vokera 20-80rs flowmatic

kelcal · 29 Jan 2009

hi all

is there anyone who can advise me as to what is wrong with my boiler its is a vokera 20-80rs flowmatic , the problem i have is this every time i switch on hot water tap everything seems fine, as in the pin that comes out to switch the micro switch seems to operate ok the boiler then fires up then about 5-10 secs later you see the pilot go out and boiler shuts down when i relight pilot all seems well when central heating on but as sooon as i turn hot tap on, boiler shuts down after about the 5-10 secs again can anyone hazzard guess as to whats going on

thanks

gary [/i]

twgas · 29 Jan 2009

quite possibly needs a service, when did it last have one

kelcal · 29 Jan 2009

just over 18months ago

twgas · 29 Jan 2009

It could be the pilot isnt as big as it ought to be and is being pulled away from the thermocouple, this should be sorted on a service.

kelcal · 29 Jan 2009

thanks mick for your input what i had failed to tell you was i had replaced the diaphram today on the CH and had inlet and outlet shut i have now adjusted these and hot water seems to be working fine dont know if that was anything to do with it but but hey all seems fine now

thanks

gary.

Sloop · 29 Jan 2009

Sounds like venturis need cleaning.

twgas · 30 Jan 2009

sloopster said:
Sounds like venturis need cleaning.

does that take the pilot out as well as main burner - can't say as I remember having that

kelcal · 30 Jan 2009

yes dont know why though but like i said all is fine now running great for past 24hrs so here`s hopeing it stays that way can only put it down to that as nothing else was touched

gary

DP · 31 Jan 2009

With CH isolating valves closed, a HW demand should not knock out the pilot. If that is the case, stand by for the fault to reoccur.

Which diaphragm was replaced? One to left or right of the gas valve?

kelcal · 31 Jan 2009

small one to the left CH heating inlet and outlet valves closed and reopened after new diaphram fitted , why do you think pilot went out but now stays on once i adjusted these ? if there is another problem then i would like to get fixed any helpfull info would be great . one other problem is the fan is very noisy i have taken off cleaned up and re built there was a lot of crap on and around this it is a lot quieter now but is on all the time is this normal ?
thanks
gary.

DP · 31 Jan 2009

the problem i have is this every time i switch on hot water tap everything seems fine, as in the pin that comes out to switch the micro switch seems to operate ok the boiler then fires up then about 5-10 secs later you see the pilot go out and boiler shuts down

When Flowmatic is in HW mode, isolating valves open or closed make no difference to boiler operation. BUT in CH mode, this valves MUST be open, else pilot outage will occur. This make me think you still have a defect on the boiler (based on what you have written)

When you cleaned the fan, did you replace the fan gasket? Did you check the main heat exchanger for leaks at the unions? Fan slow spin is a requirement of boiler operation during rest. Fan should go to high speed for HW and CH demand.

kelcal · 31 Jan 2009

yes replaced gasket there didnt seem to be any visible leaks did have to replace a few edge clips after taking panels off as they just broke away when taking screws out also gave unit a good clean out fan seems to be working as you described but is still noisier than i thought it should be do you think it maybe on its way out , cleaning it has made a huge difference tho, still a bit worried about why pilot went out tho but it has been ok for past 48 hrs
gary.

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vokera 20-80rs flowmatic

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