No hot water - three-way valve faulty?

[Rhuddleston]

Central heating works but when I move control to hot water as well the ch stops and the water doesn't work either. The water doesn't work on its own.
The Honeywell V4073A is probably 10 years old or more, I don't think it's ever had a new head.
So is it probably the head that's shot? The hot water played up last week but did eventually work. I admit to rarely having the hot water on, especially in the summer, and I never remember to periodically run it to stop anything seizing.
Thanks is advance.

 

[leethegasman]

Looks like you have answered your own question something is not working as it should.

 

[Riley]

Pop head off and see if spindle moves freely. Only 45° mind don't force it. If it's not very easy to turn then you may need the whole valve

 

[spanner]

Have you checked the cylinder thermostat is set to 60-65 degree. And I'm not sure which is the rest position obviously C/H

 

[Maryplumb]

No the V4073A mid position valve is at rest with the hot water port open

 

[Stanios]

Does the boiler fire up when you create dhw demand? You can either use programmer or run down your hot water to test but turn central heating off. If it fires go to cylinder start feeling the pipe connectingthe three way valve and the cylinder, if that stays cold feel the other two pipes around the three port and if those are hot your valve is stuck probably due to crap inside the body.
If your boiler doesnt fire at all your cylinder stat or programmer is at fault.

 

[Rhuddleston]

What I can't understand is why the boiler stops when I turn the hot water at the same time as the heating. I could understand if only the water didn't work. The valve seems to turn fairly freely without the head. Hot water tank thermostat's at 65deg.
I assume this indicates the programmer is faulty? I also assume there's no realistic way of testing it, eg by directly wiring water terminals?

 

[spanner]

Have you checked the cylinder thermostat is set to 60-65 degree. And I'm not sure which is the rest position obviously C/H

Oop sorry meant of to hot water...

 

[spanner]

Oop sorry my phone predict. Meant rests at Central heating and hot water port open when heating satisfied..

 

[Stanios]

Sounds like the programmer has had it then if you are handy with wires you can check just turn all power off in the house pop your programmer off (two small screws at the bottom) you will see a backlate on your wall with live neutral earth hw off blank hw on ch on so

So if you remove the hw off wire (1) then get a small bit of wire put one end into live so you'l have 2 cables in live now the other end of your small wire goes to hw on (3) again you'l have two cables in there now. Pop power back on boiler should fire and start heating your cylinder

Alternatively get a new programmer (try same manufacturer and model) carefully unpack it, isolate power pop off old programmer and pop new one on the old backplate, get power back on and test your hot water. You can always return the programmer if its not working still.