Fitting Room Thermostat

[Spleurker]

Hi,
I am thinking of fitting a room thermostat.
My boiler is a Sime Halstead Trio combi, which controls the CH temp by a knob on the panel. I think this is playing up. Hence a room thermostat.
Any advice on fitting one would be great please.
I presume a simple thermostat is a straight switch in the "on" signal to the burner. So all I need to do is track down the relevant wire, check voltage and break in with the thermostat.
Am I right?

 

[kevplumb]

should be a terminal block in the boiler for a stat with a link across two terminals ?

 

[Spleurker]

Thanks for that swift bit of help.
I'll be having a good look tomorrow, when the family are out and the heating will be off.

 

[Spleurker]

Just had a quick look.
Think I've found the correct terminal block.
However there is no straight link.
The block has 5 terminals.
The first 2 are live & neutral 240 Volts which go into a connector on the PCB. The next is an earth.
The next 2 terminals are what I'm after but they don't look directly linked.
They are marked with a diagram showing they should be switched, and marked:-
"TERM.AMB.-ROOM STAT"
THERMOSTAT AMBIANCE
Both have a red wire going off to another connector on the pcb, and one of these terminals also has a wire connected that is one side of the timer on/off switch.
Any ideas as to how I connect a room stat to this?

 

[kevplumb]

in a word no
do you have a built in timer or one on the wall ?

 

[Spleurker]

It's a built in timer.
The boiler is a combi, all controls are on the front panel.
A timer, and timer on/off switch, a switch for summer/winter (basically CH on/off), a heating temp control knob, a hot water temp control knob, and a gauge showing water temp & pressure.

 

[kevplumb]

if you need a manual try 01926 834844

 

[Spleurker]

Thanks
Whose number is that?

 

[kevplumb]

halstead lit request its all you get on the website sorry

 

[Spleurker]

Thanks for the info.
I'll have a play tomorrow.

 

[DP]

Call that number and she will wisper sweet nothings into your ear.

Kevin, the man wants to fit a thermostat because boiler stat is broken. I cannot see how the boiler is going to work with malfunctioning boiler stat

 

[kevplumb]

good point danny i went off on a tangent (again)

 

[Spleurker]

Halstead have kindly sent me a copy of the fitting instructions, which includes wiring diagrams.
I can now see how it all works.
Am I right in thinking the CH thermistor is a thermocouple which the contol board uses to monitor the temperature of the water in the CH. Is there any way to verify this is working correctly.
The problem I have been having is intermittent, which always makes a fault difficult to trace.

 

[kevplumb]

themistor resistance changes with temp (or should)

 

[Spleurker]

Thought so.
Thanks for all your help.