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Replacing Satchwell TLX 2356 tempstat with Honeywell CM907 Temp?
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Jim Chisholm
Nov 8, 2011, 3:58:59 PM11/8/11
to
I've a Satchwell TLX 2356 and am considering a Honeywell CM907 7 day
programmable tempstat
I've a Honeywell wiring panel in heater cupboard.
The wiring panel (Honeywell 42005748-001)
has at ROOMSTAT block:
1) Red
E) earth
2) Blue
3) Yellow
( I installed this to replace a rats-nest over 20 years ago!)
The Satchwell TLX 2356 has:
blue, red, empty, yellow terminals (right to left)
The CM907 (installation instruction downloaded from web) says it can
replace ANY roomstat but I can't see what to connect what to connect to
what!
Help?
Jim Chisholm
programmable tempstat
I've a Honeywell wiring panel in heater cupboard.
The wiring panel (Honeywell 42005748-001)
has at ROOMSTAT block:
1) Red
E) earth
2) Blue
3) Yellow
( I installed this to replace a rats-nest over 20 years ago!)
The Satchwell TLX 2356 has:
blue, red, empty, yellow terminals (right to left)
The CM907 (installation instruction downloaded from web) says it can
replace ANY roomstat but I can't see what to connect what to connect to
what!
Help?
Jim Chisholm
JohnW
Nov 8, 2011, 5:00:19 PM11/8/11
to
wires go to.
AIUI
CM907 terminal A is common, on the TLX it is terminal 3
CM907 demand is terminal B which is TLX terminal 1
CM907 satisfied is terminal C which is TLX terminal 2
TLX terminal 4 looks to be spare for a neutral which is not used on
the CM907 and needs to be insulated.
so if on the TLX the blue is on 4, red on 3 nothing on 2 and yellow on
1
Connect Yellow to B, Red to A, and insulate the Blue
John
Jim Chisholm
Nov 8, 2011, 5:20:50 PM11/8/11
to
I hadn't mapped the numbers on the plastic cover to the terminals as
there are no numbers on the black plastic body
but your description is very useful, and the colours maop to terminal
numbes as you predict.
I'd feared damaging the CM907 if I connected it incorrectly!
Jim
>
>
> John
Roger Mills
Nov 8, 2011, 5:52:12 PM11/8/11
to
has a built-in accelerator heating resistor, and thus needs a neutral
connection in addition to live and switched live. The most likely
scenario is that red is live, blue is neutral and yellow is switched
live - but you need to verify this because *function* is more important
than *colour* and you can't necessarily rely on what the last bloke did
- unless it was you!
The Honeywell programmable stat just needs a live and switched live -
connected to whichever two of the three available terminals are
connected together by the stat when heating is required, and separated
when the demand is satisfied. DO NOT connect the neutral or earth wires
to any of the terminals!
Sorry to be slightly vague about which terminals and colours are which -
but if you can't work it out, you shouldn't be doing it!
--
Cheers,
Roger
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fred
Nov 8, 2011, 6:03:26 PM11/8/11
to
In article <j9ca03$61m$1...@dont-email.me>, Jim Chisholm
<jim.ch...@ucs.nscam.ac.uk> writes
you think should connect for 'call to heat' with a switch or wire link.
If you have the connection correct then the boiler will fire when the
switch or link is made and not when it is open. In the event of an error
then a fuse may blow but your expensive thermostat will be saved.
Not suggesting this as a trial and error substitute for proper research
(as you are doing here) but as a final check before connecting the stat.
--
fred
it's a ba-na-na . . . .
<jim.ch...@ucs.nscam.ac.uk> writes
>
>I'd feared damaging the CM907 if I connected it incorrectly!
>
If you have any doubt, the safe option is to link the 2 terminals that
>I'd feared damaging the CM907 if I connected it incorrectly!
>
you think should connect for 'call to heat' with a switch or wire link.
If you have the connection correct then the boiler will fire when the
switch or link is made and not when it is open. In the event of an error
then a fuse may blow but your expensive thermostat will be saved.
Not suggesting this as a trial and error substitute for proper research
(as you are doing here) but as a final check before connecting the stat.
--
fred
it's a ba-na-na . . . .
Jim Chisholm
Nov 13, 2011, 11:11:38 AM11/13/11
to
On 08/11/2011 22:00, JohnW wrote:
After a delay in getting unit (7 day programmable Room Thermostat) it's
now installed and working.
After removing old thermostat, I discovered wire just came out of wall
with no box. Installed shallow box as more professional job.
It was more than a 5 min job as I hadn't a suitable box.
Now means that stat can be at lower temp for breakfast and even lower
during day when we should be active. Also means if temp drops very low
(12degC) at night boiler will have a burn.
I recon it should both be able to save on heating and make environment
more comfortable.
Jim Chisholm
fred
Nov 14, 2011, 2:58:39 PM11/14/11
to
In article <j9oq7q$b4t$1...@dont-email.me>, Jim Chisholm
<jim.ch...@ucs.nscam.ac.uk> writes
>
I have one of these and didn't like some of the default settings:
1. It is set to cycle 6 times per hour which I just don't want, I want
long slow burns (for efficiency) but the minimum cycle you can set it to
is 3.
2. Minimum on and off times were 1min (I think). To me this is just
daft, by the time the pipes are getting warm, it's cycling off again.
Think I set it to 3mins minimum.
Other than that it does work well but I would have preferred if
proportional control could have been turned off in some circumstances
eg. when you have it set to control at a setback temperature of say
14degC I don't need it to cycle the boiler repeatedly to be exactly
between 13.9 and 14.1, I'd be happy to have it broadly controlled
between 13.5 & 14.5 and perhaps not cycle so much.
Just my thoughts but it is still prob one of the best and easiest to
uses stats on the market.
<jim.ch...@ucs.nscam.ac.uk> writes
>
>After a delay in getting unit (7 day programmable Room Thermostat) it's
>now installed and working.
>
>After removing old thermostat, I discovered wire just came out of wall
>with no box. Installed shallow box as more professional job.
>It was more than a 5 min job as I hadn't a suitable box.
>
>Now means that stat can be at lower temp for breakfast and even lower
>during day when we should be active. Also means if temp drops very low
>(12degC) at night boiler will have a burn.
>
>I recon it should both be able to save on heating and make environment
>more comfortable.
>
Glad it worked for you.
>now installed and working.
>
>After removing old thermostat, I discovered wire just came out of wall
>with no box. Installed shallow box as more professional job.
>It was more than a 5 min job as I hadn't a suitable box.
>
>Now means that stat can be at lower temp for breakfast and even lower
>during day when we should be active. Also means if temp drops very low
>(12degC) at night boiler will have a burn.
>
>I recon it should both be able to save on heating and make environment
>more comfortable.
>
I have one of these and didn't like some of the default settings:
1. It is set to cycle 6 times per hour which I just don't want, I want
long slow burns (for efficiency) but the minimum cycle you can set it to
is 3.
2. Minimum on and off times were 1min (I think). To me this is just
daft, by the time the pipes are getting warm, it's cycling off again.
Think I set it to 3mins minimum.
Other than that it does work well but I would have preferred if
proportional control could have been turned off in some circumstances
eg. when you have it set to control at a setback temperature of say
14degC I don't need it to cycle the boiler repeatedly to be exactly
between 13.9 and 14.1, I'd be happy to have it broadly controlled
between 13.5 & 14.5 and perhaps not cycle so much.
Just my thoughts but it is still prob one of the best and easiest to
uses stats on the market.
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