Hot radiators no hot water

[paulkb]

I have a sunvic 207xl programmer and the central heating system works perfectly when switched on. However when the hot water side is switched on seems to work intermittently. The red power light seems to come on and switch off randomly. I have set the setting to always on to see if I could establish what is causing the red light to switch on and off but I have not been able to find the cause.
Any help would be fantastic before I start replacing parts of my system unneccessarily.

 

[doitall]

What other bits have you got.

Room stat.

Cylinder stat.

3port valve.

2 x 2port valves.

Gravity or pump hot water.

and the boiler make/model.

 

[paulkb]

The system is pumped, I have a Honeywell 3 way port valve. Cylinder stat (no room stat) and the boiler is a potterton neataheat 60E

 

[doitall]

What red power light are you referring to.

Have you got a multimeter to check the cylinder stat.

 

[paulkb]

On the front of the Sunvic programmer there are 2 led's that indicate when the hot water and central heating are on. The Central heating led comes on to order, the Hot water seems to come on when it feels like it.

I don't have a multi meter but might be able to borrow one. How would I test the cylinder stat please.

 

[doitall]

Sounds more like a loose connection in the clock in that case.

Check the wires are tight, and the same in the wiring center.

Isolate the sparky stuff first.