PVI Industries MAXIM Instruction Manual

PV500-17 07/13 Section 17
1
INSTALLATION & MAINTENANCE MANUAL FOR
MAXIM
INTEGRATED WATER HEATING SYSTEM
IMPORTANT: READ AND FOLLOW THE INFORMATION IN THIS MANUAL, THE GENERAL
INSTALLATION & MAINTENANCE MANUAL, AND ALL OTHER PROVIDED INSTRUCTIONS,
LABELS AND MARKINGS BEFORE INSTALLING, OPERATING OR SERVICING THIS UNIT.
TABLE OF CONTENTS
Typical Construction 2
Introduction 3
Start-up Procedures & Warnings 4 – 5
Electrical 5
Maintenance & Safety Inspections 5 – 7
MX Burner Manual, Start-up & Troubleshooting Guide 8 – 14
MXG Burner Manual Refer to PV500-21A
MXO Burner Manual Refer to PV500-22A
MXL Burner Manual Refer to Heat Wise SU-3
WARNING: If the information on the appliance and in the supplied manual(s) is not followed
exactly, a fire, explosion or exposure to hazardous materials may result causing
property damage, personal injury or loss of life.
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any
other appliance.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
Do not touch any electrical switch; do not use any phone in your building.
Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's
instructions.
If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency, or the gas
supplier.
Thisproductcontains,ormaycometocontain,materialsthathavebeenidentifiedascarcinogenic,
orpossiblycarcinogenic,tohumans.Beforeinstalling,servicing,orremovingthisproduct,readand
follow the supplied instructions.
PVI INDUSTRIES, LLC
3209 Galvez Ave.
Fort Worth, TX 76111
[phone]
www.pvi.com

PV500-17 07/13 Section 17
2
MAXIM
INTEGRATED WATER HEATING SYSTEM
TYPICAL CONSTRUCTION - MX MODEL
FIGURE 17-1
1. VENT STACK * 8. HANDHOLE CLEANOUT
2. TEMPERATURE LIMITING DEVICE (set at 200°F) 9. UPPER OPERATING THERMOSTAT (set at 130°F)
3. OPERATING THERMOSTAT (set at 120°F) 10. COLD WATER INLET & RETURN CONNECTION
4. CONTROL SWITCH(es) AND FUSE(s) 11. DRAIN
5. GAS VALVE 12. RELIEF VALVE
6. GAS INLET 13. PRIMARY SAFETY CONTROL
7. BURNER (MX model shown) 14. DIFFERENTIAL AIR PROVING SWITCH
(* NOT FURNISHED BY PVI)
WARNING! Temperatures higher than 125°F increase the risk of scald injury!
IMPORTANT! Clearance to unprotected combustible material must be 8"min. at top, sides and rear, and
24" min. in front.

PV500-17 07/13 Section 17
3
MAXIM
PRODUCT SAFETY INFORMATION
REFRACTORY CERAMIC FIBER PRODUCT
WITH CRYSTALLINE SILICA
WARNING: ThisproductcontainscrystallinesilicawhichhasbeenidentifiedbytheInternationalAgency
forResearchonCancer(IARC)ascarcinogenictohumans.Thisproductalsocontainsrefractoryceramic
fibers which have been identified by the IARC as possibly carcinogenic to humans.
Avoid breathing fiber particulates and dust.
RISKS:
Airborne fibrous insulation is a possible cancer hazard by inhalation.
Airborne crystalline silica may cause silicosis (lung disease) by inhalation.
May cause temporary irritation to eyes, skin, and respiratory tract.
PRECAUTIONARY MEASURES:
Minimize airborne fibers with engineering controls.
Use NIOSH/MSHA approved respirators as required (see MSDS).
Wear long sleeved, loose-fitting clothing, eye protection, and gloves.
FIRST AID MEASURES:
Eyes: Flush with water.
Skin: Wash with soap and warm water.
Ingestion: Do not induce vomiting. Get medical attention if gastrointestinal symptoms develop.
Inhalation: Remove to fresh clean air.
If any of the above irritations persists, seek medical attention.
WARNING! If you are unfamiliar with the safe handling of Refractory Ceramic Fiber
products, or if you wish additional information prior to beginning any disassembly of the
water heater that might expose refractory ceramic fiber materials, contact: Unifrax
Corporation, 2351 Whirlpool Street, Niagara Falls, NY 14305-2413, 1-800-322-2293.
INTRODUCTION
This manual covers installation, operation and maintenance on all PVI commercial water heaters and storage tanks. Read all
instructions thoroughly before attempting to start any unit.
CAUTION: Factory authorized start-up may be required on this equipment. Labeling on
the unit will indicate this requirement.
City, state and national codes governing installation of commercial water heaters and storage tanks must
be followed and take precedence over recommendations in this manual.
CODES FOR WATER HEATERS & BOILERS INSTALLATIONS
ANSI Z223.1 National Fuel Gas Code
ANSI Z83.1 Installation of Gas Piping & Gas Equipment
on Industrial & Certain other premises
American Gas Association
NFPA No.31 Installation of Oil Burning Equipment
ANSI Z95.1 National Fire Protection Association
NFPA No.54 Installation of Gas Appliances & Gas
Piping
CSA B149 Natural Gas & Propane Installation Code
CSA B139 Installation Code for Oil Burning Equipment
National Electrical Code National Fire Protection
Association
Canadian Electrical Code Part 1
All Provincial Ordinances
All State & Local Codes

