Rheem RRNL, Installation Instructions Manual

Page: 36 / 108

36
A. ECM MOTOR INTERFACE CONTROL AND SETTINGS
A. (RRRL UNITS ONLY)
The RRRL series units use ECM blower motors to deliver a constant level of airflow over a
wide range of external static pressures (up to 1.0" W.C.). The interface board provides the
required communications between the thermostat/IFC and the ECM blower motor. The inter-
face board features:
• An automotive-style ATC blade fuse for transformer protection (3 amp).
• An on-board LED to indicate blower CFM.
• Inputs for two-stages of cooling: Y1 (first stage) and Y2 (second stage)
• Four (4) cooling delay profiles
The DIP switches on the interface board are used to define the operation of the ECM motor
(see Table 7).
Refer to Figure 29 for switch identification and factory default settings.
IMPORTANT: Disconnect power to unit when changing DIP switch positions. Even if blower
is not operating, the motor will not recognize changes in DIP switch positions until unit power
is removed and then restored.
FIGURE 29
ECM MOTOR SETTINGS
(This board is located in the blower section)
TABLE 7
SWITCH FUNCTIONS
Switch Function
1 & 2 Not Used
3 & 4 Cooling Airflow Adjustment
5 & 6 Heating Airflow Settings
7 & 8 Cooling Delay Profiles
9 & 10 On-Demand Dehumidification
FIGURE 28
ECM INTERFACE BOARD
LED
FIRST-STAGE COOLING INPUT SECOND-STAGE COOLING INPUT
(THIS BOARD IS LOCATED IN THE BLOWER SECTION)
DO NOT WIRE DIRECTLY TO THIS BOARD. THERMOSTAT SHOULD
BE WIRED TO PIGTAILS LOCATED BELOW THE CONTROL BOX.