Vokera Compact solid red light

[rayplumber]

right lads will run you through this boiler of my customers bit of a head scratcher
plumber before me changed main ntc sensor not the hw sensor i have been told both need changing at the same time is this correct?

day 1 called out prv running filling loop had been left open to keep the heating on so replaced prv recharged expansion serviced boiler boiler running badly ketteling and bad flow
day 2 stripped the flexi pipes attached to the main heat ex they were blocked so cleaned them out and powerflushed the system
thought that would be it but still no joy red light still comes on after a couple of hours of use doing my head in lol.
i have tested the aps with a multimeter seems ok tested the high limit stat seems okm both ntc sensors change ohms when temp changes

 

[AQUAHEATashford]

Hi, got exactly the same problem, did you work this out? I'm going back tomorrow armed with powerflush/ntc / pump. Read on here it could be a gas valve though! Apparently coil heats up and breaks circuit then drops out.

 

[mcniven]

Could be the pump, also, and this may just be me, I'd replace high limit stat

 

[AQUAHEATashford]

Cheers, it confuses me why it's locking out on the ntc primary sensor and not the high limit stat if its overheating. Thought it the Kohms on the ntc were high it should just modulate or shut down burner, not lock out?

 

[AQUAHEATashford]

P.s how do you get Gs registered symbol on your profile, as I am GS.
cheers

 

[AQUAHEATashford]

Flushed system, changed pump which has helped the fact the water wasn't getting hot which it is now. Changed ntc sensor, cleaned condense trap which was chock a block ! Waited 2hours running and cycling fine, left site and it locked out! an engineer said it could be the Venturi getting blocked so will try that tomorrow. :/ any advise please as I'm never there to test the sensors when it locks out.

 

[mfgs]

when its locking out, can you reset it?

 

[AQUAHEATashford]

Yea you can mfgs, any ideas?

 

[mfgs]

venturi is always a good bet with these boilers. solid red light and resettable can be pretty much anything, you really need to see it lock out.

 

[AQUAHEATashford]

Thanks, it just won't lock out when I'm there ! Last attempt and then there getting a vaillant!

 

[AQUAHEATashford]

Ok, Venturi has solved it! Took the old one out which was an old metal design which was blocked with shale,only a pin hole left. replaced it for a new plastic version which is supposed to stop this problem. Theory to it being intermittent is that it gets blocked and un blocked when the fan runs. I took the fan out to replace it, but by removing the hose on the top fan connection you would see of it was blocked and you could eve poke it with Braddle for short term fix! Happy days

 

[Dotty]

Moving out of the public eye.