Kees DFG (DIRECT FIRED GAS) MAKE-UP AIR UNITS User Manual

Page 3

Piping the Unit

Applicable codes and standards must be followed in sizing and installing the gas piping.
A manual gas shutoff valve is provided for field installation. A 1/8" N.P.T. plugged
tapping must be installed immediately upstream of this valve for pressure test gauge
connection. The pressure at this tap must fall within the minimum and maximum
pressures shown on the nameplate in order for the unit to operate properly. 1/2" or
greater diameter pipe is recommended for the incoming pipe. Care should be taken
when fitting the piping, so that the manifold and gas train components do not get twisted
or damaged. If the minimum pressure is not met then the burner will not operate
properly. An auxiliary high-pressure regulator must be installed if the maximum is
exceeded.

Unit Gas Piping Connection Size Chart

MBH

Gas Pressure at the Unit

Input

7-8" NG

5-6” LP

9-10" NG

7-8” LP

11-14" NG

9-14” LP

100

½"

200

½"

Note: Unless otherwise specified

300

¾"

½"

at the time of the order, the gas

400

¾"

piping will be sized according to

500

¾"

the 7-8" gas pressure column.

600

¾"

700

1-¼"

800

1-¼"

900

1-¼"

1,000

1-¼"

1,100

1-¼"

1,200

1-½"

1-¼"

1,300

1-½"

1-¼"

1,400

1-½"

1-¼"

1,500

1-½"

1-¼"

1,600

1-½"

1-¼"

1,650

1-½"

1-¼"

Wiring the Unit

Applicable codes and standards must be followed in wiring the unit. For main power
wiring, bring the wires into the factory supplied disconnect switch. If one has not been
factory provided, then a disconnect switch of sufficient ampacity must be installed
according to Article 430 of the National Electrical Code, ANSI/NFPA 70-1987. In this
case once it is installed and wired the wires should be run to the service switch inside
the control compartment. Connect any field wired control components according to the
electrical drawing furnished with the unit. Spark testing or shorting of the control wires
by any means will render the transformers inoperative. Do not allow this to happen, as
it is not covered under warranty.

The unit wiring diagram and parts list are in a plastic sheet protector inside of the control
compartment.