Realy annoying intermittent central heating problem.

[arbitrary]

I'm having what sounds like exactly the same problem with the same actuator, a Sunvic SDM 1901 (installed in May 2004).

HW works on demand every time.

If CH is demanded while HW is being demanded valve goes to mid position and everything works.

However, once HW is no longer being demanded CH does not always kick in. I may need to raise and lower the wall thermostat several times or toggle the CH on and off at the controller before the CH will kick in. I've checked the voltages at the terminal block in the airing cupboard and controller and wall thermostat appear to be doing their thing; the white and grey wires go live but the valve actuator makes no attempt to move. When the actuator is removed I can turn the valve "D" shaft easily with my fingertips so I think the actuator needs replacing.

Anyone know what the current replacement actuator is? The SDM 1901 is no longer listed on Sunvic website. http://www.sunvic.co.uk/ps.html

 

[arbitrary]

Rung Sunvic; they say the valve is too new (2.5 years old in my case) to sell just the actuator. But obviously old enough to be 18 months out of warranty!

Any recomendations on a reliable brand of 3 port valve? The original one (blue case mounted on the side of the T, not the top, can't remember the name) lasted 15 years before it started to dribble. 2.5 years is underwhelming by my standards.

 

[ESL]

I am suffering the same problem. I have just replaced an SDM 1901 actuator for a replacement - and it already has the same problem.

Can anyone advise me of a replacement 3 valve actuator. Or failing that a reliable alternative make that will just drop into this system.

Many Thanks

 

[cider]

As a tip wire the new 3 port valve head into the controlls before you drain down and change the lot.
Then run the system as normal to see if it all runs ok
I always do that and can save alot of wasted time!

 

[baxpoti]

Tagging on to a 3 year old thread won't get you very far!

Start a new thread