possible 3 port diverter fault?

[darknite]

Hi every one

My traditional central heating (an Ideal Classic boiler aged 15 years, a hot water cylinder in the cupboard, a Honeywell thermostat and timer/programmer) has been working fine until a few days ago when the heating suddenly stopped working and there was no response to the stat.

The hot water was working alright. The timer and stat were OK.

The cylinder and its stat, the pump, the three way diverter valve and the electronics PCB board were replaced 3 years ago.

After some experimentation we discovered that the heating worked only when the hot water was on, the stat was high and the heating program/timer was on. When we turned off the hot water the heating stopped immediately.

When we turned off the heating program/timer then no heating worked despite hot water was on.

I checked the little lever in the diverter valve and it moved easily without resistance.

I got very much confused as I read various forums about similar valve issues and now I am not sure what to do now. A gas engineer or a plumber or electrician?

Please advise.

Thanks

 

[Dean744PiN5]

from your description it sounds like the the hot water off terminal (provides the voltage needed to power the valve fully over to shut the hot water off) in the programmer isn't wired into the circuit, meaning when heating only is on the valve isn't getting the voltage to motor across and hit the microswitch.
Which is why the heating only works when the hot water is on.

 

[kidgreen61]

Microswitch poorly in diverter valve.

If it's fairly modern, you will be able to change just the actuator, without any draining etc.

 

[darknite]

Dean7445:

Thanks for your reply.

You said " hot water off terminal (provides the voltage needed to power the valve fully over to shut the hot water off) in the programmer isn't wired into the circuit", but the programmer has been working fine until a few days back.

Any suggestions to check this or shall I go ahead and buy a new programmer?

Kidgreen61:

Thanks for your reply.

Could you be so kind to elaborate further on the microswitch? where to locate it and how does it work?

 

[twgas]

You need a multimeter, and to know how to use it, to do some diagnosing.

 

[picasso]

As the 3 port is moving across for heating the only thing not happening is the call for heat to the boiler, so as said a poorly microswitch or a loose connection at the orange wire.