Install Instructions

50
APPENDIX F – ADJUSTING GAS INPUT RATE
F-1
F-2
Input ratings shown on boiler rating label can be
used for elevations up to 2000 ft (600 m).
United States. For elevations 2000 ft (600 m) or
higher, reduce input rate 4 percent per 1000 ft
(300 m) above sea level. Do not install at
elevations above 12,000 ft (3560 m).
Boiler
Model
Input [Mbh]
Rating
Label
5000 ft.
(1525 m)
7,000 ft.
(2130 m)
10,000 ft.
(3050 m)
303B 70.0 56.0 49.0 42.0
304B 105.0 84.0 73.5 63.0
305B 140.0 112.0 98.0 84.0
306B 175.0 140.0 122.5 105.0
307B 210.0 168.0 147.0 126.0
308B 245.0 196.0 171.5 147.0
309B 280.0 224.0 196.0 168.0
Canada. For elevations 2000 - 4500 ft (600 -
1350m) use conversion kit to reduce input.
Boiler Model
Type of Fuel
Natural Gas Propane
303B, 304B, 305B, 306B 105864-06 105864-09
307B, 308B, 309B 105865-06 105865-09
When boiler installed above 4500 ft (1350 m),
reduce 2000 - 4500 ft (600 - 1350 m) rating at the
rate of 4% for each additional 1000 ft (300 m).
Boiler
Model
Input [Mbh]
0 - 2000 ft.
(0 - 600 m)
2000 - 4500 ft.
(600 - 1350 m)
5,000 ft.
(1500 m)
303B 70.0 63.0 61.6
304B 105.0 94.5 92.4
305B 140.0 126.0 123.2
306B 175.0 157.5 154.0
307B 210.0 189.0 184.8
308B 245.0 220.5 215.6
309B 280.0 252.0 246.4
Check gas input rate to boiler. Do not exceed
input rate shown on rating label or reduced input
required for elevations above 2000 ft (600m).
1. Verify inlet gas pressure (1) does not exceed
maximum inlet gas pressure shown on rating
label; and (2) exceeds minimum inlet gas
pressure shown on rating label.
2. Connect manometer or pressure gauge to
gas valve outlet pressure tap (see Figure
F-1). Place shut-off valve between gas
valve and manometer (gas pressure can be
introduced gradually to avoid pressure surge
when gas valve opens that could blow liquid
out of manometer).
3. Gas valve has step-opening regulator,
which initially opens at a lower manifold
pressure and then steps to full pressure after
approximately 30 seconds. Check manifold
pressure after step has occurred.