FloAire FAV-M User Manual

Installation & Operation

Guide

Industrial Direct Fired Heaters

Horizontal / Vertical and Single / Twin Blowers

.

Re-Circulating Systems
Static Pressure Controller – Potentiometer

FOR YOUR SAFETY

If You smell gas:

1. Open windows

2. Don’t touch electrical switches

3. Extinguish any open flames

4. Immediately call your gas supplier

WARNING!!

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!

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

ALWAYS disconnect power and gas prior to working on heater.

RECEIVING AND INSPECTION

Upon receiving unit, check for any interior and exterior damage, and if found,

report it immediately to the carrier. Also check that all accessory items are

accounted for and are damage free. Turn the blower wheel by hand to verify

free rotation and check the damper (if supplied) for free operation.

NOTE TO INSTALLER

Please complete and return the

Start-UP Checklist on the back of this

manual to validate warranty

NOTE TO INSTALLER

This manual should be reviewed with

the customer and left with the

equipment user

Revision 10 – 11.19.2013

2

3

TABLE OF CONTENTS

WARRANTY ............................................................................................................................... 4

INSTALLATION ........................................................................................................................... 4

Gas ........................................................................................................................................... 11

Electrical ................................................................................................................................... 12

Gas Connection Diagram .......................................................................................................... 12

Copper Wire Ampacity ...................................................................................................... 12

Re-Circulating Damper Control Options ..................................................................................... 14

SEQUENCE OF OPERATIONS ................................................................................................ 16

Sequence of Operation – 80/20 Static Pressure Controller ............................................... 16

Sequence of Operation – 80/20 Manual Potentiometer ..................................................... 16

START-UP PROCEDURE 80/20 ............................................................................................... 18

AIR BALANCING ...................................................................................................................... 24

TEMPERATURE CONTROL SYSTEMS ................................................................................... 26

UNIT COMPONENTS ............................................................................................................... 27

M4RT1 Flame Safety Control ............................................................................................ 27

DC Flame Signal ............................................................................................................... 27

Air Flow Switch ................................................................................................................. 28

Modulating Gas System .................................................................................................... 28

High Temperature Limit ..................................................................................................... 28

Electric Cabinet Heater ..................................................................................................... 28

TROUBLESHOOTING .............................................................................................................. 30

General Maintenance ................................................................................................................ 42

START-UP CHECKLIST ........................................................................................................... 43

Burner Orifice Drill Size .................................................................................................... 43

4

WARRANTY

This equipment is warranted to be free from defects in materials and workmanship, under normal
use and service, for a period of 12 months from date of shipment. This warranty shall not apply if:

• the equipment is not installed by a qualified installer per the manufacturer’s installation
instructions shipped with the product

• the equipment is not installed in accordance with federal, state and local codes and
regulations

• the equipment is misused or neglected

• the equipment is not operated within its published capacity

• the invoice is not paid within the terms of the sales agreement

• the Start-Up Checklist has not been filled in by a qualified technician and returned to the

Factory Service Department

The manufacturer shall not be liable for incidental and consequential losses and damages
potentially attributable to malfunctioning equipment. Should any part of the equipment prove to
be defective in material or workmanship within the 12-month warranty period, upon examination
by the manufacturer, such part will be repaired or replaced by manufacturer at no charge. The
buyer shall pay all labor costs incurred in connection with such repair or replacement. Equipment
shall not be returned without manufacturer’s prior authorization and all returned equipment shall
be shipped by the buyer, freight prepaid to a destination determined by the manufacturer.

NOTE TO INSTALLER

Please complete and return the

Start-UP Checklist on the back of this manual to validate warranty

INSTALLATION

It is imperative that this unit is installed and operated with the designed airflow, gas, and electrical
supply in accordance with this manual. Any variance to these instructions may cause the unit to not
perform to specifications and may cause severe damage to the unit or jobsite. Please call the service
department at 1-800-291-2452 for assistance on warranty issues and technical support.

Inspection on Arrival

1. Inspect unit on delivery

2. Photograph any visible damage

3. Report any damage to the delivery carrier

4. Request a written inspection report from the
Claims Inspector to substantiate claim

5. File claims with delivery carrier

Unit Location

1. Do not locate any gas-fired equipment near
corrosive or explosive vapors such as
chlorinated or acid vapors

6. Check unit’s rating plate to verify proper
electric and fuel type to meet job
requirements

7. Compare unit received with description of
product ordered

2. Avoid overhead power lines, or other utility
access to prevent accidental contact or
damage.

3. Provide clearance around installation site to
safely rig and lift the equipment into its final

5

position onto adequate supports. Refer to
the manufacturer’s estimated weights.

4. Consider general service and installation
space when locating the unit.

5. Locate the unit close to the space it will
serve to reduce long, twisted duct runs.

6. Do not allow air intake to face prevailing
winds. Air flow switch may trip in high winds.

7. Situate the unit above ground or at roof level
high enough to prevent precipitation from
being drawn into its inlet.

8. The inlet must also be located at least 10
feet away from any exhaust vents.

9. The heater inlet must be located in
accordance with the applicable building
code provisions for ventilation air.

10. All air to the heater must be ducted from the
outdoors.

11. Recirculation of room air is not permitted. If
in doubt regarding the application, consult
the manufacturer.

12. The unit must have adequate structural
support or the equipment or building could
be damaged.

13. Do not alter or otherwise restrict combustion
or ventilation openings.

14. Direct-fired units should not be installed
downstream from cooling systems which
use refrigerants for cooling.

COMBUSTABLE

CLEARANCES

The top, back, and front surfaces

of this heater may not be installed

less than 6 inches from

combustible materials. The heater

base may be installed on

combustible surfaces.

SERVICE CLEARANCES

Allow 24 inches or greater

minimum service clearance on all

sides of this heater. Allow 48

inches or greater on the vestibule

and blower door side.

Rigging

1. Size 10, 12, 15, and 18 units are supplied with lifting eyes on the top corners of the casing.

2. All other units are supplied with four mounting and lifting brackets on the bottom corners of the base
with holes for lifting hooks.

3. The main load should be on these lugs.

4. Lift the unit and accessories separately, and attach the accessories to the unit once the unit is in
place.

5. The following diagrams represent the proper methods for lifting the unit and accessories.

6. Always use spreader bars to prevent damage to the unit casing.

6

FIGURE 1: SIZE 10, 12, 15, & 18 FIGURE 2: NO SPREADER BARS

FIGURE 3: WITH SPREADER BARS FIGURE 4: ACCESSORIES

CAUTION!!

These are unbalanced loads

Lift equipment gently

Do not jerk

Spreader bars must be used and should extend
past the edges of the equipment to avoid damage
to the casing. Not using spreader bars may cause

WARNING!!

WARNING!!

damage to the casing

Damage will result if the equipment is raised by the intake hood, blower, motor shaft, or bearings

Use the provided lifting eyes and brackets on the unit

7

Curbs

The unit must have adequate structural support or the equipment or building could be damaged. The curb
and unit must be leveled or the unit may leak or be damaged. Use gasket and caulk between the curb
and unit. Use shims if necessary to level the unit. Screw or weld the unit’s base to the curb to avoid
damage to the equipment.

WARNING!!

The unit must have adequate structural

support or the equipment or building could

be damaged.

WARNING!!

Screw or weld the unit’s base to the curb

to avoid damage to the equipment.

WARNING!!

The curb and unit must be leveled or the

unit may leak or be damaged.

Accessories

Intake and discharge accessories are shipped loose and unassembled. When attaching the accessories
to the unit use gasket, caulk, and #10 sheet metal screws on all seams. All accessories must be level
them may leak and or be damaged.

WARNING!!

Use gasket, caulk, and #10 sheet metal screws on

all component intersections. Leaking may result if

the intersections are not completed properly.

The accessories must be level and support legs

attached to the hood and solid part of the roof.

Equipment that is not level or properly supported

WARNING!!

may leak or be damaged.

8

Split Units

1. Apply weather-proof gasket to the seam of the vertical or horizontal unit

2. Use provided fasteners to secure the seam of the unit using the provided pre-punched holes
a. Horizontal units internal channels and a formed frame
b. Vertical units have angles on the outside of the casing

FIGURE 1: HORIZONTAL SPLIT ASSEMBLY FIGURE 2: VERTICAL SPLIT ASSEMBLY

3. Apply silicone to the outside edge of the seam

4. Field wire the discharge air sensor using a minimum 22 gauge wire

5. Mount the high temperature limit bulb to the blower housing

6. Mount the (optional) freeze control sensor to the blower housing

FIGURE 3: BLOWER SENSOR FIELD ASSEMBLY

9

Shipped Loose Intake or Discharge Dampers

In some cases an intake or discharge damper may be shipped loose. This may be requested by the
customer or can be required because of larger units shipping size restrictions. Follow these instructions to
attach and wire the shipped loose damper. Factory mounted dampers may be attached on the unit and
will not require assembly or field wiring.

1. Attach the damper to the intake or discharge using gasket, caulk, and #10

sheet metal screws

2. Field wire the damper using the as built wiring schematic for the specific unit.

Wiring may be different depending on the model and options selected.

