Typical Field Wiring; Cfm Selection Board - York YMB SERIES Installation Manual

361813-UIM-A-0208
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.
SERVICE
ACCESS
PANEL
CONTROL
WIRING
POWER
WIRING
FIGURE 5: Typical Field Wiring
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.
6
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
D
CORNER
C
COVER B
A
COOL
HEAT PUMP
FIGURE 6: CFM Selection Board
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.

CFM SELECTION BOARD

TAP SELECTION
D
C
B
A
HEAT ADJ DELAY
REMOVE FOR
HUMIDISTAT
Unitary Products Group