vaillant 937 ecotec boiler problem

[jc162]

I am having problems with my vaillant 937 ecotec boiler, approx 7 years old

It will not give any hot water or heating and comes up with error code f.75 which says is the pressure sensor switch or pump.

I can hear a low rumble noise from the pump also clicking as if to work and have changed the pressure sensor switch for a new one, but still not working.

Have googled to see what else it could be. Someone has mentioned about the expansion vessel, I have deflated the vessel which blew out air fast at first then little dribble of water came out. when re pressurising the vessel at 1 bar the boiler will fire up but the temperature will shoot over 100 degrees and the pressure gauge rapidly goes up to 3 bar and shuts boiler down, not all the time though, i can also get it to fire up like this by opening the filler loop to 2 bar, then does same again with temperature and pressure.

Any help appreciated

 

[easyflow]

your initial problem was an easy fix, by deflating the EV you have now caused another problem.
We cant give advice on here when it involves removing a front panel that is part of a room sealed unit.
Get a GS engineer to sort the problem who will no doubt check the whole unit is in proper order.

 

[jc162]

thank you easyflow for your reply, what are your thoughts for the initial problem, what problem would occur when deflating the EV and have recharged it, i am monitoring the pressure in the EV and dropped about 0.2 bar overnight.
I have spoken to a engineer, who is coming to have a look, i am trying to get as much info as possible to aid.

 

[MTCH]

Just tell the rgi what you've already done, should be enough for them to go on without any further input tbh.