3 port valve fault

[southcoastboile]

Went to a job the other day, hot water would not work independantly of the heating. Old valve was a sunvic one, really old, had a red knob that sits on the top that swiches from hot water to heating/mid position.

It was 4 wire, blue, earth, grey and white.

I fitted a danfoss 3 port still 4 wire, blue, earth grey, white/brown

Since fitting heating and hw are on at the same time, only shuts off on programmer, room stat does not turn heating off now either.

Are these valves not compatible? I didn't have time to test voltages but I know I wired it up the same as the old one.

Hopefully someone will know. Thanks alot

 

[snowhead]

So the heating and hot water would only come on together and you changed the valve for a new one and the heating and hot water only come on together.

http://search.yahoo.com/r/_ylt=A0oG...http://www.cambourne.info/BOILER/MPEDOC_3.PDF

 

[diamondgas]

Sounds like an old 'w'plan priority valve that either switches one way or the other but doesn't have a mid position?

 

[southcoastboile]

So the heating and hot water would only come on together and you changed the valve for a new one and the heating and hot water only come on together.

http://search.yahoo.com/r/_ylt=A0oG7pftohFQ1nIAd9YPxQt.;_ylu=X3oDMTBybjFrcjVnBHNlYwNzcgRwb3MDNARjb2xvA2FjMgR2dGlkAw--/SIG=12190sd8p/EXP=1343361901/**http%3a//www.cambourne.info/BOILER/MPEDOC_3.PDF

The hot water would come on on its own but to get the heating you would also need to put the hot water on. If you put on the htg only but no call for hot water nothing would happen.
Now if you put hw on, both come on, or vise versa

It was a mid position valve, were the red knob was it said htg/mid/hw

 

[diamondgas]

Would like to see a picture 🙂 Have seen old honywell's with an external relay, manual diverters (no wires) but not something with a red knob .. 🙂 OR maybe :lightbulb: was it like a dial center, screwdriver slot in the middle? Or am I thinking of something else! Did this valve have an earth?

 

[southcoastboile]

Sorry got the colours wrong :13:
Drayton valve had same colours but white wire was white and brown rather than just white like on this one. Does that "unishare" thing mean that heating wasn't sposed to come on independantly of hw :whatchutalkingabout

 

[southcoastboile]

its a sunvic sdm1901, anyone know what I can replace it with if that danfoss is not compatile?

 

[GasmanxxxR1]

Drayton 2 channel programmers have a setting for 'gravity'. This would give the effect your seeing - cant have
heating
is there something on the programmer you can change to have 'fully pumped' setting

 

[diamondgas]

Wiring anything like this? [DLMURL]http://www.baked-design.biz/datasheets/SWC2202%20Wiring%20Center%20A4%20V6.pdf[/DLMURL]

Looks like most diverters will swap if so?

 

[southcoastboile]

Wiring anything like this? [DLMURL]http://www.baked-design.biz/datasheets/SWC2202%20Wiring%20Center%20A4%20V6.pdf[/DLMURL]

Looks like most diverters will swap if so?

Not realy sure I didnt realy go into the wiring to much just checked power from room stat to sl and nothing on orange so assumed it was faulty valve. Dont know why the danfoss doesn't work with it. Ill probably have to give sunvic a ring, thanks dg

 

[diamondgas]

Normaly to get heating only the issue lies with the cylinder stat NO (grey) It's hot water satisfied that'll move the valve to heating only and power up the orange to the boiler!