worcester 28cdi NG

[niggle100]

hi i have a worcester 28cdi boiler that ive had a few probs with lately
have replaced divertor valve,expansion tank.plate heat exchanger and pressure gauge.boiler now works fine but...... when c h been on and got to temp pressure gauge has rises form 0.5 bar to nearly 3 bar which causes release valve to empty small amounts of water which when boiler has cooled down means i have to repressure heating system. any help would be appreicated.

 

[mikegas]

sounds like the expansion vessel isnt at the correct pressure or is undersized

 

[niggle100]

the expansion vessel is origanal part pumped upto 1. bar could it be gas to water excanger?

 

[mikegas]

The plate heat exchanger can pass but the pressure would rise whilst the boiler wasnt in use not just when in ch mode

 

[mikegas]

The vessel can still be undersized even if its original part due to amount of rads and height in comparison to vessel. Prob better waitin for the more experienced members to post