Drained hot water to fit new taps and now does not heat

[fitbird57]

Please can someone help. I have just fitted a new sink in our en suite and drained the hot water from the tank in the loft by closing the tap on the pipe leading into the tank and then turning on all the hot taps until there was no water coming from them. I then opened the tap to fill up the tank and then pressed the hot water button on our central heating panel to heat the water for an hour. When I turned on the hot tap in the kitchen the water came out cold. I tried to heat the water again but still it came out cold. The central heating is working fine we just haven't got any hot water! Any ideas?

[The Builder]

usual problem after draining the roof tank is an airlock.................have you had any gurgling from the hot tap...............but, having said that, your hot is running properly................but cold?

Do you have a cold storage tank (roof) and a copper immersion cylinder (airing cupboard) ?

[fitbird57]

Hello, thank you for your reply. Yes, we do. What do we need to do?

[The Builder]

Back again..................does the hot tap run freely, or does it gurgle?

[fitbird57]

Hello Yes the hot tap does run freely.

[The Builder]

oooooo er...............no airlock then........sounds like maybe the diverter..............which moves between CH and HW to select one or the other.
Really can't tell from here Fitbird.................I wish I could help, but I think a heating engineer should look at it...........most likely something quite simple..........

[gucciman]

the diverter valve should always rest in the hot water position, so if it does fail you should get hot water and no central heating. saying that you never know what some installer as done, they could have installed it the wrong way round, they could also have rigged up some wierd zone valve system to control the hot water and that could have failed.

[fitbird57]

Thank you for your reply. Please can you tell me where I would locate the diverter valve and if it has been installed incorrectly and is the problem, how I go about fixing the problem. Many thanks

[gucciman]

the diverter or zone valves can be located anywhere including hidden under floorboards or in the loft, the usual place is next to the hot water cylinder though. it will be either a rectangular unpainted metal box or white plastic box, with a black electric cable coming from one end and also a little metal lever sticking out the end. the lever should say above it heating or water, try manually moving the lever over to the water position and see if that helps. if it does then there's a fault with the valve and it needs either a new syncron motor, a new powerhead or a complete new valve assembly.
the black cable should point towards the heating circuit so the other end should be pointing towards the hot water circuit.