possible T valve problems???

[BigHammo]

I have problems with my CH system. it looks like the motorised valve isnt working correctly. You can manually set it to be CH and HW, CH, HW. But it doesnt seem to do this when controlled bu the controller.

I have changed the motor in the motorised valve but that doesnt seem to have made a difference.

The removed motor works when you connect to 240V, though. I assume that is is something to do with the electronics in the T valve, or the valve isn't operating correctly.

Can someone tell me if the have experenced some thing similar, and I have to replace the electronics of the T valve or the whole thing.

thanks,

C

 

[PrenticeBoyofDerry]

Have you got power going to the motor head?

 

[BigHammo]

Yes there's 240v on the motorised valve

 

[stem]

How is the fault manifest? For example, does nothing work? Does only the hot water work? Does the heating come on, but only when the hot water is also being heated?

 

[BigHammo]

It manifests as follows:

- The central timer comes on.

- The Water only gets hot.

- All the CH rads all stay cold.

- I go and turn the manual valve on the T valve the CH comes on.

- and it is fine until the CH timer goes off.

And the same happens again. If i leave it the HW thermostat on Hot water tank turns off. The pump and boiler goes off.

I can get to come on again by moving the valve or by turining the manual valve.

 

[D_Hailsham]

When you say "T valve" do you mean one like this?

View media item 5946

 

[stem]

You have some odd symptoms there. Has it ever worked properly? Was anything changed / disturbed prior to the problem occurring?

 

[BigHammo]

yes thats the one D_Hailsham

and its been working for the 25 years Ive lived here STEM

 

[D_Hailsham]

The valve might be sticking.

Turn the power off (setting timer to CH and HW both off is not enough). This resets the valve.

The end lever should be at the AUTO end

Move the lever to the MAN end: you should feel resistance
Release the lever: it should move back to the AUTO end

If there is no resistance or the lever does not return, the valve is sticking.

Remove the actuator (metal box) and apply some silicon lubricant to the shaft seal.

 

[BigHammo]

thanks I'll try tha.

 

[BigHammo]

Still didn't work so I brought a new valve.

 

[D_Hailsham]

and?

 

[BigHammo]

I've yet to do it
Will try to do it this weekend.

Only thing I don't fancy draining the whole system.

 

[stem]

Depending on the manufacturer, if you have a like for like replacement, you may be able to swap just the head without draining the system. The one in the earlier photo is a Honeywell, if yours is a Honeywell and there is a raised bump on one end of the head it can be swapped.

Even if you do have to drain, if the valve is upstairs then you won't have to drain the ground floor radiators.

 

[BigHammo]

Cheers Stem