Worcester 28 cdi rsf combi

[Loki]

Hi guys

on the way home tonight got a call about banging noises from the boiler decided to pop in as it was en route and found that the boiler fires then what sounded like air rushing/lumping through it about ten seconds after when the hot water tap was opened. The boiler then cuts out and will not fire again till the tap is turned off then on again but on the second open ending all is fine and the water will stay on to say fill a bath. The boiler is fine on central heating, not got much experience with combis so not sure if this could be the p/hex or something else.

tia
rob

 

[c.gas]

Not had much experience with these boilers myself but can't see if being the p/hex as if it was blocked your hot water would be warm or cold, if it was split inside then boiler would lose pressure.

 

[c.gas]

I would be looking at possible issues with the divertor valve

 

[REDSAW]

thst not water bounce?

 

[Loki]

I will have a look at the divertor valve when i re visit

 

[Millsy 82]

I would say a circulation issue around hot water side. Possible gunked up plate or diverter. Failing that dodgy thermistor.

Try popping the microswitch off the d/v and press it in and see if boiler runs ok then. Speak to Worcester about the readings for the thermistor, if those are fine start stripping the plate out (pick up an o ring pack for the boiler as they don't cost a fortune and will save a load of hassle)