IMIT TWIN THERMOSTAT (LONG PROBE) Wiring diagram

Wexbike · Jan 21, 2022

IMIT TWIN THERMOSTAT (LONG PROBE) hi just wondering if anyone can explain the wiring diagram for this thermostat. The question has been asked before but I can get the information I need. I have asked an electrician but he’s unsure.

James · Jan 21, 2022

Can you post a copy of the diagram?

snowhead · Jan 22, 2022

It's 2 thermostats in series.
1 Stat is manual reset (for overtemp)
The other is the control stat for adjusting the operating temperature.

What's the problem, has a new one been fitted incorrectly?

[ElectriciansForums.net] IMIT TWIN THERMOSTAT (LONG PROBE) Wiring diagram

Wexbike · Jan 22, 2022

snowhead said:
It's 2 thermostats in series.
1 Stat is manual reset (for overtemp)
The other is the control stat for adjusting the operating temperature.

What's the problem, has a new one been fitted incorrectly?

View attachment 94194

View attachment 94195

Thank you snowhead for the help. I feel I have info I need to do the job. I’m getting too old and the brain ain’t what it used to be. The old one packed in and I’m waiting too long for an electrician. It wouldn’t be a problem but for the weather.

Wexbike · Jan 22, 2022

James said:
Can you post a copy of the diagram?

Thanks James. Great forum for a helping hand.. Utube wasn’t of help this time.

tbellward19837 · Apr 9, 2022

Hi guys, would really appreciate your help here. I'm a plumber and have to change one of these thermostats soon. Could someone please tell me which terminal I connect the live and neutral wires to? I'm sure live is connected to C on the left of the diagram but unsure with the negative. Thanks Tom

Avo Mk8 · Apr 9, 2022

tbellward19837 said:
Hi guys, would really appreciate your help here. I'm a plumber and have to change one of these thermostats soon. Could someone please tell me which terminal I connect the live and neutral wires to? I'm sure live is connected to C on the left of the diagram but unsure with the negative. Thanks Tom

The 'negative', or rather neutral, doesn't go to the thermostat at all, it goes to the load.
Live is connected to C as you say, and then the switched live from terminal 1 of the adjuster goes to the load you want to switch off when temp is reached (assuming that's what you want to do!)

tbellward19837 · Apr 9, 2022

Avo Mk8 said:
The 'negative', or rather neutral, doesn't go to the thermostat at all, it goes to the load.
Live is connected to C as you say, and then the switched live from terminal 1 of the adjuster goes to the load you want to switch off when temp is reached (assuming that's what you want to do!)

I'm still a little confused, so where would I connect the blue (neutral wire) please. Obviously the live, neutral and earth wires are all in one cable. Would I connect the neutral wire to 1 U on the far right off the diagram? Yes I want the load to switch off when temperature is reached

Avo Mk8 · Apr 10, 2022

tbellward19837 said:
I'm still a little confused, so where would I connect the blue (neutral wire) please. Obviously the live, neutral and earth wires are all in one cable. Would I connect the neutral wire to 1 U on the far right off the diagram? Yes I want the load to switch off when temperature is reached

Sorry I didn't get where you were coming from with the reference to 'neutral'.

Normally the three core cable is carrying live to the thermostat, and the neutral/ blue wire, as you suggest, is used to carry the switched live back to the wiring centre, or whatever it is connected to.
If done properly the blue wire should have a brown sleeve or brown tape over the exposed blue insulation, to indicate this Is carrying live when the switch is closed, but it sounds like yours doesn't have that! Good idea to add it!

If you are doing a like-for-like replacement, then what you suggest - blue wire to 1U - is correct.
On the other hand if your cable is actually connected to live and neutral at the other end, eg a 13A plug, then BANG!

Nyasha · May 30, 2022

Avo Mk8 said:
Sorry I didn't get where you were coming from with the reference to 'neutral'.

Normally the three core cable is carrying live to the thermostat, and the neutral/ blue wire, as you suggest, is used to carry the switched live back to the wiring centre, or whatever it is connected to.
If done properly the blue wire should have a brown sleeve or brown tape over the exposed blue insulation, to indicate this Is carrying live when the switch is closed, but it sounds like yours doesn't have that! Good idea to add it!

If you are doing a like-for-like replacement, then what you suggest - blue wire to 1U - is correct.
On the other hand if your cable is actually connected to live and neutral at the other end, eg a 13A plug, then BANG!

what if the blue were connected to the common and then brown to 1.....what would happen?

Avo Mk8 · May 30, 2022

Nyasha said:
what if the blue were connected to the common and then brown to 1.....what would happen?

It all depends on what the blue wire is connected to at the other end of the cable.
People have been referring to it as 'neutral'. If that is what it is, the answer to the question is "BANG'
If it is actually the switched live going to the load (U in the diagram) - in which case it should have a brown tape or sleeve on the wire - it should work!

