I've got an intermittent problem with a Honeywell V4043 motorised valve. The grey wire into the unit is always live but the orange wire never gets live when the timer unit switches on. Net result is that the heating zone doesn't work unless on manual.
On the basis of the above, I'm assuming that the internal switch has gone rather than there being any problem with the synchro motor.
Does anybody know whether replacement switches can be sourced?
Or is my diagnosis potentially wrong?
I often use Maplin, not the cheapest but handy for distress purchase. Otherwise Ebay.
I've had mucho trouble wit h 3 port valves. nearly always micro swtches. However (touch nearest timber) 2 pot ones seem ok.
The microswitch is a bog standard V, and half decent electronics supplier will have 'em. How ever it may not have failed. The motor might not be opening the valve enough to operate the switch. Take off the cover and see how far the mechanisium operates. IIRC you can see the lever and button for the microswitch easily. It maybe gunge in the wet side of the valve or lack of lubrication that is presenting to much resistance for the motor. Take the motor head off, excercise the wet side valve acutator and clean/lubricate the mechanisium.
Does the valve motor operate when the timer switches on? There could be a motor failure, a thermostat failure or simply a break in the connecting wiring somewhere along the route.
It's a button actuated V3 microswitch they use but a butchered one, you have to shorten the terminals on the standard item and solder leads onto the stubs. The o/p will need to be a half decent solderer with a good iron to avoid melting the plastic body in the process (if that turns out to be the fault).
Yup, had exactly that problem with one of mine last year - it was moving, just not freely enough. Had it apart, cleaned out some crud and lubricated the mechanism, then lubricated the shaft of the wet side and worked that back and fourth a bit.
Well, the grey wire should be permanently live and the blue wire should be permanently neutral.
The brown wire should go live when the thermostat and the timer are calling for heat. This causes the motor to open the valve and let water through. When the valve is fully open, the orange wire goes live and starts the pump and the boiler.
The system is designed this way so that the boiler and pump will *not* run if this is the *only* zone calling for heat and there is nowhere for the water to circulate.
So, (considered in isolation from other zones which may call for heat and then fire up the boiler and pump), your assertion that "the heating zone doesn't work unless on manual" doesn't quite make sense. If this zone is calling for heat, then it will get heat, provided the orange wire from *another* zone is live.
HTH
Soldering I remember but not shortening the terminals when I replaced one a while back but then a chuncky pair of snips sorts that so quickly I may have forgotten. TBH I don't think the switch had failed either just intermittent stickiness in the mechanics which a good clean and relubrication sorted out at a later date.
I couldn't remember exactly myself so whipped the top off one here and the terminals are definitely shortened, it really is a tight fit. As you say, hopefully not necessary.
Sorry to join in so late.
I know you are all talking about a different make but when I changed my gravity fed system to a fully pumped one, I bought Horstman 2 port valves from a well know seller of screws and fixings. I used 2 port valves rather than 3 port valves because the latter seemed to be criticised here.
18 months later, I had very similar problems to the OP: the boiler and pump were not receiving any power from the micro switch. Like the OP, I assumed the switch was broken. I never thought of stripping it to see (I don't know how easy the Horstman ones are to open).Perhaps you were right, perhaps it was not the switch but the mechanism not moving the switch far enough. I can't be sure now, but I think the switch did actuate when the valve was set to manual override.
I bought new valves and I think one may have failed 6 months later!
I'll see how things progress but can face draining it down to fit new valves as I'm sure that different makes of valve are different lengths, so no doubt it won't be as easy as removing the Horstman ones and dropping new ones in their place.
In summary, 2 port valves can fail the same way too.
It's a bit drastic, changing the whole valve, if you just have a problem with the actuator.
The wet part usually outlives the actuator. If it's actually leaking, you need to replace it, but if it's just gone a bit stiff, you can usually free it up by turning the shaft back and forth a few times with pliers.
If the actuator motor or micro-switch fails, you can just replace the faulty component - or the whole actuator if you prefer. Neither requires draining the system.
If you're really intent on replacing the wet bit frequently, stick a full-bore ball valve either side of it so that you can isolate it without draining the system!
Most I've come across are the same physical size. Unfortunately the threads on the compression fittings seem usually to be manufacturer's specials, necessitating replacing the olives and nuts. An olive puller simplifies this in confined spaces, else judicious use of a junior hacksaw.
these:
Or this one which does both and is a little cheaper.
Depends how nackered the pipe is. Now worth trying if the pipe won't take a new olive without difficulty.
Which I've just remembered just does standard threaded fittings (unless you can get the nut off and substitute a standard one from the other end of the pipe.
Sorry, I think you misunderstood. I was only planning on draining and replacing the valves once: to change to a more reliable brand!
When the Horstmann actuators failed, I didn't realise I could get inside them and replace the microswitches but Screwfix sent me complete replacements anyway, so I took the actuators off the valves they sent, and like you said, just swapped the dry halves over.
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