Heating only comes on with the hot water!!

[ava256]

Hi, As the heading says, HEATING ONLY COMES ON WITH THE HOT WATER! To keep the heating on, the hot water has to be drained out of the system, then the heating will turn on again. It's not the pump, nothing is making strange noises. I am hoping it is something simple like the main thermostat on the wall - does anyone know if it could be this? I know I should get someone out but having been ripped off by a central heating engineer a few years ago, I'd like to have an idea of what could be wrong. Any comments would be appreciated.

 

[PuraTherm]

Have you had any work done to the system recently? Sounds like a wiring issue. How long has it been this way?

 

[ava256]

Hi, it worked perfectly at the beginning of the year, so has only been like this since turning the heating on after the summer. The boiler, pump and all the other bits that make the system were renewed only 5 years ago and it has been working well until now.

 

[PuraTherm]

Are there two soleniod valves (one to feed the cylinder and one for the heating) or is there one valve with three pipes to it?

 

[ava256]

Hi, I think there is 1, is this the white box with a tiny black piece coming out of the side of it which I recall someone telling me that it moves up and down. If it is, then it's in the down position. If it is a problem with this valve is there any way of testing it, like if I tried to push this little lever up or is it only meant to work by itself.

 

[PuraTherm]

Sounds like a three port valve that is stuck. Try moving the lever if you can. You should feel some resistance but be able to move it. If this dosen't work then (I know this is going to sound odd but trust me) with the handle of a screw driver, tap on the pipes coming into the valve while the system is trying to work. If the valve is stuck this may free it up. If this dosen't work then it is time for the pros. Hope this helps.

 

[ava256]

Thank you very much, I'll get a screwdriver now and let you know if it works.

 

[ava256]

Hi, I turned the timer to heating only and have been tapping away at pipes but nothing has happened, so I guess I need a new 3 port valve - I have looked up the price of these, should I expect to pay approximately the same when it is supplied by a heating engineer, also what is an average hourly rate I can expect to be charged.
Back to the heating/hot water situation, I noticed today when I turned the timer to heating only, that the boiler did not spring into life. Does it only work when it gets a 'signal' from the 3 port valve or could there be something else up with the system?
I do get heating when the temperature drops below zero as then the boiler comes on and the heating does not go off until the temperature rises. Any comments would be grately appreciated.
Regards

 

[PuraTherm]

You definately need someone to look at the system. It is starting to sound more like a wiring issue. I wouldn't suggest you get any parts because it could be any number of things and just getting parts to have on hand can get expensive. You should expect to pay about 40 to 60 pounds an hour for a qualified engineer. You will pay a mark-up on parts supplied by the engineer but think of the fact that he will be buying them, picking them up and the parts will be warranted if they do fail. If you provide the parts you have to order them and if they fail or if they are the wrong ones then it falls back to you.
Good luck.