Heating Fine - No Hot Water

[Donbhoy]

Ok, I had a look at the pipe leaving the cold tank and it does have a slight slop upward (checked with a spirit level!) for about 30cms before it heads straight done. Is this the likely cause of my problems then?

If it rises by more than its own internal diameter before turning downwards you will get an airlock. There is a temporary cure for this. You connect a hot tap to a mains fed cold tap. Open the hot tap fully then, carefully, turn on the cold tap. At this point, one of two things will happen:

1) If you have a simple airlock in the cold feed, the pressure from the cold tap will blow the air up and out into the tank.

2) If you have a blocked cold fed, water will pour out of your vent pipe.

In the first case, the hot water will work afterwards. In the second case it won't and you'll have to find the blockage. Since you've checked the bottom of the tank already, the valve is now prime suspect. You could of course have an airlock AND a blockage!

PS: The water coming into your house has air dissolved in it. Very occasionally there is so much air that the water turns cloudy with microscopic air bubbles. An airlock will keep coming back! The only permanent cure is to rearrange the pipework.

Hmm, that's interesting as i wouldn't say that that the pipe rises by close to it's own diameter, it's a very slight slope. Would it be worth trying the connecting the hot to cold as you suggest anyway?

Regarding the valve, I have tried turning the valve which is attached to the cold feed just after it leaves the cold tank but try as I might, I can't get it to turn either way. Would this suggest that this may be the reason? Or do valves get sticky like this if they're not turned for a while?

Cheers

 

[Space cat]

I have tried turning the valve which is attached to the cold feed just after it leaves the cold tank but try as I might, I can't get it to turn either way. Would this suggest that this may be the reason? Or do valves get sticky like this if they're not turned for a while?

That valve has to be your prime suspect. It might be stuck shut! Does it have a wheel shaped handle? You could try loosening the gland nut a little. Use a second spanner to support the valve body while you do this and be prepared for some water to seep out. Come to think of it you might not be able to stop it seeping without putting new packing in. Play safe and drain the cold tank first.