Vokera RS 20/80 Flowmatic Burner On & Off In DHW Mode

[Gernster]

Good Evening, I have the Above Boiler which was serviced a couple of years ago by my next door neighbour ( Corgi regsitered) He trained me in general maintenece of the machine (I have an electronics & Engineering Degree so am a bit handy) and its been fine, its a big old noisy girl but keeps on chugging!

However, recently she letting me down. When we need hot water its running Hot for a minute, cold for a minute and tonight its got worse, more cold, then luke warm, then cold. Its because the burner is kicking in and out, ie not staying on. Different flow rates through the tap don't seem to make a difference, and by going through the fault guides in the user manual if got it down to the thermostat or the control board.

What do you guys think? could it be a simple fix? ( ive tried bleeding the DHW Heat Exchanger but to no avail!!

Forgot to mention. CH side seems fine, radiators are hot & burner clicks in and out as normal

 

[phildigger]

Hi mate,same boiler and same problem

just curious but does this problem only occur during strong winds cos thats the only time it happens with mine-flue exits on a south facing wall which takes the brunt of the wind and rain.

First had this problem a couple of years ago and called out a service engineer to have a shufti and he removed a small section of pipe from somewhere near the fan/flue (poss air pressure switch?) and pointed out that there was a build up of crud inside and he cleaned it out. Hot water has been ok until yesterday(high winds) so poss same prob again but I do have other problems with my boiler, fan doesn`t run at low speed, slight leak in heat exchanger which is why I`m having it replaced this Friday.


But-please please please bear in mind I obviously ain`t no central heating engineer and I`m only trying to give you a pointer as to what the problem might be and this is based on something I was told 2 yrs ago

 

[ChrisR]

Yes, could be a quick fix, standard stuff for a boiler bloke - problems with hw temp control elements .
But on the last one I went to I fixed about 5 faults, and it still isn't quite right.
They're getting on a bit long in the tooth.

 

[pannierstan]

fan doesn`t run at low speed,

Pump proving switch at bottom left corner stuck.
If you remove the switch you can usually put a bit of silicon grease on the shaft and work it back to life.
Suprised this aint causing intermittant pilot outage.

Stan

 

[John2512_00]

Gernster:

Unfortunatley the problem you describe sounds like a restriction in the fan venturies, which basically means theres dirt in a little pipe which comes off the fann and tells the electronics the fans running.

Its in general not a hard job to fix, but you will need to get a corgi registered person to fix it as it means getting right into the boiler to clean it.

 

[DP]

In a nutshell, boiler has not been serviced for many a moon. Second poster- feel sorry for you, you will most likely be getting a boiler that will unlikely be a match to the Flowmatic.

Above mentioned faults are all related to lack of service. Regularly look at these boilers and others. Build quality is spot on.

 

[Gernster]

Many Thanks for your replies guys - @Pannerstien. We have not had a prob with the pilot light till a couple of weeks ago but it has gone out twice now!!

@ phil digger: Winds are down this morning and the hot water was fine for my shower! could be that too!

Will try the easy stuff but if I dont get a result ill admint defeat and ring the proffessionals.

Cheers!

By the way, anyone know of a trustworthy engineer in the West Yorkshire Area ( Huddersfield?)

 

[Agile]

If a fan is not running at slow speed then the first and easy thing to check is the resistance of the series resistor which is fitted to the underside of the combustion chamber on the right. Has 230 VAC on it !

Its quicker for me to check the voltage on each side of it as I dont need to disconnect it but I would not advise that for a novice!

Tony