Marley 804 Series Unit Heater

Product Usage Instructions

Installation of Internal Thermostat:

1. Remove 5/16 (7.9mm) knockout from the back of heater and route the capillary tube through the hole.
2. Install the thermostat bulb clip in the slot provided in the back panel of the heater. The secure capillary bulb in clip.
3. Press on the left side of the logo label on the front of the heater to locate shaft and screw holes. Punch holes through the label.
4. Install the thermostat as shown in the diagram, coiling any excess capillary tubing inside the heater.

Installation of Fan Switch:

1. Remove 1/2 (12.7mm) knockout from the back of the heater.
2. Install the manual fan switch as shown in the diagram. Be sure to use a lock washer to prevent the switch from rotating.
3. Install leads to terminal block following the wiring diagram for proper procedure based on unit specifications.

Installation of Remote Fan Switch:

1. Use 14 gauge copper, NEC Class 1, 600V rated insulated wire.
2. Install the remote fan switch in a standard wall box ensuring wiring meets all local and NEC requirements.

Installation of Remote Pilot Duty Fan Switch:

1. Use 18 gauge (min.), NEC Class 1, 600V wiring that meets all local and NEC requirements.
2. Install the remote fan switch in a standard wall box ensuring proper installation.

Installation of Fan Relay:

1. Mount relay in the control compartment with two No. 8 mounting screws as shown in the diagram.
2. Connect the lead wires from the relay to the control terminal board following the wiring instructions provided.

Installation of Heat Recovery Thermostat:

1. Mount relay in the baffle compartment with two No. 8 mounting screws as shown in the diagram.
2. Connect the lead wires from the relay to the control terminal board following the wiring instructions provided.
3. Remove 5/16 (7.9mm) knockout from back of heater and route capillary tube through the hole.

FAQs

• Q: Can I install an Internal Thermostat on any unit heater?
  • A: Internal Thermostats can be installed on MUH, HUHAA, Dayton 804RZ6 thru 804RZ9, and 804T01 thru 804T22 Series Unit Heaters.
• Q: What type of wire should I use for the Remote Fan Switch?
  • A: Use 14 gauge copper, NEC Class 1, 600V rated insulated wire for the Remote Fan Switch installation.
• Q: Are there specific requirements for installing a Heat Recovery Thermostat?
  • A: Heat Recovery Thermostats cannot be installed on heaters equipped with built-in single-pole or two-stage thermostats due to mounting location conflicts. Refer to the provided diagrams for proper installation steps based on control circuit voltage.

INSTALLATION

INSTALLATION OF INTERNAL THERMOSTAT MT1, MT2, 2E569, 3UG72, 2YU33, 2YU95, and 810VA9

1. Remove 5/16″ (7.9mm) knockout from back of heater and route capillary tube through hole (Figure 1).
2. Install thermostat bulb clip in slot provided in the back panel of the heater. Secure capillary bulb in clip.
3. Press on left side of logo label on front of heater to locate shaft and screw holes. Punch holes through label.
4. Install the thermostat as shown in Figure 2, coiling any excess capillary tubing inside the heater.
   • WARNING
     • TO PREVENT POSSIBLE ELECTRICAL SHORT CIRCUITS OR FIRE, KEEP CAPILLARY TUBING AWAY FROM INTERNAL ELECTRICAL COMPONENTS.
5. Refer to wiring diagram, Figure 6, for wiring procedure on 3KW and 5KW (208V, 240V and 277V only). Refer to wiring diagram and figure for wiring procedure on all other heaters.
6. CAUTION: To prevent a possible fire or damage to heater, if a two-stage thermostat is provided, it MUST be wired so Stage 1 turns the rear heating element (where fan control is located) on first and off last. Stage 2 MUST turn on elements other than the rear element as the need for additional heat is required and will turn on last and off first. Remove backing from label (supplied) and install over thermostat shaft. Install knob by pushing it onto the thermostat shaft.

INSTALLATION OF FAN SWITCH FS, 3UG03 and 2YU82

1. Remove 1/2″ (12.7mm) knockout (located between ON and AUTO) from back of heater (Figure 3).
2. Install manual fan switch as shown in Figure 3. (Note orientation of slot in switch nozzle. Locate slot in the switch nozzle towards the “AUTO” position.) Be sure to use lock washer to prevent rotation of switch.
3. Install leads to a terminal block. Refer to the wiring diagram, Figure 6, for the wiring procedure on 3KW and 5KW units (208V, 240V, and 277V only). Refer to the wiring diagram, Figure 7, for the wiring procedure on all other heaters.

INSTALLATION OF REMOTE FAN SWITCH RFS1

The Remote Fan Switch is mounted externally and remotely from the unit heater. The voltage of the remote fan switch circuit is the same as the supply voltage to the heater.

