Part number 550-143-010/1021
55
GV90+
series
2
gas-fired water boiler – 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.
Installation must comply with:
National Electrical Code and any other national, state, provincial
or local codes or regulations. In Canada, CSA C22.1 Canadian
Electrical Code Part 1, and any local codes. Boiler must be elec-
trically grounded as required by National Electrical Code ANSI/
NFPA 70 - latest edition.
Wiring must be NEC Class 1. Boiler must be elec-
trically grounded as required by National Electrical
Code ANSI/NFPA 70 - latest edition.
To replace wiring, order complete harness assem-
blies from Weil-McLain. If any original wiring as
supplied with boiler must be replaced, and a har-
ness is not immediately available, use only type
105°C wire or equivalent. Use this wiring only as a
temporary repair. Obtain a complete harness from
Weil-McLain.
Wiring connections
Power wiring
Connect 120 VAC power wiring as shown in Figure 66, page 56.
The junction box is located on the inside left jacket panel.
Watch the polarity of the circuit when connect-
ing the 120 VAC power wiring. If the polarity is
switched, the integrated boiler control will lockout.
The IBC will flash the POWER light to indicate
this problem. See the troubleshooting information
beginning on
Additional limit controls
Wire additional limit controls (if used) as shown in
Thermostat(s)
Install thermostats on inside walls, 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 equipment connected to it (ignition control and gas valve, zone
valve contacts, etc.). Wiring diagram on boiler gives setting for
standard equipment (ignition control and gas valve).
Natural Gas
1. Refer to Figure 65 for pipe length and diameter. Size gas
supply piping for total flow to all connected appliances.
For each GV90+ boiler, provide for the following gas flow
(cfh = cubic feet per hour):
Boiler model
CFH natural gas
GV90+3
70
GV90+4
105
GV90+5
140
GV90+6
175
2. Inlet pressure required at gas valve inlet:
• maximum 14” w.c.
• minimum 3.5” w.c.
Install 100% lockup gas pressure regulator in sup-
ply line if inlet pressure exceeds 14” water column.
Adjust for 14” w.c. maximum.
Propane Gas
1. Contact gas supplier to size pipes, tanks and 100% lockup
gas pressure regulator.
2. Adjust propane supply regulator provided by gas supplier for
14” w.c. maximum pressure.
3. Inlet pressure required at gas valve inlet:
• maximum 14” w.c.
• minimum 5” w.c.
Gas piping
(continued)
Wiring
Figure 65
Pipe capacity for 0.60 specific gravity natural gas
Gas pipe
length
(feet)
Capacity in cubic feet of gas per hour
Natural gas only, with specific gravity of 0.60
Based on pressure drop of 0.3” w.c.
Gas pipe diameter —
½”
¾”
1”
1¼”
1½”
10
132
278
520
1050
1600
20
92
190
350
730
1100
30
73
152
285
590
860
40
63
130
245
500
760
50
56
115
215
440
670
75
45
93
175
360
545
100
38
79
150
305
460
150
31
64
120
250
380
For additional gas pipe sizing information, refer to ANSI Z223.1/NFPA
54 - latest edition (or Natural Gas and Propane Installation Code,
B149.1
or B149.2 for Canadian installations).
