Baxi WM 70

[gas4you]

Hi all

Got the above boiler that is doing my head in.

Fault is that about once or twice every week it fails, to overheat, but only in the morning. Never done it when I'm present

The pump is running ok and I've opened the auto bypass more, gave the boiler a general service and checked that the stats were in place correctly.

HW and CH heats up perfectly normally when its ok.

I even fitted a spare pcb that I had on the van to eliminate the pump over run having an intermittent fault.

Just heard back from customer that it is still occasionally over heating

Any Baxi experts out there know what I can check next? If I had any hair left I would be pulling it out

 

[namsag]

Dave is it baxi solo wm70/4 pf fan on top of boiler not in the boiler. If so the pump over run is not part of the board but gets it power from the main boiler stat. So could be faulty main stat ,sensitive overheat stat or even gas valve occasionally not closing properly. Personally would go for main stat first

 

[gas4you]

Thanks namsag. It is the WM 70/4, but I don't understand what you mean by ' fan outside the boiler'

Fan is in the casing. I will order a main stat and see how it goes.

 

[namsag]

As in the burner and heatexchanger are in the main boiler casing the fan sits on top and is attached by 3 screws and 2 wing nuts then the outer casing fit over the whole lot.

 

[baxpoti]

Check the stat capillaries are in their clips, keeping them off the side of the combustion box.

 

[gas4you]

As in the burner and heatexchanger are in the main boiler casing the fan sits on top and is attached by 3 screws and 2 wing nuts then the outer casing fit over the whole lot.

Gottcha

 

[gas4you]

Check the stat capillaries are in their clips, keeping them off the side of the combustion box.

Thanks Baxpoti, from vague memory I think the clips may be missing

Will check it out before ordering any parts