3. Refer to the factory supplied wiring print to verify the field wiring terminals.

Ductwork

This fan was specified for a specific CFM and static pressure. The ductwork attached to this unit will
significantly affect the airflow performance.

WARNING!!

• Flexible ductwork and square elbows should not be used

• Transitions and turns in ductwork near the fan outlet will cause system effect and will drastically

increase the static pressure and reduce airflow

• The Ductwork Sizing Chart shows the minimum fan outlet duct sizes and straight lengths

recommended for optimal fan performance

• Units with twin blower must have a common discharge plenum

Follow SMACNA guides and recommendations for the remaining duct run. Fans designed for
rooftop installation should be installed on a prefabricated or factory-built roof curb. Follow curb
manufacturer’s instructions for proper curb installation. The unit should be installed on a curb and/or rail
elevated not less than 20” above any surface. Be sure the duct connection and fan outlet are properly
aligned and sealed.

Adequate building relief is necessary in order to prevent over-pressurizing the building when the heater is
operating at capacity. This can be accomplished by establishing properly-sized relief openings, an
interlocked, powered exhaust system, or both.

Heaters installed with intake ductwork must be purged to replace at least four air changes of the volume
of the intake duct.

In order to avoid hazards to other fuel-burning equipment in the building (i.e., when the heater is providing
make-up air to a boiler room), the unit should be interlocked to open inlet air dampers or other such
devices.

On outdoor installations, it is recommended that the discharge duct be insulated to prevent condensation
during the “OFF” cycle in cold weather.

Units being installed in airplane hangars should be installed in accordance with the Standard for Aircraft
Hangars, ANSI/NFPA 409. Units being installed in public garages should be installed in accordance
with the Standard for Parking Structures, ANSI/NFPA 88A, or the Standard for Repair Garages,
ANSI/NFPA 88B, and with CAN/CGA B149 Installation Codes.

Flexible connectors should be employed on all ductwork connections. Vibration isolators are optional and
can be supplied in the loose parts package.

To isolate the blower and motor, a spring mounted combination blower/motor base can be factory
mounted in the unit. A flexible fabric connector is used to isolate the base from the unit’s discharge
opening flange.

Ductwork Sizing Chart Single Blower

Blower Size

Duct Size

(Inches)

Duct Length

(Inches)
10 14 x 14 30
12 16 x 16 36
15 20 x 20 45
18 24 x 24 54
20 26 x 26 60
22 30 x 30 66
25 32 x 32 75
27 36 x 36 81
30 38 x 38 90
33 44 x 44 99
36 44 x 44 108

Installation Examples

Ductwork Sizing Chart Dual Blowers

Blower Size

Duct Size

(Inches)

Duct Length

(Inches)
222 77 x 28 66
225 88 x 32 75
227 96 x 36 81
230 104 x 38 90
233 116 x 44 99
236 122 x 44 108

WARNING!!

Failure to undersize ductwork size or length

may cause system affect and reduce the

performance of the equipment.

Using the unit to support the ductwork may

cause damage to the units casing.

Figure 1: Horizontal Roof Top Installation

 Down discharge AMU reduces ductwork
 Hood weight supported by support legs
 Union, regulator, and shut-off
 Roof curb supports unit
 Intake facing away from prevailing winds

Figure 2: Vertical Outdoor Ground Installation

 Side discharge AMU reduces ductwork
 Support stand on concrete pad
 Union, regulator, and shut-off
 Filter section inside support stand
 Ease of serviceability on ground

10

Gas Connection Sizes

Gas Pressure (Inches W.C. & PSI)

158,000

½ ½ ½

275,000

¾ ½ ½

1,099,999

1 ¾ ¾

1,374,999

1 ¼ ¾ ¾

1,924

,

999 2 1 1

2,474

,

999 2 1 ¼ 1

3,574,999

2 2

1 ¼

4,124

,

999 2 2 1 ½

5,774

,

999 2 ½ 2 2

7,974,999

2 2

9,624

,

999

2 ½ 2

11,274,999

2 ½ 2

Gas

Gas piping must be installed to conform with local building codes, or in the absence of local codes, the
National Fuel Gas Code, ANSI Z223.1 (NFPA 54) – latest edition. In Canada, gas piping must be
installed in accordance with CAN/CGA-B149.1 for natural gas units and CAN/CGA-B149.2 for propane
units.

WARNING

Inlet gas pressure must not exceed pressure

indicated on name plate.

Refer to the heater rating plate for

determining the minimum gas supply

pressure for obtaining the maximum gas

capacity for which this heater is specified.

1. Always disconnect power before working
on or near a heater. Lock and tag the
disconnect switch or breaker to prevent
accidental power-up.

2. Piping to the unit should conform to local
and national requirements for type and
volume of gas handled, and pressure drop
allowed in the line. Refer to the Gas
Engineer’s Handbook for gas line capacities.

3. The incoming pipe near the heater should
be sized to match the connection on the
outside of the unit. Unit inlet sizes are shown
in the table to the right. Avoid multiple taps
in the gas supply so the unit has a steady
supply of gas at all times.

4. Install a ground joint union with brass seat
and a manual shut-off valve external to the
unit casing, as shown below, adjacent to the
unit for emergency shut-off and easy
servicing of controls.

5. Provide a sediment trap, as shown below,
before each unit and where low spots in the
pipe line cannot be avoided.

6. Blow out the gas line to remove debris
before making connections. Before starting
the unit, purge line to remove air. Purge air
from gas lines according to ANSI Z223.1­latest edition “National Fuel Gas Code,” or in
Canada: CAN/CGA-B149.

7. All field gas piping must be pressure/leak
tested prior to operating the unit. Use a
soap solution or equivalent for leak testing.
The heater and its individual shut-off valve
must be disconnected from the gas supply
piping system during any pressure testing of
that system at test pressures in excess of ½
PSI. During any pressure testing of the gas

supply piping system at test pressures equal
to or less than ½ PSI, the heater must be
isolated from the gas supply piping system
and its individual manual shutoff valve
closed.

8. This unit requires the gas pressure to be
within the unit’s minimum and maximum gas
pressure ratings. If the pressure is greater
than the maximum, the internal valve
components will be damaged. If the
pressure is below the minimum, the heater
will not perform to specifications.

9. If installing on a paint booth application, a
manual shutoff should be located for access
in case of a fire or explosion at the heater.

BTU Input

549,999

1,649,999

2,749,999

5,224,999

8,524,999

11,824,999
12,924,999
16,847,999

7” – 14” 15” – 1# 1# - 5#

¾ ¾ ¾

1 ½ 1 1

2 1 ½ 1

2 ½ 2 2

2 ½ 2

3 2
3 2 ½
3

BTU Input

158,000

11

Wire Size AWG

Maxim

um Amps

12 25

10 30

6 55

4 70

Gas Connection
Diagram

Electrical

Before connecting power to the heater, read and understand this entire section. Wiring diagrams are
furnished with each fan by the factory, and are attached to the door of the unit.

WARNING!!

Disconnect power before installing or servicing fan. High voltage electrical input is needed for
this equipment. This work should be performed by a qualified electrician.

Electrical wiring must be done in accordance with local ordinances and the National Electric Code,
ANSI/NFPA70. Be sure the voltage and phase of the power supply and the wire amperage capacity
conform to those listed on the motor nameplate. For additional safety information, refer to AMCA
publication 410-96, “Recommended Safety Practices for Users and Installers of Industrial and
Commercial Fans.”

1. Always disconnect power before working on or near a heater. Lock and tag the disconnect switch
or breaker to prevent accidental power-up.

2. A dedicated circuit should supply the units electrical disconnect with circuit protection, according to
the National Electric Code.

3. Make certain that the power source is compatible with the requirements of your equipment. The
heater nameplate identifies the proper phase and voltage of the motor.

4. Units shipped with an optional remote panel have two electrical circuit drops. It is important to run the
motor wires in a conduit separate from the remote control wiring. The DC wires from the unit
temperature controller, located in the control drop, should be either in shielded cable or run in a
separate conduit.

5. Before connecting the heater to the building power source, verify the power line wiring is de­energized.

6. Secure the power cables to prevent contact with sharp objects.

7. Do not kink power cable and never allow the cable to come in contact
with oil, grease, hot surfaces or chemicals.

8. Before powering up the heater, check fan wheel for free rotation and
make sure that the interior of the heater is free of loose debris or
shipping materials.

Copper Wire Ampacity

14 20

8 40

12

9. If necessary, the original wire supplied with the heater may be replaced with type TW wire or the
equivalent.

Remote Control Panel

For units with the optional remote control panel, a terminal strip inside the panel matches the terminals in
the heater unit. This diagram shows an example of the field wiring for a unit with a 401M remote panel.
Consult the as built wiring print supplied with the equipment. Most remote panels and VAV applications
have signal wiring which needs to be shielded cable to avoid high voltage interference.

Power Supply Wiring

The units input power supply is listed on the unit nameplate. If the units power supply does not match the
unit nameplate contact the service department for a new wiring print and parts.

Paint Booth Applications

If a low temperature control is not an integral part of the heater, it is recommended that one be installed in
areas where freeze protection is needed in the event of a burner shutdown. The space should be
ventilated following a bake cycle to purge any contaminants and cool product prior to personnel entering
the space. If the unit was supplied with paint booth controls from the factory, refer to the schematic for
installation of the interlock to disable spraying equipment unless the heater is operating in ventilation
mode. Refer to electrical schematic for interlock to disable facility lighting within the process space during
the bake cycle.

