Field Technician Guide: Actuator Transformer Installation & Q7230A 0–10 VDC Wiring

This standard operating procedure details the installation of an internal 120/24 VAC step-down transformer and the field wiring/calibration of a 0–10 VDC modulating control signal to a Honeywell Q7230A interface module inside a Series 90 Modutrol IV actuator (Trane Intellipak 1 & 2 applications).  If the step-down transformer is already added to your actuator skip to step 5.  

1. Safety & Required Materials

WARNING: HAZARDOUS VOLTAGE
Disconnect all electrical power supplies (both 120 VAC line and low-voltage control power) before opening the actuator housing or touching any electrical terminals. Verify absence of power with a calibrated voltmeter.

Part Cross-Reference Table

Required Tools: #2 Phillips screwdriver, 1/8" flathead screwdriver, precision wire cutters, wire strippers (18–14 AWG), soldering iron & solder (for tinning leads).

2. Transformer Lead Preparation & Mounting

+-----------------------------------------------------------------------------------+
|                           FIGURE 1–3: WIRE PREPARATION                            |
|                                                                                   |
|  120V Primary Leads:                       24V Secondary Load Leads:              |
|  [Black] (120V Hot)                        [Brown] ───[X] Cut off quick-connect   |
|  [White] (Neutral)                         [Brown] ───[X] Strip 1/4" to 3/8" & tin|
+-----------------------------------------------------------------------------------+

1. Unbox and Inspect: Verify the transformer kit contains the transformer assembly and two mounting screws.
2. Remove Quick-Connect Terminals (Figs. 1 & 2):
   • Locate the two brown secondary load wires.

   • Using precision wire cutters, snip the female quick-connect terminals off flush with the crimp. Retain maximum usable wire length.

        Fig. 1     Fig.2

                                                                                                   

3. Strip & Tin Secondary Conductors (Fig. 3):
   • Strip 1/4 in. to 3/8 in. (6 mm to 10 mm) of insulation from each brown lead.

   • Neatly twist the stranded copper and tin the ends with solder to prevent fraying inside screw terminals.

                                                   Fig. 3

4. Mount Transformer into Motor Well (Fig. 4):
   • Remove the four (4) corner screws securing the actuator cover and remove the lid.
   • Seat the transformer flat into the recessed casting pocket in the motor housing base.
   • Orientation: Orient the transformer so the two brown secondary wires face forward toward the terminal strip cavity, while the black and white 120 VAC primary leads face toward the outer wall.

   • Secure the transformer core using the two provided screws into the housing bosses.

      Fig 4

3. Q7230A Module Installation & Power Connections

CAUTION: CONNECTOR PIN ALIGNMENT
When plugging the interface module onto the motor terminal block, push the module straight down. Do not tilt, rock, or force the module at an angle, as this will bend or snap the quick-connect terminal prongs.

+-----------------------------------------------------------------------------------+
|                        FIGURE 5: INTERFACE MODULE UNDERSIDE                       |
|                                                                                   |
|      [ Slot 1 ]      [ Slot 2 ]      [ Slot 3 ]      [ Slot 4 ]      [ Slot 5 ]   |
|         │               │               │               │               │         |
|         ▼               ▼               ▼               ▼               ▼         |
|      ( T1 )          ( T2 )           ( R )           ( B )           ( W )       |
|                       <─── Actuator Motor Quick-Connect Blades ───>               |
+-----------------------------------------------------------------------------------+

1. Auxiliary & Stroke Adjustments: If mechanical stroke cam adjustments or auxiliary switch configurations are needed, set them now. Access is restricted once the module is seated.
2. Mount the Interface Module (Fig. 5): Align the underside connector slots with the upright male spade prongs (T1, T2, R, B, W) inside the motor cavity. Press straight down firmly until fully seated.
3. Terminate Secondary Power (Fig. 6):
   • Route the two prepared brown wires up into the terminal compartment.
   • Insert one brown lead into terminal T1 and the other into terminal T2 on the green screw terminal block.

   • Tighten terminal screws firmly (24 VAC power is non-polarized).

      Fig. 5                  Fig. 6  

4. Control Signal Wiring (0–10 VDC)

Field control wiring connects directly to the green Euro-style terminal block on top of the Q7230A:

+------------------------------------------------------------------------------------+
|                         FIGURE 6 & 7: WIRING SCHEMATIC                             |
|                                                                                    |
|         [ T1 ]     [ T2 ]     [ F ]     [ COM ]    [ I+ ]     [ V+ ]               |
|           │          │          │          │         │          │                  |
|           └───┬──────┘          │          │         │          │                  |
|               │                 │          │         │          │                  |
|          24 VAC Power        Override   (-) Common   Open    (+) 0-10V             |
|          (Brown Leads)       (Leave       Signal     (mA)     Control              |
|          From Transformer     Open)      From DDC             From DDC             |
|                                                                                    |
|      [ CW / CCW ]               ( O ) SPAN                 ( O ) ZERO              |
|     Rotation Switch             Potentiometer             Potentiometer            |
+------------------------------------------------------------------------------------+

Terminal Block Pinout Reference

5. Control and 120VAC wiring schematic.  

6. Calibration Procedure (Zero & Span Setup)

1. Configure Rotation Direction Switch:
   • CW (Electrically Normally Closed): Motor drives clockwise to open with rising control signal (standard heating/cooling valve & damper orientation).
   • CCW (Electrically Normally Open): Motor drives counterclockwise to close with rising signal.
2. Initial Potentiometer Positions:
   • Turn the ZERO trim pot fully clockwise.
   • Turn the SPAN trim pot fully counterclockwise.
3. Calibrate Zero (0 VDC / Closed):
   • Command the DDC controller to output 0 VDC (closed position).
   • Wait for the motor to stop driving closed.
   • Turn the ZERO potentiometer slowly counterclockwise until the motor just begins to drive open.
   • Turn the ZERO potentiometer slowly back clockwise until the motor is fully closed. This sets electrical zero.
4. Calibrate Span (10 VDC / 100% Stroke):
   • Command the DDC controller to output 10 VDC (full stroke).
   • Wait for the actuator to drive fully open.
   • Turn the SPAN potentiometer slowly clockwise until the motor starts to drive closed.
   • Recheck full closed at 0 VDC and full open at 10 VDC; make minor trim adjustments if necessary.

7. Final Inspection & Enclosure Closeout (Fig. 8)

1. Gasket & Cover Inspection: Verify the perimeter weather gasket is intact and unseated debris is cleared.

2. Secure Housing (Fig. 8): Replace the die-cast cover and tighten the four (4) corner screws evenly to ensure a weather-resistant NEMA 3 seal.

    Fig 8

    

   WARNING:

   Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.