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morphboy · Joined: 21 Oct 2007 Posts: 15 Location: Behill on sea

Central Heating problem on radiators circuit (OK with hot water):
The central heating does not always come on and I have to manually turn the control on the danfoss HSA3 control which I have recently replaced and that is the reason why I changed it
The programmer is Danfoss CP715.
The HSA3 control does seem to work properly sometimes.
Could poor connections cause this sort of a problem ?
Any suggestions would be appreciated

AlanE · Posted: Thu Apr 17, 2008 8:25 pm Post subject:

Is power reaching the blue and brown wires (from the valve) when there is a demand for heat??

vince knight · Posted: Fri Apr 18, 2008 8:16 pm Post subject:

When heating is selcted from the programmer and the roomstat is turned up to call for heat, check there is 240v on the white at the valve. With the hot water turned OFF there should also be 240v present on the grey.

vince

morphboy · Joined: 21 Oct 2007 Posts: 15 Location: Behill on sea

With CH and stat only on for heating then grey 240v,orange 0v, blue 0v,brown/white 240. Valve goes to mid position and nothing happens.
If I move valve to far side pump comes on and radiators are warming then grey 240v,orange 240v, blue 0v, brown/white 240v.

With HW on only and heating then grey 25v, orange 240v, blue 0v, brown/white 0v.

If HW on and heating then I add CH heating valve goes to mid position then grey 25v, orange 240v, blue 0v, brown/white 240v.

What might be wrong please ?

AlanE · Posted: Sat Apr 19, 2008 7:02 pm Post subject:

Vince I was thinking of two port valve. Just told myself to read post properly!!

Did you change the complete valve or just the actuator?

morphboy · Joined: 21 Oct 2007 Posts: 15 Location: Behill on sea

Just changed the actuator.

vince knight · Posted: Sat Apr 19, 2008 10:05 pm Post subject:

Have you changed the whole head or just the syncron motor?
The reason I ask is the valve does not seem to be moving over far enough to hit the micro switch in the vave head.

Vince

AlanE · Posted: Sun Apr 20, 2008 8:57 am Post subject:

In which case remove the actuator and check that you can manually move the valve spindle EASILY through its full range of movement.

ANY resistance then change it as the actuators do not have the power in reserve to move the valve once they start to get stiff,

morphboy · Joined: 21 Oct 2007 Posts: 15 Location: Behill on sea

Yes your right I tried the actuator off the valve head and it worked ok, I found the mechanical/water diverter tight in places, I moved it backwards and forwards a number of times and everything works ok now , but as you say I will need to get another valve as it will probably tighten up again but it will be ok until I do.
Very many thanks for the advice it is appreciated.
Regards
Morphboy

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

If its moving ok soak it with WD40 and it will be fine for a while.