Getting hot water when central heating on

[Basildon_Bond]

Hi There,

I have a Sunvic SD2701 3-port valve and I noticed recently that I am getting piping hot water even when only the central heating is on at the timer. I've seen several similar posts to this - so from what I've read it looks like the problem is with a sticking valve ? Dont think it's been replaced in several years.

Question is - is there anything I can do to override the valve in the meantime, or anything else that will help this situation? The slider on the side of the valve points to 'Normal Use' and the other end says 'Flushing Only'. Will moving the slider have any effect on this problem or am I stuck with how things are until I replace the whole unit ? I'm guessing replacement will mean a whole new valve and actuator since it looks as tho these Sunvic models are no longer available new ?

Any advice much appreciated.

Thanks

 

[CBW]

Could be microswitch could be motor, I had a look and it appears you can get your model, even if from eBay. Moving the slider will do nothing

 

[Basildon_Bond]

Thanks Chris - I think I'd assumed they were all S/H - but I see a few new ones are listed.

Do I need to drain the system to replace, or is it just a case of removing the old white box, replacing with new and wiring up ?

 

[Basildon_Bond]

Also... just a thought before I pull the trigger on a new one.... could it be that the valve itself is stuck ?

 

[CBW]

I haven’t worked on this type of valve, but judging by an internet search, it appears the head (white box) can be replaced. Yes the valve itself could be problematic, but if you remove the existing head and try to turn the spindle by hand/small spanner and it moves freely, then it’s the head.

 

[Basildon_Bond]

Thanks Chris - I'll check that out first.

 

[Basildon_Bond]

Hi Chris - I took the cover off, and can turn the valve spindle by hand - up to 90 degrees and back, How tight should these valve spindles be ? It's definitely not 'stuck' and I dont need a spanner - but it's not completely free if you know what I mean ?

 

[CBW]

If you can turn by hand, then that’s usually a good enough test to satisfy it’s not the valve but indeed the actuator

 

[Basildon_Bond]

Thanks Chris