System not firing on automatic

[HP]

I'm having problems getting my CH to fire up. The system uses a Danfoss motorised paddle valve and will only fire up the CH when switched to manual. It will fire both CH and HW together or HW alone but not CH alone when in the automatic position. I can't keep it on manual since every time the HW kicks in it resets to automatic.

Since the valve is opening on maual is the actuator knackered or is it something else

 

[MANDATE]

I've just had experience of a similar problem with a myson valve. I took the actuator off and I could see it move into the CH position but there was no voltage on the orange wire. This indicated one of the microswitches was faulty. Replacement actuator cured the problem.

 

[HP]

Having read 'millions' of threads from people with similar problems (including MANDATE's reply -thanks) I have decided that my actuator is the problem. I currently have a Danfoss HSA3 which for ease of replacement I want to replace with same.
I am a competent albeit limited DIYer and whilst the wiring to/from the WB12 unit are straight forward screw connections the wiring in the HSA3 unit are soldered. Does anyone know if the HSA3 comes with a soldered 'trailing' wire for connection to the WB12 or do I need to solder the existing wiring to the new HSA3.

Thanks

 

[ChrisR]

YOu get a long flex with the new head, with 5 (I think!) cores to the flex a,d a pre-stripped end. Going in to the connection box and carefully extricating one wire at a time where others will be you pull out the one you want and the others come too and you get in a right mess.

It's often easier to chop through the cablenear the old head, and prepare the ends. The colours will match the colours on the new head's cable. Use a suitable junction box and just join like with like. Electrical shops will sell you a translucent box designed to take terminal connector block, and clamp your cable, for about £1.
I can sell you an HSA3 for £25.

 

[HP]

ChrisR - cheers I was hoping that would be tne case. I have disconnected and reconnected the existing actuator so don't forsee a problem with a new one.
How can I get in touch with you re: your offer

 

[kevplumb]

click on name in forum