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Installation and
Service Manual
29
FIG. 28 Gas Line Connection
2. Use new, properly threaded black iron pipe free from
chips. If you use tubing, make sure the ends are cut square,
deburred and clean. Make all tubing bends smooth and
without deformation. Avoid flexible gas connections.
Internal diameter of flexible lines may not provide unit
with proper volume of gas.
3. Install a manual main gas shutoff valve at the unit’s gas
inlet, outside of the unit.
4. Run pipe or tubing to the unit’s gas inlet. If you use tubing,
obtain a tube to pipe coupling to connect the tubing to the
unit’s gas inlet.
5. Install a sediment trap in the supply line to the unit’s gas
inlet (see FIG. 28).
6. Apply a moderate amount of good quality pipe compound
(do not use Teflon tape) to pipe only, leaving two end
threads bare.
7. Remove seal over gas inlet to unit.
8. Connect gas pipe to inlet of unit. Use wrench to support
gas manifold on the unit.
9. For L.P. gas, consult your L.P. gas supplier for expert
installation.
10. Ensure that all air is completely bled from the gas line
before starting the ignition sequence. Start up without
properly bleeding air from the gas line may require
multiple reset functions of the ignition control module to
achieve proper ignition.
Gas Train and Controls
Note: The gas train and controls assembly provided on this unit
have been tested under the applicable American National
Standard to meet minimum safety and performance criteria
such as safe lighting, combustion and safety shutdown
operation.
FIG. 29 Typical Boiler Gas Train Drawing
For each elbow or tee, add equivalent straight pipe to total length from table
below.
Figure 29 on this page shows a typical boiler gas train.
ƽ WARNING: Do not have any open flame
in proximity to the gas line when bleeding air
from the gas line. Gas may be present.
Btu/hr Distance From Meter (in feet)
Input 0-50 51-100 101-200 201-300 301-500
399,999 1 1/4" 1 1/4" 1 1/2" 2" 2"
500,000 1 1/4" 1 1/2" 2" 2" 2 1/2"
650,000 1 1/2" 2" 2" 2 1/2" 2 1/2"
750,000 1 1/2" 2" 2" 2 1/2" 3"
990,000 2" 2" 2 1/2" 2 1/2" 3"
1,260,000 2" 2 1/2" 2 1/2" 3" 3"
1,440,000 2 1/2" 2 1/2" 3" 3" 3 1/2"
1,800,000 2 1/2" 3" 3" 3 1/2" 3 1/2"
2,070,000 2 1/2" 3" 3" 3 1/2" 4"
TABLE-J
Suggested Gas Pipe Size for Single Unit Installations
Diameter Pipe (inches)
3/4 1 1 1/4 1 1/2 2 3 4 5
Equivalent Length of Straight Pipe (feet)
22345101420
TABLE-K
Fittings to Equivalent Straight Pipe
COMBINATION VALVE
DOWNSTREAM
TEST VALVE
TO BURNERS
ADDITIONAL VALVES BASED
ON UNIT INPUTS