When the room thermostat calls for second stage cooling, the RCB senses a signal through "Y1" & "Y2" and engages circuit #1 and circuit #2 in cooling mode.
Indoor blower operation is initiated upon a call for first stage cooling, second stage cooling or dehumidification.
Anytime there is a call for 2 stages of cooling, the unit will not operate in the reheat mode, even if there is a call for dehu- midification at "HUM".
The unit will not operate in the reheat mode if there is any call for heating.
On units with economizers, the unit will not operate in the reheat mode if there is a call for cooling and the economizer is operating as first stage of cooling.
All safety devices function as previously described.
"ALTERNATE” MODE
When the RCB detects a need for dehumidification (24VAC) at "HUM" via the field supplied dehumidistat connected to
R
Y1
Y2
G
W1
W2
OCC
C
COM
` | P6 |
| P5 |
HGR HUM
MODE
SELECTION
JUMPER
falls below 175 psig. Both outdoor fans of circuit #1 in the DR150 also disengage to conserve energy.) The unit then operates with circuit #1 in reheat mode and circuit #2 in cool- ing mode.
When the room thermostat calls for first stage cooling while there is still a call for dehumidification, no operational change is made. The call for cooling is ignored and the unit continues to operate with circuit #1 in reheat mode and circuit #2 in cooling mode.
When the room thermostat calls for second stage cooling, the RCB senses a signal through "Y1" and "Y2" and
Indoor blower operation is initiated upon a call for first stage cooling, second stage cooling or dehumidification.
Anytime there is a call for 2 stages of cooling, the unit will not operate in the reheat mode, even if there is still a call for dehumidification at "HUM".
The unit will not operate in the reheat mode if there is any call for heating.
All safety devices function as previously described.
P4
K1
K2
K4
K3
P3
HGRR
DEHUMIDISTAT
HARNESS
CONNECTION
FIGURE 3 - REHEAT CONTROL BOARD
10 | Unitary Products Group |
