Recently had problems with DHW. Had problems in the past and it was the PCB. PCB replaced and DHW works fine, however CH is over pressurising at 3 bar. All radiators are getting hot, boiler thermostat is set at normal range (between 60 & 70 degrees). Boiler pressurises up to and above 3 bar. Boiler cuts out on waiting time and does this constantly every 3-4 mins. Also should the silver slotted screw on the Grundfos pump be rotating in the direction of the arrow marked on the pump? Any suggestions?
Ferroli optima 901 over pressurisation
- Thread starter stuzza
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i am no expert but i think this may be useful,
the over pressuring if it happens only when the boiler starts up is most likey a failing expansion vessel. if there's a filling loop and this had failed then the pressure would build up regardless of whether the boiler's on or off
when you say the boilers cuts out on waiting time do you mean it decides not to work at all and needs resetting or is just coming on and going off, on, off,on off by itself... this would be normal as it will not need to be burning constantly just intermittently to maintain the desired temperature
bear in mind if it's a sealed system especially air expands much more than water when heated so make sure you have bled all the air out. boilers like heating water but air in there can wreak havoc
a better answer to the screw question would be that the one you see is actually a cover which you undo ( anticlockwise) this reveals the pumps spindle which you can see spinning (or not if the things dead)
you can turn this yourself using a screwdriver (with the power off) to see if it's siezed
hope this helps
the over pressuring if it happens only when the boiler starts up is most likey a failing expansion vessel. if there's a filling loop and this had failed then the pressure would build up regardless of whether the boiler's on or off
when you say the boilers cuts out on waiting time do you mean it decides not to work at all and needs resetting or is just coming on and going off, on, off,on off by itself... this would be normal as it will not need to be burning constantly just intermittently to maintain the desired temperature
bear in mind if it's a sealed system especially air expands much more than water when heated so make sure you have bled all the air out. boilers like heating water but air in there can wreak havoc
a better answer to the screw question would be that the one you see is actually a cover which you undo ( anticlockwise) this reveals the pumps spindle which you can see spinning (or not if the things dead)
you can turn this yourself using a screwdriver (with the power off) to see if it's siezed
hope this helps
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