Use Central Heating without having hot water on?

PJB

Hi All

Does anyone know if I can use Central Heating without having hot water on?

I have an old mechanical Landis & Gyr timer but when I try and switch the CH on it automatically switches the HW on as well. Is there a switch or way of changing this?

In case it makes any difference I have a flexicom 12hx boiler.

Thanks for reading

PJB

slipthru

Not sure if it applies to your system but I know that you can get a three way valve that does central heating or hot water or both at the same time. Assume you just have a two way valve at the moment.

Not very technical and plumber will be best to explain it.

JJ_Egan

Depends upon the system .
Three way valve usually controls CH or HW or Both via a timer switch that has CH and HW controls .

matelodave

You'd probably need to change the programmer and possibly fit a motorised diverter valve. It all depend on how your system is currently configured, not necessarily on the boiler you've got.


Have you got a separate room thermostat and motorised valve in the system if so is it a one or two port valve. What is the model number or the programmer. Have you got a thermostat on the hot water tank.


Most systems can be upgraded to improve the controls although some are more difficult than others

ChumpusRex

Older heating systems would use "gravity pumped" hot water systems. The fact that hot water rises would cause the hot water tank to heat up, whenever the boiler was burning. The radiators would need a pump to circulate the hot water.

Because the hot water would always heat up whenever the boiler burned, the controllers were configured so that they would show the hot water on, whenever the central heating was selected.

More modern systems use diverter valves and pumps, to direct the heat from the boiler to radiators, hot water or both.

For your case, whether this is an easy conversion depends on whether your system has a diverter valve in place. If it does, it may simply need a new programmer. If it doesn't, then it may need a diverter valve fitting and other upgrades, as well as a new programmer.

However, it depends on what exactly what was upgraded when the new boiler went in.

JJ_Egan

Divert valve looks like .
https://www.plumbnation.co.uk/site/drayton-22mm-3-port-motorised-diverter-valve---5-wire-spst-switch-za5-679-3/

They can stick in one position and usually have a manual override .

molerat

My system has 2 valves and the old potterton timer switched the water on when the heating was switched but there was a commissioning setting on the back, meaning the timer had to be removed from the wall to do it, which separated the functions. My new timer has these functions completely independent.