Immersion heater, 2nd duff thermostat?

[AlwaysPondering]

Hi, just had a new immersion heater installed after the old one self destructed. Anyway, after a few hours of it being on, no hot water.

Measuring between N and the L entry side of the thermostat I get 240V. Thermostat set at the default of 60, measure between N and T/output of thermostat and get 0V.

Measured resistance of the heating element (having disconnected everything) getting 18ohms, which is in the right ball park.

Measuring across the thermostat, nothing no resistance, and no continuity. So effectively open circuit. Which would stack up with 0V between N and the thermostat output. Tried pushing the reset button, but nothing changed.

So chalk it up to a duff thermostat. Given we've already had 48hrs of no hot water, I was dispatched to screwfix to get a replacement. Thinking, if it's the thermostaic I'll just swap it, rather than empty the tank, swap the heating element.

5 mins to swap the thermostat, and nothing. All values as before, nothing coming out of the back end of the thermostat.

I've tried pushing the reset button, but doesn't seem to make any difference. Anything else I can try before I start to cry?

Thank all.

 

[terryplumb]

Very odd ,two duff thermostats ,but not impossible. With the stat not fitted ,but on the bench ,if there is no continuity across its two terminals it is duff !!

 

[AlwaysPondering]

Yep, well stat in situ, but nothing connected to either side, so functionally the same as just on a bench.

Guess it's the just because it's new, doesn't mean it works.

 

[JohnD]

show us photos of the connections please

 

[333rocky333]

As you turn the dial on the stat do you here a click

 

[ericmark]

Although in the same housing, I thought thermostat, heating element and over temperature cut out are three separate items?

 

[AdrianUK]

Although in the same housing, I thought thermostat, heating element and over temperature cut out are three separate items?

The over temperature cutout is almost certainly part of the thermostat.... never yet seem one that isnt.

 

[AlwaysPondering]

As you turn the dial on the stat do you here a click

No there's no click on the first on I tired, that was replaced with the second.

 

[AlwaysPondering]

show us photos of the connections please

Hopefully this will work

 

[AlwaysPondering]

Left the heater in situ as that seemed to be ok, and wasn't going to start messing about with changing that.

Tested new thermostat in car park, and seemed ok. All now installed and we have hot water.

Guess the lession here is, just because something is new, doesn't mean it can't be faulty.

Thanks to everyone who's commented and made suggestions.

 

[JohnD]

Hopefully this will work

too small. Can't make out the detail.

You can "copy and paste" or "drag and drop" or "upload a file" into your reply.

 

[ericmark]

I have seen this

type in an immersion heater, however for the non resettable then built into the thermostat makes sense as then when it fails you are forced to change thermostat. With two forms of DHW heating it should be resettable, with immersion only non resettable, and with two forms of heating the header tank either metal or thermal setting, thermal plastic should only be used when single form of heating which has a independent cut out, which makes it all a bit daft as how when combined to thermostat do you know if the cut out is independent.

Really the thermal plastic header tank should have been banned after the babies death.

 

[flameport]

Hopefully this will work

How did you manage to make a picture that is so ridiculously small?

 

[CBW]

How did you manage to make a picture that is so ridiculously small?

I think sometimes when uploading, it asks picture size?

 

[JohnW2]

too small. Can't make out the detail.

Obviously too small to have adequate resolution but, for what it's worth ...

Kind Regards, John