If they unit will be operating as a process heater in the re-circulating position with airborne particulate
matter, install means to facilitate inspection, maintenance, cleaning and access to fire protection devices.
In re-circulating process applications, the system shall be designed to provide 200 cfm per 1000 cfh of
natural gas based on the maximum capacity of the heater plus an allowance to sufficiently dilute the
VOC’s created by the process to maintain the lower explosive level below a 25% threshold value.

13

Re-Circulating Damper Control Options

The Re-Circulating system is for controlling the amount of make-up air being brought into a building. It
can be set from a minimum 20& fresh air, and 80% return air to a maximum of 100% fresh air, and 0%
return air. The Re-Circulating dampers can be controlled by three different options.

Manual Positioning Control (Potentiometer)

The dampers can be control at a remote location by a manual potentiometer to any position from 20% to
100% fresh air. This will allow manually setting the dampers to match the building ventilation
requirements. It will take an extra 3 control wires at the remote location. On a power failure, or if the unit
of turned off, the return air damper will close by spring return.

Two Position Control

The dampers can be controlled by a two position switch (a field supplied switching device) to open the
fresh air to 100%. On opening of the circuit, power failure, or if the unit is shutoff, the return air damper
will close by spring return.

Static Pressure Control (Photohelic)

The dampers can be controlled by a building static pressure control. This controller will sense the
difference between pressure inside the building, and pressure outside the building (sensed at the A306
outdoor sensor), and position the dampers to maintain the pressure setting on the controller. The
controller has two set points and an indicator. The two set points are a minimum desired static pressure
point, and a maximum static pressure point.

The actual building static pressure will be shown by a visual indicator between these two settings. The
controller will modulate the dampers to maintain a static pressure between these set points.

When building static pressure is below the minimum setting, the damper motor will proportion open the
fresh air damper and close the return air damper until static increases above the minimum setting. At this
point, the damper motor will stop and hold this proportion.

If the building static continues to climb and goes above maximum setting, the damper motor will reverse
proportion, closing the fresh air damper and opening the return air damper until static drops below
maximum setting.

During the “OFF” or “Night” cycle of the unit, an internal switching circuit will close the return air damper.
See additional wiring and installation information on the static pressure controller and A306 outdoor

sensor. The static pressure controller can be ordered to be shipped loose or mounted inside the unit to
reduce field wiring and assembly.

14

Static Pressure Controller Installation Instructions

Avoid locating the front of the static pressure controller in sun light or other areas with high ambient light
or corrosive levels. Bright light shining on the photocells can cause false actuation of the load relays.

The static pressure controller should be zeroed out before attaching the low and high pressure hoses.
The zero adjustment is located between the minimum and maximum dials.

Using the supplied rubber tubing the high side of the static pressure controller should be plumbed to the
inside of the building. The low side of the static pressure controller should be plumbed to the A306
outdoor sensor. See the A306 installation instructions.

A306 Outdoor Sensor

Use the installation instructions shipped with the A306 outdoor sensor.

15

SEQUENCE OF OPERATIONS

Description of Operation

Designed for indoor or outdoor installation, the Direct Fired Gas Heaters draw fresh outside air over a
gas-fired burner. The unit may be equipped to fire with natural or propane gas. Units are designed for
modulated firing of the burner, based on the discharge-air temperature or room temperature requirement.
Only outside air passes over the burner, with return air bypassing the burner.

Sequence of Operation – 80/20 Static Pressure Controller

1. With disconnect in ON position and the Summer-Off-Winter switch (SW-02) in WINTER position,
power is supplied to the damper motor (MT-02), if equipped

2. When damper motor approaches the OPEN position, the damper-end switch (SW-07) closes,
energizing blower-motor starter contactor (ST-01), powering blower motor (MT-01)

3. Power is supplied to the damper motor through the low-temperature limit control (TS-07), if equipped.
After a 5-min timed period, the low-temperature limit control shuts the unit off if discharge
temperatures do not reach minimum set points on the low-temperature limit control

4. The Photohelic Static Pressure Control (PS-05) modulates the return air and fresh air bypass
dampers (MT-03) to maintain the desired building pressure

5. The RCS (Re-Circulating Control System) will drive the unit into 100% fresh air if the temperature
drops below the Minimum Outdoor Set-Point (TS-10) or the Minimum Indoor Set-Point (TS-09) until
the minimum set-points are satisfied. There are several RCS systems see the chart below to see
your systems factory settings

6. When airflow switch (PS-01) is proven, the flame relay (RE-07) is energized through the high­temperature limit control (TS-04), the optional low- and high-gas pressure switches (PS-03 & PS-04),
and the burner ON/OFF intake air stat (TS-06), if equipped. The pilot valve (VA-03) opens, and the
ignition transformer (TR-03) energizes

7. After the flame rod (SN-02) proves flame, the main valves (VA-01 & VA-02) open, and the ignition
transformer de-energizes

8. The temperature control systems amplifier (AM-01), monitors the discharge air sensor (TS-01) and
the remote discharge air set-point (TS-08), and modulates DC voltage to the modulating valve (VA-

05) to maintain discharge temperature

Sequence of Operation – 80/20 Manual Potentiometer

1. With disconnect in ON position and the Summer-Off-Winter switch (SW-02) in WINTER position,
power is supplied to the damper motor (MT-02), if equipped

2. When damper motor approaches the OPEN position, the damper-end switch (SW-07) closes,
energizing blower-motor starter contactor (ST-01), powering blower motor (MT-01)

3. Power is supplied to the damper motor through the low-temperature limit control (TS-07), if equipped.
After a 5-min timed period, the low-temperature limit control shuts the unit off if discharge
temperatures do not reach minimum set points on the low-temperature limit control

4. The Manual Potentiometer (PO-01) adjusts the return air and fresh air bypass dampers (MT-03) to
the desired building pressure

5. The RCS (Re-Circulating Control System) will drive the unit into 100% fresh air if the temperature
drops below the Minimum Outdoor Set-Point (TS-10) or the Minimum Indoor Set-Point (TS-09) until
the minimum set-points are satisfied. There are several RCS systems see the chart below to see
your systems factory settings

16

(TS-10)

(TS-09)

Percentage

Temperature

6. When airflow switch (PS-01) is proven, the flame relay (RE-07) is energized through the high­temperature limit control (TS-04), the optional low- and high-gas pressure switches (PS-03 & PS-04),
and the burner ON/OFF intake air stat (TS-06), if equipped. The pilot valve (VA-03) opens, and the
ignition transformer (TR-03) energizes

7. After the flame rod (SN-02) proves flame, the main valves (VA-01 & VA-02) open, and the ignition
transformer de-energizes

8. The temperature control systems amplifier (AM-01), monitors the discharge air sensor (TS-01) and
the remote discharge air set-point (TS-08), and modulates DC voltage to the modulating valve (VA-

05) to maintain discharge temperature

RCS

System

RCS5 -30  F 7  F 60% 90  F
RCS10 -30  F 25  F 50% 120  F
RCS15 -25  F 58  F 80% 90  F
RCS20 -25  F 54  F 60% 120  F
RCS25 -20  F 55  F 50% 140  F
RCS30 -15  F 47  F 60% 120  F
RCS35 0  F 52  F 80% 90  F
RCS40 0  F 35  F 50% 140  F

Minimum Outdoor

Air Temperature

Minimum Indoor
Air Temperature

Maximum Re-

Circulation

Maximum

Discharge

17

START-UP PROCEDURE 80/20

 Check for signs of damage. Do not operate if damage exists and contact your manufactures sales

representative. Units are easier to fix before the equipment is installed.

 Check all installation clearances.

Clearance from Combustibles Clearance for Serviceability
Top: 6” Sides: 6” Base: 0” Unit: 24” Service Accesses: 48”

 Check that the unit has been set level and secured.

 Unit must have adequate structural support or the equipment or building may be damaged.
 Curb and unit must be leveled or the unit may leak or be damaged.
 Gasket and caulk the seam between the curb and unit base
 Screw or weld the unit’s base to the curb to avoid damage to the equipment.

 Check that the accessories are set level and secured.

 Accessories must have adequate structural support or the equipment or building may be damaged
 Gasket, caulk, and screw each accessory to unit seam

 Check that the unit’s intake and discharge are free of debris
 Check that the filter are installed in the (optional) filter section or intake hood in accordance to the air

flow direction

 Check that the unit’s ductwork size and length match the minimum ductwork size chart
 Check that all field wiring has been completed in accordance to the factory supplied wiring diagram

 Field wires are shown as dashed lines on the wiring prints

 Check that all terminal screws are tight and that wires are in place
 Check pulley alignment. Correct if necessary

 Check that the power supply matches the nameplate

voltage, phase, and amperage

 Record the voltage on the Start-Up Sheet

 Check that the gas type and pressure matches the

nameplate type and pressure

 Check that the gas type and pressure matches the

nameplate type and pressure

 Contact the service department is the power or gas

supply needs to be changed in the field. Different parts
might be necessary for the change

 Turn the Summer Off Winter switch to OFF
 Set the Maxitrol Set-Point to the maximum
 Turn the main power disconnect ON

 Bump the blower motor starter to check the blower

wheel rotation

 The decal is located on the blower housing
 If the rotation is backwards turn off the power and

correct the wiring

 The rotation can be corrected by interchanging two

legs of 3 phase power on the disconnect or blower
motor start contactor

SOW SWITCH

MAXITROL

SET-POINT

DIAL

18

 Turn the blower service switch ON. The

(optional) intake or discharge damper
motor will start to open. Once the damper
is 70% open the damper motor internal end

BLOWER
SERVICE

SWITCH

switch will close and energize the blower
motor starter.

