Modine Manufacturing DBP Installation And Service Manual Download

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5-565.1

WARNING

1. All field gas piping must be pressure/leak tested prior to

operation. Never use an open flame. Use a soap solution or
equivalent for testing.

2. Gas pressure to appliance controls must never exceed 14"

W.C. (1/2 psi).

3.  To reduce the opportunity for condensation, the minimum
  sea level input to the appliance, as indicated on the serial
  plate, must not be less than 5% below the rated input, or 5%
  below the minimum rated input of duel rated units.

unit installation

gas connections

1. Installation of piping must conform with local building codes,

or in the absence of local codes, with the National Fuel Gas

Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In Canada,

installation must be in accordance with CAN/CGA-B149.1

for natural gas units and CAN/CGA-B149.2 for propane

units.

2. Piping to units should conform with local and national

requirements for type and volume of gas handled, and

pressure drop allowed in the line. Refer to Table 14.1

to determine the cubic feet per hour (cfh) for the type of

gas and size of unit to be installed. Using this cfh value

and the length of pipe necessary, determine the pipe

diameter from Table 8.1. Where several units are served

by the same main, the total capacity, cfh and length of

main must be considered. Avoid pipe sizes smaller than

1/2". Table 8.1 allows for a 0.3" W.C. pressure drop in the

supply pressure from the building main to the unit. The inlet

pressure to the unit must be 6-7" W.C. for natural gas and

11-14" W.C. for propane gas. When sizing the inlet gas

pipe diameter, make sure that the unit supply pressure can

be met after the 0.3" W.C. has been subtracted. If the 0.3"

W.C. pressure drop is too high, refer to the Gas Engineer’s

Handbook for other gas pipe capacities.

3. The gas piping to the unit can enter the unit from the side of

the unit or from below. Install a ground joint union with brass

seat and a manual shut-off valve external of the unit casing,

and adjacent to the unit for emergency shut-off and easy

servicing of controls, including a 1/8" NPT plugged tapping

accessible for test gauge connection

(See Figure 8.1). Verify the manual shut-off valve is gas

tight on an annual basis.

4. Provide a sediment trap before each unit in the line where

low spots cannot be avoided. (See Figure 8.1).

5. When Pressure/Leak testing, pressures above 14" W.C.

(1/2 psi), close the field installed shut-off valve, disconnect

the appliance and its combination gas control from the gas

supply line, and plug the supply line before testing. When

testing pressures 14" W.C. (1/2 psi) or below, close the

manual shut-off valve on the appliance before testing.

figure 8.1 - recommended sediment trap/manual

shut-off valve installation - side or Bottom gas

connection

GAS

SUPPLY LINE

GAS

SUPPLY LINE

GROUND

JOINT

UNION

W/ BRASS

SEAT

MANUAL GAS

SHUT-OFF VALVE

MIN.

SEDIMENT

TRAP

PLUGGED

1/8" NPT TEST

GAGE CONNECTION

CONTROLS

➀

Manual shut-off valve is in the “OFF” position when handle is perpendicular

to pipe.

CAUTION

Purging of air from gas supply line should be performed as
described in ANSI Z223.1 - latest edition “National Fuel Gas
Code”, or in Canada in CAN/CGA-B149 codes.

IMPORTANT

To prevent premature heat exchanger failure, the input to the
appliance, as indicated on the serial plate, must not exceed
the rated input by more than 5%.

table 8.1 - gas Pipe capacities

gas Pipe capacities (up to 14” W.c. gas Pressure through schedule 40 Pipe)

cubic feet per Hour with Pressure drop of 0.3” W.c.

natural gas - specific gravity - 0.60

Propane gas - specific gravity - 1.50

length

Pipe diameter

of Pipe

1/2"

3/4"

1-1/4"

1-1/2"