Radiators getting warm with only HW on

[andy519005]

I have a Honeywell y system which is about 24 yrs old but generally still works well. I recently replaced a noisy pump- direct replacement- no problem. Whether its coincidence, but since then the V4073a 3 way is giving hot water to the heating side when only HW is selected on programmer.

Can operation of valve be checked without drain down or has it finally given up?

 

[kevplumb]

with system cool /cold select h/w on the programmer feel the pipe at port a if it starts heating the valve is passing

 

[andy519005]

Ive checked this & both outlets of the 3 way get warm. The hot water side may be hotter than the heating side, but not by much

 

[kevplumb]

valve might be stuck

or the motor might be shot

can you hear it motor / move when you alter the cylinder stat

 

[cmother1]

With H/W only selected can you check the override lever on the side of the valve to see if it's under spring pressure as it should be, rather than flopping about. If it is and is still passing it's either a bit of loose rubbish holding it open slightly or the rubber ball/paddle is worn out. If the lever flops about it sounds as if it's stuck in mid position. Most likely a fault in the valve head, but could be the programmer. If you've a multi-meter check it out.

 

[andy519005]

Theres no obvious spring pressure on the lever. I wouldn't say its floppy, but it moves throughout its travel with not much resistance.

 

[heatingman]

sounds like valves jammed in midish position, jammed motor, or the mechanisem is shot and sticking.

 

[cmother1]

You've had a damn good run out of it. I don't know if the head is removable on units that old, but I suspect not. You might still be able to get the motor off if it's gone - they haven't changed in decades and are fairly cheap to replace. I suspect a microswitch is a more likely candidate, though. Not really a repair to attempt "in situ".
If the valve has leaked around the spindle and seized you're best off replacing it.

 

[andy519005]

I think 25yrs is a pretty good service life, so I'll quit thinking and replace the unit. Do you happen to know if a new unit will directly fit the plumbing or have installation dimensions changed over time?

many thanks for your replies

 

[kevplumb]

if its the one with the 4 screws new valve time

 

[gaspro1981]

the new valve should fit like a glove but i cant remember if you will be able to use the existing nuts and olives tho

 

[kevplumb]

the new valve should fit like a glove

na its only got 3 fingers

 

[gassafeman]

If the top (the silver bit) has a raised 'bump' on it, you may get away with a head change. If its the whole lot, get a tower (half the price and identical to the h/well) and no olives to saw off. In my local plumbing shop, they are £22.50 plus the dreaded.

Paul

 

[andy519005]

No there's no bump on the top
Sorry-but why do you say no olives to saw off?

 

[kevplumb]

No there's no bump on the top
Sorry-but why do you say no olives to saw off?

same thread on the "tower " valve

so just a case of one out one in