 Check that the motor amp draw is less than

the FLA (full load amps) of the blower
motor.

 The fan RPM may need to be reduced

to decrease motor amps.

 Opening the driver pulley decreases

RPM and motor amps.

 Closing the driver pulley increases

RPM and motor amps.

 Record the motor amps on the Start-

Up Sheet.

 If the RPM was adjusted in the field use a

tachometer to record the new RPM on the
Start-Up Sheet.

 Check the belt tension after any RPM

adjustments. See the belt tension detail.

 Check the air flow pressure drop in 100% fresh air and re-circulating mode. Use the re-circulating

damper motor control to switch the unit between modes.

 The damper is controlled by one of the following control options;

Manual Switch – Potentiometer - Photohelic

 This will ensure proper pressure drop across the burner profile.
 The air flow switch on the re-circulating units is a low and high air flow switch and opens below

0.15 in w.c and above 0.95 in w.c.

 The target pressure drop range for the re-circulating unit is 0.40 – 0.60 in w.c. Both 100% fresh air

and re-circulating mode should be within this range.

 Use the profile plates or blower RPM to increase or decrease the pressure drop.
 Record the pressure drops on the Start-Up Sheet.

If the pressure drop is too low, in

fresh and return air mode, add

more blank-off panels to the

burner profile opening and bypass

fresh air and return air damper,

which will increase the pressure

drop. (There must be at least 2

inches of area minimum around

the burner.) If the correct air flow

pressure drop is still not achieved

adjust the blower drives to

increase the blowers RPM.

If the pressure drop is too high, in

fresh mode only, remove or adjust

the bypass damper blank-off

panels, which will decrease the

pressure drop. The return air

damper opening may need to be

adjusted to maintain the correct air

flow pressure drop when switching

back to return air mode.

If the pressure drop is too high, in

fresh and return air mode, remove

or adjust the bypass fresh air and

return air damper blank-off panels,

which will decrease the pressure

drop. If the correct air flow

pressure drop is still not achieved

adjust the blower drives to

decrease the blowers RPM.

If the pressure drop is too high, in

fresh and return air mode, remove

or adjust the bypass fresh air and

return air damper blank-off panels,

which will decrease the pressure

drop. If the correct air flow

pressure drop is still not achieved

adjust the blower drives to

decrease the blowers RPM.

19

 Close the burner gas shut off valve

+

 This will allow the unit to fire the pilot only and will be opened at a later time

CLOSE VALVE

 Set the Burner Intake On Off Switch is set above the outside air temperature

SET DIAL 10

DEGREES ABOVE

OUTDOOR TEMP

 Turn the burner service switch ON

BURNER SERVICE
SWITCH

 The Fireye Flame Safety Control energizes the ignition transformer and pilot gas valve
 After the pilot flame is established, the main gas valves will open

 At this time the pilot will be the only flame in the burner

 The pilot regulator should be adjusted so the pilot flame signal is above 15 VDC

PILOT REGULATOR

 Use the DC terminals under the Fireye cover to read the pilot flame signal
 This will ensure that the unit will start in cold damp weather with a strong pilot flame signal

POSITIVE TERMINAL
NEGATIVE TERMINAL

 Record the pilot flame signal in the Start-Up Sheet
 Record the low and high fire flame signal on the Start-Up Sheet

20

Setting High Fire – Discharge Temp Method

 Open the Burner Gas Shut Off Valve

OPEN VALVE

 Measure the intake air temperature.
 Add the intake air temperature to the units nameplate design temperature rise.
 This result will be the desired high fire discharge temperature.

Example: Intake Temp 70 F
Design Temp Rise 72 F
Discharge Temp 142 F

GAS TYPE: NATURAL
MAX. TEMP. RISE: 140 F
DESIGN TEMP. RISE: 72 F
MAX. DISCHARGE TEMP.: 80

 Use the Maxitrol Amplifier to override the heater

into high fire.

 On the A1014 amplifier remove the #4 wire
 On the A1044 amplifier remove the #2 and #4

wire

 On the M-Series adjust the set-point to be

160 F

 Adjust the manifold gas pressure to achieve the

desired discharge air temperature.

 See the details for the high fire pressure

adjustment locations.

 On manifolds with an MR212 modulation

valve, adjust the small regulator inside the
MR212 modulation valve

 On manifolds with either an M511 or M611

modulation valve, adjust the regulator located
before the main gas valves

 On manifolds with a combination gas valve,

adjust the regulator under the brass cap on
the combination gas valve.

 Measure the discharge temperature using a

thermometer. Laser thermometers are not as
accurate as a thermocouple type.

 If the discharge ductwork outlet is hard to reach,

you may feed a thermocouple into the mixing tube
inside the blower discharge.

HIGH FIRE

HIGH FIRE

21

Setting High Fire – Manifold Pressure Method

GAS TYPE: NATURAL
MAX. TEMP. RISE: 140 F
DESIGN TEMP. RISE: 72 F
MAX. DISCHARGE TEMP.: 80

 Turn the burner service switch ON
 Open the Burner Gas Shut Off Valve

OPEN VALVE

 Use the Maxitrol Amplifier to override the heater into

high fire.

 On the A1014 amplifier remove the #4 wire
 On the A1044 amplifier remove the #2 and #4 wire
 On the M-Series adjust the set-point to be 160 F

 Adjust the manifold gas pressure to achieve the desired

manifold pressure

 See the details for the high fire pressure adjustment

locations.

 On manifolds with an MR212 modulation valve,

adjust the small regulator inside the MR212
modulation valve

 On manifolds with either an M511 or M611

modulation valve, adjust the regulator located
before the main gas valves

 On manifolds with a combination gas valve, adjust

the regulator under the brass cap on the combination gas valve.

 The manifold pressure can be read at the 1/4” pressure tap located after the modulating gas valve.

HIGH FIRE

HIGH FIRE

22

Setting Low Fire

 Use the Maxitrol amplifier to override the heater into low

fire.

 Remove the 24V power source from amplifier

 Adjust the low fire setting on the modulation valve so

the flame is 2-3 inches without dark spots

 See the details for the low fire pressure adjustment

locations

 Use the burner observation port on the end of the

unit to view the flame size

 Replace all amplifier wires in the place they were

removed to set high and low fire

 Additional capacity is provided via a low fire bypass

when MR212 low fire capacity is insufficient. Additional
adjustment is made via the R400S regulator installed in
the low fire bypass.

LOW FIRE

LOW FIRE

Final Start-Up

 Set the Burner Intake On-Off Thermostat to the desired setting

 This will automatically open the burner circuit when the outside air is above the selected

temperature

 Turn the blower and burner service switches OFF

 Now the unit will be operated from the control panel only

 Operate the unit from the remote panel checking the lights, switches, set-points, and optional

thermostats or timers

 Review the proper operation and sequence of operation with the customer to ensure that the unit is

operated properly and that the customer does not misuse the equipment

 Complete the Start-Up Sheet and fax it to the service department to validate the warranty

Start-Up Complete

23

AIR BALANCING

Unit Type

Air Flow

Low

High

Target Pressure

Target Pressure

DDP-106-256

WARNING!!

The Direct-Fired Gas, make-up heater requires the correct air flow velocity across the burner. The burner
profile opening creates a pressure drop which increases the air velocity across the burner. The air flow
switch monitors the pressure difference, and will open the burner circuit if pressure difference is not
correct. The air flow switches have low and high pressure settings. The pressure drop should not be
near the minimum and maximum of the air flow switch. Balancing may be required to fine tune the burner
profile pressure drop. The air flow pressure drop should be checked in fresh and return air modes on the
re-circulating heaters. See the specifications and instructions below on air balancing a re-circulating
heater.

Re-circulating

Switch

Part Number

Setting

In. W.C.

0.15” 0.95” 0.45” – 0.65” 0.45” – 0.65”

Setting

In. W.C.

Drop In. W.C.

Natural Gas

Drop In. W.C.

Propane Gas

The pressure drop should be checked with the burner off or operating at 70 degree discharge if ambient <
65 degrees. Read the pressure drop at the extra probes supplied with the blower ON. This should be
repeated in fresh and return air modes.

Disconnect power and close all gas valves before and while making burner profile adjustments.

The heaters profile and damper openings are

sized to the units designed airflow. While

balancing the unit to jobsite static pressures the

profile and damper blank-off plates may need to

be moved to achieve the correct air flow

pressure drop.

