Heat Pump Thermostat Problem

[mcp6453]

Back in November, my HVAC guy replaced my thermostat on my heat pump with a Honeywell TH8320. He did it at the same time that he corrected a wiring problem near the air handler underneath the house. A terminal overheated and melted a wire. The thermostat wiring was not affected. The heat has been working fine.

Today it got warm enough that we turned on the air conditioning. After a few minutes, we noticed that it had gotten noticeably warmer in the house. The vents were blowing very warm air. The heat strips may have been on.

My natural assumption is that the new thermostat is wiring wrong. Here is the way it is wired:

RC - Red (cooling power) R - no connection (heating power) O/B - Orange (changeover valve) Y - Yellow (compressor) G - Green (fan) C - Blue (common) E - White (emergency heat relay) AUX - White (aux heat relay)

E and AUX are jumpered together.

The manual says that R and RC should be jumpered together UNLESS the system is a two-transformer system. My system has only one transformer.

Here are my questions, with what little I know:

1. Should there be a jumper between R and RC?
2. If there should be a jumper, how is heat working with a wire going to RC?

While I was troubleshooting, my HVAC guy called me back. He's in bed with the flu. Just my luck.

I'll post a picture to the present wiring in a few moments. You guys have helped me tremendously before. Thanks!

[mcp6453]

Here is a picture of the present wiring:

or the direct link:

You can't see it well in the picture, but there is a jumper between E and AUX. It's hidden by the black wire.

[trader4]

Yes, just like the manual says, unless you have seperate transformers for heating and cooling.

R and RC provide the power source that the thermostat then connects to the various wires to initiate action. Since they are connected together, let's just call them R/RC. By connecting that point to Y it activates the compressor. Connecting it to G turns on the fan, etc.

I have this thermostat, but it's on a conventional system, not a heat pump. My understanding of the difference between aux heat and emergency heat is that aux is used in conjunction with the heat pump in cases where the heat pump cannot supply enough heat, eg outside temps too low, but the heap pump keeps working too. Emergency heat disables the heat pump and uses whatever the emergency heat source is. I would think in many, if not most cases, that heat source would be the same. So, I would guess that it would be common to have aux and emerg heat terminals jumpered.

What you need to do is figure out what terminals those wires are connected to at the other end. It's possible something is wired up wrong, but you won't be able to tell without seeing what the wires connect to on the other end.

You should also put the thermostat into installer mode and verify that it is set up correctly for the system you have. You have to select the system type, number of stages, etc.

[mcp6453]

I caught the techs at Honeywell before they left at 8:00. They had me verify that location 170 is 7, but they had me change location 190 to 1. Then I added the jumper. It didn't cool, so I called an HVAC company that a friend uses. A tech answered the phone, and we scheduled an appointment for Monday morning.

He asked me to step through the things I had done. He knew the thermostat by heart. He asked me what was in location 190. Then he asked me what unit I have, which is Carrier. He said that 190 needs to be a 0. I changed it back, and everything seems to be working.

He's still going to come out Monday morning to verify that everything is okay. There was a wiring problem on the air handler (unrelated to the thermostat) in November, so he's going to check to make sure that's okay. Hopefully all is well until then.

Thanks very much for your input. This information is very helpful for me to understand what's going on.

[trader4]

Glad to see it worked out for you. Interesting that you got Honeywell to answer your questions for you. I called them up a few weeks ago on the same thermostat and they told me to get lost. The help desk refused to answer ANY question related to the "install" menu. He insisted that product is "to be installed by a licensed contractor only". You can't find the install manual on their website either. Unbelievable. There position is that having bought their product, if I wanted to change an install menu item, like say the number of cycles it will run per hour, I have to call a "licensed contractor". So, on top of paying for their thermostat and presumbly an HVAC contractor to install it in the first place, if I want to change it's operation at all, I should pay $100 for an HVAC guy to come out and change one bit for me..... Totally pissed me off. It's a great thermostat, but given a choice I won't buy any Honeywell products from here on out.

BTW, where does a contractor get a license to install a thermostat? The imbecile on the phone couldn't answer that question. In most parts of the USA, thermostats are routinely installed by everyone from homeowners to handymen. Obviously, what they really want to protect is their silly marketing strategy, even though you can buy these thermostats all over the place on Ebay. And you can buy their other thermostats at HD and Lowes.

[starrin]

Here's the installation manual for the series. Installer setup manual access is addressed about half way in:

[trader4]

Thanks, but I had that install manual at the time. My remark was just to let others know how Honeywell operates. It is all the more remarkable because as you point out, the install manual is available on the internet to anyone from various websites, but not from Honeywell.

[mcp6453]

in:

> HTH- Hide quoted text -

I had to call them three or four times, but all but one person was willing to speak with me about it. One guy was a jerk. Maybe it helped that I told them truthfully that at 8PM on Friday afternoon with my HVAC guy in bed with the flu, I was out of options.

For what it's worth, Honeywell helped me understand a lot about the thermostat, but much of the advice they gave me was wrong. The last guy was great, but he had me change 190 to a 1 without asking what brand of unit I had. The location had to be a 0 for a Carrier. Nevertheless, the help they gave me enabled me to get to a solution with a local HVAC guy, so I do appreciate the assistance.

The link above is the correct manual on the Honeywell site, if someone needs it.

[trader4]

That;s probably the guy I got. Sounded like Lawrence Welk. Maybe it was his son. Wasn't he from Minnesota?

That's interesting. So, their position is they won't support it unless you're a "licensed contractor", but they themselves don't know how it works.

Not to be nit picky, but the link above is NOT to Honeywell's site. I could not find the installation manual anywhere on Honeywell's site. . It's probably there in some hidden part, only accessible by authorized agents. If you google, it comes up at HVAC companies, etc, but not at Honeywell.