hi all, i have a danfoss hsv3 valve on my central heating that is malfunctining... it is fine when ch is on or hw and ch is on but not when hw only should be on...it stays in mid position. other than draining down and fitting a new one or changing the powerhead...are they repairable? i have some skill with a soldering iron so would be happy to give it a go! anyone help me out with some tips?
ta!
steve
These things can occasionally get confused, and need a master reset!
The first thing to try is to remove *all* power to the thing. This means turning off the isolator which provides power to the whole heating/hot water system - *not* just turning off at the programmer.
With all power removed, does it return to the home (hot water only) position? If it *does*, try using it as is for a few days - this may have fixed it.
If it *doesn't* there is either a problem with the spring return mechanism in the actuator, or the mechanical (wet) part of the valve is stuck. Remove the actuator from the valve (2 screws, no need to drain down). Does the actuator *then* return to the home position? If so, the valve is probably stuck. You should be able to turn the spindle with your fingers or - at any rate - with only *light* pressure, using a pair of pliers.
If the valve is stuck, you may be able to free it by rotating the spindle back and forth. If not, it's a new valve - which *does* require a partial drain down - unless you have strategically placed isolator valves.
HTH.
i havenet tryed turning off the power yet...will try tonight...but i have taken the actuator off and the spindle is free...so if tonight with the power off it dont move to hw only...then the spring return is faulty? is it possible to repair?
steve
I'm pretty sure it *will* return when you turn the power off. From what you say, it already moves ok from the CH to the "both" position - so the spring is probably ok.
If the spring has come unhooked, you should be able to re-attach it. If it is actually broken, I'm not sure whether you can buy replacements - I've never tried.
In message , snipped-for-privacy@tiscali.co.uk writes
There are two possibilities Either the valve shaft ha become stiff through water ingress or the return spring has lost some of it's springiness
The former can be resolved by dismantling the valve (prolly a drain down job), the latter will only be reliably resolved by buying a new actuator head.
Going from closed to mid or open position, it is driven under power by the synchron motor, from open to mid or closed, the spring is under more tension and generates momentum. From mid to closed, the spring is no longer strong enough to return the valve to the closed position
for closed, mid and open, read HW, HW/CH and CH - I'm thinking in terms of testing them
In message , Set Square writes
See my post
In message , snipped-for-privacy@tiscali.co.uk writes
There was a thread about just the very same point a week ago, you can google for it
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