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P/N 42-9472 Copyright 2008 Mestek, Inc.
Cast iron condensing boiler
Cast iron condensing boiler
— Control manual
Method 3: External 4-20ma control
3
Overview — control setup sequence
Follow the Boiler manual
— Install the boilers according to the 200i
Boiler manual before att empting to set up the control system.
Th is method can be used for from 1 to 5 boilers.
Install all boilers per the Boiler manual.
Close the external gas valve on every boiler.
Wire all boilers following the guidelines in this section.
DO NOT install a header sensor on any of the boilers.
Disconnect the wires to the boilers’ Remote Enable terminals (and any override
wiring to Heat Demand or DHW Demand terminals) to ensure there will be no
call for heat while proceeding.
Set the boilers’ control parameters using their display/keypads.
Follow the instructions in the Boiler manual to start up each boiler before proceed-
ing further.
Finish by reconnecting call for heat wiring, then operating the complete system to
verify operation in all modes.
Connect 4-20mA wiring
See Figure 16, page 19 for wiring from the 4-20mA controller. Th e control must
provide the 4-20mA signal and a contact for each boiler to enable its operation by
closing across the Remote Enable contact.
Power supply (120 VAC)
See Figure 11 and Figure 12.
Connect minimum 14awg copper wire to the power connection as shown in Fig-
ure 12.
Install a fused service switch, mounted and installed in accordance with all appli-
cable codes.
1.
2.
3.
4.
5.
6.
7.
8.
9.
1.
1.
2.
3.
Figure 11
Electrical connection board (see item 10,
page 3 for location — Also see the wiring
summary illustrations on the next pages)
Figure 12
120VAC power service terminals on electrical
connection board — See Figure 15 for loca-
tion of the power terminal strip
Electrical shock hazard —
Disconnect all electrical power
sources to the boiler before making any electrical connections.
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation!
Verify proper operation aft er servicing.
Failure to comply with the above could result in severe personal
injury, death or substantial property damage.
Th e electrical connections to this boiler must be made in
accordance with all applicable local codes and the latest
revision of the National Electrical Code, ANSI /NFPA-70.
Installation should also conform to CSA C22.1 Canadian
Electrical Code Part I if installed in Canada. Install a separate
120 volt 15 amp circuit for the boiler. A properly rated shut-
off switch should be located at the boiler. Th e boiler must be
grounded in accordance with the authority having jurisdiction,
or if none, the latest revision of the National Electrical Code,
ANSI/NFPA-70.
Line voltage fi eld wiring of any controls or other devices must
use copper conductors with a minimum size of #14 awg. Use
appropriate wiring materials for units installed outdoors.
