Vaillant Ecotec F.75

[kb76]

Got to go to one of these tomorrow and can't for the life of me remember what it was last time round but took ages I recall. Any pointers gents?
Cheers

 

[thereisawizza]

Pressure switch, espesh if one of the old pink ones! Or can be pump.

 

[Aquazone]

Check if it's losing pressure (usually get F22 if pressure is down) and start repressurising EV and changing water pressure switch as it's usually this. Otherwise you can check the canoe filter behind the pressure switch isn't blocked, then look at pump. I've also had PCB give this but only once.

 

[Billy Bob Bob]

DV could also be leaking or just low pressure think this is the switch if its failed LW.325 Low Water Sensor Vaillant ECOTEC Water Pressure Sensor 0020059717 Original

 

[Last Plumber]

Got to go to one of these tomorrow and can't for the life of me remember what it was last time round but took ages I recall. Any pointers gents?
Cheers

F75
Pressure sensor not detecting rise
Isolate and depressurise the boiler, the readout on panel should zero. if not, then it's the sensor that isn't reading correctly. The pressure sensor reads standing pressure and has to detect a 0.2 min rise in pressure when the pump starts.
If it does zero and read correctly when you re-pressurise the boiler it will be something else. next target is pump and that daft plastic filter in the flow !

 

[kb76]

Thanks all. Will let you know findings when I get over there

 

[Gary80gas]

If you've got the right system pressure. Its the pressure sensor. Only £20 so replace or tap out crap.

 

[zeebeedee]

F75 is several issues.

1. Blocked or faulty low pressure sensor.
2. Failed or failing pump. With the boiler in idle bring up the digital pressure display. - on the old type. Top right button twice on the new ones. Give the boiler a demand. You should get a 0.2 bar rise.
3. Which links into number 2. The old rubber hose connections are full of crap. Give them a squeez if they are solid replace. This causes the pump to work to hard and burn out. Personally I'd upgrade them to the new copper ones when you renew the pump.

 

[gas2016]

A very common fault on the vaillants even on the new ones

 

[London Gas]

F75 is several issues.

1. Blocked or faulty low pressure sensor.
2. Failed or failing pump. With the boiler in idle bring up the digital pressure display. - on the old type. Top right button twice on the new ones. Give the boiler a demand. You should get a 0.2 bar rise.
3. Which links into number 2. The old rubber hose connections are full of crap. Give them a squeez if they are solid replace. This causes the pump to work to hard and burn out. Personally I'd upgrade them to the new copper ones when you renew the pump.

Also can be blockages in the plate caused by those lovely hoses :dead: