[woodardhsd]

I bought a new construction home back in July 2010. House has Trane heat pump with two zones. Trane 4TEC3F24B100A air handler with BAYHTR1008+++ auxiliary heat (according to air handler label). Both thermostats were TH3110D1008, but I replaced the main floor thermostat with a RTH7600D 7-day programmable touch-screen thermostat. It's all controlled by a Aprilaire 6303 zoned comfort control system.

I never really paid any attention to it, but after talking with a neighbor (his house was built by the same builder) about his heat, I think I discovered that my auxiliary heat is either not wired correctly, or not hooked up at all. I've attached a few photos below.

Here is the programmable thermostat I installed. I connected the wires exactly the same as the thermostat I removed.

Here is the upstairs thermostat wiring connections:

Here are the connections at the zone controller:

From what I can get from reading the manuals for my components, the only way the emergency heat will work is if I manually flip the switch on the controller to "on" . It sounds like the heat will work in emergency mode only until I switch it back off. Shouldn't the auxiliary heat be wired to come on automatically if the difference between room temperature and the thermostat setting is more than 4 degrees or so? Does it look like my equipment was wired incorrectly? Should I call the pros in on this one?

 

[Houston204]

Your zone 1 stat can be rewired to give you emergency heat from the stat as you have posted...

Turn off power to the Aprilaire control board and the air handler (probably the same breaker).

Connect orange to the O/B terminal at the stat and connect orange to O at the zone 1 stat input on your zone control board.

Connect white to Aux at the stat and jumper Aux to E.

Set the aprilaire control panel top toggle to Z1 HP.

Restore power.

Set option 170 to 7 and 190 to 1 on the thermostat.

 

[woodardhsd]

Awesome post, thanks for that. I was going mad trying to go back and forth between the pics I took and all the different manuals I found, matching up wires.

I'm assuming that due to the way everything was wired, my auxiliary heat has never come on? It has never been a problem so far, we've never felt like the heat wasn't working well enough or anything. Always seems to blow decently warm air (for a heat pump)

Another thing I noticed, the upstairs (zone 2) thermostat has a toggle on the back for "electric or heat pump" or "gas or oil". It is currently set for "gas or oil". Will that need to be changed?

 

[JScotty]

Awesome post, thanks for that. I was going mad trying to go back and forth between the pics I took and all the different manuals I found, matching up wires.

I'm assuming that due to the way everything was wired, my auxiliary heat has never come on? It has never been a problem so far, we've never felt like the heat wasn't working well enough or anything. Always seems to blow decently warm air (for a heat pump)

Another thing I noticed, the upstairs (zone 2) thermostat has a toggle on the back for "electric or heat pump" or "gas or oil". It is currently set for "gas or oil". Will that need to be changed?

Probably not. That Elec/Gas switch is somewhat misleading. Most electric furnaces that I've seen actually work better when set in the "gas" position. All that switch does is energize "G" (for the blower) at the same time it energizes "W" (electric heat). This is done because some electric furnaces "G" has to be energized to run the fan, without it the elements will just run with no fan. However from my experience those units are somewhat rare. Most electric furnaces I've run into the fan is turned on by the same switch that turns or the first element.

In those cases flipping that switch to electric causes yor fan to turn on 30 seconds to a minute before your elements and it uses high fan speed (usually heat is set on low) causing you to get a blast of cool air when the unit first comes on. Also when the unit shuts down the blower will reduce speed for a minute or so becuase the elements take a minute or so to shut down, but because "G" is deenergized as soon as the call for heat stops, the fan switches to low because it's still being powered from the switch for your 1st element.

 

[Houston204]

I'm assuming that due to the way everything was wired, my auxiliary heat has never come on?

Looks like the heat strips are energized if the heating demand exists for more than 20 minutes when the control board is set for electric heat.

Another thing I noticed, the upstairs (zone 2) thermostat has a toggle on the back for "electric or heat pump" or "gas or oil". It is currently set for "gas or oil". Will that need to be changed?

I don't see how it will have an effect on operation if the zone control is set for electric operation.

7. SEQUENCE OF OPERATION
Heat/Cool Thermostat Input Definitions: Heat = W, Cool =Y, Fan = G
Heat Pump Thermostat Input Definitions: Heat = Y, Cool = Y + O, Fan = G, Aux. Heat = Y + W, Emergency Heat = W

Fan Operation: A call for Fan from any zone will initiate the G equipment output terminal. The “NO” contact of the damper terminal for a zone not
calling for Fan also energizes, while the “NC” contact de-energizes.

Heating Operation: When a zone makes a call for heat, the B, Y and G output terminal will energize. The “NO” contact of the damper terminal for
any zone not calling for Heat also energizes, while the “NC” contact de-energizes. Following a 4-minute minimum on time, the Y terminal will deenergize
when (1) all zones stop calling for heat, (2) the call has exceeded the heat/cool changeover time limit while a cooling call exists or (3)
the call is interrupted by the high limit setting. Any energized damper terminals remain energized for a one-minute purge (if set to PURGE) or a
3.5 minute purge (if set to NO PURGE). Should the same call exist for 20 minutes, the W terminal will also energize (if set to ELECTRIC) or the W
terminal will energize immediately after the Y and G terminals de-energize (if set to GAS). Following a 2-minute minimum on time (if set to GAS) or
immediately (if set to ELECTRIC), the W terminal will de-energize at the end of the heat call. When the W terminal is de-energized, it has a 4
minute minimum off time if set to GAS or no minimum off time if set to ELECTRIC. When the Y terminal is de-energized, a minimum off time delay
of 4 minutes must elapse before it can energize again. The B terminal remains energized until there is a call for cooling.



4. SET UP THE CONTROL PANEL FOR THE APPLICATION
• Z1 HC/Z1 HP is set according to the type of thermostat installed in Zone 1. If a heat/cool thermostat is used in Zone 1, place the pin jumper
block on the left two pins (Z1 HC). While set as Z1 HC, emergency heat can only be controlled with the on board E-HEAT switch. If a heat pump
thermostat is used in Zone 1, place the pin jumper block on the right two pins (Z1 HP). Using a heat pump thermostat in Zone 1 allows for
emergency heat control from the Zone 1 thermostat.

• GAS/ELECTRIC refers to the auxiliary heat source. If gas (or propane or oil) heat is to be used, place the pin jumper block on the left two pins
(GAS). This will allow the auxiliary heating equipment to control the fan operation through the use of a plenum switch. If electric heat is to be
used, place the pin jumper block on the right two pins (ELECTRIC).

• PURGE/NO PURGE determines whether the zone control panel or the equipment will control the fan purge. If set to PURGE, pin jumper block on
left two pins, the G terminal and any energized damper terminals will remain energized for a one-minute purge delay following the completion
of a cool call, regular heat call or an electric auxiliary heat call. If set to NO PURGE, pin jumper block on right two pins, the G terminal will deenergize
immediately and any energized damper will remain energized for 3.5 minutes following the completion of a call. The NO PURGE
setting is designed for use with systems where the equipment has a built-in fan purge.

• HT-160/120: If using a plenum temperature sensor, this jumper controls the temperature at which the heating equipment will cut out to prevent
overheating. Set the high limit temperature that is appropriate for the equipment being used. For a high limit temperature of 160°F, place the pin jumper block on the left two pins (HT-160). For a high limit temperature of 120°F, place the pin jumper block to the right two pins (120).

• CL-45/40: If using a plenum temperature sensor, this jumper controls the temperature at which the cooling equipment will cut out to prevent
freezing the indoor coil. For a low limit temperature of 45°F, place the pin jumper block on the left two pins (CL-45). For a low limit temperature
of 40°F, place the pin jumper block to the right two pins (40).

 

[woodardhsd]

Looks like the heat strips are energized if the heating demand exists for more than 20 minutes when the control board is set for electric heat.