PV500-17 12-2004 Section 17
4
MAXIM
START-UP PROCEDURES
WARNING!
This water heater is equipped with an
adjustable thermostat to control water
temperature. Hot water temperatures
required for automatic dishwasher and
laundry use could cause scald burns
resulting in serious personal injury and/or
death. The temperature at which injury
occurs varies with the person’s age and
time of exposure. The slower response
time of disabled persons increases the
hazards to them. Never allow small
children to use a hot water tap or to draw
their own bath water. Never leave a child
or disabled person unattended in a
bathtub or shower. Since the thermostat
temperature setting could be set too high,
adjust the thermostat temperature setting
to 125°F or lower. Lower settings help
reduce risk of scald injury. Remember, no
water heater system will provide exact
temperature at all times. Allow a few days
of operation at this setting to determine
the correct temperature setting consistent
with your needs and remember, “Hotter
water increases the risk of scald injury.”
Also, the water heater should be located
in an area where the general public does
not have access to set temperatures.
WARNING!
Failure to follow these instructions can
result in serious person injury or death.
Do not relight pilot or start burner with
combustion chamber full of gas or oil
vapor, or with very hot combustion
chamber.
1. Study the burner start-up information included
in this manual carefully.
2. Fill the water heater tank with water. Open the
relief valve or a nearby hot water faucet to
allow air in the tank to escape.
Be sure all connections into the tank are tight
as leaks at tank fittings will damage the
insulation.
3. The top thermostat is a temperature limiting
safety device set at 200°F. The thermostats
are set at the factory at 130°F on the upper
operating thermostat and 120°F on the lower
operating thermostat. The lower operating
thermostat should be set 10° lower than the
upper operating thermostat setting. Adjustment
may be made by turning the thermostat dial to
the desired temperature.

