AFE18-60A
ALL FUEL SYSTEM CONTROL BOARD INSTALLATION INSTRUCTIONS
Goodman Manufacturing Company, L.P. © 2004 - 2008 5151 San Felipe, Suite 500, Houston, TX 77056 www.goodmanmfg.com
P/N: IO-627A Date: October 2008
DESCRIPTION
The AFE18 control is designed for use in heat pump applications where the indoor coil is located above/downstream of a gas or fossil fuel furnace. It will operate with single and two stage heat pumps and single and two stage furnaces. The AFE18 control will turn the heat pump unit off when the furnace is turned on. An anti-short cycle feature is also incorporated which initiates a 3 minute timed off delay when the compressor goes off. On initial power up or loss and restoration of power, this 3 minute timed off delay will be initiated. The compressor won’t be allowed to restart until the 3 minute off delay has expired. Also included is a 5 second de-bounce feature on the “Y, E, W1 and O” thermostat inputs. These thermostat inputs must be present for 5 seconds before the AFE18 control will respond to it.
An optional outdoor thermostat, OT18-60A, can be used with the AFE18 to switch from heat pump operation to furnace operation below a specific ambient temperature setting, i.e. break even temperature during heating. When used in this manner, the “Y” heat demand is switched to the “W1” input to the furnace by the outdoor thermostat and the furnace is used to satisfy the first stage “Y” heat demand. On some controls, if the outdoor thermostat fails closed in this position during the heating season, it will turn on the furnace during the cooling season on a “Y” cooling demand. In this situation, the furnace produces heat and increases the indoor temperature thereby never satisfying the cooling demand. The furnace will continue to operate and can only be stopped by switching the thermostat to the off position or
removing power to the unit and then replacing the outdoor thermostat. When the AFE18 receives a “Y” and “O” input from the indoor thermostat, it recognizes this as a cooling demand in the cooling mode. If the outdoor thermostat is stuck in the closed position switching the “Y” demand to the “W1” furnace input during the cooling mode as described above, the AFE18 won’t allow the furnace to operate. The outdoor thermostat will have to be replaced to restore the unit to normal operation.
AFE18-60A INSTALLATION |
The AFE18-60A should be installed on the side of the furnace close to the 24Vac controls wires for field connections. The system must be connected in accordance with the wiring diagram supplied with the AFE18 control and shown in these instructions. Standard thermostat cables can be used for wiring connections between the thermostat and heat pump unit. See Fig. 1.
ATTENTION INSTALLING PERSONNEL
As a professional installer you have an obligation to know the product better than the customer. This includes all safety precautions and related items.
Prior to actual installation, thoroughly familiarize yourself with this Instruction Manual. Pay special attention to all safety warnings. Often during installation or repair it is possible to place yourself in a position which is more hazardous than when the unit is in operation.
Remember, it is your responsibility to install the product safely and to know it well enough to be able to instruct a customer in its safe use.
Safety is a matter of common sense...a matter of thinking before acting. Most dealers have a list of specific good safety practices...follow them.
The precautions listed in this Installation Manual are intended as supplemental to existing practices. However, if there is a direct conflict between existing practices and the content of this manual, the precautions listed here take precedence.
An optional outdoor thermostat, OT18-60A, can be installed in the heat pump unit and used with the AFE18. When used, the tab on the AFE18 control board next to the terminal strip for the heat pump field wiring connections must be broken for the outdoor thermostat to function with the control. The thermostat can be field adjusted to a breakeven temperature set point appropriate for the installation. Refer to the installation instructions provided with the OT18-60A for the appropriate mounting location for the heat pump unit.
OPERATION
1.0 COOLING
On heat pump units, when the room thermostat is set to the cooling mode, 24Vac is constantly supplied to terminal “O” of the AFE18 at the thermostat input and to the reversing valve. The constant 24Vac at the “O” terminal of the AFE18 is a signal that the unit is in the cooling mode and its software won’t allow the furnace to be turned on.
1.1.On a demand for cooling on a single stage heat pump, the room thermostat energizes “Y” and “G”. This supplies 24Vac to terminals “G” and “Y” of the AFE18. If the 3 minute anti-short delay has expired, the “Y” output to the heat pump unit will be energized and the compressor and condenser fan will start. On ASZ two stage heat pumps, the room thermostat energizes “Y1” and “G”. This supplies 24Vac to terminals “G” and “Y1” of the AFE18. If the 3 minute anti-short delay has expired, the “Y” output to the heat pump unit will be energized and the compressor will operate on low stage and condenser fan and indoor fan will operate on low speed.
1.2When an “Y2” demand is initiated on ASZ two stage heat pumps, 24Vac is supplied to terminal “Y2” of the AFE18 and terminal “Y2” of the heat pump. The control board in the ASZ unit changes the compressor to high stage and condenser fan and indoor fan to high speed operation. When the “Y2” demand is satisfied, the control board in the ASZ unit will return the compressor to low stage and condenser fan and indoor fan back to low speed operation. On some digital/ electronic thermostats, “Y2” will remain energized until the first stage demand “Y” is satisfied.
1.3When the “Y” cooling demand is satisfied, the room thermostat removes the 24Vac from terminals “Y” and “G” and the unit turns off. The 3 minute anti-short cycle delay is initiated for the compressor.
2.0 HEATING
On heat pump units, when the room thermostat is set to the heating mode, the reversing valve is not energized. This is a signal to the AFE18 that the unit is in the heating mode. As long as the thermostat is set for heating, the reversing valve will be in the de-energized position for heating except during a defrost cycle.
2.1On a demand for heat on a single stage heat pump, the room thermostat energizes “Y” and “G”. This supplies 24Vac to terminal “Y” of the AFE18, to the “Y” terminal of the defrost board in the heat pump and the to the “G” terminal of the furnace. The heat pump and indoor fan will start in the heat mode. On a demand for heat on an ASZ two stage heat pump the room thermostat energizes “Y1” and “G”. This supplies 24Vac to terminal “Y1” of the AFE18, to the “Y” terminal of the defrost board in the heat pump and to the “G” terminal of the furnace. The compressor will start in low stage and the condenser fan and indoor fan will start on low speed in the heat mode. As long as 24Vac is present at terminal “Y” of the defrost board during the heating mode, the defrost board accumulates compressor run time.
2.2When an “Y2” demand is initiated on ASZ two stage heat pumps, 24Vac is supplied to terminal “Y2” of the AFE18 and terminal “Y2” of the heat pump. The control board in the ASZ unit changes the compressor to high stage and condenser fan and indoor fan to high speed operation. When the “Y2” demand is satisfied, the control board in the ASZ unit will return the compressor to low stage and condenser fan and indoor fan back to low speed operation. On some digital/ electronic thermostats, “Y2” will remain energized until the first stage demand “Y” is satisfied.
2.2B If outdoor thermostat, OT18-60A, is used and the temperature is below the set point, i.e. break even point, the outdoor thermostat will switch the “Y” heating demand to the “W1” input to the furnace. The AFE18 will remove the “Y” and “Y2” demands from the heat pump if present and remove the “G” demand from the furnace. With the “Y” input to the heat pump removed, the compressor will be turned off and the defrost board will store the compressor’s accumulated run time in memory. The furnace will be turned on and remain on until the “Y” demand for heating is satisfied. The indoor blower will operate at the speed designed for furnace only operation. The unit will operate this way on a demand for heating as long as the outdoor thermostat remains in this position.
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