Kees DIRECT FIRED GAS MAKE-UP AIR UNITS User Manual

KEES, INC.

Installation & Maintenance Manual

DFG Series Direct Gas Fired

Make-up Air Heaters

Table of Contents

Page # Topic

1 Description of Operation
1 Receiving the Unit
1 Positioning the Unit
1 Curbing the Unit
2 Piping the Unit
2 Wiring the Unit
3 Optional Equipment
5 Controls Description
9 Troubleshooting Guide
13 Start-up of the Unit
15 Maintenance Schedule

FOR YOUR SAFETY

If you smell gas:

1. Open windows.

2. Don't touch electrical switches.

3. Extinguish any open flame.

4. Immediately call your gas supplier.

FOR YOUR SAFETY

The use and storage of gasoline or other
flammable vapors and liquids in open
containers in the vicinity of this appliance is
hazardous.

WARNING: Improper installation, adjustment,

alteration, service or maintenance can cause
property damage, injury or death. Read the
installation, operating and maintenance
instructions thoroughly before installing or
servicing this equipment.

INSTALLATION INSTRUCTIONS

Description of Operation

The KEES DFG series heater is a direct gas fired heater using 100% outside air. It is
designed for outdoor installation but may be mounted indoors provided the intake is
ducted to the outdoors. Natural gas or propane fuel the burner. The flame is modulated
to provide a constant preset discharge temperature or room temperature (optional). In
areas where freeze-ups may occur, it is recommended that a low temperature limit be
installed to protect the indoor space in the event of a burner shutdown.

Receiving the Unit

Upon receipt of the unit, carefully inspect it for any visible damage. Each unit is
inspected prior to shipment. If any damage is found, immediately notify the carrier and
file a claim with that carrier. Also, verify that the items shown on the packing list were
received and that they agree with what was ordered. Notify KEES, Inc. of any
discrepancies. Prior written permission must be obtained before any merchandise may
be returned.

Positioning the Unit

When determining the location for the roof curb, minimum clearances to combustible
materials must be maintained. Shown below are the tested minimum clearances. Local
codes prevail, however, if greater clearances are required. The intake of the unit should
not be placed in the direction of prevailing winds if at all possible. Make sure the top of
the curb is level so that a good seal can be made to the heater. Once the curb is set in
place, the roofing material can be finished around it.

Minimum Clearances to Combustibles
Service side or top ----------24.0 inches
All other sides ----------------0.0 inches

Curbing the Unit

The discharge of the unit, which is underneath the blower section, must be placed over
the roof curb. The other end of the unit rests on the support rail. Note: the standard
roof curb height is twelve (12) inches. In areas with heavy snowfall, a greater height
may be required.

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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
100 ½" ½" ½"
200 ½" ½" ½" Note: Unless otherwise specified
300 ¾" ¾" ½" at the time of the order, the gas
400 ¾" ¾" ¾" piping will be sized according to
500 1" ¾" ¾" the 7-8" gas pressure column.
600 1" 1" ¾"
700 1-¼" 1" 1"
800 1-¼" 1" 1"
900 1-¼" 1-¼" 1"

1,000 1-¼" 1-¼" 1"
1,100 1-¼" 1-¼" 1-¼"
1,200 1-½" 1-¼" 1-¼"
1,300 1-½" 1-¼" 1-¼"
1,400 1-½" 1-¼" 1-¼"
1,500 1-½" 1-¼" 1-¼"
1,600 1-½" 1-½" 1-¼"
1,650 1-½" 1-½" 1-¼"

9-10" NG

7-8” LP

11-14" NG

9-14” LP

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.

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OPTIONAL EQUIPMENT

LOW TEMPERATURE LIMIT SWITCH

This control is commonly called a Freeze Stat. This unit mounted, low limit thermostat will shut the
blower off if the discharge temperature drops below 40°F. A Bypass Timer which is part of the control will
allow the unit to run on a cold start-up. After 5 minutes, control power will pass through the low
temperature thermostat. If the remote panel has operating lights, the red light will glow on "ALARM".
Turn the unit

FLAME FAILURE RELAY

A relay is interlocked with the burner control module. When the burner fails to light within the allowable
time (30 seconds), the relay is energized, which opens the circuit to the blower starter, and shuts the unit
down. If the remote panel has operating lights, the red light will glow on "ALARM". Turn the unit
then back ON and then reset the burner control module.

MILD WEATHER THERMOSTAT

This control is often called an "Intake Air Thermostat". The sensing element of the thermostat is mounted
in the incoming air supply to the unit. If the temperature exceeds the setting of the thermostat, the burner
will de-energize. The burner will re-ignite when the outside air temperature falls below the thermostat set
point.

