Anyone worked on a Worcester Greenstar HE

[JAH HEATING]

Called out quite late last night, didn't have time to spend too much time on it and said I'll return Monday

Basically, the tennant says the boiler is fine of a day, but of a night it keeps going to EA..

I thought it could be a pressure problem at first, but the WP and IP are fine.

Only removed the case to have a nose, basically it fires up and then pretty much cuts out, then fires up and does the same for about 4 times ?

Was thinking probes and possibly a board myself ?

Anyone had this before ?

 

[Blake]

Flame rectification error from memory, check all leads and electrodes etc.

 

[JAH HEATING]

Flame rectification error from memory, check all leads and electrodes etc.

Cheers

 

[Roger Welton]

Changed a few electrodes on these and also a pcb, intermittent ea fault.

 

[JAH HEATING]

Changed a few electrodes on these and also a pcb, intermittent ea fault.

out of interest, did you swap the transformer aswell on the board ?

 

[Danv44444]

I had this before as well ons a newer worcester. It was the electrodes

 

[Roger Welton]

out of interest, did you swap the transformer aswell on the board ?

Don't remember doing so but it was a couple of years ago now.

 

[mfgs]

electrodes are normally the cause of the intermittent EA fault.

 

[arran197]

Electrodes burn out to a very small bit of metal, which you can check by pulling them out the heat ex, but I would also be checking the gas valve adjustment with your FGA.

Press and hold the spanner button. Move the dhw temp control knob until the display says 2.0. It will then flash 0. Change the 0 to a 1 for minimum and a 2 for maximum fan speed using the CH temp control knob. The CO2% should be 9.2% on min and 9.8% on max +/- 0.2%. Then once you have adjusted the valve using the red throttle adjustment under the grey cap on the black tube going to the fan for the max and the screw on the front of the gas valve behind the white cap for the min, turn the CH temp control knob back to 0. The burner should go out. Then press and hold the spanner to put the boiler back in to standby.

On quite a few occasions I have found on min that the valve is out of adjustment and it won't stay lit on low fan speed.

 

[vern]

Using the test menu as above you can get a electrode condition read out from 0 to 3 basically 0 or 1 reading replace electrode assy, only check this reading after FGA checks on high and low co2 as Arran has pointed out above!

in the real world if they ain't been changed for 4 to 5 years for NG OR 3 years for LPG change anyhow!

 

[JAH HEATING]

cheers

 

[JAH HEATING]

changed the electrodes, stayed on till 7 last night fine then went off

fga readings all good, surely the board ?

 

[vern]

changed the electrodes, stayed on till 7 last night fine then went off

fga readings all good, surely the board ?

If all is good with readings and probes, double check condensate trap clean, inc pipework, if not your probably looking at the pcb