Following an unplanned cold shower this morning I would be appreciative of an explanation of the workings of the single port version.
Manually forcing the valve open allows water into the cistern coil but does not start the pump or boiler. Pump and boiler run OK from the central heating command.
ISTR having to replace the valve coil before but cannot remember the symptoms.
AFAIAA this is an S plan set up.
regards
Tim Lamb wibbled on Thursday 05 November 2009 08:34
So there's no microswitch on the valve? Often there is, so that the valve must be proven operated before the system will pump/fire. This does have the advantage that if the coil's gone, then manual operation is possible.
Sounds like the motor.
If it's the 4043H valve, then it's either
1- the microswitch inside the head body has gone open circuit, or the associated wiring to that has failed. The motor drives the valve open and should strike that.2 - the motor has died.
However, if you are manually forcing the valve with the lever, and it's not going, I'd go with the first one. You can check by taking off the top of the body of the head, and with the valve forced open try operating the microswitch (with a bit of wood - mains voltages beware).
That head is available seperately for about £50-£60. I keep the old ones for Frankenstein replacement work of bits. I've also stuck coloured neon lights across both HW & CH motors circuit for both valves, so I can readily see what's going wrong.
Sorry, I read it wrong.
The valve is not being driven If forced, the boiler does not switch on
Not the valve head. Got to be somewhere else? Confuzzled.
If the valve is getting mains voltage across its brown and blue wires from the programmer and cylinder thermostat, but not opening, then it's a valve problem; otherwise the problem is with the programmer or cylinder stat.
If it's a valve problem then, when you manually open the valve, does it feel abnormally still (compared to the central heating valve)? If it's stiff then the hydronic part of the valve is probably knackered and you'll need a new valve. Otherwise it may be the head, possibly just the motor.
If it's a Honeywell with a metal cover then if you take the cover off the head you can see how the gear train operates when you move the override lever manually: it opens the valve hydronically, but there's a sort of folded tag on the brass gear which has to push the button on a microswitch to make it work electrically (i.e. to tell the boiler to fire up). You can prod the microswitch button using e.g. an insulated screwdriver to test this.
Motors are about £10 and are easy to fit - remove one screw, twist the motor and pull it out, swap wires over and refit new motor.
If by 'coil' you mean motor sounds as if you've done this before.
Mains power off while doing it, of course!
In message , Tim Lamb writes
OK Chaps.
I suppose my question should have been *does operating the valve manually also operate the microswitch*?
If it does then the problem is the switch or the wiring. If not then the problem could include the tank stat.
This is the sheet steel covered valve and yes the *motor* has been changed before.
Prodding anything with a screwdriver involves disassembling the entire airing cupboard whereas the tank stat is easily accessible:-(
Thanks
Can you get to the wiring centre?
In article , Tim Lamb writes
No, on a Honeywell 2 port valve, manual operation of the valve does not operate the microswitch.
When the valve is off, the manual lever should spring to the off position and operating the valve manually should have some spring opposition.
If the valve motor is operating the valve then the manual lever will be moveable without opposition.
If no opposition, it points to the microswitch which can be replaced on its own. From memory it's a V3 type button microswitch but with the connection tabs cut very short and soldered to. Usual suspects or
In message , fred writes
Ah!
Definitely opposition.
Sounds like the motor.
Job for tomorrow.
The boss is away so I am self catering or rather microwaving prepared meals.
Thanks again.
Yes.
From what Fred has said, the motor looks to be suspect.
I'll unload and remove the shelves this evening.
I am hurrying to finish erecting a barn roof before the weather changes again.
regards
>In article , Tim Lamb writes
Have you eliminated the cylinder stat? In case it helps, the coil resistance of a good motor will be about 2.5kohms, you should be able to check that from the stat end if is more accessible, one term will be live (but turned off), the other should be connected to the valve motor with the other end of the motor going to neutral.
In message , fred writes
OK. I'll look tonight.
regards
No.
Why do plumbers install things so you can't get at them to service them?
One other thing to think about is that the motor might be working fine but not quite enough grunt to fully open the valve and/or operate the microswitch. One of mine plays up like that occasionally. When closed and then powered up you may be able to hear a quiet whirring as it motors open. If it should be on/open and has been on for a minute or so on turning it off you should hear it whirring closed.
It does on mine.
No, it does not. It ONLY opens the water part of the valve.
When you manually open these valves, when it's not opened electrically, they should feel fairly 'stiff', as you manually drive the gear mechanism. It should take a few seconds of sustained finger pressure to move the lever through it's operating range.
If the valve is already open electrically, the manual lever will flap about loosely.
Only electrical opening will activate the microswitch ( or a screwdriver! )
The looseness of the lever is an important diagnostic tool!
If it's stiff, but manually moveable, the valve is not seized, but it not being operated electrically. Either there's no power to it, or the motor is kaput. Use a meter to discover which.
If it's stiff, and not maually moveable, the wet part of the valve is probably seized.
If it's flapping loosely, the valve is activated, and the microswitch
*should* have operated. Use a meter to fault-find further.
I have to confess. The plumber installed his mares nest of pipes in an open space. The builders chippies then built cupboards. The householder then put in lift out shelving as directed by higher authority. The result is that the hot water valve is trapped by the shelving and the supposedly automatic air bleed is buried in a flock of towels or gentlemen's underwear.
No whirring.
Big mistake tonight. I have been microwaving meals directly from the freezer. Today's moussaka turns out to be 45 mins. oven only.
regards
>
While waiting for the moussaka to cool, zillions of towels not seen for the last decade, shelving and valve cover removed. Now who in their right mind installs a valve such that the cover release screw is 30mm away from the cistern lagging?
Operating the micro switch starts the pump and fires up the boiler. Access to the motor connections is not easy but I can get to the control box and will check that the motor is energised. Trip to the nearest plumbing outlet tomorrow.
Thanks to all
>
No, I don't think it does (at least, it didn't on the one I repaired last week).
You are correct.
As others have said, the tab does not reach the microswitch button when the valve is operated manually.
I found 234V across the motor winding last night so I am confident that a replacement will sort out my problem.
regards
In message , Tim Lamb writes
Job done!
Once again uk.d-i-y triumphs over adversity and the vicissitudes of plumbing systems.
Synchron motor, 15ukp but probably not the cheapest source.
regards and thanks to all
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