Lochinvar 399, 999 - 750 Gas Train and Controls, Table-J, Btu/hr Distance From Meter in feet

Installation and

Service Manual

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.

COMBINATION VALVE

DOWNSTREAM

TEST VALVE

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.

TO BURNERS	ADDITIONAL VALVES BASED
	ON UNIT INPUTS

FIG. 29 Typical Boiler Gas Train Drawing

TABLE-J

Suggested Gas Pipe Size for Single Unit Installations

3.

Install a manual main gas shutoff valve at the unit’s gas

Btu/hr

Distance From Meter (in feet)

inlet, outside of the unit.

Input

0-50

51-100

101-200

201-300

301-500

4.

Run pipe or tubing to the unit’s gas inlet. If you use tubing,

399,999

1 1/4"

1 1/4"

1 1/2"

2"

2"

obtain a tube to pipe coupling to connect the tubing to the

unit’s gas inlet.

1 1/4"

1 1/2"

2"

2"

2 1/2"

5.

Install a sediment trap in the supply line to the unit’s gas

500,000

inlet (see FIG. 28).

650,000

1 1/2"

2"

2"

2 1/2"

2 1/2"

6.

Apply a moderate amount of good quality pipe compound

750,000

1 1/2"

2"

2"

2 1/2"

3"

(do not use Teflon tape) to pipe only, leaving two end

threads bare.

990,000

2"

2"

2 1/2"

2 1/2"

3"

7.

Remove seal over gas inlet to unit.

8.

Connect gas pipe to inlet of unit. Use wrench to support

1,260,000

2"

2 1/2"

2 1/2"

3"

3"

gas manifold on the unit.

1,440,000

2 1/2"

2 1/2"

3"

3"

3 1/2"

9.

For L.P. gas, consult your L.P. gas supplier for expert

installation.

1,800,000

2 1/2"

3"

3"

3 1/2"

3 1/2"

10.

Ensure that all air is completely bled from the gas line

before starting the ignition sequence. Start up without

2,070,000

2 1/2"

3"

3"

3 1/2"

4"

properly bleeding air from the gas line may require

multiple reset functions of the ignition control module to

For each elbow or tee, add equivalent straight pipe to total length from table

achieve proper ignition.

below.

Figure 29 on this page shows a typical boiler gas train.

WARNING: Do not have any open flame in proximity to the gas line when bleeding air from the gas line. Gas may be present.

TABLE-K

Fittings to Equivalent Straight Pipe

Diameter Pipe (inches)

3/4	1	1 1/4	1 1/2	2	3	4	5
	Equivalent Length of Straight Pipe (feet)
2	2	3	4	5	10	14	20

29