Potterton Statesman Flowsure - Overheat

[Igorian]

Hi guys, I think it's bad news, but maybe you can give me an idea of the work involved.

I have a Potterton Statesman Flowsure oil fired boiler. My daughter has just tried to run a bath, but no hot water.

The boiler is showing an overheat warning and is venting air through the pressure release valve. Temp guage is max. Pressure guage dropping slowly.

I checked for pressure in the expansion vessel and although there is, it is also spraying small quantities of water, which I guess is not good.

Currently powered off and waiting further suggestions/questions

Regards
Ian

 

[kevplumb]

sounds like the expansion vessel has gone ian

 

[Igorian]

I kinda thought u were gonna say that.

After it cooled a little, I refilled it and it appears to be running. Not sure if this is to be expected? DHW pressure seems a little low

Is replacing the expansion vessel strictly CORGIland, or can it be DIY? It appears to be reasonably accessible.

 

[kevplumb]

no reason why you cant diy is the system pressure rising a lot ?

ie towards 3
you might have to clean / replace the prv as well they have a habit of leaking once opened

 

[Igorian]

No, pressure was at 1 and then dropped to zero during overheat. After refilling, I didn't have to bleed the rads, so not sure where all the air came from.

 

[kevplumb]

if the ex vessel was full of water the pressure should be rising fast when burning

you didnt by any chance press a brass thing top left

 

[Igorian]

the re 2 pressure devices, one with a black nurled screw like device, which was venting gas, and the other, marked with a 3, which wasn't venting anything.

Pressure is now back at 1 after refill. It appears as though the boiler was empty, as it took ages for it to bleed. The rads were full. Wierd.

 

[kevplumb]

the one with the knurled screw is the auto air vent
the one merked 3 is the pressure relief valve
the expension vessel is on the front above the burner

remind me not to break my pooter again

 

[Igorian]

The air vent is the one wot woz ventin' then.