Central Heating Water only becomes tepid but radiators hot

Postby fzrexupru » Wed Nov 05, 2008 5:58 pm

I have a vented indirect central heating system driven by a gas boiler. When the central heating is on the radiators get nice and hot but the water in the cylinder for baths etc does not. There is an electric immersion heater as well and this heats the water fine but I don't want to have to keep using it.
Any ideas?
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Simply Build It

Postby Steve the gas » Thu Nov 06, 2008 5:32 am


Check the motorised valve for operation.
Steve the gas
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Postby fzrexupru » Fri Nov 07, 2008 2:31 pm

I would do but i don't have a clue where the motorised valve might be or what it would look like. Could you point me in the right direction?
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Postby Steve the gas » Sat Nov 08, 2008 5:32 am

Also have you got a cylinder thermostat?
Find your copper cylinder and check both, MV should be near this.
Steve the gas
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Postby nitro23456 » Sun Nov 09, 2008 1:02 pm

cylinder thermostat should be set to 60 celcius.... they are normally located centrally just up from the bottom of the cylinder stuck to the front of the cylinder - looks like a dial.

The motorised valve will look like this - http://www.awin1.com/awclick.php?mid=12 ... ised-Valve

It has three positions to it - HOT WATER / CENTRAL HEATING / BOTH and it should move to where heat is being called for ... i.e. if your house is up to temp but your hot water is not it should move to HW to heat your water.

If you have two of these valves in your airing cupboard you likely have an S plan system (above is Y plan) and the valves will be ON / OFF for each HW and CW repectively.

Fialing it being any of this, you may have an airlock in the cylinder coil - touch where the pipes come in and out on the same side (top and bottom) and they should both be hot to touch when HW is being heated.
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Postby boxall » Wed Nov 19, 2008 11:20 am

From a previous question where the radiators are hot but the water from the hot water cylinder is lukewarm such as is my problem, how can an airlock in the coil be cured?
The inlet pipe from boiler is very hot but even after several hours of operation, the outlet pipe is lukewarm.
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