Gravity fed central heating

[NigelRS]

I have a 1970's built house with a standard hot water gravity fed system. Last year the boiler went and both the thermostate and transformer were replaced and it was working as normal.

However, 2 days ago, the hot water feed has stopped. When the timer comes on, the boiler kicks in and hot water is circulated to all of the radiators as per normal and that works fine in conjunction with the room/wall thermostate controller. However, no hot water comes out of the hot water tap.

If I then turn on the immersion tank to see if that makes a difference, it doesn't really. It was put on a hour and the water came out luke warm (for a short while) instead of room temperature (like it does from when the boiler is sending hot water up to heat the tank. Nothing happened or changed on the system to make this happen and as there are no pumps, valves or anything else like that; I am not sure what to elimiate next to find the solution.

Any suggestions?

 

[Gray0689]

Could be as simple as a motorised valve needs replacing

 

[Billy Bob Bob]

sound like immersion heaters faulty anyway,in regards to your other fault ch tank ball valve may have stuck check the ch tank(small one) if no water in it thers your fault push the ball valve down it may re activate it if how ever the ch tank is full you may have a blocked coil on your cylinder

 

[Billy Bob Bob]

Could be as simple as a motorised valve needs replacing

wont have one if its gravity domestics

 

[Gray0689]

wont have one if its gravity domestics

Didn't see it said gravity domestics??

 

[tamz]

You have an air lock in the gravity circuit.

Btw an immersion will take over 2 hrs to raise the temp of a tank of water by 50º

 

[justlead1]

Check the expansion/feed cistern. (the ball valve may be stuck) The first thing to be effected is normally gravity circuit to cylinder.

 

[NigelRS]

Thanks folks.

The small feeder/overflow tank was dry, the ballcock was stuck. Sorted this and, after a while of filtering through, the hot water is running.

 

[RoryD]

There may well be an airlock which can be "boiled" out, however, the anti gravity valve (non return valve) is knackered, gotta locate and replace, it's a brass coloured broad fitting on the pipework.