Random loss of CH system pressure Worcester 440CDi

[Scatter]

Hello, all I am experiencing random loss of system pressure. Thus since CH drained and re-pressurised, the system can stay at 1.5 bar for several weeks on regular use, but then suddenly drop to zero when we left on holiday for a week. Prior to drain / refill it was loosing pressure reguarly and in random amounts.

Checked the obvious - no visible leaks anywhere around radiatiors or valves and PRV outlet pipe appears dry. Obvioulsly can't vouch for underfloor pipes but assume they are OK based on the two weeks of flawless operation upon refill.

The boiler is 1.5 months old and the installers were of no particular help, suggesting the problem is with pipes.

Could you suggest a step by step checklist I can go through to isolate the problem?

Thanks a lot in advance :star:

Scatter

 

[Scatter]

Oh OK no-one is volunteering a step by step guide? How about just some ideas before I start ripping out floor boards...:svengo:

 

[plumbdocter72]

lift up floor boards starting at the boiler checking the flow and return pipes as hope you have carpets and not laminate.

 

[ederz]

Get the installers back.

 

[kay-jay]

you say its worked ok since drain down and refill?? could it have been the filling loop not completely isolated?

 

[dontknowitall]

Or contact Worcester directly. Your boiler has a 2 year warranty and they're also interested in keeping their customers happy (and if an issue with the boiler it won't cost you).

 

[Scatter]

you say its worked ok since drain down and refill?? could it have been the filling loop not completely isolated?

Thanks for the idea, but no - the filling loop is isolated. I have to connect a small hose every time I fill up...

What puzzles me is that pressure is mostly lost when the system is cold (or so it seems). Also the problem gradually changes in magnitude from the point of complete drain / refill. So far I have observed two cycles:

Installation end August -> almost no noticeable drops for two weeks -> then gradual drops - > until I had to fill up almost every day

Full drain and two new radiators in (end Sep) -> refill -> 2.5 weeks of stable pressure at 1.5 bar with CH used mornings and evenings -> 10 days holiday (CH set to 15C) -> pressure at "0" upon our return :sick:

Worcester are coming 15/11, but I would prefer to check all avenues before their visit so I know what to say when they come.

 

[approach]

Hi Scatter

I have a conventional Worcester Greenstar 40CDI and experiencing the exact same problem as you. My CH is two years old and has been running faultlessly until i had cause to drain and refill system. Have Worcester resolved the issue for you, if so what was the action taken?