Vaillant ecotec plus 831 advise please

[IndieAce]

Hi all,
I am new to this forum, but I have a problem, and I have seen there are some knowledgeable people on here that maybe able to help.

I have a Vaillant ecotec plus 831 boiler, and I repeatedly get the F75 error code. I have been advised that the problem is the pressure sensor, and if I have the orange one it needs replacing to the new one which is black. I have managed to find out the partnumber for this, and have ordered one,and it has arrived.

The problem I have is I have removed the sensor before to clean and at the time water came gushing out, despite me emptying the boiler or as I thought anyway. Could someone that has experience of changing or removing these advise me on how to stop the water coming out - (ie is this water coming from mains or is it coming from boiler, and if so what is the best way to stop it whilst I swap it over.

Thanks in advance

[heatman]

its connected to central heating and requires draining down fully and maybe a black bag under part your changing to stop water going over boiler.

[plumbgod]

F75 is normally a pump fault (normally blocked pump)

[wnjswozo]

as plumbgod says its a pump fault,how olds the boiler,vaillant have modifed pumps on new 831,s ,they have found on the older models the pump cant cope if the water is dirty,i would cleanse system,replace pump,you cant just change pump head

[Mike Rabbit]

Hi, I was a Vaillant engineer for 21 years. I recently had the same problem on the same model. Through my contacts I was advised to change both the pump (wilo) for Grunfos AND the pressure sensor. It is also worth noting that the rubber pipes burst after a couple of years leading to a VERY expensive repair. They have a conversion kit for it that replaces the rubber pipes with copper ones @ about £50 EACH!!!

[Puddle]

Were's all the Vaillant lovers now !!

imho

[Mike Rabbit]

As regards the water coming out when you remove the sensor. Pump out the expansion vessel before removing the sensor. It wont stop ALL the water but will help big time if the vessel is empty of pressure. Mike.