Thermostat wiring help

stant98November 12, 2010

Hi all,

With the winter approaching, I thought to take some time to review / update my condo's heating. Sealed the windows, installed window and door weather stripping. While doing all that, I came across my 5-yr old RiteTemp 8022C thermostat and had a thought to upgrade it.

I have 12 SEER Bryant heat pump with an indoor air handler that is equipped with a 10KW heat strip. The HVAC system is all electric, and, if I understand it right, it is 1 stage cool 2 stage heating system.

So back to the issue. I noticed that my indoor thermostat is currently wired with 5 wires as follows:

Black wire on C terminal

Red wire on RC terminal with a jumper wire to RH terminal

Orange wire on O terminal

White wire on W terminal with a jumper wire to Y terminal

Yellow wire on Y terminal

Green wire on G terminal

So now, I am thinking: does the wiring as I have it right now make the aux. heat come on together with the stage 1 heat (i.e. compressor)?

Then, I looked at the new programmable thermostats by Honeywell and Lux. And from what I can tell for 1 cool 2 heat systems they have W1, W2 Y1, Y2 terminals.

As I have it right now, there are 5 wires that are fed to the indoor thermostat:

C terminal wire - black

RC terminal wire - red

O wire - orange

W wire - white

Y wire - yellow

G wire - green

The question I have is what thermostat do I need (if the new ones have W1 Y1 terminals and currently my wiring is as described above).

Am I right in my statement that I have a single stage heating system with aux. electric heat, i.e. 1 cool 2 heat system?

Thanks in advance!

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What do you mean by 'upgrade'? Isn't this a programmable t-stat?
Unless it is broken- I wouldn't bother. A newer thermostat isn't any more efficient.

    Bookmark   November 12, 2010 at 9:40PM
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I mean buy a new one. My concern is that there is a jumper between the W and Y terminals and I suspect that this makes the aux. heat come on EVERY TIME the condensing unit, i.e. the heat pump comes on. Don't know how to make sure that this is or isn't so.

    Bookmark   November 12, 2010 at 10:05PM
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(1)Little to no test equipment method. Remove the jumper, set thermostat up just enough to make the system call for heat. If the air from your registers is significantly colder, then your suspicion is probably correct, removing the jumper disabled heat strips.

(2) If you have a clamp on ammeter. Check the current draw of your inside unit when the system calls for heat. if it is 40A or so your heat strips are on. If about 5A, then they are not.

You do not have a "1 cool 2 heat" system. You have a heat pump, with electric strip heat. You need a heat pump compatible 'stat with an O lead for the reversing valve.

(Disclaimer- I'm not an HVAC expert, the above advice is based on my own experience with my heat pump and a dozen thermostats before I found one that keeps the house comfortable and doesn't result in huge power bills.)

    Bookmark   November 12, 2010 at 10:48PM
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Here is the install guide for your thermostat. It does illustrate a jumper between W and Y in a heat pump application. Apparently, it does not provide separate control of strip heat.

Here is a link that might be useful: Install guide

    Bookmark   November 12, 2010 at 11:11PM
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I understand you want to buy a new one- my question was why?

    Bookmark   November 13, 2010 at 9:48AM
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Why I want to buy a new thermostat because the one installed right now appears to be wrong that is it does not provide a separate control for aux heat, which causes, the aux. heat to come on with the heat pump call for heat (compressor Y) every time. Isn't this so with the W to Y jumper hookup?

What is the purpose of the W to Y jumper? Why some tstat installs require this? Why couldn't I have a yellow wire to Y and white wire on W and that's it?

    Bookmark   November 13, 2010 at 10:41AM
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Yellow is usually 'turn on the compressor'. For a heat pump, Orange or Blue is used for determining the direction of the reversing valve, active in Heat or active in Cold. The valve direction depends on the manufacturer.

White is usually used to turn on the auxiliary heat.

A Tstat that has Y1 and Y2 can handle multistage heat pumps.

A Tstat that has W1 and W2 can handle multistage auxiliary heat.

This thermostat doesn't really control a heat pump. For one thing, it has no Emergency Heat setting. Apparently, it does not control the W for heat and the Y for compressor separately. Rather it turns on W for heat and Y for cool (which is why there is a jumper). Without the jumper, you would have no compressor during heat modes.

Go get you a new unit that is HP compatible.

    Bookmark   November 14, 2010 at 1:03PM
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I would recommend a honeywell model with outdoor temp sensing so you have 'real' control of what is going on and when.

These units have what are called lockouts for the heat strips and heat pump. If the weather is moderate enough your heat pump can do the job with no help of the strips you can 'lock them out' so they will not come on. You can also lock out the heat pump below very frigid temps which is beneficial on units without demand defrost and low seer.

Here is a scenerio.

above 35 degrees heat pump only.. strips locked out

Below 15 degrees.. strips only.. heat pump locked out

25 degrees out.. heat pump operating and strips operating as needed.

This allows better control and can save a load of money. For people in moderate climates or people who use the daily setbacks they calculate by outside temp when to start ramping up the temp so it is at the desired temp at the right temp.

Honeywell is one that makes this type of stat and they are really reasonable on Ebay.

The Honeywell Visonpro series 8320 will do what you want for around 100.00 shipped and outdoor temp sensor is like 15.00 more. There is another that does dehumidification and humidification for slightly more.

The Visionpro IAQ will do humidification if you have a humidifier on the system already and dehumidification and the best part is only THREE wires are needed at the stat. The rest go to the control module at the furnace which saves a ton of headache. These are around 200.00 with the outdoor sensor.

There are others out but the honeywell units are the only ones I have experience with. There is also a model with a color display. All of these are touch screen and not horrible to set up.

You will save enough money to pay for either option you choose this year I am sure.

The heat strips can possibly be staged so you do not run all of the strips and the heat pump at the same time which will be even more beneficial.

I would stay in the pro install units so you have the best features. They are not bad to install and set up for the average DIY'er.

Here is a link that might be useful: Honeywell visionpro. Pro Install units only.

    Bookmark   November 22, 2010 at 12:23AM
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