2441TH Thermostat Does Not Power

[jesn]

I thought I would start a new topic instead of hijacking someone else's thread.

Anyway I just bought the comfort kit and wired up the 2441th with no success. My current thermostat was only using 4 of the 5 wires (blue was not used) and is battery powered. I wired up the 2441th and nothing happens. I measured the voltage and the systems is 24volts.

I attached a pic of the existing system.

[BLH]

Did you verify the wire connections on the controller end of the wiring ?
The Blue wire may not be connected at the other end or the wiring may not be to what is the commonly used wire color pin out.

[jesn]

Thanks. Ill check it out.

[blackofe]

got exactly the same issue!

initially i have a 4 wire thermostat, but actually it seems to me prewired for more: the red, white, yellow and green wires are used, however there are blue, black, orange and brown as well:

WP_20150124_003.jpg

since i have only one heater and one A/C, i didn't use the brown, orange and black ones:

WP_20150124_004.jpg

1. turned A/C power switch off.
2. replaced the thermostats.
3. closed the new thermostat's cover.
4. turned A/C power switch on.

unfortunately nothing happened. i've checked the voltage on the red and blue wire - it's about 22.7 volts. is it enough?

i've tried the black wire instead of the blue one - no success.

no idea what to do. can i have some help?

[stusviews]

Does the thermostat light up?

[BLH]

Same answer. Look at the Furnace controller end of the wire and see exactly what is connected to what color wire.

[Danowe36]

if the old was a battery you may need a fifth wire or eliminate the fan. I know the nest you can use 4 wire but the honeywell you need 5 wire. if you need a 5th wire you need a jumper put in. and move wire in your furnace I don't want to tell you what wire because I can't see what you have going on.

in most cases

white heat
yellow ac
green fan
red hot 24 volt
so you may need to add a wire for com. to keep display powered up. I would need to see wiring diagram to verify this.

[jesn]

I checked the wires on the furnace end this morning and the blue wire was not connected to anything. I connected it and I will try to see if it will work when I get home.

[blackofe]

Does the thermostat light up?

nope. this is the problem.

[stusviews]

blackofe,

Disconnect the red and blue wires at the thermostat. What is the voltage between the disconnected red and blue wires?

[blackofe]

if the old was a battery you may need a fifth wire or eliminate the fan. I know the nest you can use 4 wire but the honeywell you need 5 wire. if you need a 5th wire you need a jumper put in. and move wire in your furnace I don't want to tell you what wire because I can't see what you have going on.

initially I got a battery powered thermostat (named Robertshaw model 9600). following the manual it might be connected with 5 wires:

connections.png
however RC has been never used (see my pictures above) - there's a jumper connected RH and RC together. when I replaced the thermostat by the insteon, I've used the blue wire came out of the wall. may be I was wrong and I should use a jumper, too?

in most cases

white heat
yellow ac
green fan
red hot 24 volt
so you may need to add a wire for com. to keep display powered up. I would need to see wiring diagram to verify this.

this is the question. I used the blue wire connected to 24 VAC common. what if I was wrong? how can I check, if the blue wire works with insteon thermostat? should I use a jumper instead?

insteon proposes to use an additional device for 4-wire systems.

INSTEON Thermostat is designed to operate on a minimum 5-wire, 24V HVAC unit. If you have only 4 wires you can purchase the "Add-A-Wire" adapter item #304AAW from www.smarthome.com.

can it help? the only question: do I really need such a device, if I have 8 (!) wires coming out of the wall?

[stusviews]

You have enough wires. But, when not used, as with the Robertshaw thermostat, the blue wire is not connected to anything at the other end (i.e., HVAC panel). Check the other end of the thermostat cable.

[jesn]

Well, I connected the blue wire inside the furnace to the only terminal that was open and i still get noting at the thermostat. Any more ideas?

[stusviews]

Which terminal? Did it have a letter? What are all the terminals labelled? BTW, it's not a good idea to just randomly connect wires, you may burn something out.

[jesn]

Figured it out. The furnace had a terminal labeled "c". Connected the blue wire to that and everything works great.