Dodgy 3 way valve?

[andyt1968]

My boiler trips to reset when the central heating comes on.

The hot water system seems ok, but boiler overheats and goes into an error state when the hot water is hot but there is a demand for heat from the central heating system.

I suspect it's the 3 way valve, am I right to replace this item?

 

[andyt1968]

Added info, It's a Gloworm Micron boiler and Honeywell 3 way valve.

The situation has worsened somewhat. The pump does not run unless the valve is manually held open, then everything is fine. As soon as the lever on the valve is released it returns to it's original position, pump stops and a cold cold house.

Wife and kids complaining. Please help.

 

[ChrisR]

SOunds like faulty 3 port, but that wouldn't normally make the boiler overheat, unless the wirings odd. Try a new head for the valve. (head only is changeable as long as it has a pimple on top)

 

[andyt1968]

Thanks for the quick reply, just taken a look at the 3 port and yes there's a pimple on the top.

Removed the cover, hell of a bang and big flash, now the timer has no power......Ooooops!

Number inside the cover is V4073A1039

Whats broken now?

 

[Softus]

Thanks for the quick reply, just taken a look at the 3 port and yes there's a pimple on the top.

Then you can unscrew the powerhead, but don't remove the cover without electrically isolating and checking for dead.

Removed the cover, hell of a bang and big flash, now the timer has no power......Ooooops!

Oh.

Number inside the cover is V4073A1039

The replacement powerhead part number is 40003916-003.

Whats broken now?

You might have tripped an MCB, or melted a fuse, or, if the nearest fuse was 13A instead of 3A, then you might have irreparably damaged the programmer.

 

[andyt1968]

Thanks for all your help so far.

I have replaced the 3 way diverter valve head.

Unfortunately the nearest fuse was a 13A and it has blown a component on the programmer PCB.

It looks like the failed component is marked as RV1A on the PCB and has the marking Y75110.

As I am competent at PCB work could I just replace this component, the programmer is only a few weeks old and don't really want to shell out on a new one.

Thanks

 

[75pete]

You can but try and as its your trade expect parts should be easily got.

 

[andyt1968]

Damn it, replacing components on the PCB did not fix it!

New programmer installed with a 3A fuse protecting it this time!!

Everything now functioning as it should.
Thanks for all your help

Andy