16
Boilerless Changeover Temperature — Switch 8 on S1 pro-
vides selection of boilerless changeover temperature set point.
Select OFF for set point of 50 F or select ON for set point
of 40 F.
If switch 8 is set for 50 F, then the compressor will be used
for heating as long as the FP1 is above 50 F. The compressor
will not be used for heating when the FP1 is below 50 F and the
compressor will operates in emergency heat mode, staging on
EH1 and EH2 to provide heat. If a thermal switch is being used
instead of the FP1 thermistor, only the compressor will be used
for heating mode when the FP1 terminals are closed. If the FP1
terminals are open, the compressor is not used and the control
goes into emergency heat mode.
DIP SWITCH BLOCK 2 (S2) — This set of DIP switches is
used to configure accessory relay options.
Switches 1 to 3 — These DIP switches provide selection
of Accessory 1 relay options. See Table 13 for DIP switch
combinations.
Switches 4 to 6 — These DIP switches provide selection
of Accessory 2 relay options. See Table 14 for DIP switch
combinations.
Table 13 — DIP Switch Block S2 —
Accessory 1 Relay Options
LEGEND
NOTE: All other DIP switch combinations are invalid.
Table 14 — DIP Switch Block S2 —
Accessory 2 Relay Options
LEGEND
NOTE: All other switch combinations are invalid.
Auto Dehumidification Mode or High Fan Mode (Not used
on 50RTG) — Switch 7 provides selection of auto dehumidifi-
cation fan mode or high fan mode. In auto dehumidification fan
mode the fan speed relay will remain off during cooling stage 2
if terminal H is active. In high fan mode, the fan enable and fan
speed relays will turn on when terminal H is active. Set the
switch to ON for auto dehumidification fan mode or to OFF for
high fan mode.
Switch 8 — Not used.
D Control Accessory Relay Configurations —
The following accessory relay settings are applicable for both
D controls only:
CYCLE WITH FAN — In this configuration, the relay will be
ON any time the Fan Enable relay is on.
CYCLE WITH COMPRESSOR — In this configuration, the
relay will be ON any time the Compressor relay is on.
DIGITAL NIGHT SET BACK (NSB) — In this configura-
tion, the relay will be ON if the NSB input is connected to
ground C.
NOTE: If there are no relays configured for digital NSB, then
the NSB and OVR inputs are automatically configured for
mechanical operation.
MECHANICAL NIGHT SET BACK — When NSB input is
connected to ground C, all thermostat inputs are ignored. A
thermostat set back heating call will then be connected to the
OVR input. If OVR input becomes active, then the D control
will enter Night Low Limit (NLL) staged heating mode. The
NLL staged heating mode will then provide heating during the
NSB period.
Water Valve (Slow Opening) —
If relay is config-
ured for Water Valve (slow opening), the relay will start 60 sec-
onds prior to starting compressor relay.
Outside Air Damper (OAD) —
If relay is configured
for OAD, the relay will normally be ON any time the Fan
Enable relay is energized. The relay will not start for 30 min-
utes following a return to normal mode from NSB, when NSB
is no longer connected to ground C. After 30 minutes, the relay
will start if the Fan Enable is set to ON.
START-UP
Use the procedure outlined below to initiate proper unit
start-up.
NOTE: This equipment is designed for indoor installation only.
Operating Limits
ENVIRONMENT — This equipment is designed for outdoor
installation ONLY. Extreme variations in temperature, humidi-
ty and corrosive water or air will adversely affect the unit per-
formance, reliability and service life.
POWER SUPPLY — A voltage variation of ± 10% of name-
plate utilization voltage is acceptable.
UNIT STARTING CONDITIONS — All units start and op-
erate with entering air at 40 F, entering water at 20 F and with
both air and water at the flow rates used.
NOTE: These operating limits are not normal or continuous
operating conditions. It is assumed that such a start-up is for
the purpose of bringing the building space up to occupancy
temperature. See Table 15 for operating limits.
1. Restore power to system.
2. Turn thermostat fan position to ON. Blower should start.
3. Balance airflow at registers.
4. Adjust all valves to the full open position and turn on the
line power to all heat pump units.
5. Operate unit in the cooling cycle. Room temperature
should be approximately 70 to 75 F dry bulb. Loop water
temperature entering the heat pumps should be between
60 and 110 F.
ACCESSORY 1
RELAY OPTIONS
DIP SWITCH POSITION
1
2
3
Cycle with Fan
On
On
On
Digital NSB
Off
On
On
Water Valve — Slow Opening
On
Off
On
OAD
On
On
Off
NSB —
Night Setback
OAD —
Outside Air Damper
ACCESSORY 2
RELAY OPTIONS
DIP SWITCH POSITION
4
5
6
Cycle with Fan
On
On
On
Digital NSB
Off
On
On
Water Valve — Slow Opening
On
Off
On
OAD
On
On
Off
NSB —
Night Setback
OAD —
Outside Air Damper
To avoid equipment damage, DO NOT leave system filled
in a building without heat during the winter unless anti-
freeze is added to system water. Condenser coils never
fully drain by themselves and will freeze unless winterized
with antifreeze.
When the disconnect switch is closed, high voltage is
present in some areas of the electrical panel. Exercise
caution when working with the energized equipment.
