Central heating problem

[benny2009]

Hi all

A few days ago, my central heating would not come on but the hot water was working fine. I have a 3 port diverter valve on which there is a lever which I turned to the right but with no luck. The lever just seems to push to the right wihout any sort of resistance.

I opened the cover on the diverter valve where I came accross a set of teeth on a spindle. I therefore turned the central heating to on and then I gave the teeth on the spindle a little push and hey presto, the heating came on.

However, I have noticed that the hot water gets hot when the central heating is on for a few hours. It gets hot as if the hot water was put on. Because of this, I have not bothered to switch the hot water on! This is not normal and I was wondering what the problem might be. Also, is this dangerous and would the hot water stat kick in when the water reaches its set temperature?

Any help would be appreciated.

Thanks.

 

[electronicsuk]

However, I have noticed that the hot water gets hot when the central heating is on for a few hours.

I'm not sure why this is surprising when you've already identified a faulty 3-port valve?

Also, is this dangerous and would the hot water stat kick in when the water reaches its set temperature?

If the valve is letting by or not moving to the position that's being called for, there's nothing the stat can do to halt the flow of water to the cylinder coil, regardless of whether or not thermostat set temperature is satisfied. However, it's not dangerous in the same way as an electric immersion heater stuck on, as the cylinder water cannot reach a temperature higher than the flow temperature of the water in the coil (as set by the temperature dial on the boiler).