Vokera 20/80, no C/H, DHW fine.

[mr2gti]

Right then, quite a wierd one this.

The hot water circuit works spot on with the boiler.

Flick the Central heating on (is bled fine, I can put on the water fill and the flow around the system is fine and strong) and no water flows around the system.

Now, I'm spot on with cars and will happily do anything to my motor or anyones in the family, boilers though, i'm a dubious about (gas side of it, is a total no-no).

So, at the bottom of the pump there is a bolted on manifold that acts, looking at the diagram, as a valve to allow water to flow around the boiler circuit, byassing the C/H system. Are these known to stick open??

If I flick on the C/H with the thermostat on full whack, it all operates fine, water circulates the boiler fine, low light works spot on, initial full light works ok, everything, but the water will not go around the radiators.

I have even locked off all the radiators, flushed the system out (closed the output valve, opened the water fill and forced water around the house the out through the 3bar safety valve - clean water omits).

I'm happy to say that all works fine, but is there an obviuos thing I am doing wrong, or is something stuck open?

2 year old PCB and PUMP too on it, which I did replace myself.

Many thanks for reading. Rick.

 

[gas4you]

If the hot water is working ok then it seems the pump is working ok.

Could be stuck in dhw mode so shuts off quickly.

Does the ch flow under thw boiler get hot at all when on for ch?

 

[Agile]

Look at the diverter valve and see if the pin at the front is staying stuck out when the DHW flow stops.

Tony

 

[mr2gti]

Right, you 2 have just totally confused me, so, i'll take a couple of pictures and show you what it is and isn't doing lol...

OK, using any tap in the house, the hot water system works spot on.

The 3-way unit below the heat exchanger, has a little plunger on it with pops out, dependant on flow. This plunger does NOT move when I flick on the Central heating.

Now the unit below the pump, with the switch connected to that, that too has a plunger with pops IN when you use the Hot water, and it does the same when you strike up the Central heating.

Thats the one below the heat exchanger, with the hot water ON.

Thats the other one, below the pump.

I appreciate the help folks

 

[mr2gti]

DIVERTER VALVE...

If thats the one below the Heat Exchanger, the plunger does come out, pushing the 3 way/stage switch, and when I turn off the hot water, it retracts the plunger. Not all the way in though, but the boiler does settle to a standby state.

Hope that helps. Can take a clearer picture in OFF mode if required.

 

[Agile]

The pin should go most of the way back for CH.

Can you try gently pushing the pin and see if it goes any further back?

If it does then does it restore the CH operation ???

Probably all gunged up with sludge.

Tony

 

[scatmanjohn]

Show us a picture of the diverter pin when its at rest.
It should go all the way back in.

 

[mr2gti]

Thats with the water off, CH off too.

And thats with the water ON full chat.

Now, this has pointed something out to me, there is a definate black line on that plunger, is that where it's normally been returning to I wonder.

Many thanks again.

 

[gasandoilman]

did you try gently pushing pin back

 

[scatmanjohn]

Thats were your fault lies...the pin should go all the way in so you can't see it.

As others have said , try pushing it in and see what happens.

I predict that the fault will not be in the 3 way valve but in the dhw flow valve behind it. (a blockage...venturi...mini expansion vessel)

 

[mr2gti]

It will NOT push back in, even with quite a bit of force.

Strip time I guess???

 

[scatmanjohn]

It will NOT push back in, even with quite a bit of force.

Strip time I guess???

Good guess

You are going to need some parts if you are starting to strip it down.

Whenever i do one i always use:

3 way valve service kit.(you need a special tool to do it...but if you are a mechanic you may have something that will do it)

diverter tail plate.

dhw/flow valve service kit.(diaphragms / o rings /seals etc).

Good luck

 

[mr2gti]

Well, im in debt to you, after a litle pay about with it, water on, off, on, off and helping that pin move in, it's started to work!

It doesn't fully return without a helping hand, and when I do push it in all the way, the switch arm is a goo 4-5 mm away from it, but IT WORKS!!!

May I take this opportunity to thank you greatfully for your help

Rick.

 

[DP]

If you are having to push to reset, then the fault is still there.

Almost certain a new tail piece will be required. Domestic manifold spindle could be gunged up. Front end on the valve (that oiperates the microswitch) should be looked at.

Typical defect result of boiler not serviced as per maker's requirements.

 

[mr2gti]

I'll go with that, not beeen serviced as reegular as it should, bit slack on my part, now paying the price.

Gunged up is a safe bet, once you operate the hot water, the pin pops out, but won't return in under it's own steam.

Might just order a complete 3 way diverter and throw that on, get the rust inhibitor in and away we go