Hot water fine but no CH.

[Mark J]

Hi all,

I woke up this morning to no central heating ( it would this morning would it, when we'd had a frost )
I thought to start with it was the stat so off I plod to the merchants buy a new one and fit it; but to no avail.
After checking the system It seems that when I run all the hot water out the boiler and pump start and fill it back up. But when there's enough hot water, the boiler and pump stop.
When i turn the heating stat up to maximum nothing happens.

So from this I assume that the boiler/pump/ 3 way valve is fine.

So where should I go from here?

Thanks for your time,

Mark

 

[weargas]

you can assume the boiler and pump are fine but you really need to look closer at the 3 way valve.

 

[Mark J]

Thanks for replying so quickly.
Can I assume then that the motorised valve may be U/S even though the boiler and pump don't kick in? Does the valve control the pump/ boiler?

Mark.

 

[ollski]

yes it does...the thermostat sends a signal to the 3 port valve which sends it on to both the boiler and pump. If it's a honeywell valve you may get away with a new synchron motor in the valve actuator.

 

[Mark J]

I've been mulling over that and came to the conclusion that was probably at fault.

I've rang the merchants for a replacement price. does £59 sound resonable? Never having changed one I have no idea of price.

Thanks for the fantastic response,

Mark.

 

[ChrisR]

If it is a Honeywell you can buy the head (silvery metal bit) or just the motor which is inside. Motors £15 in Wickes. Same motor fits many other makes too. A bit fiddly to change but not difficult as such.

Meantime, with ch and hw on at the programmer, turn boiler stat DOWN, cylinder stat right UP, latch the lever on the side of the valve to "MAN", and your rads will heat up.

 

[Mark J]

Thanks Chris,

I'll pop down today, and let you know how it goes.

Mark.

 

[weargas]

some honeywell valves (if that's what yours is) don't have removeable heads so be careful before buying a head and for that fact removing the old one............you could get a little wet.

 

[Mark J]

Couldn't buy just a head, so had to buy the whole thing. Took the head off and fitted that; now working a treat.

Thanks for the fantastic response, most sites you post a question on you're lucky to get 1 response a month.

Cheers
Mark