Vokera 20-80 RS Flowmatic - Gas Pressure - Help!

Robbie1980 · 11 Dec 2008

Tony,

Yes replaced the 470 micro farad cap which my dad later tested and was functioning OK.

Hence my question as which component to try next.

Most logical will be diode/brige rectifier

I have the option to purchase a replacement PCB if i have no look with individual components. There aren't many so worth a try first i guess.

DP (Mr Watson)

If it's not trial and error then what would your next rectifying component to change be?
R

Robbie1980 · 17 Dec 2008

Problem was just min HW adjustment screw was resonating sometimes, so mechancail rather than electrical.

Turned in half a turn and been OK. Minor change to low rate HW burner setting, but problem solved

DP · 17 Dec 2008

Removed

DP · 17 Dec 2008

I think you will have to replace the bridge rectifier. Have never known the min pressure adjustment screw to be the culprit. Out of adjustment min screw will cause greater fluctuation of primary water temperature

You should see about 12 volts at the mod coil.

""The voltage to the mod coil varies according to the power required from the boiler""

Contrary to what Tony says, you will not get a variable voltage on the Flowmatic as here it is step modulation

Agile · 17 Dec 2008

I thought it was either full or a ( preset ) low rate with usually about 4-6v on the low rate?

That would still be a varying voltage to me although not fully varying of course.

Tony

Robbie1980 · 18 Dec 2008

i was getting around 6v on low and about 10v as i recall on high

hence i dont think there's anything wrong with the rectification components more mech resonance. Hasn't made the noise since changed the screws natural frequency....

We shall see though! DP has 100% record with me so far so i've not discounted what he said

DP · 18 Dec 2008

Should be 12, even 13 volts. Chances are rectifier is duff so voltage output is down.

Robbie1980 · 4 Sep 2011

Hi All,

Been a while since my last post.

My Vokera Flowmatic has been good to me but I am upgrading to a new more efficient condensing boiler as I am looking to rent my house shortly.

My RS 20/80 FM is working just fine so I would like your opinion as whether worth selling whole or as parts and if so what sort of price it is worth complete and which major parts maybe of some value.

Any advice appreciated. Still installed at the moment and located in Wakefield if anyone is interested. Condition (in my opinion) very good for age.

Few pics here
//www.diynot.com/network/Robbie1980/albums/9843

Cheers,
Rob

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Vokera 20-80 RS Flowmatic - Gas Pressure - Help!

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