Weil-McLain 550-141-826/1201 - Manual (Page 22)

SERVICE TECHNICIAN ONLY — read and follow completely.
Supply
Circ.
Circ.
Chiller
Strainer
Exp. tank
Exp. tank
1
1
1
1
2
Use with refrigeration systems
• Install boiler so that chilled medium is piped in
parallel with heating boiler. Use appropriate valves
to prevent chilled medium from entering boiler.
Consult I=B=R Installation and Piping Guides.
• If boiler is connected to heating coils located in
air handling units where they can be exposed to
refrigerated air, use flow control valves or other
automatic means to prevent gravity circulation
during cooling cycle.
Connect water piping
(continued)
Figure 15 Use with refrigeration system
1
Isolation valve
2
Balancing valve
General wiring requirements
Electric shock hazard. Can cause severe personal injury or
death if power source, including service switch on boiler, is
not disconnected before installing or servicing.
• Installations must follow these codes:
• National Electrical Code, ANSI/NFPA 70, latest edition and
any additional national, state or local codes.
• In Canada, CSA C22.1 Canadian Electrical Code Part 1 and any
local codes.
• Wiring must be N.E.C. Class 1. If original wire as supplied with boiler
must be replaced, type 105°C wire or equivalent must be used. Supply
wiring to boiler and additional control wiring must be 14 ga. or heavier.
• Provide electrical ground at boiler as required by codes.
Thermostat wiring
• Install thermostat on inside wall away from influences of drafts, hot
or cold water pipes, lighting fixtures, television, sun rays or fireplaces.
• Follow instructions with thermostat. If it has a heat anticipator, set
heat anticipator in thermostat to match power requirements of equip-
ment connected to it. Boiler wiring diagrams give setting for standard
equipment.
Connect wiring
DO NOT connect directly from 3-wire zone valves
to the T-T terminals on the boiler
. When using 3-wire
zone valves, install an isolation relay. Connect the zone
valve end switch wires to the isolation relay coil. Connect
the isolation relay contact across the boiler T-T termi-
nals. Failure to comply can result in damage to boiler
components or cause unreliable operation, resulting in
possible severe property damage.
Zone Valve Wiring
4- wire zone valves may be connected directly to the boiler control.
Part number 550-141-826/1211 22
GOLD
WGO
OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 —
Boiler Manual