heating but no hot water jaguar 24 ktvj

[zombie]

Hi all,
I have a Jaguar 24 ktvj combi-boiler which has (while I was away) stopped giving hot water. The CH works fine.

I have trawled the various forums looking for an answer to this and most said it was likely to be the Diverter Valve, however, I have dissassembled that and the diaphragm looks fine. I guess that leaves the microswitch or PCB.
My question is, how do I get the micro switch off to check/replace it? It's in an awkward position and I can't see how it's attached (screws, etc?) I'm hesitant to just pull on it...
Also, I have a photo of it and just want to confirm that I'm looking at the right bit.
<a href="http://s386.photobucket.com/albums/oo303/alan_blackstock/?action=view&current=DSCN1609.jpg" target="_blank"><img src="http://i386.photobucket.com/albums/oo303/alan_blackstock/DSCN1609.jpg" border="0" alt="Photobucket"></a>
Is the microswitch the bit circled and marked "2"?

I'm not that often online, so will check from time to time.
Thanks in advance

 

[Agile]

The DHW demand awitch is labelled "2" on one of the photos.

However, it is behind the gas valve which normally needs to be removed to work on it and that should be done by a registered engineer.

All I can suggest you do is to measure the voltage at the PCB end of the cable to the switch.

The chances are that the diverter valve is not moving. It could be jammed in one of several places.

You could remove the hydraulic unit as labelled "1" and push the pin and see if that brings on the boiler as if in DHW demand mode.

Tony

 

[zombie]

OK thanks Tony, I will try that.
When I removed the DV, the push rod on that seemed to move freely, but when I put my finger inside the unit it was attached to, the pin was rock solid. I assumed that it was a fixed contact rather than a sliding pin.
So, that should be a sliding pin then? That would likely be the problem if so.

Cheers

 

[zombie]

I rechecked the push rod, and I found that it did move but that the spring was very stiff for pushing by hand (by finger).
It appears to move fine but not trigger the boiler to start, and so I now suspect the microswitch itself.

 

[Agile]

It is too stiff to push with a finger.

You need a short wooden dowel to push it.

It moves about 8-10 mm.

Tony

 

[zombie]

I had left this for a while since it's not so urgent right now.
I tried bridging the contacts on the PCB and hey-presto, the gas lit. But it only ran the CH.
I then surmised (correctly as it turns out), that the push rod opens a valve to the hot water.
After removing the DV, I pushed the rod with a cork and this time got a moderate heating of the HW.
THEN, I reassembled the DV and tried again while running the hot tap
The problems remain that 1. The micro switch never triggered ignition
and 2. the DV never diverted the HW to heating enough.

Does that imply that I have 2 separate problems?

I said before that the DV diaphragm looks OK, but maybe it needs replacement after all.
Or.... maybe there's some blockage preventing sufficient extention of the valve to both open the valve and trigger the microswitch.

 

[gaspro1981]

complete dv will sort both issues
however check quality of system water to clarify if failure has happened due to sludge or iron oxide deposits

 

[zombie]

Thanks,

will check prices.