Replacement Thermostat

[RP66]

Is there a replacement for the Eberle ETS1 4wire Thermostat?

 

[ianmcd]

what is the thermostat controlling ?

 

[RP66]

The heating system, it is fitted in the hall.

 

[ianmcd]

Afraid we need more information combi-boiler ? system boiler? what other controls tanks etc , if you dont know post pics of what you have

 

[RP66]

Greenstar Ri Boiler.
See https://photos.shutterfly.com/album/90234766824

 

[RP66]

Problem is that the CH comes on via the time clock and then never switches off even when I turn the thermostat back to zero.
It was all working fine yesterday.

Thanks for your help much appreciated.

 

[fixitflav]

Problem is that the CH comes on via the time clock and then never switches off even when I turn the thermostat back to zero.
It was all working fine yesterday.

Thanks for your help much appreciated.

Has it been OK for some time, not just yesterday? I installed an Eberle 4-wire stat (ie with accelerator) 20 years ago, it still works fine. Don't know which model, no markings on it (on the outside) and I've lost any paperwork.
I'd be inclined to take it apart and see if you can find the problem, it might be contacts stuck together.

 

[stem]

I've not heard of a Eberle ETS1. Do you mean an RTS1 like this?

If so, it's the same as a Drayton RTS 1

But it's doesn't have 4 wires.... unless you are counting an earth.

It would be worth having someone test it before you go replacing it. Whilst it may be faulty, there are other faults that can cause what you have just described.

 

[RP66]

Has it been OK for some time, not just yesterday? I installed an Eberle 4-wire stat (ie with accelerator) 20 years ago, it still works fine. Don't know which model, no markings on it (on the outside) and I've lost any paperwork.
I'd be inclined to take it apart and see if you can find the problem, it might be contacts stuck together.

Yes its been working fine for years

 

[RP66]

I've not heard of a Eberle ETS1. Do you mean an RTS1 like this?

View attachment 151668

If so, it's the same as a Drayton RTS 1

View attachment 151669

But it's doesn't have 4 wires.... unless you are counting an earth.

It would be worth having someone test it before you go replacing it. Whilst it may be faulty, there are other faults that can cause what you have just described.

The stat I have is a mechanical type not electronic I think.

 

[fixitflav]

But it's doesn't have 4 wires.... unless you are counting an earth.

Why wouldn't you count the earth? Mine has 4 wires - live from the programmer, switched live to boiler and pump, neutral for the accelerator, and earth.

 

[stem]

I said regarding an RTS thermostat that it....

...doesn't have 4 wires....

which is quite correct as can be seen from the manufacturers diagram below.

But because the OP had mentioned 4 wires, is why I then said....

unless you are counting an earth.

Which was in case a 4 core cable had been used to connect it, and one core of which was an unused earth.

All irrelevant anyway if the OP doesn't have an RTS1.

 

[RP66]

Timer calls for heat, thermostat calls for heat, boiler comes on, when temperature reached heat does not switch off.
Checked the stat with a meter between L & N is 240v, between yellow switch wire and N is 240v which goes to zero when temperature reached, therefore the problem does not appear to be the thermostat, could it be the 3 way valve?
Only way to shut down heating is to set the timer to off.

 

[ianmcd]

if switching the timer to off turns the boiler off then it is likely to be the timer rather than the three way valve, your thermostat is working correctly

 

[fixitflav]

Timer calls for heat, thermostat calls for heat, boiler comes on, when temperature reached heat does not switch off.
Checked the stat with a meter between L & N is 240v, between yellow switch wire and N is 240v which goes to zero when temperature reached, therefore the problem does not appear to be the thermostat, could it be the 3 way valve?
Only way to shut down heating is to set the timer to off.

I suppose it could be the 3-port valve faulty, but if so, you would only get CH with the room-stat satisfied, if HW is calling (via the cylinder stat). If the 3-port is stuck in the CH position the cylinder will get no heat, so the stat remains unsatisfied. You could try turning the cylinder stat right down (it should have an Off position) and see if that stops it. That's as a test, it doesn't solve the problem.