24

If the pressure drop is too high, in fresh and

return air mode, remove or adjust the bypass

fresh air and return air damper blank-off panels,

which will decrease the pressure drop. If the

correct air flow pressure drop is still not

achieved adjust the blower drives to decrease

the blowers RPM.

If the pressure drop is too low, in fresh and

return air mode, add more blank-off panels to

the burner profile opening and bypass fresh air

and return air damper, which will increase the

pressure drop. (There must be at least 2 inches

of area minimum around the burner.) If the

correct air flow pressure drop is still not

achieved adjust the blower drives to increase

the blowers RPM.

If the pressure drop is too high, in fresh mode

only, remove or adjust the bypass damper

blank-off panels, which will decrease the

pressure drop. The return air damper opening

may need to be adjusted to maintain the correct

air flow pressure drop when switching back to

return air mode.

If the pressure drop is too high, in return air

mode only, remove or adjust the return air

damper and burner profile opening blank-off

panels, and add the blank-off panels to the

bypass damper, which will decrease the

pressure drop.

25

TEMPERATURE CONTROL SYSTEMS

401M

402M

403M

404M

• The 401M replaces building-exhaust air with tempered make-up air.

• A discharge-sensing controller that compensates for intake air temperature changes modulates

the burner flame.

• A manual, remote SUMMER/OFF/WINTER selector switch controls the unit’s operation.

o Summer: blower only operation.
o Winter: blower and burner operation.

• The 402M is used primarily in door-heater applications. Its space override and low-limit

thermostat raise the discharge-air temperature when needed to maintain temperature in loading
dock areas.

• A discharge sensor and remote controller modulate the burner flame to heat loading-dock door

areas.

• A space thermostat overrides the set-point and increases the discharge-air temperature if warmer

air is needed in the total area.

• A manual, remote SUMMEROFF/WINTER selector switch controls the unit’s operation.

o Summer: blower only operation.
o Winter: blower and burner operation.

• The 403M replaces building-exhaust air and maintains a constant space temperature.

• A modulating space thermostat adjusts the burner to maintain the supply-air temperature

necessary to compensate for changes in the building heat losses and gains.

• High- and low-discharge controllers limit the maximum and minimum temperature of the supply

air the unit delivers.

• A manual, remote SUMMER/OFF/WINTER selector switch controls the unit’s operation.

o Summer: blower only operation.
o Winter: blower and burner operation.

• The 404M replaces building-exhaust air and maintains a constant space temperature, day or

night. During day operation, a modulating-space thermostat adjusts the burner to maintain the
supply-air temperature necessary to compensate for changes in building heat losses and gains.

• High- and low-discharge controllers limit the maximum and minimum temperature of the supply

air the unit delivers.

• During night operation, a space thermostat cycles the unit ON or OFF to maintain the space

temperature. The high-discharge sensor controls the discharge temperature during the night
cycle.

• The unit’s operation is controlled by a manual remote SUMMER/OFF/WINTER selector switch.

o Summer: blower-only operation.
o Winter: blower and burner operation.

•

The electronic time clock changes the space-temperature control from the day thermostat to the
night thermostat.

26

Flame Safety Controller

SC10 Signal Conditioner

• When computer of other process controls are specified instead of standard electronic controls,

the signal conditioner provides compatibility with modulator / modulator-regulator valves.

• This system requires a customer supplied 4 to 20 milliamp or 0 to 10 DC voltage signal from a

building control system.

UNIT COMPONENTS

M4RT1 Flame Safety Control

The first system to understand is the Flame Safety Control. The FSC is
there only to monitor the flame, NOT to control temperature. The FSC
uses a flame rectification sensor mounted on the pilot assembly to detect
the presence of flame in the burner. Flame strength and presence can be
measured at the FSC by reading the rectified flame signal. This is done
by removing the FSC cover and using a DC voltage meter in the test
jacks. Flame is present when the DC voltage reads between 6 and 18
VDC. Ideal flame intensity produces a signal of 12 VDC or greater. The
FSC is also wired into an airflow switch, which tells it whether there is
proper airflow through the unit (not just any airflow, but proper airflow).
Proper airflow occurs when there is a .15 in. w.c. to .95 in. w.c.
differential pressure drop across the burner. When the airflow
through the heater produces a pressure drop in this range, the FSC
indicates so by illuminating the AIRFLOW LED. The FSC controls the
opening of the redundant solenoid gas valves and the operation of the
spark igniter to initiate a pilot flame upon start-up.

The OPR CTRL LED indicates that there is power to the FSC. Next, the
AIRFLOW LED will come on if there is proper airflow through the unit.
Third, the unit will pause to purge any gasses or combustible vapors
before attempting flame ignition. Then, there is a Pilot Trial For Ignition (PTFI) and the PTFI LED comes
on. During PTFI, the FSC opens the pilot gas valve and allows gas to flow to the pilot assembly. At the
same moment, the spark igniter is started, causing the spark to ignite the pilot gas. When the flamerod
sensor detects the flame, it turns on the FLAME LED, turns off the PTFI LED, and powers the modulating
gas system. This is the normal operating mode. The FSC continues to monitor the flame and airflow.
Once this occurs, the unit is in a main flame cycle and thus powers the main gas valve and the
modulating gas system. This is the normal operating mode. The FSC continues to monitor the flame
and airflow. The last LED on the FSC is the ALARM LED. This will turn on when the FSC determines
an unsafe condition has occurred, and will not allow the unit to recycle for heat until it has been properly
reset. Anytime the FSC has gone into “Alarm” mode, the problem must be diagnosed and corrected to
avoid future lockouts after resetting. To begin troubleshooting, or to reset the FSC, shut down power to
the heater and restart the heater. This will clear the alarm from the flame safety.

DC Flame Signal

DC Voltage Flame Status

0 to 5 VDC No Flame

6 to 11 VDC Weak Flame

12 to 18 VDC Strong Flame

27

Maxitrol 14

Air Flow Switch

High Temperature Limit

Air Flow Switch

Unit Type

Air Flow

Low

High

Target Pressure

Target Pressure

DDP-106-256

There are both high and low airflow switches contained within one housing
measuring the pressure drop across the burner. This is to insure that there is
proper airflow (.15 in. w.c. to .95 in. w.c.) across the burner and proper
combustion at all times. Both switches are wired in series and have single pole
double throw (one common contact, one normally open contact, and one normally
closed contact) switches that are ‘switched’ by air pressure. There are two airflow
tubes in the heater, located near the burner and profile plate assembly (profile plates
surround the burner and control air into the burner section). In the case of clogged
filters, blocked intake, excessive duct static pressure, or a broken belt, the correct
burner differential pressure may not be achieved, not allowing the low airflow switch
to close. The high airflow switch protects against profile plate failures that cause
excessive airflow through the burner. In the event that the pressure drop across the
burner is not in the range of the airflow switch, gas flow to the burner is stopped by the Flame Safety
Control.

Switch

Part Number

80/20

Modulating Gas System

The second system, the Maxitrol modulating gas system, consists of a
temperature selector dial, a discharge air sensor, an amplifier, and a modulating
gas valve. The two types of Maxitrol systems used are the Maxitrol 14 series or
the Maxitrol 44 series. The Maxitrol 14 utilizes a discharge air sensor and
modulates the Maxitrol gas valve to provide discharge air to match the selected
temperature on the temperature selector. The Maxitrol 44 utilizes a room
temperature sensor to control room temperature as well as a discharge air
sensor in order to control the discharge air temperature. The modulating gas
valve controls the amount of gas flow to the burner based on the temperature rise
needed. When the modulating gas valve is all the way open and achieving the
maximum BTUs and temperature rise of the unit, it is called “high fire”.

High Temperature Limit

One of the safety device is the high temperature limit switch. This switch is a
mechanical thermostat that measures the temperature inside the unit downstream of the
burner. If the factory-set temperature is exceeded, it will signal the FSC to turn off the
burner. This requires a manual reset of the high temperature limit. This insures that the
discharge does not exceed 185°F.

Setting

In. W.C.

0.15” 0.95” 0.45-0.65” 0.45-0.65”

Setting

In. W.C.

Drop In. W.C.

Natural Gas

Drop In. W.C.

Propane Gas

Amplifier

Electric Cabinet Heater

On units shipped with an optional electric cabinet heater, ensure that the heater is wired to a separate
120V, 15 amp input, the thermostat sensing bulb is mounted correctly in the control vestibule where the
heater is located, and the thermostat set to 0 Degrees Fahrenheit.

28

ELECTRICAL VESTIBULE

1. IGNITION TRANSFORMER

2. INTAKE AIR THERMOSTAT

3. FLAME SFAETY CONTROL

4. MODULATING AMPLIFIER

5. BLOWER SERVICE SWITCH

6. BURNER SERVICE SWITCH

7. CONTROL TRANSFORMER

8. FREEZE CONTROL

9. HIGH TEMPERATURE LIMIT

MANIFOLD VESTIBULE

10. POWER TRANSFORMER

11. MOTOR STARTER

12. MOTOT OVERLOAD

13. CLOGGED FILTER SWITCH

14. AIR FLOW PROVING SWITCH

15. 120 VOLT TERMINALS

16. 24 VOLT TERMINALS

17. MINIMUM OUTDOOR AIR SETPOINT

18. MINIMUM RETURN AIR SETPOINT

1. GAS INLET

2. 1ST MAIN GAS VALVE

29

3. 2ND MAIN GAS VALVE

4. BURNER SHUT OFF VALVE

5. MODULATING GAS VALVE

at the outlet

motor

Dirty or clogged filters

Clean and/or replace

Blower speed to high

Reduce fan RPM

Filters not installed

Install filters

Misaligned pulleys

Align pulleys

of the fan curve

replacement

6. PILOT SHUT OFF VALVE

8. PILOT GAS VALVE

9. 80/20 DAMPER ACTUATOR

7. PILOT REGULATOR

TROUBLESHOOTING

The following tables list causes and corrective actions for possible problems with direct fired heater units.
Review these lists prior to consulting the manufacturer.