1. Use 14 gauge copper, NEC Class 1, 600V rated insulated wire. Wiring must meet all local and NEC requirements.
2. Install the remote fan switch in a standard wall box in any convenient location that is protected from traffic or other accidental damage.
3. Connect the 14 gauge copper field wire to the switch lead wires with suitable connectors.
4. A 1/2-inch (12.7mm) knockout is provided in the back of the heater adjacent to the control terminal board. Use a crimp-on terminal suitable for the No. 8 screw on the control terminal board. Connect one field wire terminated lead to terminal F1 and the other terminated lead to terminal F2. Refer to Figure 6 for connecting to heaters without built-in contactors. Refer to Figure 7 for connecting to heaters equipped with built-in contactors.

INSTALLATION OF REMOTE PILOT DUTY FAN SWITCH RFS2 (Including Wall Switch and Relay)

The Remote Fan Switch is mounted externally and remotely from the unit heater.

1. Use 18 gauge (min.), NEC Class 1, 600V wiring that meets all local and NEC requirements.
2. Install the remote fan switch in a standard wall box in any convenient location that is protected from traffic or other accidental damage.
3. Connect the field wire to the switch lead wires with suitable connectors.
4. A 1/2-inch (12.7mm) knockout is provided in the back of the heater adjacent to the control terminal board. Use a crimp-on terminal suitable for the No. 8 screw on the control terminal board. Connect one field wire terminated lead to terminal “R” and the other terminated field wire lead to terminal “G”. Refer to Figure 7.
5. Install relay as indicated below.

INSTALLATION OF FAN RELAY (For RFS2)

1. Mount relay in control compartment with two No. 8 mounting screws as shown in Figure 4.
2. Connect the lead wires from the relay to the control terminal board as shown in Figure 7. Each lead wire is marked for proper terminal location; connect the lead wires as indicated.

INSTALLATION OF HEAT RECOVERY THERMOSTAT HRTA, 3UG63 and 2YU90

NOTE: This accessory cannot be installed on heaters equipped with built-in single-pole or two-stage thermostats, because they use the same mounting location (see item 5 below).

(For heaters with 24 Volt Control Circuit refer to Fig. 7 and proceed to step 1. For heaters with Line Voltage Control refer to Fig. 6 and proceed to step 3.)

1. Mount relay in baffle compartment with two No. 8 mounting screws as shown in Figure 4.
2. Connect the lead wires from the relay to the control terminal board as shown in Figure 7. Each lead wire is marked for proper terminal location; connect lead wires as indicated.
3. Remove 5/16″ (7.9mm) knockout from back of heater and route capillary tube through hole (See Figure 1).
4. Install the thermostat bulb clip-in slot provided in the back panel of the heater. A secure capillary bulb in clip.
5. Press on left side of logo label on the front of the heater to locate the shaft and screw holes. Punch holes through a label.
6. Install heat recovery thermostat as shown in Figure 2, coiling any excess capillary tubing inside the heater.
7. Use the wire tie to hold the thermostat leads to other wiring at approximately the midpoint of the leads between the control terminal board and the thermostat.
   • WARNING TO PREVENT A POSSIBLE ELECTRICAL SHORT CIRCUIT OR FIRE, KEEP CAPILLARY TUBING AWAY FROM INTERNAL ELECTRICAL COMPONENTS.
8. Refer to wiring diagram, Figure 6 or Figure 7 for wiring procedure.
9. Install knob by pushing onto the thermostat shaft.
10. Set the thermostat for desired turn-on temperature. Full counter-clockwise rotation of the knob is approximately 70°F (21° C). Full clockwise rotation of the knob is approximately 120°F (49° C).

INSTALLATION OF 24 AMP AND 60 AMP POWER DISCONNECT SWITCH

• DS25 – 25A MAX LOAD 20A
• DS25, DS60, 3UG68, 3UG69, 2YU93 and 2YU94
• DS60 – 60A MAX LOAD 50A

1. Use copper conductor supply wire only when using these switches.
2. Remove the 5/8″ (16mm) knockout and the two knockout slots from back of the heater, below the OFF-ON markings.
3. Install power disconnect switch with two mounting screws as shown in Figure 5.
4. Install the knob with the pointer position at the “OFF” position marking when the switch is rotated to the full counterclockwise position.
5. Before connecting the wires of the switch, check the pointer index. Check to be sure the pointer end of the knob points to “OFF” when the switch is rotated full counterclockwise. It may be necessary to rotate the switch 180° to index the pointer knob.
6. Refer to wiring diagram, Figure 8, for wiring procedure.

(NOTE: For single-phase, remove and discard leads “L2” and “S2”).

Documents / Resources

Marley 804 Series Unit Heater [pdf] Instruction Manual HUHAA-PRO Series, 804 Series Unit Heater, 804 Series, Unit Heater, Heater

References

• User Manual