due to an issue in the system, rather than a leak, and because the system has been drained this has reset everything?

Is this a possibility and if so if we bleed the radiators to bring the pressure back to 1.5 bar would the problem come back?

Really stumped with this and ideally want to prevent having to rip up floor boards if I can.

Thanks for your help

 

[easyflow]

Vent one of the radiators to reduce the pressure back to 1.5 bar.
This should be the end of the problem.
If the pressure has been sitting on 2.3 bar this will rise due to the heating expansion.

 

[Nothingdoing]

Thanks easyflow.

Just to clarify, if we vent the radiator back to 1.5 bar is it likely that the leak issue will happen again or is it more likely that the venting of the entire system has fixed whatever was causing the pressure drop in the first place?

 

[easyflow]

If the leak has been repaired there should be no more pressure loss problems the only other things that will cause pressure loss is the EV or PRV.
Assuming they are ok all should be fine.
Venting air from the system will cause pressure loss.

 

[Nothingdoing]

Thanks again.

Both EV and PRV were checked by an engineer and found to be working fine.

Leak is yet to be fixed, but should be in the next few days.

What I am finding strange however is that since draining the system, the pressure has been holding steady at 2.3 bar when cold, while I would have thought that because of the leak this would have kept falling?

Am I being daft here?

 

[easyflow]

If the pressure is holding steady at 2.3 bar when system is drained think you,ll find the boiler heating valves are closed ???????????

 

[Nothingdoing]

Not too sure?

When the CH is on the heaters are all heating up still, would this happen if the valves were closed?

I believe that the plumber refilled the system once he was done with the leak detection so we would have CH until the guys could come to pull up the floor boards.

 

[easyflow]

You would not have heating if the heating valves were closed so I think the system has just had a bit too much pressure put into it.