Worcester 24 CDI hot water problem

[Euan26]

Hi Guys

I have a problem with my 24CDI I am aware that there have been a number of posts in the past but they dont seem to cover my situation.

When you run the hot eater it runs hot then cold. at which point the boiler (flame) light goes out for about 20 seconds and then relights and hey presto hot water again. The problem can be solved in the short term by turning the water temp down to minimum but this is only a stop gap measure. When the temp is set higher the water seems too hot.

We have already replaced the diverter valve diaphragm so any other ideas would be most welcome.

Cheers Euan

 

[kitch0978]

plate heat exchanger.............

 

[garyo]

Sounds a lot like the problem I've having with my CDi, which kitch has also responded to : //www.diynot.com/forums/viewtopic.php?t=211967

 

[fitz1]

min gas pressure set too high. should be at about 2mbr

 

[Euan26]

Hi
Thanks for the quick replies, the heat exchanger looked clean when it was removed to fit the new diaphragm.

As for the gas pressure this has not been altered since the boiler was fitted any idea what could cause it to change as the problem is only recent and boiler is several years old.

Cheers Euan

 

[clf-gas]

Its nothing to do with the gas pressure.
Change the sensor to the left of the primary heat ex,(C/H thermister).
If that doesn't cure your problem then it is deffinately the PCB.

If your 100% certain the plate ex is clear then this sensor has gone out of range, if the plate ex is partially blocked then the sensor is doing its job, 94' and burner shut down until 84' is sensed then reignition. Symptoms hot water running hot and cold.

Simples Euan