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361813-UIM-A-0208

6

Unitary Products Group

FIELD CONNECTIONS POWER WIRING

1.

Install the proper size weatherproof disconnect switch outdoors
and within sight of the unit.

2.

Remove the screws at the bottom of the corner cover. Slide corner
cover down and remove from unit. See Figure 6.

3.

Run power wiring from the disconnect switch to the unit.

4.

Remove the service access panel to gain access to the unit wiring.
Route wires from disconnect through power wiring opening pro-
vided and into the unit control box as shown in Figure 6.

5.

Install the proper size time-delay fuses or circuit breaker, and
make the power supply connections.

6.

Energize the crankcase heater if equipped to save time by pre-
heating the compressor oil while the remaining installation is com-
pleted.

FIELD CONNECTIONS CONTROL WIRING

1.

Route low voltage wiring into bottom of control box as shown in
Figure 6. Make low voltage wiring connection inside jumper box
per Figures 7-11.

2.

Replace the corner cover and service access panel that were
removed in Steps 2 and 4 of the “Field Connections Power Wiring”
section.

3.

All field wiring to be in accordance with national electrical codes
(NEC) and/or local-city codes.

NOTE: 

A Start Assist Kit is available and recommended for long line set

applications or in areas of known low voltage problems.

4.

Mount the thermostat about 5 ft. above the floor, where it will be
exposed to normal room air circulation. Do not place it on an out-
side wall or where it is exposed to the radiant effect from exposed
glass or appliances, drafts from outside doors or supply air grilles.

5.

Route the 24-volt control wiring (NEC Class 2) from the outdoor
unit to the indoor unit and thermostat.

NOTE: 

To eliminate erratic operation, seal the hole in the wall at the

thermostat with permagum or equivalent to prevent air drafts affecting
the operation of in the thermostat.

DEHUMIDIFICATION CONTROL

A dehumidification control accessory 2HU06700124 may be used with
variable speed air handlers or furnaces in high humidity areas. This
control works with the variable speed indoor unit to provide cooling at a
reduced air flow, lowering evaporator temperature and increasing latent
capacity. The humidistat in this control opens the humidistat contacts on
humidity rise. To install, refer to Figures 7-11 in this manual and also
refer to the installation manual packed with the control accessory
2HU06700124. 

Prior to the installation of the dehumidification control, the jumper
across the HUMIDISTAT terminals on the indoor variable speed air han-
dler or furnace CFM selection board must be removed.

During cooling, if the relative humidity in the space is higher than the
desired set point of the dehumidification control, the variable speed
blower motor will operate at lower speed until the dehumidification con-
trol is satisfied. A 40-60% relative humidity level is recommended to
achieve optimum comfort.

If a dehumidification control is installed, it is recommended that a mini-
mum air flow of 325 cfm/ton be supplied at all times.

For additional connection diagrams for all UPG equipment refer to “Low
Voltage System Wiring” document available online at www.upgnet.com
in the Product Catalog Section.

CFM SELECTION BOARD SETTINGS

For proper system operation the CFM Selection Board jumpers must be
set properly. 

Refer to the Tabular Data Sheet for the recommended air flow settings
for each size condensing unit.

Set the cooling speed per the instructions for the air handler or furnace
by selecting the correct COOL and ADJ taps. Verify the airflow using
the LED display on the CFM selection board.

The HEAT PUMP jumper 

MUST

 be removed for proper system opera-

tion.

The HUMIDISTAT jumper must also be removed if a dehumidistat is
installed.

 FIGURE 5: 

Typical Field Wiring

CONTROL
WIRING

POWER
WIRING

CORNER
COVER

SERVICE
ACCESS
PANEL

 FIGURE 6: 

CFM Selection Board

CFM SELECTION BOARD

TAP SELECTION

D
C
B
A

D
C
B
A

COOL

HEAT

ADJ

DELAY

REMOVE FOR

HEAT PUMP

HUMIDISTAT

Summary of Contents for YMB SERIES

Page 1: ...ry It is also used to alert against unsafe practices and hazards involving only property dam age Improper installation may create a condition where the operation of the product could cause personal in...

Page 2: ...to be installed on a hot sun exposed roof or a black topped ground area the unit should be raised sufficiently above the roof or ground to avoid taking the accumulated layer of hot air into the outdo...

Page 3: ...stalling tubing of longer lengths and elevation differences NOTE Using a larger than specified line size could result in oil return problems Using too small a line will result in loss of capacity and...

Page 4: ...coil Braze the vapor line to the evaporator vapor connection After the connection has cooled slide the grommet back into original position Refer to the Tabular Data Sheet for proper vapor line siz ing...

Page 5: ...se soft solder Install the TXV bulb to the vapor line near the equalizer line using the two bulb clamps furnished with the TXV assembly Ensure the bulb is making maximum contact Refer to TXV installat...

Page 6: ...ON CONTROL A dehumidification control accessory 2HU06700124 may be used with variable speed air handlers or furnaces in high humidity areas This control works with the variable speed indoor unit to pr...

Page 7: ...r W Auxiliary Heat BS Bonnet Sensor BSG Bonnet Sensor YORKGUARD VI CONTROL SINGLE STAGE HEAT PUMP 1 H 3 YMB YZB OD MODELS Part Numbers SAP Legacy 126768 031 09137 18395 031 01996 340512 031 09178 1 C...

Page 8: ...E Emergency Heat W2 Second Stage Heat B O Switch on Thermostat must be in the O position C 24 Volt Common Y1 First Stage Compressor O B Reversing Valve L Malfunction Light Y2 Second Stage Compressor G...

Page 9: ...the O position C 24 Volt Common Y1 First Stage Compressor O B Reversing Valve L Malfunction Light Y2 Second Stage Compressor G Fan DN22U00124 THERMOSTAT E Emergency Heat AUX Auxiliary Heat R 24 Volt...

Page 10: ...mergency Heat W2 Second Stage Heat B O Switch on Thermostat must be in the O position C 24 Volt Common Y1 First Stage Compressor O B Reversing Valve L Malfunction Light Y2 Second Stage Compressor G Fa...

Page 11: ...must be in the O position C 24 Volt Common Y1 First Stage Compressor O B Reversing Valve L Malfunction Light Y2 Second Stage Compressor G Fan DN22U00124 THERMOSTAT E Emergency Heat AUX Auxiliary Heat...

Page 12: ...ls the following subcooling charging method must be used Superheat charging charts are not valid with TXV equipped systems Subcooling Charging Method For the heating operation there is no accurate sub...

Page 13: ...ed with a crankcase heater to prevent the migration of refrigerant to the compressor during the OFF cycle The heater is energized only when the unit is not running If the main switch is disconnected f...

Page 14: ...e Printed in U S A 361813 UIM A 0208 Copyright by Unitary Products Group 2008 All rights reserved Supersedes 170761 UIM D 1106 Unitary 5005 Norman Product York OK Group Drive 73069 SECTION X WIRING DI...

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