
18
Rinnai Corporation Hydronic Furnace (37AHB) Manual
Shunt Jumper Options:
An additional feature of the 37AHB series is its
selectable operating sequence option; the 3-pin shunt
header (P7) allows the control to operate the proper
heating logic based on the following system
requirements:
The 37AHB unit in Open Loop configuration:
“FS” Shunt selection: The “FS” logic sequence will
configure the unit for operation with all Rinnai®
Tankless Water Heaters; this logic monitors the ratio
of available flow for space heating (via Flow Sensor);
this status is then communicated to the PCB whose
operating characteristics is primarily determined by the
status of the Flow Sensor input (sequence allows
domestic priority).
Failure to follow this warning could result in an
electrical shock, fire, or death.
To minimize personal injury if an electrical fault should
occur, cabinet grounding MUST be an uninterrupted
ground and MUST comply with NEC, ANSI/NFPA 70
and all local codes having jurisdiction. The ground
may consist of electrical wire or metal conduit when
installed in accordance with existing electrical codes.
WARNING
THERMOSTAT WIRING DIAGRAMS
Installation
FIRST STAGE HEAT/COOL
AUX HEATING
FAN
24VAC HOT
24 VAC COMMON
SINGLE STAGE
HYDRONIC FURNACE
SINGLE SPEED
CONDENSING
UNIT
HEAT/COOL & COOL ONLY
THERMOSTATS
Y1
W
G
R
C
Y1
Y2
W
G
O
R
C
Y1
C
Single Stage Hydronic Furnace w/ Single Stage A
Figure 16
FIRST STAGE HEAT/COOL
AUX HEATING
FAN
RVS COOLING
24VAC HOT
24 VAC COMMON
HEAT PUMP THERMOSTATS
SINGLE STAGE
SINGLE STAGE
HEAT PUMP
Y1
W
G
O
R
C
Y1
W
G
O
R
C
Y1
O
R
C
Y2
Figure 17
Single Stage Hydronic Furnace
w/ Single Stage Heat Pump
FIRST STAGE HEAT/COOL
SECOND STAGE HEAT/COOL
AUX HEATING
FAN
24VAC HOT
24 VAC COMMON
HEAT/COOL & COOL ONLY
THERMOSTATS
SINGLE STAGE
TWO STAGE
CONDENSING
UNIT
Y1
Y2
W
G
R
C
Y1
Y2
W
G
O
R
C
Y1
Y2
C
Figure 18
Single Stage Hydronic Furnace w/ Two Stage A/C
FIRST STAGE HEAT/COOL
SECOND STAGE HEAT/COOL
AUX HEATING
FAN
RVS COOLING
24VAC HOT
24 VAC COMMON
HEAT PUMP THERMOSTATS
SINGLE STAGE
TWO STAGE
HEAT PUMP
Y1
Y2
W
G
O
R
C
Y1
Y2
W
G
O
R
C
Y1
Y2
O
R
C
Figure 19
Single Stage Hydronic Furnace
w/ Two Stage Heat Pump
HYDRONIC FURNACE
HYDRONIC FURNACE
HYDRONIC FURNACE