vaillant ecotec 831 plus

[buckley plumb]

been to this today intermittent f75 .it had this just over a year ago and I replaced the orange pressure switch with the new type.checked x2 green wire and got 2.16 volt dc pump not running and 2.24 volt dc with pump on . sods law boiler would not fault when there . called vaillant to see what voltage increase should be when pump runs - they said 0.5 volt dc min of 0.2 volt I was not getting anywhere near that 0.08volt dc yet boiler was working . the property was 3 storey and all rads go hot quick so pump seems ok .tech suggested I replace press sw / flexi pipe on the flow pipe and the pump - going back with new press sw as all the rads are old and I suspect the crap has blocked the press sw .

 

[flesi]

F75....Every engineer struggle to diagnose immediately. Weak pump, poor circulation, blocked pressure sensor & built-in-filter in the hydroblock . In the past I have removed that filter and clean or replace the pressure sensor and seem to sort it out. If the heating system is slugged up the fault will occur again, I would recommend to powerflush the system.

 

[buckley plumb]

F75....Every engineer struggle to diagnose immediately. Weak pump, poor circulation, blocked pressure sensor & built-in-filter in the hydroblock . In the past I have removed that filter and clean or replace the pressure sensor and seem to sort it out. If the heating system is slugged up the fault will occur again, I would recommend to powerflush the system.

how do i get to the filter did it on a vailliant course years ago but cant remember . looking at the parts diagram to get to the filter I will have to remove the rubber connector hose and clips so will need new . do the later ones have the rubber pipe .

 

[ambrosia]

filter is behind pressure sensor on the flow

those pressure sensors are a week point on vaillant, my merchants reckons he sells about 30 a week

other thing to check is the expansion vessel

 

[moogwai]

Them silly rubber pipes on flow and return to heat ex always clog up!!! You can buy a copper kit to replace them....i normally just take them out and clean them along with cleaning pressure switch and the filter....in my opinon there's no need for a filter on the flow....on the return yes as it makes sense!

 

[Nostrum]

My experience of vaillant tech is that I wouldn't trust what they say at all. They tell you what you want to hear to get you off the phone.

 

[ambrosia]

i have no idea why they have a filter on the flow, doesnt make any sense to me, but a few manufactures do it that way

do you know how much those copper flow and return pipes cost

 

[flesi]

The reason for the filter is intended to protect the plate hex , the pipes cost about £70 for two piece of pipes. Vaillant should provided for free as are really bad designed

 

[Nostrum]

That's £70 a side so if you want to replace both flexi's your looking at a stupid amount of money to upgrade a supposedly premium rate boiler.

vaillant have gone down hill a bit over the last few years if you ask me, even though I've got one for my own house, I don't think the extra cost over other manufacturers is money worth spending now.

 

[buckley plumb]

Them silly rubber pipes on flow and return to heat ex always clog up!!! You can buy a copper kit to replace them....i normally just take them out and clean them along with cleaning pressure switch and the filter....in my opinon there's no need for a filter on the flow....on the return yes as it makes sense!

got one rubber pipe not sure if its the flow or rtn one though and clips £10 inc vat cheaper than the copper pipes . to get to the filter I am assuming I must remove the flow pipe where it joins the brass by the press sw and pull the filter out

 

[buckley plumb]

drained the boiler and the digital display still said 2 bar . replaced pressure switch and ok for now - quoted for flush and magnetic filter to be fitted