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Page 10 of 15

507861-01

Issue 2120

heat stage 2). If a 2-stage thermostat is used, “pigtail” W1 

and  W2  wires  together  when  connecting  the  thermostat 

wires at the unit.

Defrost Cycle

If the outdoor ambient conditions are such that frost forms 

on the outdoor coil, the defrost control monitors the need 

for, initiates, and terminates defrost cycles as necessary to 

maintain system performance. The defrost control is time/

temperature initiated and temperature terminated with 

a maximum defrost time (time-out) of 14 minutes. Time 

between defrost cycles is preset at 90-minute intervals at 

the factory, but can be field adjusted between 30, 60, or 90 

minutes. To field adjust time between defrost cycles, place 

defrost time plug in the proper position (see Figure 9).

Figure 8. Defrost Control

24V TERMINAL

STRIP

CONNECTIONS

DIAGNOSTIC

LEDS

HIGH PRESSURE

SWITCH

TEST

PINS

REVERSING

VALVE

DEFROST

THERMOSTAT

LOW PRESSURE

SWITCH

SERVICE LIGHT

CONNECTIONS

FIELD SELECT 

DEFROST INTERVAL 

TIMING PINS

30

TEST

90

60

P1

Figure 9. Defrost Interval Timing Jumper

Defrost control will initiate a defrost cycle if the time period 

has elapsed and the defrost sensor sees a temperature 

below freezing. At the start of a defrost cycle, the defrost 

control will energize the reversing valve solenoid, shifting 

the reversing valve and de-energizing the outdoor fan. 

The defrost control will also energize auxiliary heat for 

increased comfort during defrost. The unit will remain in 

defrost until the defrost sensor has determined that the 

frost has been removed from the coil or a 14-minute time 

period has elapsed.

The defrost control is also equipped with a set of pins to aid 

in the troubleshooting of the defrost system (see Figure 9). 

The following is a brief outline of the testing of the defrost 

system.

1. 

Defrost  sensor  must  be  closed,  32°F  or  below.  If 

temperatures are such that the switch will not close, 

jumper between defrost sensor terminals on the 

defrost control.

2.  Start system in heating operation.

3. 

Place the defrost pin jumper on the test pins for a brief 

second, then place back on the proper defrost time 

setting (30, 60, or 90). This will speed up defrost time 

interval as shown in Table 7.

Defrost Control Setting

Defrost Test Cycle Time

30 minutes

7 seconds

60 minutes

14 seconds

90 minutes 

21 seconds

Table 7. Defrost Test Cycle Time

The reversing valve will then shift to defrost mode and 

the outdoor fan should stop. After 2 seconds of defrost 

operation, the reversing valve should shift back to heating 

operation and the outdoor fan should start.

Diagnostic LEDs

The state (Off, On, Flashing) of two LEDs on the defrost 

board (DS1 [Red] and DS2 [Green]) indicate diagnostics 

conditions that are described in Table 8.

Mode

Green LED (DS2)

Red LED (DS1)

No power to control

Off

Off

Normal operation / 

power to control

Simultaneous slow flash

Timed lockout

Alternating slow flash

Low pressure switch 

fault

Off

Slow flash

Low pressure switch 

lockout

Off

On

High pressure switch 

fault

Slow flash

Off

High pressure switch 

lockout

On

Off

Table 8. 

Summary of Contents for All-In-One MHP4 Series

Page 1: ...e consulted before installation is made Such applicable regulations or requirements take precedence over the general instructions in this manual CAUTION P 507861 01 P507861 01 Installation These units are not approved for mobile home applications Such use could result in property damage personal injury or death WARNING General These instructions explain the recommended method of installation of th...

Page 2: ...n company If any damages are discovered and reported to the carrier do not install the unit as claim may be denied Check the unit rating plate to confirm specifications are as ordered Limitations The unit should be installed in accordance with all national and local safety codes Limitations of the unit and appropriate accessories must also be observed The outdoor fan is designed to operate against...

Page 3: ...f unit is required for service If the unit is enclosed a door or access panel aligned with the front of the unit is the preferred method of providing access The door or access panel opening must be a minimum of 30 wide centered on the unit and be as tall as the unit If a return duct is not installed in order to provide adequate return air the minimum clearance required between the front of the uni...

Page 4: ...rille Installation Refer to installation instructions included with the wall sleeve kit and the louver grille kit along with Figure 2 for guidance in assembling and installing the wall sleeve and louver grille The sleeve is not intended as the sole support for the unit An additional support must be provided for adequate support see Figure 2 CAUTION Installing and Securing Unit to Wall Sleeve 1 Mak...

