Boiler doesn't fire on heating

[benjamin31]

Hello,
Just finished fitting a bathroom at a customers house.

They have an old boiler, an Ideal W wall mouted with gravity hot water. The boiler fires up when the hot water is on, but doesn't fire when the heating only is put on, and the rads get hot when hot water only is on.

Any ideas why?

 

[powell30]

Broken/jammed 3 port valve, heating controls broken......was the system fully working before you started working?? Did you check?? Just i have been caught out trying to fix problems i percieved were of my making only to find the customer 'knew' the system was duff before i worked on something unrelated......

 

[benjamin31]

I did check it before doing any work, and the customer knew it wasn't working correctly.

There is no 3 port valve, the hot water is gravity, there's just a pump on the heating circuit.

 

[seco services]

you said it doesn't fire up on heating only.

 

[JPC]

room stat turned up ?

 

[petit_pablo]

Heating wont work on its own if its gravity hw.

HW can be run on its own, heating can only be run with HW on. Sounds like its working as it should.

 

[seco services]

Heating wont work on its own if its gravity hw.

HW can be run on its own, heating can only be run with HW on. Sounds like its working as it should.

this is what info where trying to get as the post don't make any sence

 

[benjamin31]

The programmer has a heating and a separate hot water switch. The rads get hot when hot water only is on.

 

[seco services]

if you can switch heating on on its own its the wrong programmer for a hw gravity system.

you sure hw / heating are not both running off the hw on the programmer and the wall stat is controling the pump.
so the heating switch on programmer is not wired up

 

[gas4you]

Sounds as if it has been wired up incorrectly to me.

It's not unusual for rads to get warm when HW only is selected on a gravity system, especially upstairs ones. This is probably because the system does not have a anti-gravity valve (single check valve) fitted in the rad flow pipe.

 

[benjamin31]

Thanks for all the advice.

You're right Dave there is no anti gravity valve fitted.