Airflow Troubleshooting Chart

Problem

Fan inoperative Blown fuse or open circuit breaker Replace fuse or reset circuit breaker

Motor overload Fan rotating in the wrong direction Be sure fan is rotating in the direction

Insufficient airflow Fan rotating in the wrong direction Be sure fan is rotating in the direction

Potential Cause

Disconnect switch in “OFF” position Turn to “ON” position
Motor wired incorrectly Check motor wiring against wiring

Broken fan belt Replace belt
Motor starter overloaded Reset starter and check amps
Remote panel set to “OFF” position Set Remote Panel to “MANUAL” or

Fan speed is too high Reduce fan RPM
Motor wired incorrectly Check motor wiring against wiring

Overload in starter set too low Set overload to motor FLA value
Motor HP too low Determine if HP is sufficient for job
Duct static pressure lower than design Reduce fan RPM

Poor outlet conditions There should be a straight, clear duct

Corrective Action

and check amps

diagram located on fan motor

“AUTO” Position
shown on rotation label

diagram located on fan motor

shown on rotation label

Intake damper not fully open Inspect damper linkage and replace
Duct static pressure higher than

design
Blower speed too low Increase fan RPM. Do not overload

Supply grills or registers closed Open and adjust
Belt slippage Adjust belt tension

Excessive airflow

Duct static pressure lower than design Reduce fan RPM

Excessive vibration and noise

Damaged or unbalanced wheel Replace wheel
Fan is operating in the unstable region

Bearings need lubrication or
Fan speed is too high Reduce fan RPM

Belts too loose, worn, or oily Inspect and replace if needed

30

damper motor if needed
Improve ductwork to eliminate or
reduce duct losses

Refer to performance curve for fan
Lubricate or replace

Burner Troubleshooting Chart

Dirt in pilot orifice

Clean orifice with compressed air.

Excessive drafts

Re-

direct draft away from unit.

Loose valve wiring

Check wiring to valve.

and main gas begins to flow

pilot gas tube with burner cement.

on size 4

-

5 heater).

Gas controls not wired

properly

Check wiring.

Thermostat malfunction

Check/replace thermostat.

Thermostat setting too high

Decrease thermostat setting.

Thermostat wired incorrectly

Check thermostat wiring.

Proper Spark Gap

Problem

Pilot does not light/stay lit Main gas is off Open main gas valve.

Main burner does not light
(Pilot is lit)

Not enough heat Main gas pressure too low Increase main gas pressure – do not

Potential Cause

Air in gas line Purge gas line.
Gas pressure out of range Adjust to proper gas pressure.

Pilot valve is off Turn pilot valve on.
Leaking pilot orifice fitting Tighten pilot orifice.

Safety device has cut power Check limits and airflow switch.
Dirty flame sensor Clean flame sensor.
Remote panel in “Vent” mode Change to “Heat” mode.
No spark at igniter Check wiring, sensor, and ignition

Defective valve Replace combination valve.
Defective pilot sensor Replace pilot sensor.

Shut-off valve closed Open shut off valve.
Defective flame safety controller Replace flame safety controller.
Pilot fails as main gas valves open

Too much airflow Decrease airflow if possible.
Burner undersized Check design conditions.

Corrective Action

controller. Check spark gap as shown
below.

Plug the first burner port next to the

exceed 14 in. w.c. inlet pressure (5 psi.

Thermostat setting too low Increase thermostat setting.
Unit locked into low fire Check wiring.

Too much heat Defective modulating gas valve Check/replace modulating valve.

Unit locked into high fire Check wiring.

31

Main Disconnect in “OFF” position

Heat/Vent switch in “VENT” position

tripped

satisfied

Excessive airflow

Problem with air probes

(Unit sizes 1

-3)

Remote Panel Troubleshooting Chart

Light Indication

No lights Power not available to Remote Panel Bad voltage to unit

POWER light only Proper unit Off Operation No problem

POWER light and
BLOWER ON light

Condition

No power to motor starter Manual/Off/Auto switch in “OFF”

Proper ventilation operation No problem
No power to flame safety controller Manual/Off/Auto switch in “OFF”

Improper airflow Insufficient airflow

Possible Cause

Circuit breaker tripped
Bad main transformer

position (3-position Remote Panels
only)
Improper damper function
Low Temperature Thermostat timed out
(option)

position (2-position Remote Panels
only)

Gas pressure switch Tripped (option)
High Temperature Limit Thermostat

Manual/Off/Auto Switch in “AUTO”
position and Intake Air Thermostat not

POWER light and
BLOWER ON light and
BURNER ON light
CLOGGED FILTER light on
(optional)
FLAME FAILURE light on Flame safety alarm activated

Proper heating operation No problem

Filters clogged Filters dirty or need replacement

No flame detected during pilot
establishment period

Bad airflow switch
Problem with airflow tubing

Broken belt

Combination valve in “OFF” position
Stuck closed gas valve

No or low gas pressure
Bad spark electrode
Bad ignition transformer
Flames sensor malfunction
Clogged pilot orifices

32

Troubleshooting Flowcharts

Nothing

Happens

Is Overload

tripped on

starter?

NO

Is Freeze-Stat

open?

NO

Is end switch on

Motorized

Damper closed?

Reset & measure FLA

YES

of motor. Is it higher

YES

NO

than rating?

Adjust or
Replace

Adjust or
Replace
actuator

YES

Adjust

or

change

Pulley

Blower runs

but there is

no heat

Is the air flow LED

on Flame Saftey

illuminated?

Is outside air cooler than

intake air thermostat

YES

setting?

YES

Is High Temp.

Limit Tripped?

NO

Is there a

Remote Panel

Installed?

YES

Is Remote set to

"Heat"

YES

Refer to Flame

Safety Guide

NO

YES

NO

NO

Adjust pulley to
achieve proper

NO

economizer

Check wiring

Set Remote

"Manual" and
"Heat" mode.

airflow.

Proper

operation

Reset

Panel to

Burner lights but

heater stays in

Low Fire

Is there voltage on

Terminal #17

Yes

Are all valves

powered and open?

Yes

With wires 3 & 4

removed from the

Maxitrol Amplifier, is

there 9.5K to 11K

Ohms between the

wires?

Yes

Remove Terminal #4

from the Maxitrol

Amplifier. Does the

heater go into High Fire?

Yes

With wires 1 & 2

removed from the

Maxitrol Amplifier, is

there 9.5K to 11K Ohms

between the wires?

No

Replace

FSC

No

Check valve wiring

or open valves

Replace

No

Discharge Air

Sensor

Is there a short or open

No

circuit in Modulating
Valve? Should be 45-55
Ohms (60-80 on MR212)

No

Replace
Amplifier

Replace the

No

Temperature

Selector

Yes

Replace

Modulating

Valve

Burner lights but heater

stays in High Fire

Is there a jumper between

terminals 2 & 3 on the

Maxitrol Amplifier?

Yes

Is there a short circuit in

the Remote Temperature

Selector or wiring?

No

Is there an open circuit in

the Discharge Air Sensor

or wiring?

No

Is Plunger in the

Modulating Valve jammed?

Inspect and clean. It

should operate freely in

the sleeve.

No

Foreign object holding

valve open. Remove
bottom plate and inspect
valve and seat. Clean or

replace valve.

No

Yes

Yes

Install

Jumper

Repair short or

replace

Temperature

Selector

Repair Circuit or

replace the

Discharge Air

Sensor

33

Maxitrol Preliminary Circuit Analysis

The basic Series 14 system consists of an amplifier, a discharge-air sensor and mixing tube, a remote­temperature selector, and a modulating valve or a modulator-regulator valve.

Series 14 Preliminary Wiring Testing Procedures:

• Disconnect the discharge-air sensor and replace with a 10,000-Ohm, 1/4-watt test resistor at
Terminals 3 & 4.

• Connect a dc-volt meter on the modulator-regulator or modulator-valve terminals.

• Set the temperature to 55° F. Voltage should read 0-V.

• Rotate dial to 90° F. Voltage should gradually increase to a minimum of 20-V.

• If these voltages are obtained, the valve function can now be checked out.

• In the event proper voltages are obtained, and the valve responds correctly to these voltages, the
problem could be in the wiring to the discharge-air sensor or the discharge-air sensor itself.

• If the proper voltages are not obtained when wired as shown above, the problem can be isolated to
the electronics.

After these preliminary tests are completed, remove the test resistor and reconnect the discharge air
sensor to Terminals 3 and 4 and continue checking system, following the Series 14 Troubleshooting
Steps.

