3 port valve sticking open

[mutley racers]

Ok so the 3 pot valve must be naffed. Stays in mid position when calling for hot water. But boiler won't fire when calling for just heating. I don't get 240v in wiring centre on stat. But if I put motorised valve in manual I get 240v

 

[lame plumber]

is the programmer set up for gravity hw and pumped ch, may need to change some dip switch settings, had just this today, reset programmer all working as a midposition should with fully pumped system.

 

[mutley racers]

she said that it used to work normally. i couldn't even get the thermostat to click on and off. Thought it might have been because it was up to temp, but then i got temp gauge out and it wasn't up to temp. If it was for gravity only, would it always be running in mid position then

 

[mutley racers]

when you say dip switch, do you just mean wires in programmer to 3 port valve

 

[diamondgas]

Hot water only - - Spring return to rest.
Hot & Heating -- White 240v - R/stat moves diverter to mid.
Heating only - White 240v, grey 240v... r/stat to mid, cyl stat satisfied (NO) or H/W off from programmer moves valve to C/H only.

If the valve is stuck in mid position on water only then it's buggered!!

 

[mutley racers]

hey diamond, I have the honeywell wiring guide, and have seen all those stages, but what confused me is why the boiler and r/s calling for heat but not 240v on c/heat calling.

would I not get 240v if the diverter was knackered?

Oh, and I bled all air out of that cylinder and all is working fine. So no problem with the pump. But I shall remember this for next time!

 

[RoryD]

I have had similar in the past. It ended up being the cylinder stat!! yep, the cylinder stat

 

[diamondgas]

hey diamond, r/s calling for heat but not 240v on c/heat calling.

would I not get 240v if the diverter was knackered?

The room stat supplies the white with the power to move the valve to mid. If you're calling for heating and there's no power to the white then you look 'upstream'! That'd be the r/stat.. If the hot water is satisfied then the cylinder stat supplies power to move the valve to heating only unless the programmer is on heating only. In that case the programmer supplies the grey (hot water satisfied) to motor the valve! The white only ever gets power from the room stat!

Hope that helps

 

[mutley racers]

Great. That is a help. But can I say that the valve is knackered as it is going down the heating circuit when only calling for hot water?

I remember when we moved into our house there was a set up in the programmer that didn't have a wire in hot water off. So hot water was always on. Or the reverse?

 

[mutley racers]

Cylinder stat, interesting

 

[diamondgas]

Well if the valve's passing then it's knackered...! No 'hot water off' supply from the programmer just means you can't have it programmed for heating only! You have got to have the heating programed times fall within the hot water timing! *shrug*

 

[mutley racers]

Thanks feller. These danfoss valves, do I just change the motor or the whole valve?

 

[diamondgas]

whole valve ,,,,,,,,,,, specially as its passing

 

[Plum Bob 66]

Out with the bungs mutt..

 

[mutley racers]

Nooooo not the whole valve. Plenty of dirty water. I have never used bungs for a valve before. I actually have not got any. You have to order them from merchant. Never just pick up.

Thanks for all advice diamond. Appreciate it.

 

[diamondgas]

I'd use bungs only if i can guarantee catching any water. I rarely use bungs if the heating flow drops straight under the floor from the valve! Chance of a wet ceiling in my experience Otherwise bung it! Much less hassle and quicker IMHO

 

[mutley racers]

It is how you say, straight from floor. But I have a wet vac at side. So maybe ok