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  • Fan G circuit not energized when heating

    I have a 2441TH and it is wired correctly with 5 wires to an electric heat and A/C combo unit. Wires are:
    Insteon = Color = Connects to on unit
    24COM = Black = Common
    24R = Red = 24 VAC
    W1 = White = W2
    G = Green = GH (unit has GH and GL for high and low fan speeds)
    Y1 = Yellow = Y/W1
    The unit also has a B connection but that is because this unit comes in models with either electric heat or heat pump and they probably use the same board. I have the electric heat model.

    When I turn on Fan Always on the Insteon the fan comes on and stays on, no problem.

    When I set it into cooling mode the compressor and fan both come on and it cools, no problem.

    When I put it in heating mode the it does not operate and I get the light on the board blinking an error code of "Bad thermostat inputs".

    The unit requires W2 + G be energized to produce heat (or Y/W1 + B + G). I disconnected the thermostat, jumpered 24VAC to W2 and G and it produced heat so it works.

    I called Insteon and asked if the G circuit is supposed to be energized when the thermostat is calling for heat. At first the techie said no. Then I told him it did when calling for cooling and he put me on hold and came back and said yes, G should energize when heat is called for. That's what I would expect. The techie told me the thermostat was defective.

    I checked with a meter and verified that G circuit is NOT energizing when the Insteon calls for heat. It stays at 13 to 17 VAC instead of jumping up to 24 VAC. I put it in Fan Always mode and the fan came on, then I put it in heating mode and it worked, the unit produced heat.

    I had a 2nd one so switched it out. Same thing.

    Question: Is this a changeable setting on the Insteon, G is energized during heat or not? If so, how do I set it? If not, what can I do?

    I know many heating systems need to have G energized during heating to work. Some do not. All the other digital thermostats whose installation instructions I have downloaded have settings for this. I would think that the default would be to energize G just in case it is needed. But I am going to be really surprised if an expensive thermostat like this cannot be setup either way.

  • #2
    What is the original thermostat, model and brand?
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    • #3
      There was no original thermostat. The unit is one of those through-the-wall combos like you see in hotel rooms. It has a switch and dial on the console but is equipped to connect a remote thermostat too. I am adding the thermostat and I can disable the console controls via an on-board console-remote selector switch.
      Last edited by adv; 12-04-2016, 11:38 PM.

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      • #4
        The connections you described are not standard. The Insteon thermostat is not meant for electric heat, but the unit you have may connect to a standard thermostat. Provide details about the unit.
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        • #5
          It is one of those ubiquitous PTAC units. This one is branded Amana but I have seen them branded Comfort-Aire, Honeywell, Century, Gree, Freidrich, PerfectAire, etc and they all seem to have been built by a company called Heat Controller Inc out of Jackson, Michigan. Around 2012-13 that company was aquired by MARS Motors and Components Division out of Hauppauge, NY. My unit is circa 1980's.

          These come as A/C with electric heat (PTAC) or A/C / heat pump. Mine has electric heat. The knob controls on the unit allow for Fan Only, Low Heat, High Heat, Low Cool, and High Cool and there is a temperature thermostat knob too. The connections for the remote thermostat are the 7 outlined in the original posting. A sheet that was with the unit says that signals for the remote thermostat should be:
          Fan only = G
          Cooling = G + Y/W1
          Heating = G + W2 or G + B + Y/W1, A note says the 2nd option is for a heat pump thermostat used for conventional I have it hooked up the 1st way. I do have extra wires to try the other way but it is not going to work anyway if the G is not energized for heating.

          I had a Hunter digital thermometer sitting around and it had buttons on it to select which type of system and functions it needed to work with. This one only works 1 way?

          Question: If I got the Insteon Thermostat for Heat Pumps would it energize G during heating?

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          • #6
            No, the heat pump thermostat will not help. The instructions are unusual, in particular Y/W1 for cooling and W2 for heating is not standard. Y is normally the designation for cooling, W1 is the label for single stage heat or the first of two stage heat and W2 is for the second stage of two stage heating.

            Do you have a link to the manual or a model number?
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            • #7
              I think that the odd inputs stem from the fact that these units have A/C and can come with a heat pump, heat pump with electric heat (2-stage), or just electric heat and they use the same board for all models. G + Y/W1 + B calls for 1st stage heat (heat pump) and G + W2 calls for 2nd stage heat (electric heat). My unit does not have a heat pump so either input combination will turn on the electric heat. BTW, G + Y/W1 calls for cooling so the Y/W1 just controls the compressor.

              I get that oil or gas furnaces often have only a W terminal and no G terminal and the fan for heat is controlled internally by the furnace controller. I also get that A/C units often have both Y and G terminals and the compressor and fan are turned on by the thermostat and the fan is NOT controlled internally by the A/C controller. But in a heat pump system the heat is the same system as the A/C but with the reversing valve reversed, right? And you are telling me that on a heat pump system the fan is controlled internally by the controller when it is heating but the fan is controlled externally by the thermostat when it is cooling? I am just asking this again to double check whether my problem would be solved if I got the Insteon Thermostat for Heat Pumps.

