Switch beside immersion switch

macmathuna1

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So there is a switch just to the left of the normal immersion "on/off,bath/sink" switch

I've asked the landlord and he doesn't know either.

When turned on it turns a light on on a little blue box near the bottom of the hot water tank.

Any ideas what this is and when if ever it should be turned on.

Thanks Eoin

Doolittle51

The 'blue box' is an automated valve. I'd imagine it allows the water in the cylinder to be heated when the boiler is on. If the switch is off, the boiler will only heat your radiators. Bit of a strange setup, usually the automated valve only opens when the boiler is on and will close when the tank temperature is sufficient (if there's a thermostat on the hot water tank)

macmathuna1

I'll give it a try and see if the boiler works to heat the water.

I don't know how the landlord wouldn't have known about this.

Thanks

K.Flyer

Might be for switching the heating circuits (rads) on or off as that blue box (zone valve) seems quite close to those manifolds.

Leave the switch off and turn on your central heating system and see if your radiators heat up. If they don't then turn on the switch and see if that makes a difference to the radiators.