honeywell 3 way valve

[ajp26]

i have a potterton boiler but cant get no hot water, the central heating is fine but when i go for just hot water the boiler fires up and then dies down again the pump in the airing cupboard runs and the honeywell valve motor turns but still no hot water . some one has suggested that the valve is faulty is this true ???

 

[ChrisR]

1 x 3 port (T shaped) valve or 2 x 2 port (straight through) ones??

 

[ajp26]

its a 3 way motorised v4073a

thanks for your reply

 

[ajp26]

sorry, it is a t shaped 3 way valve with the motor sat on top

 

[ChrisR]

Then if it's wired correctly the motor shouldn't be operating for HW only. The lever on the end should spring back completely, so you don't feel any slack in it.
Is the heat getting along the pipes from the boiler to the pump, valve, cylinder??

 

[ajp26]

when the heating is on the heating side of the valve gets hot and the heating runs fine but when you put it to hot water only nothing gets hot the pump runs for so long and then stops but the actual motor on top of the valve gets hot and we have to turn it of at the mains to cool it down, also the lever on the side is allways free it does not seem to do anything

 

[ChrisR]

COuld be the valve or the head mechanism is stuck.
Assuming the head case has a pimple on it, you can take the head off, two screws inside.
The flattened shaft which sticks up only moves about 30º, but check it's free to twist. Put a small spanner on it and wiggle to and fro. If it gets easier, it was stuck.
When not on the valve, the head mechanism is kinda slippy but you should note that with no power on, it has sprung back to the start position.

See here for the wiring and I assume a pic showing the pimple...

http://content.honeywell.com/uk/homes/Catalogue/Sundial Plans/3.4 Y Plan.pdf

Nope, it doesn't show the pimple !