Lochinvar 90 Gas connections, Gas Supply Gas Pressure Test, Gas Connection, Manifold Pressure

Installation & Service Manual

3Gas connections

Gas Supply

Gas Pressure Test

Verify that the appliance is supplied with

the type gas

1.

The appliance must be disconnected from the gas supply

specified on the rating plate. This appliance is orificed for

piping system during any pressure testing of that system at

operation up to 2000 feet altitude. The appliance will be

a test pressure in excess of 1/2 PSIG (3.5kPa).

derated 4% per 1000 feet above 2000 feet elevation. Consult

2.

The appliance must be isolated from the gas supply piping

the factory for installations above 2000 feet elevation. Field

system by

closing

a manual

shutoff valve during

any

conversions for operation at high altitude must be performed

pressure testing of

the gas

supply

piping

system

at

test

by certified personnel only. The appliance will be marked to

pressures equal to or less than 1/2 PSIG (3.5kPa).

indicate suitability for high altitude operation.

GAS SUPPLY PRESSURE: Measured at the inlet pressure tap

3. The appliance and its gas connection must be leak-tested

before placing it in operation.

located upstream of the combination gas valve(s) see

FIG.’s 3-5 and 3-6, page 23.

Gas Connection

TABLE - 3A

1.

Safe operation of the appliance requires properly sized gas

GAS SUPPLY PRESSURE

supply piping.

2.

Gas pipe size may be larger than appliance gas connection.

Natural Gas

LP Gas

Max. (Inches Water Column)

3.

Installation of a union is suggested for ease of service, see

14

14

FIG. 3-1 on page 20.

Min. (Inches Water Column)

*4.5

11

4.

Install a manual

main gas

shutoff

valve, outside

of

the

Min. (Inches Water Column)

**5.0

11

appliance gas connection and before the gas valve or

manifold connection, when local codes require.

*Models 90,000 - 360,000 Btu/hr Only

**Models 399,999 - 500,000 Btu/hr Only

5.

A trap (drip leg) MUST be provided by the installer in

Maximum inlet

gas pressure

must not

exceed the value

the inlet of the

gas connection to the

appliance,

see

FIG. 3-1 on page 20.

specified. Minimum value listed is for the purposes of input

adjustment.

6.

The combination gas valve has an integral vent limiting

MANIFOLD PRESSURE: Measured at the pressure tap on

device and

does

not require

venting to atmosphere,

outside the building.

the downstream side of the combination gas valve(s) (see

FIG.’s 3-5 and 3-6, page 23). The gas regulator settings for

7.

Optional gas controls may require routing of bleeds and

single stage and two stage operation are factory set to supply

vents to the atmosphere,

outside

the building

when

proper manifold pressure for normal operation. To check

required by local codes.

manifold pressure, see Manifold Adjustment Procedure. Do

not increase manifold pressure beyond

specified pressure

TABLE - 3C

settings shown below in Table 3B.

FITTINGS TO EQUIVALENT STRAIGHT PIPE

TABLE - 3B

Diameter Pipe (inches)

MANIFOLD PRESSURE

3/4

1

1 1/4

1 1/2

2

3

4

5

Single and Two-Stage

Two Stage

Input Gas

Equivalent Length of Straight Pipe (feet)

Full or High Fire Settings

Low Fire Settings

Btu/hr

2

2

3

4

5

10

14

20

Natural Gas

LP Gas

Natural Gas

LP Gas

90,000 - 180,000

3.5"

10"

0.9"

2.5"

TABLE - 3D

199,999

2.9"

7.5"

0.9"

2.5"

GAS CONNECTIONS

215,000 - 399,999

3.5"

10"

0.9"

2.5"

Btu/hr

Pipe Size

INPUT

500,000

3.5"

10"

N/A

N/A

90,000 - 135,000

1/2"

(two valves)

180,000 - 315,000

3/4"

360,000 - 500,000

1

19