The operation of the modulating-valve regarding voltage is as follows:

o 0 to 5-V The heater should be at bypass or low.
o 5 to 15-V The heater should respond to various input rates.
o 15-V and up The heater is at maximum input.

• If the voltage is obtained on the valve terminals, but the heater does not respond as described, the
problem can be isolated to the valve itself or to the gas-control manifold of the heater.

Series 14 System

34

negati

ve pressure.

inlet air restrictions.

Symptom

No Gas Flow Modulating valve improperly

Continuous low fire
(electronics problem)

Continuous low fire
(electronics OK)

Incorrect minimum fire Incorrect by-pass metering

Maxitrol Series 14 Troubleshooting

Possible Cause Field Test Remedy

installed
Short circuit or no voltage to
the amplifier

Open circuit in TD114 remote
temperature selector or wiring

Short circuit in TS114 remote
temperature circuit or wiring

Faulty amplifier
Open circuit in modulator coil

Plunger missing, jammed, or
improperly installed

valve adjustment

Excessive negative burner
pressure

Arrow on side of valve should
point in direction of gas flow
Check for 24-V at amplifier
terminals 7 & 8

Check wire connections
between amplifier terminals 1
and 2 and remote
temperature selector terminals
1 and 3

Follow test procedures as
outlined in the preliminary
testing section of this manual

Check Td114 for internal open
circuits. Maximum 11,500
ohms across terminals 1 and 3
with external wiring
disconnected. Measure
resistance across modulator
terminals with interconnecting
wires disconnected.

Inspect: Plunger should
operate freely in solenoid
sleeve.
Re-set low fire (see start-up
instructions)

Close main-gas supply and
measure manifold pressure
with blower opening. Reading
should be less than 1.5-in wc

Install properly

Prove power source

Tighten connections or
replace wiring

If modulating voltages
are obtained, check
TS114 if necessary. If
these items check out
and modulating voltages
are still not obtained,
amplifier may be
assumed defective.
Install replacement.
Replace modulator head
if not approximately 45
to 55 ohms for the M611
and M511 and 60 to 80
ohms for the MR212.

Clean or replace plunger
if necessary.

Adjust to proper low fire

If reading is greater than

1.5-in wc negative
pressure, check for
clogged filters or other

Continuous high fire
(electronics problem)

35

Short circuit in remote
temperature selector circuit

Open Circuit in the TS114
discharge air sensor circuit

Jumper not connected across
amplifier terminals 2 and 3

Inspect for shorts at or
between amplifier terminals 1
and 2 and at TD114 terminals
1 and 3.

Check TS114 for terminal
shorts, minimum 8,000 ohms
across terminals 1 and 3 with
external wiring disconnected.

Connect test resistor as
described in the preliminary
circuit test.

Correct wiring if a short
is present. Replace
TD114 if defective.

If modulating voltages
are obtained, check
TS114 circuit for shorts.
Replace TS114 if
necessary.

Correct if necessary.

Symptom

Possible Cause

Field Test

Remedy

Continuous high fire

maintain an even flame

contain surges.

sensed.

(electronics OK)

Incorrect maximum
fire

Foreign object holding valve
open or plunger jammed

Inlet pressure too low

Incorrect outlet pressure
adjustment of pressure
regulator

Hunting

Inspect: plunger should be
smooth and clean, and
operate freely in the solenoid
valve.
Read pressure at inlet to
modulating valve using a
manometer with unit
operating at high fire.
Pressure should be equal to
the sum of the outlet pressure
setting plus pressure drop of
the valve.

Read manifold pressure using
manometer and compare with
recommendation of the heater
manufacturer.

Adjust sensitivity control
counter clockwise.

Clean or, if necessary,
replace plunger

Increase inlet pressure,
if possible.

If flame stabilizes, adjust
sensitivity control to

Erratic or pulsating
flame

Incorrect discharge air
temperature

Erratic air patterns or improper
TS114 location

TD114 wiring is run next to
high voltage switching circuits
causing induced voltages

Faulty amplifier or erratic
voltage supply

Incorrect wiring

Improper TS114 location

Connect test resistor as
described in the preliminary
circuit analysis section. Turn
TS114 selector dial so heater
goes though its entire
modulating range.

Temporarily remove TD114
from its remote locating and
reconnect at valve location.
Observe heater observation.

With test resistor connected
as described in the preliminary
tests, and TD114 locally
connected as described above,
turn TD114 selector dial
though entire modulating
range. Observe voltage
across modulator terminals.

Check installation according to
the diagram in the preliminary
circuit analysis section.

Sensed temperature does not
represent average discharge
air temperature.

If the flame is steady
thought-out the entire
modulating range, the
TS114 must be
relocated.

If smooth operation
results, isolate TD114
wiring from source of
induced voltage.

If erratic or unstable
voltages are obtained
throughout the
modulating range, the
amplifier may be
assumed defective.
Replace. If erratic
operation is noted only
over a small range, the
voltage source may

Correct wiring

Move TS114 to location
where average
representative
temperature can be

36

Maxitrol Preliminary Circuit Analysis Series 44 System

The basic Series 44 system consists of an amplifier, a discharge-air monitor with mixing tube, a
selectrastat, and a modulating valve or a modulator-regulator valve.

Series 44 Wiring for Preliminary Testing Procedures:

• Turn the test potentiometer to 2,000-Ohm minimum resistance. The dc voltage should read 0-V.

Slowly turn the test potentiometer to maximum resistance or 12,000-Ohms. The dc voltage
should gradually increase to at least 18-V.

• If proper voltages are observed, continue with the following test procedures.

• If proper voltages are not observed, the problem is identified with the amplifier, the 24-V ac power

supply, or the circuit connected to Terminals 6 and 7.

• Turn power OFF. Wire system as shown. Turn power back ON.

• Turn the test potentiometer to minimum resistance. The dc voltage should read 0-V. Slowly turn

the test potentiometer to maximum resistance. The dc voltage should gradually increase to at
least 18-V.

• If proper voltages are observed, continue with the following test procedures.

• If proper voltages are not observed, the problem is identified with the amplifier, the 24-V ac power

supply, or the circuit connected to Terminals 6 and 7.

• Observe burner flame and burner pressure as test potentiometer is turned through full range.

o 0 to 5-V The heater should be at bypass or low.
o 5 to 15-V The heater should respond to various input rates.
o 15-V and up The heater is at maximum input.

• If proper voltages are observed, continue procedures to check

operation of sensing and selecting components.

• If proper voltages are not observed, see checklist on the following

page to test the MR212 or M611 modulating valve and
connecting wiring.

• With proper voltages present and modulator responding correctly,

return to the wiring configuration as shown below, except have the
TS144 discharge-air monitor connected in place of the jumper. Set

minimum-temperature selector at least 10° F above outdoor
temperature. Set maximum-temperature selector at mid-range.
Heater is now under control of the discharge-air monitor.

• Turn test potentiometer to maximum resistance. Air temperature

should be at maximum-temperature setting. Turn test
potentiometer to minimum resistance. Delivered air temperature
should be at minimum temperature setting.

• If proper voltages are not observed, check calibration. See

checklist on the following page.

• If proper voltages are observed, the problem is identified with the space temperature sensing and

temperature selecting components and circuits.

• After these preliminary test procedures are completed, remove all test equipment and reconnect

components.

37

Maxitrol Series 44 Troubleshooting

negative pressure.

inlet air restrictions.

or TD244 to maximum setting.

+-

150 (TD2440)

Symptom Possible Cause Field Test Remedy

No gas flow Modulating valve installed

improperly
Continuous low fire
(electronics problem)

Continuous low fire
(electronics OK)

Incorrect minimum fire Incorrect by-pass metering

No voltage to amplifier

Short in modulator coil circuit

Short in TS144 circuit

Defective amplifier

Open in modulator coil circuit

Plunger missing, jammed or

improperly installed

valve adjustment

Excessive negative burner

pressure

Arrow in side of valve should
point in direction of gas flow.
Check for 24-v ac at amplifier
terminals 8 and 9

Remove wires connected to
amplifier terminals 6 and 7;
measure resistance
MR212: 60 – 80 ohms
M611 & M511: 45 to 55 ohms

Remove wires connected to
amplifier terminals 1, 2, and

3. Measure resistance across
wires 1 and 3, then across 2
and 3. Meter should read
greater than 2500 ohms.

Follow procedures in the
preliminary circuit analysis
section

Remove wires connected to
amplifier terminals 6 and 7
measure resistance
MR212: 60 – 80 ohms
M611 & M511: 45 to 55 ohms

Inspect: plunger should
operate freely in solenoid
sleeve.
Re-set low fire (see start-up
instructions)

Close main-gas supply and
measure manifold pressure
with blower opening. Reading
should be less than 1.5-in wc

Install properly

Provide 24-v ac to
amplifier

If proper resistance
values are not observed;
replace modulator head
or repair wiring.

If readings are incorrect,
replace the TS114 or
repair wiring.

