Important – Steffes 7140 User Manual
Page 20
LOW VOLTAGE CONNECTIONS
HYDRONIC HEATING SINGLE ZONE SYSTEM
FIGURE 12
Installation
Installation
n
3.09
Comfort Plus Commercial Hydronic
LOW VOLTAGE ELECTRICAL CONNECTIONS -
ROOM THERMOSTAT
A low voltage (24VAC) room thermostat may be used for room temperature
control with the Comfort Plus Commercial Hydronic system. Steffes recom-
mends using a digital thermostat. If utilizing a mechanical thermostat, a load
resistor may be necessary due to the low current draw (.01 amps) on the heat
call input circuit of the system. Contact the factory for information on thermo-
stats available from Steffes.
SC
Y2
R C
Y
O
G
O2
H
W
OS
DS
R
W
Outdoor Sensor
Hydronic Heat Thermostat, Zone
Valve End Switch, or Pump Control
Low voltage wires MUST
never enter any line
voltage enclosure.
IMPORTANT
SINGLE STAGE HEAT PUMP APPLICATION WITH VARIABLE SPEED BLOWER
FIGURE 13
IMPORTANT
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(
Б
Б
Б
!(
(
) ! * '
#
+$ ,-.
(
/01/
)$1 0
)$1 0
В
2
(3
! *
+
Thermostat
Stage
Thermostat
Output
Heat
Pump
Stage
% of
Selected
CFM
Heat Call
Status on
Digital Display
Discharge Air
Temperature
Target
1
Y1/G
1
100%
HC1
L048
2
Aux/Y1/G
1
100%
HC3
L049
Fan
G
0
400 cfm
HCF
N/A
Cool Y1/G/O
1
100%
COOL
N/A
Hydronic
Heat Control
H/E
N/A
N/A
HC3
N/A
*Contractor Use Only
SINGLE STAGE HEAT PUMP