PLUS Line Instruction Manual Supplement
PLUS & 
PLUS WATER HEATERS WITH 
3 Field wiring (continued)
Wiring a system circulator
1.For combined systems, to activate a system circulator when the Boiler circulator operates, wire as shown at bottom of Figure 7, page 8.
2.You must install a relay as shown. DO NOT wire in parallel with the Boiler circulator. See CAUTION in Figure 7.
Routing line voltage wiring
1.Route line voltage connections to the jacket openings shown in Figure 8.
Low voltage connections (Fig. 9)
1.Connect low voltage wiring to low voltage terminal strip (Figure 9, item 1) as shown in Figure 9 and the boiler wiring diagram.
2.Route all low voltage wires through grommeted jacket opening to right of low voltage terminal strip, as shown in Figure 8.
Room thermostat (space heating)
1.For combined space heating/water heating systems, connect Figure 9, item 2, room thermostat or end switch (isolated contact only) between terminals 5 and 6.
2.Install thermostat on inside wall away from influences of drafts, hot or cold water pipes, lighting fixtures, television, sunrays, or fireplaces.
3.Thermostat anticipator (if applicable):
a.If connected directly to boiler, set for 0.1 amps.
b.If connected to relays or other devices, set to match total electrical power requirements of connected devices. See device manufacturers’ specifications and thermostat instructions for details.
Outdoor temperature sensor
1.Outdoor reset operation applies only to combined space heating/water heating systems.
2.Connect outdoor temperature sensor (Figure 9, item 6) between terminals 1 and 2 to enable outdoor reset operation of the Ultra boiler. If fixed- temperature operation is required, do not install outdoor sensor.
3.Mount sensor on exterior wall, shielded from direct sunlight or flow of heat or cooling from other sources.
4.Install a summer/winter switch (Figure 9, item 7) across terminals 1 and 2 to force
switch is closed, boiler will attempt to maintain constant temperature.)
5.Route sensor wires through the grommeted hole at right of the electrical entrance (see Figure 8).
PLUS water heater thermostat
1.Connect PLUS water heater aquastat terminals “C” and “1” to Ultra Boiler low voltage terminal strip between terminals 3 and 4 (Figure 9, item 3).
Additional limits
1.Connect additional limit controls and interlocks between the terminals shown in Figure 9.
2.Controls connected between terminals 6 and 7 (see Figure 9, item 4) will cause a soft lockout (automatic reset). When limit(s) closes, boiler will resume normal operation.
3.Controls connected between terminals 6 and 8 (see Figure 9, item 5.) will cause a hard lockout (manual reset). The boiler will only restart after the Ultra display panel RESET switch is pressed.
Figure 8 Routing field wiring
Part number IWHA016A/1103 | 9 |
