Woscester 30cdi Greenstar system boiler

[matthew20]

Hi I have a Worcester bosch 30cdi greenstar system boiler when i turn the heating on the flow pipe becomes hot the flame light is on ,flue fan on , pump running after about 5mins the flame led turns off and the pump stops, have tried the reset button

 

[Spanner2k7]

hi, sounds like the boiler is over heating, does your hot water work ok?

 

[matthew20]

It was ok but that has also stopped working

 

[Spanner2k7]

Have you got enough pressure in the boiler should be set about 1 - 1.5 bar

 

[matthew20]

Have got about 1.2 bar

 

[Spanner2k7]

Does the pressure remain constant or do you have to refil it.

 

[matthew20]

it did loose about 0.2bar and while it was working about a week ago it was discharging water through the pressure relief

 

[Spanner2k7]

If you are regulary refiling the system, It could be a faulty pressure relief valve, or a faulty expansion vessel, or the expansion vessel needs recharging.

 

[matthew20]

i only topped it up once and twisted the valve which stopped it discharging

 

[Spanner2k7]

when the boiler fires up does the pressure rise quickly and then shut off?

 

[matthew20]

No pressure remains constant flame led turns off U6 is displayed on led screen

 

[AllyBongo]

sounds like its overheating. check your pump

 

[matthew20]

have checked the pump it is not jammed or sticking but there is power going to it and its not running (only runs for about 5mins when boiler starts)

 

[Spanner2k7]

Could be a motorised valve faulty, not sure what the U6 code means, when hot water is on do you get the same fault code

 

[matthew20]

Very strange it has now started to work again is there sensors on the flow and return pipes ?
Does the display on the from indicate the temp of the flow ?

 

[Spanner2k7]

if it has started to work again, it does sound like a overheat problem, see if the boiler runs with heating and hot water on, make sure the hot water tank is cold. If the boiler continues to works but the radiators are not heating up, it is very possible that the motorised is stuck on hot water, therefore when the demand for heating is on, the boiler will over heat as there is no where for the water to go.

 

[AllyBongo]

CDi's display U when its over 99 degrees. U1 U2 U3 etc. Defo overheating. Not circulating for some reason mate

 

[sunnyp]

@matthew did you get this sorted?