Y plan system locking on.

[MANDATE]

Any chance of a progress report?

 

[matt1e]

Surely there is only 1 microswitch in the valve head, for activating the ch.

The mid position valve has two microswitches. Both have to be switched over for CH to work. See these diagrams

View media item 17313

D_ out of interest what model valve is that diagram? are you sure about the R2/S1 connection, usual way is

View media item 18208
honeywell accuators usually have an extra low impedance resistor between the orange/S2 connection too but left it out on the edit to your diagram as it serves no purpose to the working of the valve

to your problem tony
I very much doubt its a failed resistor they usually fail open
when you say disconnecting the orange

Both switches clicked and sounded OK. I did not have time to electrically test them. However as dissing the orange stopped the problem without the valve moving so I think the valve may not be the problem.

Tony

firstly "clicking" means nowt, testing is much more revealing but disconnecting the orange should have no effect on the movement of the valve anyway

Do we presume this only sticks on after a demand for ch has ended?

If you replace the orange wire immediately after this 'second' of disconnection, does the demand manifest itself again, or remain off?

this was A really good Question but dont think you answered it

what position is the valve in when you are making the disconnection?
if it is the heating position then try turning the roomstat down, if the boiler then turns off then suspect t the programmer ( CH connection has stuck "on")
if that fails grab yourself a multimeter believe me it will be much quicker to diagnose

Matt

 

[D_Hailsham]

D_ out of interest what model valve is that diagram?

I am actually quoting from the Honeywell patent for the mid position valve.

are you sure about the R2/S1 connection, usual way is

View media item 18208

That must be the latest way of connecting up. It achieves the same objectives: R1 reduces the half-wave rectified current to the motor, thus reducing the residual magnetism so the spring is able to close the valve. R2 is now in series with R1 so the back voltage to the orange is less. It also means the trickle current to the motor is less (this also helps reduce the residual magnetism.

Can't see what purpose the resistor between orange and S2 serves.

If that is the latest wiring, I will have to amend my diagrams.

 

[Agile]

Some resistor values would help to explain how it works.

I have not been back yet because I have been busy and she expects me to spend about a couple of hours with her.

Tony

 

[namsag]

Perhaps she has a sleep disorder and just needs you to start talking so she can drop off

 

[heatingman]

wtf, multi-meter, 10mins diagnosis made, fix fault. jesus h christ.