Heating Programmer quirk? Or working as expected.

[oilhead]

Which 3 way valve do you have?

 

[dishman]

turn the HW off and confirm that the 3 port valve definately motors over to Heating only and not mid position

OK, I managed to do a few tests. Sat a voice recorder on the 3 way valve, and while changing the programmer settings, I listened back for any motor clicks etc.

So...

Hotwater only (off to on) - click and motor whirr
Hotwater only (on to off) - can't hear any type of click or whirr

Central heating only (off to on) - click (can't make out any whirr)
Central heating only (on to off) Click and whirr

Testing each setting while the other is also on:

Turning the heating off - Click and motor whirr
Turning the heating on - click (no whirr audible)

Turning the HW off - no click or whirr (just the pump stops)
Turning the HW on - no sounds of clock or whir.

I think that is the best I can do based on sound an observation.

Any further thoughts on this? Just an incorrect programmer set-up?

 

[oilhead]

You need to start from a de energised state. Your first test HW only on may have given a whirr as the three port valve may have been in a hold mode if the last call was for heating.
The way it works is HW only on, valve is in rest stae and boiler is switched by cylinder stat.
Both HW and CH on boiler is fired by cylinder stat but valve moves to mid position. When HW is satisfied, valve moves to CH position and makes the microswitch to fire boiler and pump.
CH only and valve opens fully to switch boiler and pump.
You may not hear the valve open as it is very slow, compared to the motor being closed by the spring return.
As previously asked, what valve do you have? If a Drayton MA1, then they are notoriously short lived.