Residential Air Conditioners and Heat Pumps Using R-22 and Puron® Refrigerant: Application Guideline and Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
52
TWO-STAGE 286B/289B 180B/187B
Application Guidelines
Bryant designed and tested the two-stage air conditioner and heat pump
products with Puron refrigerant to operate at a minimum outdoor
operating ambient in cooling mode at 55
_
F / 12.8
_
C without low
ambient cooling enabled and the maximum outdoor operating ambient in
cooling is 125
_
F/51.6
_
C. On Evolution communicating systems, only
low ambient cooling is available to 0
_
F/-17.8
_
C.
The maximum outdoor operating ambient in heating mode is
66
_
F/18.8
_
C on all heat pumps. Continuous operation in heating mode
is approved to -30
_
F/-34.4
_
C. Thermostat options for the two stage
units are as follows:
• A,B,C,D four-wire connections for Evolution User Interface.
• R,C,W,Y1,Y2, and O wire connections for standard,
non-communicating thermostat.
286B, 289B, 187B, and 180B units can run, and are matched with, User
Interface (UI) communicating and non-communicating indoor fan coils
and furnaces. Only unit combinations listed in the two-stage Product
Data are recommended.
Line sets for two stage units are similar to the single stage units.
However, some restrictions may apply to specific combinations in long
line applications. Refer to the
Long Line Guideline
for further
information.
The Tennessee Valley Authority (TVA) requires that electric strip heat
have a lockout feature. This is achieved through Bryant thermostats
required per above and must be used on all TVA approved units.
The new control board in the two stage units with Puron refrigerant has
dip switches for defrost timing. The Evolution controls provide these
two stage units with high stage latching and Hybrid Heat
t
(dual fuel)
capabilities. The standard Hybrid Heat
t
(duel fuel) thermostat can be
used on two stage units with Bristol reciprocating compressors only.
Model Plug
Each control board contains a model plug. The correct model plug must
be installed in order for the system to operate properly. (See
.)
The model plug is used to identify the type and size of unit to the control.
On 286B models, the model plug is also used to determine the start
sequence timing for each individual model.
On new units, the model and serial numbers are inputted into the board’s
memory at the factory. If a model plug is lost or missing at initial
installation, the unit will operate according to the information input at
the factory and the appropriate error code will flash temporarily. An RC
replacement board contains no model and serial information. If the
factory control board fails, the model plug must be transferred from the
original board to the replacement board for the unit to operate.
NOTE:
The model plug takes priority over factory model information
input at the factory. If the model plug is removed after initial power up,
the unit will operate according to the last valid model plug installed, and
flash the appropriate fault code temporarily.
Table 15 – Model Plug Information
MODEL
NUMBER
MODEL PLUG
NUMBER
PIN RESISTANCE
(K-ohms)
Pins 1-4
Pins 2-3
286B024
HK70EZ041
18
91
286B036
HK70EZ043
18
150
286B048
HK70EZ045
18
220
286B060
HK70EZ047
18
360
289B024
HK70EZ010
5.1
120
289B036
HK70EZ012
5.1
180
289B048
HK70EZ014
5.1
270
289B060
HK70EZ016
11
5.1
180B024
HK70EZ009
5.1
91
180B036
HK70EZ011
5.1
150
180B048
HK70EZ013
5.1
220
180B060
HK70EZ015
5.1
360
187B0
24
HK70EZ040
18
75
187B0
36
HK70EZ042
18
120
187B0
48
HK70EZ044
18
180
187B0
60
HK70EZ046
18
270
