Worcester Bosch 280RSF Problem

[carlito79uk]

Recently I have been having problems with my Worcester Bosch 280RSF combi boiler.

I have had the Auto Air Vent changed and also the Pressure Release Valve changed as it wasn't releasing air and the PRV was dripping constantly making the pressure in the boiler drop) but i am still getting issues ...................

The pressure for the boiler is a solid 1.2bar pressure when off, i can turn the central heating on and it fires up successfully. All the radiators will start to heat nicely and the pressure will start to build slowly. After a while when the radiators are quite hot the pressure will continue to rise gradually still, the potentiometer ?? (CH control knob on the front) does not seem to operate as even when turning right down to min the CH gas flame does not deactivate at any time and alows the pressure to continue to rise until approx 2.9bar and as i don't wis it to activate the PRV i manually turn the Central Heating off.

Today after i turned it off at 2.9bar the CH stopped (pressure gradually goes down) after a few seconds and the the reset button popped out ............ after pressing the reset button it then popped back out after a second or two a few attempts did not get this to stay. I then ran the hot water tap (obviously no hot water as reset button out) the pressure dropped a little still (possibly not related) but then slightly below 2.5 bar it allowed me to press the reset button and it stayed in.

It then allowed me to use the hot water fine but i left the CH until the pressure gradually went back down.

Any ideas or thoughts would be greatly appreciated ......................... Im considering changing the potentiometer (CH control knob) to see if its this that is the problem. But wondered if anyone had any suggestions.

Many thanks

 

[Bodd]

I would not spend to much money as it is an old boiler. Get it replaced it'll be cheaper inthe long run

Bod

 

[adlplumbing]

remove the filling loop or key can`t rember which this one is and then try it as it might be drawing water into the system but as bodd said don`t spend money on it unless you can`t afford new boiler

 

[anotherbgeng]

2 faults
pressure rising when hot .check the expansion vessel for a pre charge of approx 1 bar...chances are that the precharge has gone and just needs recharging or new pressure vessel fitting.
temperature ,renew the central heating temperature thermistor (these commonly go out of range causing overheating)
(both jobs should be only done by a RGI )