Central Heating Programer Problem

dieselglider

Checked cylinder stat -when calling for heat, 1 and 2 both live. When satified 2 is live. Is this as it should be?

As I see it, C and 1 should be live when calling for hot water, then C and 2 should be live when hot water temp reached and stat switches over. However 1 should become live again after a second or so, due to feedback from the 3way valve internal microswitch as the valve moves to the CH only position.

You really need to test the grey wire to the 3-way valve as I said before. And check the white one while you're at it.

(Connection 1 on the cyl stat should be linked to the Orange wire on the 3-way valve, which also feeds to the boiler/pump. When the cyl stat switches to satisfied (connection 2) the feed to the boiler is then lost, but the 2 connection feeds the grey wire to the 3-way valve which then moves to the CH only setting, switching an internal valve microswitch to feed the orange boiler/pump wire again.
The fact that switching the HW off at the programmer brings the heating back on, to me shows that the 3-way valve is working ok, as the programmer no.1 connection also feeds the grey wire to the 3-way valve.)

Of course, all the above assumes that it is wired the same same as the standard diagrams I am reading.

Clear as mud!!

ps, don't go spending your money yet, it may be as simple as a loose wire somewhere..