Immersion troubleshooting - is there anything else I can test

[aetos]

Immersion isn't providing any hot water. There's not gas to the property, just a coal back boiler, which isn't currently lit.

Here's what I've done so far, can I do anything more?
Pressed the reset switch on the thermostat
Replaced the thermostat
Called out an electrician to confirm electricals are all OK, but he didn't have a clue about anything else to do with it
I had a good careful look, and tested the connectivity across the elements with my multimeter. Resistance was 19.8 ohms.

What might be wrong here? Can I test anything else myself? Is it plumber and new immersion time?

 

[Johntheo5]

Is it a dual immersion with sink/bath elements?.
With power off do you get continuity across the thermostat terminals?.

 

[aetos]

With power off, continuity across the thermostat terminals reads .002.

Not sure what you mean by dual immersion, sorry, it just has an on/off switch on the wall

 

[Johntheo5]

There seems to be a separate Hi limit stat on the body of the immersion, opposite to "55" on the control stat, is there a reset button on this?, can you check that out for continuity?

(A dual immersion has two elements, one short for the sink, one long to heat enough for a bath, you will have a switch marked sink/bath but you havn't got this so a single element?)

 

[aetos]

oh interesting, I can't see anything on the cylinder other than where the element is, and where the pipes go into the cylinder. How can you tell? Do you know what would I be looking for?

and yes looks like it's a single element

 

[HERTS P&D]

Fit a new immersion.

Andy

 

[Johntheo5]

You have a brown wirefrom the wiring cable that goes into the control stat, another brown wire that comes out of the stat and goes to the ele.ent, another brown wure from the other element terminal that goes to this hi likit stat?

 

[polesapart]

c. 20 ohms resistance is the correct reading for a healthy immersion element.

 

[terryplumb]

Have you taken any voltage measurements at the immersion heater ?

 

[aetos]

You have a brown wirefrom the wiring cable that goes into the control stat, another brown wire that comes out of the stat and goes to the ele.ent, another brown wure from the other element terminal that goes to this hi likit stat?

here's a closer look at the cables at the back, I can't see anything that looks like a switch though

 

[Johntheo5]

Its the white item, can you press the black button down and/or check for continuity across it, also as suggested have you 230V at the immersion?

 

[aetos]

Its the white item, can you press the black button down and/or check for continuity across it, also as suggested have you 230V at the immersion?

yes! That clicks down and has reset it. Water is heating up now. Thank you!

 

[HERTS P&D]

Just a heads up:

I wouldn't be calling that electrician again.

Andy

 

[Johntheo5]

That external hi limit stat can be bypassed by linking the two brown wires if its giving nuisance tripping as the new combined TS225 stat has a hi limit cut out at 90C.

 

[CBW]

That external hi limit stat can be bypassed by linking the two brown wires if its giving nuisance tripping as the new combined TS225 stat has a hi limit cut out at 90C.

Are you suggesting a safety device be bypassed? I know there’s the high limit stat, but should something happen could be liable?