Sime boiler pressure control & lack of hot water

[JulieC]

Help! I know nothing about DIY.

I moved into this house in November last year and got the boiler serviced as the previous owners had confirmed that they never had. There are no markings on the boiler - only that it is a Sime - and there are no instructions.

Since the service, the pressure has first dropped to nothing (which managed to revert back up to the norm by turning a tap underneath which sounded like water filling it up) and is now sky rocketting whenever the heating comes on.

Also, before this pressure dropped, hot water was available when the heating was not switched on. Now the heating needs to be on for the hot water to work. The water at this point comes out scaldingly hot.

Any suggestions on why the hot water isn't working without the heating? Or how to regulate the pressure? Or why the water is so hot? (there are two dials on the front of the boiler I assume for the radiator & water temperature, but adjusting them make no difference).

Or should i go check in with British Gas and get a new system?!

 

[JulieC]

Ok, I called a plumber and the lack of hot is caused by the diaphragm overstretching and not working.

Apparently it's not just a case of replacing this but the whole unit at a cost of 200 quid.. is this likely? or can just the diaphragm be replaced?

 

[ollski]

difficult to tell you without any appliance details but the myson divertor valve kits used to fit the sime boilers....still a pretty expensive job though due to the drain down and the awkwardness.