Test Cylinder thermostat

[mikeusername]

My Hot Water has gone, on a system that has been fine for 3 years.

I have no hot water but good radiator temperatures and the timer controls the heating fine. So, as I understand it, there must be a fault in either the cylinder thermostat, or a motorised valve on the system.

I want to test the cylinder thermostat as that seems the easy thing to replace as a DIY job.

Can I just bypass the thermostat to see if the water heats up??

I am thinking of disconnecting the 2 cables that feed the therm, and connecting them to a 240v switch - if the water heats up when the switch is on, then its a faulty therm, if it doesn't it must be the valve.

Is that OK

Anyone see any problems with this??

Thanks
Mike

 

[Diyisfun]

Im not a plumber, but if you can get access to the t/stat, just move it away from the tank, as I would expect to switch off(open circuit) when water is hot, so by removing it from tank it should close & the demand for hot water will be sent to m/valve & boiler.
Must be easier than playing with the wiring.

 

[MANDATE]

What motorised valve(s) are in the system?.
It must be easy to verify if the cylinder stat is receiving 240v.when HW is on
Likewise it must be easy to verify a path of continuity across the terminals of the stat. If you have 3 port valve, then cylinder stat has 1 input terminal (common) and 2 output terminals 'not satisfied' to feed boiler and 'satisfied' to divert the power to the 'grey' wire of 3 port valve