Heating Operation: When a zone makes a call for heat, the B, Y and G output terminal will energize. The “NO” contact of the damper terminal for
any zone not calling for Heat also energizes, while the “NC” contact de-energizes. Following a 4-minute minimum on time, the Y terminal will deenergize
when (1) all zones stop calling for heat, (2) the call has exceeded the heat/cool changeover time limit while a cooling call exists or (3)
the call is interrupted by the high limit setting. Any energized damper terminals remain energized for a one-minute purge (if set to PURGE) or a
3.5 minute purge (if set to NO PURGE). Should the same call exist for 20 minutes, the W terminal will also energize (if set to ELECTRIC) or the W
terminal will energize immediately after the Y and G terminals de-energize (if set to GAS). Following a 2-minute minimum on time (if set to GAS) or
immediately (if set to ELECTRIC), the W terminal will de-energize at the end of the heat call. When the W terminal is de-energized, it has a 4
minute minimum off time if set to GAS or no minimum off time if set to ELECTRIC. When the Y terminal is de-energized, a minimum off time delay
of 4 minutes must elapse before it can energize again. The B terminal remains energized until there is a call for cooling.

I don't see how it will have an effect on operation if the zone control is set for electric operation.

I didn't catch the 20 minute part. Next time it runs for a long period, I'll check to see if it's actually kicking in or not.

My final questions:
Did they wire my system incorrectly?
Should I rewire it according to the directions you posted, or leave it as it is?

 

[Houston204]

I wouldn't say that they wired it incorrectly. You have every function now, but you would need to move a switch on the zone control board if you ever needed emergency heat.


Emergency heat is not something that you would need on a regular basis.
If the zone control board is located where you have easy access to it should your unit fail in the middle of a cold night you might consider leaving it as it is currently wired.

I would rewire it, but I like working with low voltage wiring.

If you decide to rewire it, remember to remove power to the air handler and zone control first...

 

[woodardhsd]

I think I will try to re-wire it then.

This may be a stupid question, but is the box in the picture below the proper way to shut off power to the unit?

I wanted to post this picture too, since i noticed in the comfort zone manual it says "do not mount the control box on the air handler unit". It also says do not mount the unit where it could get below freezing. The air handler is in an uninsulated attic space (you can see the exterior wall behind it). It never gets really cold here in our area (maybe into the upper teens 2 or 3 days a year) so I'm not sure if it ever gets below freezing in this space.

This picture also shows the level of care the HVAC techs put into installing our system. All the junk/brackets on the top of the air handler were left just like that after the unit was installed. I haven't tossed any of it out since I'm not sure what it was all for. I don't want to throw out anything that may be needed later.

 

[Houston204]

Yes, that pull type disconnect is the correct place to remove power.

 

[woodardhsd]

That's what I thought, just wanted to make sure.

Thanks for all your help

 

[Houston204]

The odd looking post by the hijacker looks like a virus.
Maybe a moderator can delete it.

 

[beenthere]

The odd looking post by the hijacker looks like a virus.
Maybe a moderator can delete it.

It was spam.

When you see things like that, use the report feature, and all Mods will receive an email about it. I just happen to see this thread.

Report is the red circle with the exclamation mark in it.


PS: Thanks for all the help you give here Houston.

 

[Houston204]

The RTH7600 option 190 should be set to 0 (not 1).

(0 = O/B terminal is O) (1 = O/B terminal is B)

I don't want to throw out anything that may be needed later.

The black plastic cover on the air handler should cover the wiring inside of the service disconnect.
I recommend locating and turning off the breaker in your breaker panel if you want to put it back into the disconnect.
I would tighten the 6 set screws securing the wires in the disconnect with a straight screw driver while in there. I usually find at least 1 loose.

The white cover looks like it should cover a damper actuator if it is plastic.
The rest looks like it can be thrown out.


Thanks Beenthere.
I see the icon now.