Inhibited CH system but can't repressurise

[Phil Robinson]

Hi folks,

Refreshed the inhibiter in my pressurised CH system today. On repressurising I couldn't get the system off the zero bar mark and found it was discharging straight through the pressure relief valve. I took the whole repressurisation process very steadily, stopping and venting and watching the pressure very closely so I'm as sure as I can be that I didn't over-pressurise.

All I can think is that the previous 7 days I was running cleaner in the system as there seemed to be a fair amount of magna in the filter. Could the cleaner have played a part?

Many thanks,
Phil

 

[cross thread]

Gauge possible blocked . Give it a tap

 

[Madrab]

If it's filling and the gauge isn't showing any pressure are both valves to the boiler open? If not, then as suggested, the gauge tube might be blocked.

 

[Phil Robinson]

Thanks guys. Just had an expert in, PRV needed replacing.

 

[Madrab]

Wow, that's unusual for a PRV to fail full open where there system then wouldn't hold any pressure at all.

You weren't using the PRV to drain the system were you