Carrier Thermostat Troubleshooting - I have a Carrier thermostat with an intermittent problem that recently has started to oscillate between off, cool, and heat, seemingly randomly. We set the temps for cooling and heating, time, day, and all of those programmed pieces of data remain, but the t-stat just randomly switches between heat, cool, and off (doesn’t ever go blank, it only displays “off”).
The switching between each setting might happen every second. Or there might be a minute or so between the setting changes.
I am wondering where I should begin looking to diagnose the thermostat problem.
Thanks in advance! Jeff
How to Wire a Heat Pump for Control - There may be a time when you will want to change your old heat pump thermostat with a new heat pump thermostat. We have other articles here that will help you with thermostat wiring. These other articles help you with thermostat wiring colors and thermostat wiring diagrams. In this article, we will provide specific information for wiring a heat pump for control.
Wiring a heat pump is different than wiring an air conditioner with a gas furnace or boiler. There are extra controls in heat pumps that require extra attention and understanding to get the wiring correct. Additionally, changing an older mechanical thermostat to a newer digital thermostat will require some extra wiring that also may require you to pull new wire to the thermostat from the air handler.
Before doing any wiring for your thermostat
or otherwise, always make sure you turn off the power at the breaker and the air handler/condenser. Furthermore, you can cause serious damage to your system for not doing so.
Variations for Heat Pump Thermostat Wiring | How to Wire a Heat Pump for Control
There are many variations to wiring a heat pump for control because there are many types of heat pumps. Heat pumps provide heating and cooling for a home or business. Heat pumps use the process of refrigeration to move heat in one direction or another depending on the season and the setting of the thermostat. Additionally, air-source heat pumps have backup methods of heating for two reasons. (more…)
Thermostat Wiring Instructions not Matching New - I have a slightly older Rheem unit with the typical slide temp adjuster thermostat. I want to replace the old Thermostat with a digital, TP-N-721 from Vive Comfort that I have (not programmable, just digital. My current (old) thermostat is wired as such: Red - R | Blue - B | Green - G | Yellow - Y | Orange - O | White - W2 | Black - E | Brown - X. 8 Connections. The Terminal “L” on the old thermostat is not used.
The connections on the new TP-N-721 are. (one the left side of the base plate: C, O, B, E, and W2. Then on the right side of the base plate R, G, and Y. Here is what I can presume the new thermostat wiring will be, some are obvious: Red - R | Orange - O | Green - G | Yellow - Y | Blue - B | White - W2 | Black - E (That’s 7) but is this right and where does BROWN go? The only one left is “C”. . . Which should be “Common, which changes my presumption. I really do appreciate your help. Thanks! (more…)
Honeywell Heat Pump Thermostat Troubleshooting. Hello Richard! We have a Honeywell VisionPro (8000) thermostat with a Carrier heat pump that has two stages for heating and cooling. We are having problems with the staging of the system, especially in heating mode.
I know the problem also occurs in the cooling mode but it seems worse in the heating mode. The house seems to get uncomfortable even though the system is running and then finally after the thermostat gets to a certain point the second stage will turn on and we feel the difference. It doesn’t matter where we set the thermostat to for temperature. A friend of mine suggested I had a problem with a limit switch.
We also notice sometimes the outside temperature reading on the thermostat is incorrect sometimes and rarely matches the reported temperature from our News sources where we live. Just wondering what your thoughts are and if you can guide us in the right direction. We found your site by doing a search for Honeywell thermostat problems. Anyhow, can you help us, please? Thanks in advance!!! (more…)
Two-Stage Furnace Air Conditioner Thermostat Control Problem | Hi I was wondering if you can help me with a two thermostat… because I don’t think my condenser is using the second stage…. I open the thermostat and see the jumpers, but is there a way you can illustrate my brain and the correct set up I have an Amana 16 seer 2 stage 5 ton units and no one seems to understand this unit,
I went into the attic. found my models my Condenser ASXC160601BC serial #1307225441 Is a two-stage scroll compressor cooling. my furnace is model AMVC950905CXBA serial #1307131781 two-stage gas furnace burner variable speed blowers… this is how is wired at this moment: (more…)
Thermostat Terminal Designations Explanations - You are wiring a new thermostat or about to wire a new thermostat and you want to understand what the terminal designations are on your old and your new thermostat. Why is it such a mystery with these terminal designations? Once you get into seeing how this works it all becomes common sense. This is as long as whoever wired the thermostat originally followed the common sense code of designations.
A good example of this is I have opened thermostats and seen black used on the R terminal. Green used on the W terminal and red used on the Y terminal. Once you see the thermostat wire and the colors of thermostat wire that are available you will understand. As far as those unconventional wired thermostats I’ve seen, I can only think that the person was color blind. And that is giving them the benefit of the doubt. Now, on to the designations. (more…)
4 Wire or 5 Wire Thermostat Wiring Problem - Question: We have a 19-year-old condo with an old Carrier mercury thermostat. We have both a natural gas furnace and an AC unit. There are only four wires going into the existing thermostat - red, green, blue, white. On the back of the thermostat are a number of labeled contacts, only the following have wires connecting them:
W - white wire
Y - blue wire
R - red wire
G - green wire
Y wire jumpered to a contact labeled 1 (more…)
How Can I Tell 1 or 2 Transformers for Heating Cooling System? I get this question a lot and I also see this question used in my stats on how people find the site but I do not believe I have directly addressed or dedicated an article to this subject yet but there are residential HVAC systems out there that use 2 transformers and it befuddles some people. How to tell if you have a Dual Transformer HVAC System.
Programmable Thermostat Wiring Diagrams - Installing a programmable thermostat is not unlike installing any other thermostat for your HVAC system. The key is to get the right thermostat for your HVAC system. And to make sure it is wired properly. (more…)
Heat Pump Thermostat Wiring Chart Diagram - HVAC - The following graphics are meant as a guide only. Always follow the manufacturer’s instructions for both the thermostat and the HVAC system. Additional articles on this site concerning thermostats and wiring can help you solve your problem or correctly wire a new thermostat. (more…)