Heating works but no hot water

netmann

Just moved into house. Has an old Ideal Mexico gas burner. My heating works fine but I've no hot water. The previous owners had turned off a number of valves including the main water supply under the sink. I've turned them all on but still no hot water. I've checked for a motorised valve but can't see one. Any ideas what the problem is?

ART6

Look at the hot water cylinder. You should find two valves on the side, one just above the bottom and one about two-thirds of the way up. Those are the valves to the coil in the tank, and it's that which heats the hot water circuit. There should also be a valve connecting their two pipes.

The first thing to do is open fully the higher valve and open the bottom valve about three or four turns then close the the connecting valve by about the same amount (but don't shut it). Now you need to check your radiators, because if you open the lower valve too much you will starve the rads. It's then a case of trial and error, easing the valves open or closed until you have both hot water and hot rads.

The way it works is that the boiler supplies both the radiator circuit and the tank coil. The coil is large diameter and if its valves are fully open then all the heating from the boiler will go through the coil and none will get to the rads. The connecting valve (the "bypass valve") allows heated water to bypass the coil and go on to the radiators. It's called balancing the system, and you need to play tunes on the bypass valve and the bottom coil valve until you get the system into balance.

In your case I would expect that the previous owner has shut off one or more of the coil valves and fully opened the bypass.