Installation & Operation Manual
3 Gas connections
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.
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.
Do not have any open flame in proximity to WARNING the gas line when bleeding air from the gas
line. Gas may be present.
Gas train and controls
NOTICE | The gas train and controls assembly | |
provided on this unit have been tested under | ||
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| the applicable American National Standard | |
| to meet minimum safety and performance | |
| criteria such as safe lighting, combustion | |
| and safety shutdown operation. | |
| 402 MODEL | |
COMBINATION |
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VALVE |
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COMBINATION | 2072 MODEL |
VALVE |
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DOWNSTREAM |
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TEST VALVE |
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TO BURNERS
DOWNSTREAM
TEST VALVE
TO BURNERS
Figure 3-2_Typical Boiler Gas Train Drawing
TABLE 3B
SUGGESTED GAS PIPE SIZE FOR
SINGLE UNIT INSTALLATIONS
Distance from Meter (in feet)
MODEL
| 0 - 50 | 51 - 100 | 101 - 200 | ||
402 | 1 1/4" | 1 1/4" | 1 1/2" | 2" | 2" |
502 | 1 1/4" | 1 1/2" | 2" | 2" | 2 1/2" |
652 | 1 1/2" | 2" | 2" | 2 1/2" | 2 1/2" |
752 | 1 1/2" | 2" | 2" | 2 1/2" | 3" |
992 | 2" | 2" | 2 1/2" | 2 1/2" | 3" |
1262 | 2" | 2 1/2" | 2 1/2" | 3" | 3" |
1442 | 2 1/2" | 2 1/2" | 3" | 3" | 3 1/2" |
1802 | 2 1/2" | 3" | 3" | 3 1/2" | 3 1/2" |
2072 | 2 1/2" | 3" | 3" | 3 1/2" | 4" |
For each elbow or tee, add equivalent straight pipe to total length from Table 3C.
TABLE - 3C
FITTINGS TO EQUIVALENT STRAIGHT PIPE
Diameter |
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Pipe | 3/4 | 1 | 1 1/4 | 1 1/2 | 2 | 3 | 4 | 5 | |
(inches) |
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Equivalent |
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length of | 2 | 2 | 3 | 4 | 5 | 10 | 14 | 20 | |
Straight Pipe | |||||||||
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(feet) |
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Water heater models do not have downstream test valves, but the rest of the gas train is represented by FIG.
Combination gas valves
These units fire in multiple stages of burner input. Each stage of burner operation has a combination gas valve(s) to cycle the gas supply on and off and regulate gas to the burners. Each combination valve consists of a gas regulator and two valve seats to meet the requirements for redundant gas valves. The valve has a gas control knob that must remain in the open position at all times when the unit is in service. The gas control valve has pressure taps located on the inlet and discharge sides of the valve. Manifold pressure is adjusted using the regulator located on the valve. A manifold gas pressure tap for each burner stick is located on the discharge side of the valve.
The manifold pressure is preset at the factory and adjustment is not usually required. If you must adjust regulator pressure, follow the instructions in the
Venting of combination gas valves
The combination gas valve/regulator used on all units is equipped with an integral vent limiting orifice per ANSI Z21.78. The vent limiter ensures that the volume of gas emitted from the valve in the event of a failed gas diaphragm does not exceed the maximum safe leakage rate allowed by agency requirements.
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