REMOTE CONTROL PANEL

This consists of either a three position “SUMMER-OFF-WINTER” switch in a flush mounting stainless
steel bezel plate and masonry box or two toggle switches (“FAN ON/OFF” and “HEATER ON/OFF”) in a
flush mounting stainless steel bezel plate on the kitchen hood face.

, and back ON, to reset the Bypass Timer.

OFF

OFF

,

REMOTE CONTROL PANEL WITH INDICATOR LIGHTS

Up to four labeled pilot lights are mounted on the face of the remote control panel, indicating primary
functions of the unit. The “SUMMER-OFF-WINTER” switch is included next to the pilot lights.

1 - Green - Blower Run Light – “BLOWER”
1 - Green - Burner On Light – “BURNER”
1 - Red - Low Temperature Failure Light – “ALARM”
1 - Red - Flame Failure Shut Down Light – “ALARM”
1 - Red - Clogged Filter Light – “FILTERS”

A minimum of two lights is available. If more than the standard 4-light panel is required, a circuit analyzer
panel must be used.

CLOGGED FILTER SWITCH WITH INDICATOR LIGHT

A pressure sensitive switch, mounted in the unit, will sense the air pressure drop across the filter. When
the filter becomes dirty, the switch will activate a light on the remote control panel, indicating a filter
change is required.

PREPURGE TIMER

A timer allows the unit blower to run for 1 minute, purging any gas residue in the unit, before the burner
circuit is allowed to energize.

TIME CLOCK

A time clock cycles the unit ON and
selected days, as needed.

, at selected times of the day. This time clock can also "skip"

OFF

115V DUPLEX SERVICE RECEPTACLE

The receptacle is mounted to the outside of the unit in a weatherproof enclosure. It provides power for
service equipment when the main power to the unit is shut off for service work. It requires a separate
115V circuit.

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CONTROL SYSTEM DIAGNOSTIC INDICATOR

This component is used as a diagnostic tool for troubleshooting burner problems. It attaches to the
burner control module monitoring the function of the module and storing in memory any failures that
occur.

AUDIBLE ALARM

An alarm horn is supplied with the remote control panel. On a flame failure, the horn will sound. A reset
of the flame failure relay will silence the horn.

DISCHARGE DAMPER WITH 2-POSITION MOTOR AND INTERLOCK

A motor operated Parallel Blade Damper can be added to the discharge of the unit. This will prevent the
warm air from escaping out of the building through the unit. The damper motor spring returns the damper
to a

CLOSED

outdoors.)

INTAKE DAMPER WITH 2-POSITION MOTOR AND INTERLOCK

A motor operated Parallel Blade Damper is installed to the fresh air intake of the unit. This keeps cold air
from entering the unit when

FILTER SECTION

The filter section with 1” cleanable or throwaway filters is supplied as standard on the units. 2" cleanable
or throwaway filters as well as Farr 30/30 throwaway filters are also available.

position during shutdown. (A discharge damper is recommended on units installed

SHUT-OFF

. (An intake damper is recommended on units installed indoors.)

INTAKE HOOD WITH BIRD SCREEN

This standard accessory is sized to fit the fresh air intake of the unit. It has 1/2" mesh birdscreen on the
face of the hood and is designed to help prevent rain or snow from entering the unit. It is shipped as a
loose item for field installation. It can be deleted on indoor units that are ducted to the outside.

GALVANIZED STEEL CURB

The standard roof curb is flat, 12" high, insulated and formed of 18 gauge galvanized steel. It fits under
the fan discharge of the unit. Other heights and one way or two-way pitches are available.

SUPPORT RAIL

It supports the rear of the unit and is sized to match the roof curb. Support legs may be necessary if an
intake hood is included.

FULL PERIMETER ROOF CURB

This curb goes under the full length of the main unit (burner and blower section). A support rail is not
required for the back of the unit. However, support legs may be necessary if an intake hood is included.

MODULAR CURB CAP AND CURB

The curb cap is custom sized to house an exhaust fan as well as the supply fan on one common curb.
The exhaust fan extension is also sized to meet NFPA96 requirements for discharge height. The supply
fan extension fits under the fan discharge like the standard curb described above.

HOUSING INSULATION

1" 1-1/2# density insulation is standard on the units. It is glued and pin spotted, to the inner surface of the
walls and ceiling of the unit. As an optional cost saving, it can be deleted from the burner and filter
sections if a discharge damper is included.

VIBRATION ISOLATORS

Isolators are standard equipment underneath the blower and motor. Floor rubber in shear, floor spring
and hanger spring isolators are also available to provide additional vibration isolation for floor mounted
and indoor hanging units. They are shipped as loose items for field installation.

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