17
Part Number 550-142-785/0812
GWI
Series 2
Gas-Fired Water Boilers –
Boiler Manual
For your safety, turn off electrical power supply at
service entrance panel before making any electrical
connections to avoid possible electric shock hazard.
Failure to do so can cause severe personal injury
or death.
Wiring must be N.E.C. Class 1.
If rollout thermal fuse element wire as supplied
with boiler must be replaced, type 200 °C wire or
equivalent must be used. If other original wiring as
supplied with boiler must be replaced, use only type
105 °C wire or equivalent.
Boiler must be electrically grounded as required by
National Electrical Code ANSI/NFPA 70-latest edition.
Electrical installation must comply with:
1. National Electrical Code and any other national, state, provin
-
cial or local codes or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and
any local codes.
Wiring connections
Boiler is shipped with controls completely wired. See wiring dia-
gram on page 24 and 25
for details. Circulator is shipped loose,
but wiring harness is pre-attached to the boiler. Connect wires in
circulator junction box.
Thermostat
1. Connect thermostat as shown on wiring diagram on boiler.
2. Install on inside wall away from influences of drafts, hot or cold
water pipes, lighting fixtures, television, sunrays or fireplaces.
3. If thermostat has a heat anticipator, set heat anticipator in
thermostat to match power requirements of equipment con
-
nected to it. If connected directly to boiler, see Wiring diagrams,
6 Field wiring
page 24 and 25
, for anticipator setting. For other devices, see
manufacturer’s specifications. Wiring diagram on boiler gives
setting for control module and gas valve. Also see instructions
with thermostat.
DHW
(if used)
Connect DHW aquastat as shown in wiring below. Economy
function isn’t utilized with DHW input.
R & C Connections
(if used)
24 Vac leads should be used for power stealing thermostats only!
Junction box (furnished)
1. Connect 120 VAC power wiring (
Figure 15
).
2. Fused disconnect or service switch (15 amp. recommended)
may be mounted on this box. For those installations with local
codes which prohibit installation of fused disconnect or service
switch on boiler, install a 2 x 4 cover plate on the boiler junction
box and mount the service switch remotely as required by the
code.
Wiring multiple zones
See zone valve manufacturer’s literature for wiring and application.
A separate transformer is required to power zone valves. Zoning
with circulators requires a relay for each circulator.
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 terminals. Failure to
comply can result in damage to boiler components
or cause unreliable operation, resulting in severe
property damage.
Figure 15 Field wiring connections — service switch, DHW (if used) and thermostat (or end switch) provided by installer
