I have a White Rodgers T-stat in a multi-family home that I'm trying
to hook up a remote temp sensor. I have a basic steam boiler with the
connections to the T-stat as shown on the top of page 4
When I tried hooking up the remote sensor, I followed the instructions
of cutting a jumper on the T-stat and also setting the programming to
"sensor on", but it still does not read the sensor. One thing it
mentions in the manual is that the sensor needs constant 24v and that
I might need an "isolation relay" on power stealing t-stats as shown
on the bottom of page 2:
Now this confuses me. I thought that I do have 24v coming from the
boiler Xfrmr. Is this isolation relay necessary? And is the Xfrmr they
show on page 2, is this a seperate Xfmr from the one on the boiler?
On Sat, 22 Nov 2008 07:20:04 -0800 (PST), Mikepier
You may or may not have 24v coming from the boiler tx to the stat. A
power stealing thermostat has the following wiring Red(24v),
White(Heat), Yellow(AC), Green(Indoor Blower) Blue(24v Common). A non
power stealing thermostat will have all the same wires EXCEPT the Blue
common. The wire colors I have described may be different in your
setup if the wiring color code convention was not followed. Not too
familiar with oil systems or boilers but it would appear from the
diagram that your stat is NOT power stealing. One way to tell is to
take the batteries out of it. If the display stays lit then it is
power stealing, if the display goes dark then it is not power
stealing. There is a note on page 11 that says
"The remote sense feature will not work if
the system does not provide 24V to the
thermostat (example: millivolt heating-only
systems or 3-wire zone valves).
To use a remote sensor, jumper W922 must be
clipped (see figure 10) and the REMT SEN
option in the configuration menu must be set on."
Again, your thermostat does not appear to be power stealing based on
the diagram you provided. You can make it power steal by doing the
1. At the boiler identify the point that the thermostat wires connect
2. Find a terminal labeled "c".
3. Take any spare thermostat wire in the bundle and connect it to that
4. Go to the thermostat and connect the other end of the same wire to
the common terminal of the thermostat.
5. In the diagram you provided it appears that the thermostat may not
have a common connection.
On Sat, 22 Nov 2008 08:42:45 -0800 (PST), Mikepier
The light is dimming slowly because there is a capcitor in the
thermostat that acts like a battery. Because your thermostat is
dimming when you remove the batteries it is most definetly not a power
stealing thermostat. You need to get a thermostat that is a power
stealing one (one that has a common connection, or "c" terminal). Why
are you using a remote sensor anyway? Check this out:
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