              There are a ton of manuals for these hotel PTAC units on the web but I had trouble finding one for exactly my unit. Most of the manuals I found are for newer units with push button/LED controls instead of knobs. The link below seems to be a manual for the older units including mine, or something very similar:
              http://delpuerto.com.mx/wp-content/u...ERApth_new.pdf

              This manual is for several different series and my unit seems to be a "C-E Series" straight cool (NOT a heat pump) with the 14-pin connector for the remote controls. The info on wiring the remote thermostat starts on page 20, wiring diagrams are on page 21, and instructions continue on page 22. The full wiring schematic for my unit is on page 73 and I know it is for my unit because it is identical to the sheet that was in a plastic envelope inside my unit and looks like it has been there for the duration. On that schematic is a chart that indicates what inputs should be energized for fan, cooling, and heating.

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              • #8
                I did not tell you any of what you stated. In a standard HVAC system, the fan turns on when heat is called for, when cooling is called for or manually. In each situation, then fan is controlled by the thermostat.

                A concern is that the fan doesn't turn on when heat is called for. Disconnect both the white and yellow wires. Measure the voltage between G and 24COM for each of heating and cooling modes. What did you find?
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                • #9
                  OK, what I was saying is that the Insteon Wired Thermostat for Conventional energizes both G + Y when calling for cooling but only energizes W when calling for heating, not G. I assumed it was that way because central A/C units need the G to be energized to get their fans to run. No? Why, then, does the Insteon energize G when calling for cooling but not when calling for heating?

                  I assume you wanted me to check those voltages at the unit side, not the thermostat side, right? Would it make a difference if W and Y were connected or not? I checked and found that during cooling G is energized but not during heating. That was with W and Y still connected. It runs fine when cooling but throws a code when heating (unless I turn on Fans Always On).

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                  • #10
                    All three of my 2441TH thermostats energize G (~24VAC) whether calling for heat or for cool, otherwise the voltage is 0 (zero). That you're getting an unusual voltage suggests that the cause is something wired to the thermostat. The only way to verify that is to disconnect both the yellow and white wires.
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                    Saving energy is not always free. Be a world saver.

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                    • #11
                      Oh!

                      But Insteon tech support told me on the phone the other day that G was NOT supposed to be energized when it called for heating. Of course, that was after they told me last week that it WAS and that was just after that is wasn't (in the same phone call) so I am not sure.

                      Just tested, in a few configurations. All measurements made at the heater unit control board and VAC. This is what I get:

                      W & Y disconnected: R=25.4 W=10.1 Y=13.6 G=13.3

                      All connected, while cooling: R=? W=12.7 Y=22.9 G=22.8

                      All connected, while heating (Fan Always On switch on): R=22.8 W=21.9 Y=12 G=21.9

                      All connected, calling for heat but not heating: R=24.18 W=23.9 Y=? G=13.3

                      All disconnected form board: R=25 W=10 Y=13.5 G=13.3

                      Is there supposed to be residual voltage on the pins on the control board when they are nto even connected to anything?

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                      • #12
                        That indicates that the control board is propriety and requires a particular thermostat. A standard thermostat is not appropriate. You can test this yourself by installing a low cost thermostat such as this one.
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                        Please don't PM with questions that can be asked in a forum.

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                        • #13
                          It works with my Hunter programmable thermostat but that has switches to set for heat pump, conventional, O, B, etc. It also works fine with this Insteon Thermostat when I put it in Fan Always On mode but I don't want to run the fan 24/7, of course. If I can just get the G circuit to turn on when it calls for heat then I will be all set.

                          You wrote earlier that "All three of my 2441TH thermostats energize G (~24VAC) whether calling for heat or for cool, otherwise the voltage is 0 (zero)." Are you 100% sure that is true? If so, then I have a bad thermostat and just need to replace it. So, please verify that is true so if I go out and get yet another one then I won't have yet the same problem.

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                          • #14
                            A reread of your measurements make no sense. If all the wires are disconnected from the control board, the you should not get any voltage reading at any terminal.
                            Stu's Views is Education and Fun. What do YOU want to VIEW today?
                            MathLandia High school mathematics learning fun.
                            Both Stu's Views and MathLandia are free websites that do not sell anything.
                            Saving energy is not always free. Be a world saver.

                            Please don't PM with questions that can be asked in a forum.

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                            • #15
                              Yeah, that's what I thought. So does that indicate that the board is defective? Obviously, there is some sort of voltage coming to those pins from the system itself. And I have a decent meter and I checked all of the readings like 5 times each and both to frame ground and the C pin. There was sometimes a difference between readings from frame to C pin but < 1 VAC.

                              But the strange thing is that IT WORKS FINE if I get the G circuit in the thermostat to energize. I just need that to happen without the fan always running.

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