Diverter valve failed - set at manual setting as temporary fix

[mega]

My heating stopped today and the Honeywell 4043A 3 way diverter valve wont autoswtich from HW. The thermostat and boiler send correct signals and system works if I hold the valve switch to manual so HW and CH are running. First question - can I leave this as a temporary fix for a few days then I can swap out the complete valve (25 years old and I cant swap the head only) - I can't see that this would be any worse than having the ball stuck so both run. Second question - any thoughts on whether to change the whole valve or use the Honeywell adapter/sealing plate and replacement head - cost would be same but which is least hassle and least likely to be problematic. Thanks

 

[PlumbBobBob]

hi mega welcome along. as you will have to drain down to change either, you might as well change the whole valve and less likely to be problematic.

 

[mega]

Thanks for the fast reply - my thoughts too I am just hoping the compression fittings will be ok since it's been there for so long. I guess you dont see a problem leaving it with the valve wedged in the manual position for a few days. Thanks

 

[PlumbBobBob]

no problem leaving the lever locked over

 

[plumber0808]

will be fine as a temporary fix, just remember that it will warm your hot water upto the temp set on the boiler as the valve wont switch off.
you can turn the stat down on the boiler.
if you are not confident in doing it maybe get someone in to do it, shouldnt cost that much.

 

[AWheating]

change the whole valve. it may be the valve is broken, stuck, full of gunk etc.... if you can add some cleaner into the system for a few days before draining down and if the system is full of sludge it will help clean some of the sludge out on drain down.

 

[mega]

many thanks for the info and advise - and so fast!! Happy New Year to all of you and best wishes for 2012.

 

[jtsplumbing]

An other tip if you are changeing valve your self when power is off cut the cable to the valve close to the old head strip back wires and join togeather with new valve (wires same colour) useing junction box this saves going into wireing center and disturbing any of the connections inside.

:thinking:

 

[midge]

It may be just the Synchron motor failed? An easy cheap replacement if so.

 

[mega]

One of the wires is neutral/earth and the other has 240V on it when the thermostat switches - but the motor doesn't turn so I guess it must be dead. There is open circuit (no connection) across the two wires. Other than connecting the two wires up to the mains via a mains plug (??) I can't think of another way to confirm this is the cause.
I would be much happier if i could just change the motor for now because I also want to change about 7 TRV's and replace a kitchen tap (with no isolating valves fitted yet!) so I'd rather do all this when the weather is warmer. I'd probably change the whole valve then too as it is 27 years old.

 

[midge]

Even B&Q sell replacement motors, you may be able to get it cheaper elsewhere though. Google time!

 

[jtsplumbing]

Somthing of this age I would replace the complete valve, you just know that the body will fail a few days after you change the motor.

 

[rm1]

just change the syncron motor easy job no need to drain simplesss

 

[mega]

JOB DONE!
I thought that I should follow this up for completeness. i bought a new motor from Screw Fix for £13 (it's a Drayton labelled unit but has the brand Synchron on) and changed it in about 15 mins total and everything works. I will change the whole valve for a new Honeywell unit in the summer when the heatings off, together with a system flush and replacement of some TRVs and the main Grundfos pump too (I forgot to mention it was on level 3 but started to rumble so it's been on 2 now and the noise is much less).
Thanks all for the help, and if anyone finds my thread from a search and is interested, I found this link on YuTube relevant and helpful:
Port valve diagnosis and repair - YouTube
or you could look up "Port valve diagnosis and repair"