Page 5: ...ion to top and bottom corners of unit to sleeve seal Caulk if needed Ductwork Ductwork should be designed and sized according to the methods in Manual Q of the Air Conditioning Contractors of America ACCA Check unit air supply outlet for debris before making ductwork connections It is recommended that supply and return duct connections at the unit be made with flexible joints If flexible ducts are...

Page 6: ...kW TAP 4 AUX HEAT 615 93 590 97 555 101 N A N A N A N A TAP 5 AUX HEAT 715 127 685 134 655 140 630 146 600 151 5 kW TAP 4 AUX HEAT 665 110 635 114 605 118 N A N A N A N A TAP 5 AUX HEAT 750 148 725 154 700 160 675 166 650 171 7 kW TAP 4 AUX HEAT 725 137 705 144 675 150 N A N A N A N A TAP 5 AUX HEAT 825 194 800 200 780 205 755 209 725 213 10 kW TAP 4 AUX HEAT 750 148 725 154 700 161 N A N A N A N ...

Page 7: ...peed for Cooling operation Blower speed must be field adjusted to Speed Tap 3 for higher duct static applications As shipped speed for Heating operation Blower speed must be field adjusted to Speed Tap 5 for higher duct static applications Table 3 Blower Performance 208V or 230V Air Filter All indoor return air must be filtered A washable filter is furnishedwiththeunit locatedinthereturnaircompart...

Page 8: ...e wall sleeve and louver assembly to the outside of the building Use thread sealant on the threaded fittings Install threaded fittings by hand only Do not over torque the fittings Do not thread metal condensate fittings to unit drain pans CAUTION Outdoor Ventilation Air Units are fitted with a panel that seals the return air compartment at the outdoor air duct If introduction of outdoor air is des...

Page 9: ...r inlets to flue gas terminals Improper installation could result in personal injury or death WARNING Figure 7 Auxiliary and Factory Panel for Outdoor Air Duct Factory panel Outdoor Air Duct Auxillary panel with knockouts 1 2 3 4 5 6 7 8 9 Thermostat The room thermostat should be located on an inside wall where it will not be subject to drafts sun exposure or heat from electrical fixtures or appli...

Page 10: ...fort during defrost The unit will remain in defrost until the defrost sensor has determined that the frost has been removed from the coil or a 14 minute time period has elapsed The defrost control is also equipped with a set of pins to aid in the troubleshooting of the defrost system see Figure 9 The following is a brief outline of the testing of the defrost system 1 Defrost sensor must be closed ...

Page 11: ...m cleaner Wash filter in soap or detergent water and replace after filter is dry It is not necessary to oil the filter after washing Motors The indoor and outdoor fan motors are permanently lubricated and require no maintenance Outdoor Coil Foreign material should not be allowed to accumulate on the outdoor coil surface or other parts in the air circuit Cleaning should be as often as necessary to ...

Page 12: ...m Color 29 Height ALVRAL 1P Extruded Aluminum Louver Kit 33 Height ALVRAL 2 Extruded Aluminum Louver Kit Custom Color 33 Height ALVRAL 2P Extruded Aluminum Louver Kit 33 Height ALVRAL 7 Extruded Aluminum Louver Kit Custom Color 33 Height ALVRAL 7P Extruded Aluminum Louver Kit 45 Height ALVRAL 3 Extruded Aluminum Louver Kit Custom Color 45 Height ALVRAL 3P Extruded Aluminum Louver Kit 45 Height ALV...

Page 13: ... Louver ASLEEVE8 2 8 32 3 4 16 16 5 8 32 7 8 for 45 Louver ASLEEVE8 5 8 45 16 16 5 8 45 1 8 10 Wall Sleeve Kit for 29 Louver ASLEEVE10 1 10 29 16 16 5 8 29 1 8 for 33 Louver ASLEEVE10 2 10 32 3 4 16 16 5 8 32 7 8 for 45 Louver ASLEEVE10 5 10 45 16 16 5 8 45 1 8 12 Wall Sleeve Kit for 29 Louver ASLEEVE12 1 12 29 16 16 5 8 29 1 8 for 33 Louver ASLEEVE12 2 12 32 3 4 16 16 5 8 32 7 8 for 45 Louver ASL...

Page 14: ...Page 14 of 15 507861 01 Issue 2120 Wiring Diagrams Figure 11 Connection Diagram MHP With Single Circuit and Hard Start Enabled ...

Page 15: ...507861 01 Issue 2120 Page 15 of 15 Figure 12 Connection Diagram MHP With Dual Circuit and Hard Start Enabled ...

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