Sunvic 3 way valve ticking noise..rads on permanently

[markyhud]

Today my diverter valve (Sunvic SD2701) starting making a ticking noise and now the radiators are on permanently even when the stat is turned down and the CH switched to off. I am presuming that the head is broken and have read on the net that the circuitry/microswitches in the head can be prone to failure. My system is very prone to sludge so I have had experience draining down the system and running a cleaner through it (thanks to very helpful people on this forum) so am prepared to sort this myself. I have had problems with it sticking for months now and I have at times had to give it a bit of gentle persuasion with my fist for it to move position. That'll teach me to put things off!! I was intending on draining the system down again soon as I think the sludge is building up again so the question is should I replace the head only or the whole valve? Is sunvic a reliable/decent make? Should I replace with another head and will a head from another manufacturer fit?

 

[SimonG]

You need to check if it's the valve body that's causing the issue or just the head. If it's the body then replace the whole lot with a Honeywell one.

 

[markyhud]

You need to check if it's the valve body that's causing the issue or just the head. If it's the body then replace the whole lot with a Honeywell one.

I've just taken the head off. When the CH is switched on it moves through it's arc to the uppermost position. I am presuming that when the HW is on it should move to the opposite end of its range of motion but it doesn't. It just stops roughly halfway in between and starts making the clicking noise. Should i try and see if the valve moves manually through its full range of motion or is this enough to suspect it's just the head? Also if I do just decide the head needs changing should I drain the system down, take off the valve and make sure no debris/sludge is impeding it's movement. Do all makes fit these three way valves? Also do all valves have the function to move it to a flushing position in order to fully drain the system down?

 

[diamondgas]

If you can move the spindle manually then it's free enough to not have to change the body ... However a modern diverter would save you in the long run IMHO ... Systems prone to sludge sounds dodgy mind!!! I'd be concerned there as there's most likely an underlying issue giving you that grief

 

[markyhud]

If you can move the spindle manually then it's free enough to not have to change the body ... However a modern diverter would save you in the long run IMHO ... Systems prone to sludge sounds dodgy mind!!! I'd be concerned there as there's most likely an underlying issue giving you that grief

Cheers for that. I see you are not too far from me.. I live in Bedlington now but am originally from the town. I'll try and keep this brief. Our system was new 13 years ago when the house was built but has always tended to be noisy with bubbling/kettling type noises and air will always accumulate in the bathroom rad. A mate of mine is a DIY plumber and he recommended draining it down which we did a few years back and it was totally black!! I have always intended on doing this but then running something like Sentinel X400 through to clean everything or take off each rad and hose it through clean. The key word there is "intended" as i never got round to it but for the past few weeks the diverter has been sticking all the time it was on my list of things to do some time within the next few weeks. Seems my hand has been forced a little earlier than i thought though!!!
What do you mean by a modern diverter?

 

[diamondgas]

By modern I mean a newer model valve. I'd bet the SD2701 actuator is about the same price as a new valve? Did you put any inhibitor in when you drained it? Even if you did it sounds like it may need some more? It could well be gas not air that's accumulating, by-the-way? One of the bi-products of corrosion is hydrogen!

 

[diamondgas]

Here's a good link that explains a bit about systems http://www.eskimodesign.co.uk/wp-content/uploads/2011/11/Technical-help-air-or-gas-in-radiators1.pdf

 

[markyhud]

Here's a good link that explains a bit about systems http://www.eskimodesign.co.uk/wp-content/uploads/2011/11/Technical-help-air-or-gas-in-radiators1.pdf

Thanks for that. I think it probably is hydrogen due to corrosion as even when I bleed the radiators the water is still black. I have just been up and the valve will turn manually. There is some resistance and it's pretty awkward to reach but it is turnable by hand. So I'm thinking....new head (which type/make??). Finally put some cleaner in followed by an inhibitor. I have to say that the cleaner and inhibitor were highly recommended but I just didn't get round to sorting it. What a tool!

 

[diamondgas]

:lol: You can get the SD2701 straight swap

 

[markyhud]

:lol: You can get the SD2701 straight swap

Yip that's what i intended but I just thought if I could get something like a Honeywell it might last longer. Anyway I'm just going to replace the head like for like and get another Sunvic. I've just taken the panel off the junction box to see about the wires. I thought if i just took note of the wiring i could just replace like for like. Until i saw the orange wire from the Sunvic was hanging out of the terminal block. it almost looked like it should have been in there but had dislodged. Grrrrrrrrr that wiring looks far too complex!!!!! Might have to admit defeat and get a professional in.

Just searched for the wiring diagram and it seems that the orange is HW only. It seems strage this is the wire that seems like it has come out of the terminal block. Too scared to try and put it in with the yellow wire which is where it seems to have come from.