Potterton Suprima 60L keeps turning off with Green Flashing

[jemthebullfrog]

I've got a Suprema 60L with an updated PCB in the Siemens grey plastic housing. I've realised that the boiler is turning itself off after running for a few minutes. It displays a green flashing light after I hear the fan turn off, then after a minute or so a relay clicks and the light turns amber. It then proceeds to light again and run for a few minutes, repeating the process with the green light flashing.

I have put a meter across the SWL and N, and it is getting 240v with the thermostat turned up, and 0v with the thermostat turned down. I looked at the PCB to see if there were any dry joints as per the older boards but couldn't see any. Took the precaution of re-flowing all the major joints anyway. This hasn't resolved the error.

Am I barking up the wrong tree with the PCB or should I be looking at the overheat sensor or the thermistor?

Thanks

 

[petit_pablo]

Check the pumps running and there is water in the system.

 

[jemthebullfrog]

Yes the pump is running and there is water in the system.

 

[jackecole]

PCBs are often faulty on these - also check the fan's running at speed and the APS

 

[jemthebullfrog]

PCBs are often faulty on these - also check the fan's running at speed and the APS

That didn't really answer my question. I am aware of the common fault with the old PCBs, but as you will see from my original post, the boiler has had an upgrade kit fitted.

What is an APS?

Thanks

 

[jackecole]

sorry

APS- air pressure switch

have you tested the pump? when you say it's running it doesn't mean it is working correctly

Also the fan - have you tested that?

Byt fan and aps are gas related and you need a gas safe enginerr to test them

 

[Beerlover]

I think petit_pablo is pointing you in the right direction the pump may be running, but is it pumping?

 

[jemthebullfrog]

I think petit_pablo is pointing you in the right direction the pump may be running, but is it pumping?

I believe that it is because the radiator get hot and I've got hot water. It's just the cutting out of the boiler doesn't seem right.

 

[petit_pablo]

Whats the boiler stat set at?

Green flashing light indicates that the boiler has a demand for heat but is up to temperature.

Do you have any way of testing how hot the pipes are getting?

 

[jackecole]

is the pump rotor free? you need to check the resistance of thw windings and also see if the impeller is ok.

 

[jemthebullfrog]

Whats the boiler stat set at?

Green flashing light indicates that the boiler has a demand for heat but is up to temperature.

Do you have any way of testing how hot the pipes are getting?

The boiler stat is at MAX.

I can't find my thermometer to plug into my multimeter. The pipes are too hot to touch for more than a second.

 

[jackecole]

try turning the boiler stat down a bit and see what happens - if set too high or to max they sometimes cause the boiler to overheat

 

[petit_pablo]

It does sound as though the system is suffering from poor circulation.

Are there any airbleeds in and around the hot water tank?

Has the header tank got water in it?

If you drain a little (a buckets worth) of water from the system, does the header tank refill?

jackecole - if the boiler was over heating it would be locking out. (red flashing light)

 

[Andygasman2010]

try turning the boiler stat down a bit and see what happens - if set too high or to max they sometimes cause the boiler to overheat

The boiler should be able to work fine with the stat on maximum, it's designed to. If it doesn't then the system is at fault.

This is either a pump fault or a blockage, as PP suggested.

 

[jackecole]

sometimes instead of locking out some boilers just cycle on and off the boiler stat

if air was in the system/circulation problem then that would also cause overheat and lock out if that was the case