PV500-17 07/13 Section 17
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MAXIM
START-UP PROCEDURES (con't)
CAUTION!
Conduct the following gas train leakage test before start-up, at annual intervals and
prior to investigating the cause of any reported occurrences of delayed ignition.
1. Using an appropriate bubble detection
solution, thoroughly coat all gas train pipe
connections. If any bubbles are detected, the
leaking connection must be tightened,
recoated and rechecked to assure stoppage
of the leak.
2. Attach a manometer, to measure gas
pressure, at the manual gas shutoff valve
located just upstream of the gas train. Adjust
gas train inlet pressure to the specified value
(e.g. 14 in. W.C.), and tightly close the gas
train manual shutoff valve closest to burner.
3. Reattach the manometer to the gas train
manual shutoff valve at the burner and record
the measured gas pressure in inches of water
column (in W.C.). Measure gas pressure
again after 15 minutes. If gas pressure has
increased 0.5" W.C. or more, the gas leak
must be isolated to one or more of the
operating gas valves, for example, a solenoid
actuated gas shutoff valve. After any leaking
valve is replaced, the reassembled gas train
must be leak tested again before start-up is
attempted. (NOTE: All gas valves removed
because of suspected leakage must be
returned to PVI Customer Service for
disposition.)
ELECTRICAL
1. Wiring to the unit should conform to the
National Electrical Code or the code legally
authorizedin your locality. A fuseddisconnect
switch should be used for water heater
control.Service wiring connections of120V, 1
phase, 60 Hz. are located in the enclosure on
the water heater.
IMPORTANT
Use only copper wire of proper sizing for
incoming service. Damage resulting from
use of aluminum wiring will be excluded
from coverage under the warranty of this
unit.
MAINTENANCE AND SAFETY INSPECTIONS
1. Establish a preventive maintenance program
to assure a longer water heater life.
2. The tank should be flushed at two- or three-
monthintervals depending on water conditions
in your location. To flush, turn off electrical
disconnect switch to prevent the burner from
operating. Open drain valve and allowwater to
flow through the tank until it runs clear. Close
the drain valve and turn the electrical switch
back on. Draining two orthree gallons from the
bottom of the tank on a weekly basis will also
help prevent the accumulation of sediment.
Water impurities consist of fine particles of soil
or sand that will settle out and form a layer of
sediment on the bottom of the tank.
3. A scale of lime will normally form during
operation and will accumulateon the bottom of
the tank. Lime is formed from the natural
chemicals in the water that precipitate out
during heating cycles. Some water supplies
contain more of these chemicals than others
and scale buildup will occur more rapidly.
Other factors affecting scale buildup are the
amount of hot water used and temperature of
the water. The more hot water used, the more
freshwatercontainingscale-formingchemicals
is brought into the tank. As the temperature of
water increases, the rate of scale deposition
will be increased.

PV500-17 07/13 Section 17
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MAXIM
MAINTENANCE AND SAFETY INSPECTIONS (con't)
4. The tank will have a handhole for inspection
and cleaning. (See Figure 17-1, page 2.) To
inspect tank for scale buildup, remove the
handhole cover. If scale is present, it can be
loosened with ahighpressure stream of water.
The smaller pieces can be flushed through the
drain and the larger pieces removed by hand
through the handhole. The frequency of
inspections will be determined by the rate of
scale buildup. Intervals of 30-60 days are
recommended.
5. If a firetube leaks for any reason, consult
factory for instructions.
IMPORTANT
Condensate coming from the tubes on a cold
start is normal and does not indicate a leaking
tube.
6. Regularly inspect the bottom tubesheet.
Inspect the SCALEGUARDtubesheet
insulator for holes or areas that may have
pulled away from tubesheet. Repair or replace
as required.
CARBON MONOXIDE WARNING!
CAUTION: IMPROPER COMBUSTION MAY CAUSE SERIOUS INJURY.
PVI recommends a seasonal or annual combustion check-out be performed by a
qualified service agency to ensure safe and efficient operation.
Periodic Inspection of Operational Components
Periodic inspection and check-out of the burner ignition, control system, and fuel valve operation (for tight
close-off) should be made. Refer to the burner installation instruction for recommendations.
1. Examine the venting system at least once each
year for proper connections, alignment and
corrosion. The blower inlet will collect dust from
the air during operation. Disconnect the power to
the heater and clean the blower wheel when
necessary. Inspect all parts and make
replacements when necessary. Check wiring for
loose connections and burned wires.
CAUTION!
The relief valve is a primary safety device.
2. The temperature and pressure relief valve may
be checked by slowly lifting the seat lever on top
of the valve to determine its condition for safe
operation. The openings inside the valve may
become restricted by a buildup of scale and
become inoperative. If the valve does not open
and close properly when tested, it must be
replaced. Replace the relief valve with like kindor
one meeting the requirements stated on the
rating decal located adjacent to the relief valve.
3. A table of periodic safety inspections is an
attachment of this manual for ease of
referenceby the building service technicianor
licensed equipment operator. Since water
heater designs vary, onlysome of these listed
inspections may be appropriate for your
particular model.
4. PVI strongly recommends the recording of
significant events, such as maintenance or
repair actions and safety inspections, and
encourage the preparation of an event log for
this purpose. All recorded events should be
dated, fully described, and signed by the
individual performing the service, repair, or
inspection. (See Table 17-1, page 7 for
sample of Inspection Record.)
Call your PVI Customer Service Representative
if you have any questions. (1-800-433-5654)

