Hello all
Recently my early model Domobar Super has started to over fill the boiler and flood onto the bench through the over pressure valve on top of the boiler.
I have a timer set on my machine to come on for an hour and a half in the mornings, so it's not running constantly all day. For several days it will work fine, no leaks or apparent issues. Then one morning there will be water all over the bench. If I drain some water from the boiler it will work fine again.
I have not heard the pump cycling to fill the boiler when the machine is sitting idle, so I'm guessing that water is entering the boiler some other way?
What should I do first to trouble shoot?

Thanks in advance.

If it's plumbed in, the steam boiler refill solenoid could be failing to close, either due to excessive pressure or scale. If it's not plumbed, then maybe the water level sensor is coated with scale, causing it to overfill the boiler. Of course, if the pump isn't running and it's not plumbed in, I have no idea where the water could be coming from.

Thanks. Not a plumbed in machine. I would have assumed that if it was scale on the level sensor then I would hear the pump running to cause it to be over filling? But I don't.

Ok, some clarification to my original post: when I said leaking from the cover pressure valve I actually meant to say 'anti vac valve'.
Machine is HX, tank / not plumbed in.

Pointyendforward wrote:Thanks. Not a plumbed in machine. I would have assumed that if it was scale on the level sensor then I would hear the pump running to cause it to be over filling? But I don't.

I agree with you on this. Your problem is most likely that the boiler-fill valve is leaking internally (Leaking through the valve to the boiler when the valve should be closed).