After following the
preliminary circuit
analysis test without
satisfactory results, the
amplifier can be
assumed defective.
Install replacement.
If proper resistance
values are not observed,
replace modulator head
or repair wiring

Clean or replace plunger
if necessary

Adjust to proper low fire

If reading is greater than

1.5-in wc negative
pressure, check for
clogged filters or other

Continuous minimum
discharge temperature

38

Defective amplifier

Short in T244 or TS244/TD244

circuit

Refer to the preliminary circuit
analysis section

Remove wires to amplifier
terminals 4 and 5. Set T244

Measure resistance across
wires. Meter should read
6000 ohms +- 1000 ohms. If
TS244/TD244 are used, meter
should read 4500 ohms +­1000 (TS244) and 2100 ohms

If amplifier is proven
defective, install
replacement

If reading is incorrect,
replace T244,
TS244/TD244 or repair
wiring

Symptom

Possible Cause

Field Test

Remedy

Incorrect minimum or

this manual

than 2500 ohms

to maximum setting.

maximum discharge
air temperature

Improper TS144 location

Incorrect discharge air

temperature control calibration

Compare sensed temperature
at TS144 with average
discharge air temperature

Refer to the preliminary circuit
analysis section

Move TS144 to location
where average
temperature can be
sensed

If proper temperatures
are not observed, refer
to control calibration of

Continuous high fire
(electronics problem)

Continuous high fire
(electronics OK)

Incorrect high fire Inlet pressure too low

Continuous maximum
discharge air
temperature

Open in TS144 circuit

Foreign material holding valve

open

Plunger jammed

Incorrect outlet pressure

adjustment

Defective amplifier

Open in T244 or TS244/TD244

Incorrect space temperature

control calibration

Remove wires to amplifier
terminals 1, 2, and 3.
Measure resistance between
terminals 1 and 3, then
between terminals 2 and 3.
Meter should read greater

Remove bottom plate and
inspect valve and seat

Inspect: plunger should be
smooth and clean, and
operate freely in solenoid
valve
With heater operating at full
fire, take pressure reading at
inlet to modulation valve.
Pressure should meet or
exceed the units minimum gas
pressure

Read outlet pressure using a
manometer and compare with
recommendation of unit
capacities
Refer to the preliminary circuit
analysis section

Remove wires to amplifier
terminals 4 and 5. Set T244
or TD244
Measure resistance across
wires. Meter should read
6000 ohms +- 1000 ohms. If
TS244/TD244 are used, meter
should read 4500 ohms +­1000 (TS244) and 2100 ohms
+- 150 (TD2440)

See control calibration section
of this manual

If readings are incorrect,
replace TS114 or repair
wiring

Clean and replace valve
and seat. Replace if
necessary

Clean, or if necessary,
replace plunger

Increase inlet pressure if
possible, or change to a
larger modulation valve.
Contact manufacturer for
increasing valve size.

See control calibration of
this manual

Replace amplifier if
defective

If reading is incorrect,
replace T244,
TS244/TD244 or repair
wiring

If proper action is
obtained, see calibration
section of this manual

39

Flame Safety Service Guide

(Airflow LED may or may not be illuminated)

40

Flame Safety Service Guide (continued)

(Airflow LED may or may not be illuminated)

41

To guarantee trouble free operation of this heater, the manufacturer suggests following these guidelines.
Most problems associated with fan failures are directly related to poor service and maintenance.

DO NOT ATTEMPT MAINTENANCE ON THE HEATER UNTIL THE ELECTRICAL SUPPLY HAS BEEN
COMPLETELY DISCONNECTED AND THE MAIN GAS SUPPLY VALVE HAS BEEN TURNED OFF.

WARNING!!

General Maintenance

1. Fan inlet and approaches to ventilator should be kept clean and free of any obstructions.

2. Motors are normally permanently lubricated. Check bearings periodically. If they have grease
fittings, lubricate each season. Use caution when lubricating bearings. Wipe the fittings clean.
The unit should be rotated by hand while lubricating. Caution: Use care when touching the

exterior of an operating motor. Motors normally run hot and may be hot enough to be
painful or cause injury.

3. Before starting a unit after maintenance checks, check all fasteners for tightness.

4. Blowers require very little attention when moving clean air. Occasionally oil and dust may
accumulate, causing imbalance. If the fan is installed in a corrosive or dirty atmosphere,
periodically inspect and clean the wheel, inlet and other moving parts to ensure smooth and safe
operation.

Re-Setting Of The Unit

If the flame safety control is locked out (alarm
light on), reset the unit by:

1. Turn OFF power to the unit.

2. Turn power to the unit back ON.

Emergency shutdown of unit

To shut down the unit in the event of an
emergency do the following:

1. Turn unit’s power OFF from the unit from
main building disconnect.

2. Turn the external disconnect switch to the
OFF position.

3. Close the inlet gas valve located on the
heater.

Lubricating Blower Bearings

Blower bearings require little lubrication. A general rule is one half pump from a grease gun for ½” to 1
7/16” shaft diameters and one pump for 1 11/16” and large diameter shafts for every 1500 to 3000 hours
of operation. A lithium based grease should be used. Bearings should be rotated as they are lubricated
to evenly distribute the grease, either by hand or via extended grease lines. Do not attempt to grease
bearings from inside the enclosure while the motor is energized.

Prolonged shutdown of the unit

For prolonged shutdown the following steps
should be done:

1. Turn the external disconnect switch to the
OFF position.

2. CLOSE the inlet gas valve located on the
heater.

To re-start the unit the following steps

should be done:

1. Turn the external disconnect switch to the
ON position.

2. OPEN the inlet gas valve located on the
heater.

42

2 Weeks after Start-Up

1. Belt tension should be checked after the first two weeks of fan operation. Belts tend to stretch
and settle into pulleys after an initial start-up sequence. Do not tighten the belts by changing
the setting of the motor pulley. This will change the fan speed and may damage the motor.

To re-tension belts, turn the power to the fan motor OFF. Loosen the fasteners that hold the
blower scroll plate to the blower. Rotate the motor to the left or right to adjust the belt tension.
Belt tension should be adjusted to allow 1/64” of deflection per inch of belt span. Exercise
extreme care when adjusting V-belts as not to misalign pulleys. Any misalignment will cause a
sharp reduction in belt life and produce squeaky noises. Over-tightening will cause excessive
belt and bearing wear as well as noise. Too little tension will cause slippage at startup and
uneven wear. Whenever belts are removed or installed, never force belts over pulleys
without loosening motor first to relieve belt tension. When replacing belts, use the same
type as supplied by the manufacturer. On units shipped with double groove pulleys, matched
belts should always be used.

2. Before restarting a unit after maintenance checks, all fasteners should be checked for tightness.

Every 3 months

1. Belt tension should be checked quarterly. See instructions in the previous maintenance section.
Over-tightening will cause excessive bearing wear and noise. Too little tension will cause
slippage at startup and uneven wear.

2. Filters need to be cleaned and/or replaced quarterly, and more often in severe conditions.
Washable filters can be washed in warm soapy water. When re-installing filters, be sure to install
with the airflow in the correct direction as indicated on the filter.

Yearly

1. Inspect bearings for wear and deterioration. Replace if necessary.

2. Inspect belt wear and replace torn or worn belts.

3. Inspect bolts and set screws for tightness. Tighten as necessary.

4. Inspect motor for cleanliness. Clean exterior surfaces only. Remove dust and
grease from the motor housing to ensure proper motor cooling. Remove dirt and
grease from the wheel and housing to prevent imbalance and damage.

5. Check for gas leaks and repair if present.

6. Clean flame sensor by rubbing with steel wool to remove any rust build-up,

7. Clean burner with a wire brush and insure burner ports are free of debris. Then wipe the burner
with a clean rag.

Burner Orifice

Orifice Drill Size

Gas Port 31

Air Port 43

START-UP CHECKLIST

WARNING

-The Start-Up must be completed after all field wiring and air balancing has been completed

-The Start-Up must be completed by a qualified HVAC technician

-The Start-Up Check list must be faxed into the Service Department to validate the product warranty

Drill Size

43

JOB

INFORMATION

TECHNICIA

N INFORMATION

Name Plate and Unit Information

Field Measured Information

Serial Number

Motor Amperage*

Motor Hertz

100% Differential

Pressure

in.

w.c.

Motor Phase

80/20 Differential Pressure

in.

w.c.

Job Name Service Company
Address Address
City City
State State
Zip Zip
Phone Number Phone Number
Fax Number Fax Number
Contact Contact
Purchase Date Start-Up Date

Refer to the start-up procedure in this manual to complete this section.

Model Number

Motor Volts

Motor FLA
Motor HP
Blower Pulley
Motor Pulley
Belt Number
Gas Type
Min. Btu/Hr
Max. Btu/Hr

*

If measured amps exceed the FLA rating on the nameplate, fan RPM must be reduced to decrease the

measured amps below the nameplate FLA rating.

Motor Voltage

High Speed RPM

Pilot Flame Signal VDC
Low Fire Flame Signal VDC
High Fire Flame Signal VDC
Gas Type Natural

High Fire Inlet Gas Pressure in. w.c.
Low Fire Manifold Gas Pressure in. w.c.
High Fire Manifold Gas Pressure in. w.c.
Temperature Control Discharge

Airflow Direction Correct

Propane

Space
Incorrect

Factory Service Department

Phone: [phone]

Fax: [phone]

Revision 10 – 11.19.2013 44