Instruction manual
20
P/N HN-IOM-1 82-0331 Copyright 2009 Mestek, Inc.
Finned copper tube gas boilers & water heaters – Control manual
Wiring
6
Power supply
Refer to the Boiler Manual/wiring diagram and rating plate 1.
for required voltage and amperage.
Connect minimum 14 awg copper wire to the power con-2.
nection. See Figure 3, page 22.
Install a fused service switch, mounted and installed in ac-3.
cordance with all applicable codes.
Circulator wiring
All circulators operated by the HeatNet control
require a motor starter or relay to handle the
power load of the circulator. Use the output
terminals of the HeatNet control ONLY to
operate the starter or relay coil.
Boiler circulator
If the boiler circulator is to be controlled by the boiler’s •
HeatNet control, power the boiler circulator starter or relay
coil through the local pump or valve terminals provided on
J13 (see Figure 3, page 22).
System circulator
If the system circulator is operated by one of the HeatNet •
controls (by the MASTER boiler control for HeatNet mul-
tiple boiler systems), power the boiler circulator starter or
relay coil through the system pump terminals provided on
J13 (see Figure 3, page 22).
Sensor wiring
Factory-installed sensors — • boilers are provided with a
factory-installed supply sensor (boiler outlet water temper-
ature) and return sensor (boiler return water temperature),
connected to the terminals on J10.
Parameters that require the supply water temperature •
sensor are OP LIMIT and LOCAL SETPOINT.
Parameters that require the return water temperature •
sensor are DELTA TEMP (under PUMP OPTIONS)
and EXCHGR DELTA (under AUX FUNCTIONS).
Header (SYSTEM HEADER) sensor is required• — A header sensor (SYS-
TEM HEADER) must be installed in the system supply piping for HeatNet con-
trolled systems.
Connect the header sensor ONLY to the master boiler• .
Install the header sensor in an immersion well.•
Locate the sensor where it will accurately sense the system water supply tem-•
perature.
Connect the sensor leads to the MASTER boiler electrical connection board •
terminals on J10 as shown in Figure 4, page 23.
e header sensor can be used with a stand-alone boiler to allow regulation of •
a primary/secondary system.
Domestic hot water (DHW) sensor• —
A DHW sensor must be installed in the tank for HeatNet-controlled systems •
if providing domestic hot water.
Connect the DHW sensor ONLY to the master boiler• .
Install the DHW sensor in an immersion well.•
Locate the sensor where it will properly control tank temperature, in accor-•
dance with tank manufacturer’s instructions.
Connect the sensor leads to the MASTER boiler electrical connection board •
terminals on J10 as shown in Figure 4, page 23.
e DHW sensor can also be connected to a stand-alone boiler connection •
board.
e DHW sensor can be connected to a MASTER boiler control, in addition •
to a space heating SYSTEM HEADER sensor, for combined space heating/
domestic water heating applications.
Outdoor reset application• — To operate with outdoor reset, purchase and
install an optional outdoor sensor.
Mount the sensor such that it is shielded from direct sunlight if possible and •
not likely to be covered by snow dris or debris.
Connect the outdoor air sensor leads to the electrical connection board termi-•
nals on J10 as shown in Figure 4, page 23.
e sensor must be connected to the MASTER boiler for a HeatNet system.•
A member boiler could have its own outdoor sensor if it is to be activated in •
override mode by closing the Heat Demand terminals.
e outdoor sensor can also be connected to a stand-alone boiler connection •
board.