Just to recap on the diagram:
It shows two things - there is a very faint grey line showing a box around the thermostat bit. That is the extent of what you have in the thermostat. Terminals labelled '1', '2' and 'C'.

The two 'U' boxes are not in the thermostat, each 'U' is a representation of a possible load (eg immersion or valve) to be controlled
So if you want to switch something off when the thermostat is hot enough, you take a wire from right hand terminal 1 (in the diagram, which is a switched live) to the thing you want to switch. It will be a live wire to feed the load, and the other side of that load needs to be connected to 'neutral'.
You need to find out if your blue wire goes to the live side of the thing you want to switch on/off, in which case it's not a neutral wire, it's a switched live, and the blueness is misleading.
Or is it actually a neutral? I suspect not, but I would test it with a meter first,

Nyasha · May 30, 2022

Avo Mk8 said:
It all depends on what the blue wire is connected to at the other end of the cable.
People have been referring to it as 'neutral'. If that is what it is, the answer to the question is "BANG'
If it is actually the switched live going to the load (U in the diagram) - in which case it should have a brown tape or sleeve on the wire - it should work!

Just to recap on the diagram:
It shows two things - there is a very faint grey line showing a box around the thermostat bit. That is the extent of what you have in the thermostat. Terminals labelled '1', '2' and 'C'.

The two 'U' boxes are not in the thermostat, each 'U' is a representation of a possible load (eg immersion or valve) to be controlled
So if you want to switch something off when the thermostat is hot enough, you take a wire from right hand terminal 1 (in the diagram, which is a switched live) to the thing you want to switch. It will be a live wire to feed the load, and the other side of that load needs to be connected to 'neutral'.
You need to find out if your blue wire goes to the live side of the thing you want to switch on/off, in which case it's not a neutral wire, it's a switched live, and the blueness is misleading.
Or is it actually a neutral? I suspect not, but I would test it with a meter first,

I meant with the blue wire as a switched live going to the load. infact what I was asking what would happen if I vice versa the connection and put brown (incoming live) to 1 and my blue (switched live) to C. How would the thermostat behave?

Avo Mk8 · May 30, 2022

Nyasha said:
I meant with the blue wire as a switched live going to the load. infact what I was asking what would happen if I vice versa the connection and put brown (incoming live) to 1 and my blue (switched live) to C. How would the thermostat behave?

If you mean the No1 contact on the right of the diagram in post #3, then it should work fine as a thermostat that switches off when it gets hot.
You are presumably not talking about the limiter No 1 contact on the left, which turns on when the limit stat reaches temperature.

Nyasha · May 31, 2022

Avo Mk8 said:
If you mean the No1 contact on the right of the diagram in post #3, then it should work fine as a thermostat that switches off when it gets hot.
You are presumably not talking about the limiter No 1 contact on the left, which turns on when the limit stat reaches temperature.

I have a thermostat that doesn't cut power at set temperature. What could be the problem?? I was suspecting the connection but as you say it may not be the issue

Avo Mk8 · May 31, 2022

Nyasha said:
I have a thermostat that doesn't cut power at set temperature. What could be the problem?? I was suspecting the connection but as you say it may not be the issue

It could be that contacts have become welded together, or some other failure in the mechanism.
Does it cut power at all if you turn the adjuster to a lower temperature? Or do you hear a faint 'click' when you adjust it back and forth?
If not, best to replace it.

Nyasha · Jun 1, 2022

Avo Mk8 said:
It could be that contacts have become welded together, or some other failure in the mechanism.
Does it cut power at all if you turn the adjuster to a lower temperature? Or do you hear a faint 'click' when you adjust it back and forth?
If not, best to replace it.

it cuts when I reduce to less than 30

Avo Mk8 · Jun 1, 2022

Nyasha said:
it cuts when I reduce to less than 30

OK - I just need to clarify:
Are you doing this test with the thermostat at ambient temperature, or is it in a hot tank?
If the former, I think you are using an incorrect terminal on the thermostat - using the normally open contact rather than the normally closed.
If your thermostat has a changeover switch like the right hand one in the diagram in post #3, sounds like you have one of your wires on terminal 2 instead of terminal 1.

IMIT TWIN THERMOSTAT (LONG PROBE) Wiring diagram

Wexbike

IMIT TWIN THERMOSTAT (LONG PROBE) hi just wondering if anyone can explain the wiring diagram for this thermostat. The question has been asked before but I can get the information I need. I have asked an electrician but he’s unsure.

James

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snowhead

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Wexbike

Wexbike

tbellward19837

Avo Mk8

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tbellward19837

Avo Mk8

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Nyasha

Avo Mk8

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Nyasha

Avo Mk8

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Nyasha

Avo Mk8

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Nyasha

Avo Mk8

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IMIT TWIN THERMOSTAT (LONG PROBE) hi just wondering if anyone can explain the wiring diagram for this thermostat. The question has been asked before but I can get the information I need. I have asked an electrician but he’s unsure.