Dettson Atmos Heat Pump 24V Adapter Kit Installation Guide

Dettson Atmos Heat Pump 24V Adapter Kit Installation Guide

Safety

Follow all safety information provided in the outdoor unit manual X62434.

Warning
All electric work must be performed by a licensed technician according to local regulations and the instructions given in this manual. Do not operate with wet hands.

Dimensions

Location

This adapter must be installed indoors, in an area free of drips, moisture and condensation.

Maintain at least 5.9″ (150mm) spacing to walls and ensure it is elevated from areas that can retain water.”

Warning
Do not install the adapter near flammable liquids or gases.

Installation

1. Remove the cover of the adapter box by removing the 8 exposed screws.
   

2. Mount the back plate of the box vertically on a wall using 3 screws (M4x20) and anchors. The direction of the arrow on the cover must point upwards.
   

3. Wire and configure the control box (see following sections).

4. Reattach the cover using the screws.

Important notes:

• TXV or other metering devices must be removed from the indoor coil.
• Both refrigerant lines must be insulated.
• The airflow should be set nearest to 400 CFM/ton.

Wiring

This figure shows the recommended wiring setup for a 3-heat 2-cool heat pump thermostat.

Important notes:

• The power to the indoor and outdoor units must be disconnected before any wiring.
• Make sure that the provided ferrite clamps are installed on the return temperature sensor and the outdoor unit cable.
• The outdoor unit cable is protected by the outdoor unit breaker and must be sized appropriately, according to the nameplate of the outdoor unit.

Wiring steps:

1. Disconnect the transformer from the board (TRANS_IN and TRANS_OUT).

2. Connect 1, 2 and 3 from the outdoor unit to the control box. Use the ferrite clap.

3. Connect the thermostat.

   • Connect together R of the thermostat, the furnace and the control board.
   • Connect together C of the thermostat, the furnace and the control board.
   • Connect together G of the thermostat, the furnace and the control board.
   • Connect B of the thermostat to B/O on the control board. Make sure the thermostat is set to output a B signal.
   • Connect Y2 and Y1 of the thermostat to the control board.
   • Connect AUX (3rd heating stage) of the thermostat to the control board. Connect to W1 to stop the heat pump when auxiliary heat kicks in. Connect to E/AUX to keep the heat pump running with the auxiliary heat.
     If using only one cooling stage, ignore the Y2 wire.
     If using a conventional thermostat (no B signal), connect W of the thermostat to W on the control board and ignore the B wire.

4. Connect the furnace.

   • Connect the first fan speed G1 of the control board to Y1 of the furnace.
   • If the furnace provides a second cooling speed (Y2), connect the third fan speed G3 of the control board to Y2 of the furnace.
   • Connect W1-out of the control board to W of the furnace.
   • To turn on the auxiliary heat during the defrost cycle, also connect DF to W of the furnace (see section 8.1).

5. Connect the return air sensor to T1 of the control board and install it in the return air duct. The wire length must not exceed 23’ (7m).

6. Attach the coil sensor to the indoor coil as shown: using the provided clip, fix it on the crossover at mid-height of the coil. Run the wire through the refrigerant line opening and connect it to T2 on the control board.
   

Connection Terminals

running
G| Input| Fan signal from thermostat
G1| Output| First fan speed when outdoor unit is running
G2| Output| Second fan speed when outdoor unit is running
G3| Output| Third fan speed when outdoor unit is running
L| Output| Signal activated on system fault
ON/OFF| Input| Enable for remote control (when circuit is closed)
R| In/Out| 24V hot
S1 S2| –| Do not use
T1| Input| Return air sensor
T2| Input| Indoor coil sensor
TRANS_IN| Output| 240V power for transformer (should be disconnected)
TRANS_OUT| Input| 24V power from transformer (should be disconnected)
W| Input| Heat pump heating signal from thermostat (conventional)
W1| Input| Auxiliary heating signal from thermostat, shutting off the heat pump
W1-out| Output| Auxiliary heating signal (furnace)
WATER| Input| Water level error detection (when circuit is open)
WORK| Output| Dry contact closed when system is running
Y1| Input| First stage cooling signal from thermostat
Y2| Input| Second stage cooling signal from thermostat

DIP Switches

Off
SW1-4| Fan stops during defrost| Disabled| Enabled| Off
SW2-1| Degrees above the balance point for the heat pump to be re- enabled| 1°C| 2°C| Off
SW2-2| Not used| –| –| Off
SW2-3| Indoor coil sensor (T2) usage (must be turned on when the sensor is installed)| Enabled| Disabled| Off
SW2-4| Not used| –| –| Off
SW3-1| Leave off| –| –| Off
SW3-2| Leave off| –| –| Off
SW5-1| Water level detector usage (WATER)| Enabled| Disabled| On
SW5-2| Remote control (switch) usage (ON/OFF)| Enabled| Disabled| On

ENC1
The rotary switch ENC1 is used to select the capacity (BTU/h) of the unit

ENC2
The rotary switch ENC2 is used to select the balance point of the system. The balance point is the outdoor temperature below which the heat pump will be disabled and only the auxiliary heat will be used. If disabled, there will be no switch based on the outside temperature.

Operation

1. On a first stage call for heating or cooling (Y1), the outdoor unit will modulate according to the return air temperature. The system will try to reach and maintain the same temperature that satisfied the last call. After 30 or 60 minutes (based on the position of SW1-2), the unit will increase its capacity to fulfill the demand, regardless of the return air temperature. Based on the capacity, the control will enable up to three different fan speeds of the air handler (G1, G2 and G3).
2. On a second stage call (Y2), the outdoor unit will run at maximum capacity.
3.  When the outdoor unit performs a defrost cycle, the indoor fan will stop. The DF output is activated and can be used to start an auxiliary backup heater.
4. In heating mode, when the outside temperature drops, it may become more efficient or more economical to stop the heat pump and only use the auxiliary heating. The control board can manage this switchover, based on the position of the ENC2 switch. Otherwise, the switchover is managed by the position of dip switch SW1-3 and the thermostat signals
5. If a malfunction occurs, an error code will be displayed on the control board. Also, 24V output (L) and a dry contact (ALARM) are activated.

Considerations
When pairing with a gas or oil furnace, or in an add-on installation (coil installed in the supply air of the air handler), it is important that both heat pump and auxiliary heat do not work simultaneously. To achieve this, the auxiliary heat signal from the thermostat must go in the W1 input terminal of the 24V adapter control.

When the indoor coil is installed in the return air of the air handler (electric furnace), both heat pump and auxiliary heater can run at the same time. To achieve this, the auxiliary heat signal from the thermostat needs to connect to the E/AUX input terminal of the 24V adapter control.

Defrost

By default, the indoor fan will stop during a defrost cycle. This is set by dip switch SW1-4 (see section 7).

To turn on the auxiliary heat during the defrost cycle, DF of the control board must be connected to W of the furnace.

Manual Defrost
To force a defrost cycle, press and hold the button KEY (next to ENC2) for three seconds. The board will display DF and the defrost cycle will commence.

Error Codes

DISP1 will display the status or error code of the system. Other codes starting with 0 show a normal running status.

For troubleshooting assistance, refer to the Atmos advanced troubleshooting guide.

www.dettson.com/x62435_atmos_troubleshooting

References

• dettson.com/x62435_atmos_troubleshooting

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