Vaillant VCW 25 No HW - Will Anyone Mend One in Brighton ?

Got an old boiler, CH works, DHW does not work.
Suspect it could be divertor valve- I have manual but no mention of this - I think it called the 'water section'. So probably new valve or diaphragm

Also possible problem with flow switch have adjusted actuator for the two microswitches -this gives me Immediate HW, but then they go out of adjustment shaft moves but not enough. So suspect that I need to change flow switch stuffing box too.

Is this all worth doing ?

Three heating engineer so far and no-one even wants to hear whats wrong just want to sell me a new boiler for £2.5K (more efficient, cheap to run blah, blah-Even if I use half the gas payback is ten years)

I've got to take up and trash my brand new wooden floor cause old boiler runs on 15mm not 22m gas pipe if I fit new boiler !!

Anyone who knows how to mend an old Vaillant combi' in Brighton

I assume this is an open flue boiler.

If the pin doesn't move enough on the water section the diaphragm may be holed/weak. The venturi inside the water section may also be partially blocked. Diaphragms are available as is the stuffing box. The heat exchanger/flue hood should be checked first though - any cracks etc and its for the skip.

As you have found no one wants to fix it due to its potential age (normally printed on the expansion vessel at the back) and lack of some spares.

I look after a few old Vaillant combi's of 25 years old. They first started importing them in 1977!

Isn't this the early open flued version of the Sine 18 ?

If the problem is only the diaphragm unit at the bottom then the diaphragm can be replaced easily when you have removed the five pipes ( Chris Hutt counts them! )

Tony

don`t ask me I`m not Corgi...last went to Btn for the Rockers Reunion .....your`e not a skinhead ,are you

Hello

Thanks for the comments VCW 25 id open flued not sure of the vintage, but will look for a date code on the expansion vessel when I try to mend it,

I've opened the control box and manually tweaked the micro switches and the hot water comes on. So I think I that changing the diverter valve diaphragm (aka 'water section') might do the trick.

Still a bit confused about the flow switch though,both microswitches are working , I adjusted it to get immediate hot water by turning the adjustment nut S10, but then in a few minutes it went out of adjustment and stopped working-some movement but not enough to actuate switch.
I don't really need immediate hot water, but this setting works without the diverter valve working

Do I need to change the seals in the flow switch stuffing box, or is it likely to be a problem with the internal seals r1 and r2 in the thermostatic element ? I heard someone talking about there being problems with the 'wax cylinder' is that part of the flow switch or something. Not sure what is in the cylinder underneath the flow switch (bottom part of figure 68) and above the thermostatic element shown in 69

euk-dar

(more efficient, cheap to run blah, blah-Even if I use half the gas payback is ten years)

Click to expand...

payback?

What , so if you are not getting it for free you are not interested.

There is NO payback