procombi 85 HE

[snoopy8888]

came across a fault on this boiler today. Ran hot water, after about 2 mins boiler shut off, green led flashes every 0.6 sec. According to the MI (temporary fault e.g APS faults, low water pressure).

Checked water pressure o.k, APS was changed by last gas engineer which didn't fix the fault. If there is a fault with the aps the boiler wouldn't light in the first place. Appreciate help from anyone who have came across this fault before.

 

[AMGasServices]

Check min and max pressure. I always keep a spare pcb and ignition board for the they are common. Also check the condensing

 

[snoopy8888]

Went back to check the boiler, the boiler works fine if in DHW mode only. If in CH/DHW mode, it goes to temporary fault when CH is switched off or turning the hot water tap off. It also goes to fault if the CH temperature control is in the minimum position or turning from max to min when boiler running in CH mode.

I have by-pass the pressure sensor and condensate sensor switches, check APS. I don't want to jump to faulty PCB conclusion, have I missed anything ? any help please ?

 

[snoopy8888]

btw anyone know who makes this boiler ? thanks

 

[lame plumber]

hole in aps pipes?

 

[vern]

btw anyone know who makes this boiler ? thanks

Vokera.....needs a Venturi kit, now plastic not brass due to this very issue

 

[vern]

BTW Green led flash is not a fault it is heating anti cycle indicator, but flash is different depending on what mode the boiler is in etc, get some M.i's

 

[julesverne]

As vern says although had few ch thermistors do the same thing and not go to fault aswell. Voketa compact in disguise

 

[snoopy8888]

Thanks everyone for the help, this is from the MI
Green LED
ON every 0.5-secs Temporary fault, e.g.:

APS fault

low water pressure

The thing I don't understand is, this only happens in CH/DHW mode.

 

[snoopy8888]

so according to the MI, if the temperature rises and exceeds the CH temp setting by 6 °C, the burner will shut down and the boiler will perform a three-minute anti cycle. A new ignition sequence will be enabled when the 3-minute anti-cycle has been performed and the temperature at the primary thermistor has dropped 6 °C below the set-point.

So I looking at a faulty primary thermistor or heating potentiometer ?

 

[vern]

Do the thermistors first pal, cheap and easy enough they cause a good 80% of faults with these, I do these on a service now if boiler is a couple of years old...