PV500-17 07/13 Section 17
7
MAXIM
MAINTENANCE AND SAFETY INSPECTIONS (con’t)
Instructions for Taking Water Heater Out of Service
Extended shutdown of the appliance and
restarting are as follows:
A. Turn off all power and fuel supplies.
B. Drain and flush tank as previously discussed.
C. Tag power switch(es) that fuel is off and tank
is empty.
D. Refill tank with water and turn fuel and power
switch(es) ontorestart. Reset all controlsand
conduct start-up of the appliance as
discussed in the previous pages.
MAINTENANCE & SAFETY INSPECTION REPORT
DATE BURNER
INSPECTION COMBUSTION ANALYSIS TANK INSPECTION TANK FLUSH & CLEANOUT TANK FITTING INSPECTION VENT INSPECTION THERMOSTAT INSPECTION GAS TRAIN LEAK TEST
Recommended
Inspection
Intervals YEARLY 6 MONTHS 6 MONTHS 3 MONTHS 6 MONTHS YEARLY YEARLY YEARLY
TABLE 17-1
NOTE: Burner Inspection and Combustion Analysis should be done by a factory-authorized service person.

PV500-17 07/13 Section 17
8
MAXIM
AXIAL FLOW GAS BURNER
CARBON MONOXIDE WARNING!
CAUTION: IMPROPER COMBUSTION MAY CAUSE SERIOUS INJURY.
PVI recommends a seasonal or annual combustion check-out be performed by a
qualified service agency to ensure safe and efficient operation.
TYPICAL CONSTRUCTION
MX MODEL APPLICATION
FIGURE 17-2
1. FAN HOUSING 9. AIR PROVING SWITCH
2. AIR DAMPER 10. DAMPER ADJUSTMENT KNOB
3. GAS NOZZLE ASSEMBLY 11. MANUAL SHUTOFF VALVE(s)
4. PRESSURE PLATE 12. GAS PRESSURE REGULATOR
5. BLAST TUBE & BURNER HOUSING JUNCTION 13. GAS VALVE
6. IGNITION TRANSFORMER 14. AUXILIARY GAS VALVE
7. IGNITION ELECTRODE 15. MAIN GAS TRAIN
8. FLAME SENSING ROD 16. ELECTRODE CLAMP

PV500-17 07/13 Section 17
9
MAXIM
AXIAL FLOW GAS BURNER START-UP
(Refer to Figure 17-2, page 8 to identify burner parts)
1. Remove the enclosure panel cover on the
water heater or boiler to expose the control
circuit. A wiring diagram, included in this
packet, will show the controls used in our
circuitry.
2. Visually check that all components are
intact and no damage has occurred during
transit.
3. Check all connections within the control
cabinet. A loose connection could cause
intermittent shutdowns.
4. Some burners willusedirect spark ignition.
They may use a single gas pressure
regulator and gas valve or multiple valves
and regulators. On a call for heat, the
motor starts, the gas primary control is
energized, and after a short delay (pre-
purge) the gas valve(s) opens and ignition
should occur.
IMPORTANT
Do not tamper with or readjust program
dipswitch settings. This will cause the
control to become inoperable. Damage
resulting from tampering will be
excluded from coverage under the
warranty of this unit.
5. Remove the flame safeguard control from
its base. Check the connections in control
mounting base; loose connections can
cause nuisance shutdowns. Check the
timecard or programmer, when applicable,
for good connection.
IMPORTANT
Always secure gas lines and tag "Out of
Service" before servicing burner nozzle
or electrodes.
6. Pull the nozzle assembly to check the
flame and ignition electrodes. This is done
by first disconnecting the gas train by
breaking at the unions. Then removing the
nozzle assembly which will have the
electrodes and pressure plate attached.
Disconnect the electrode wires and take
care not to damage the insulation on the
electrodes.
7. With the electrodes exposed, check them
for the proper settings as called for in
Figure17-3, page 10. Check forany hairline
cracks in the insulators. Should
replacement of burner electrodes be
required, certain procedures must be
followed. In all cases, removal of the
electrodes is accomplished by loosening
the electrode mounting clamps. Draw the
electrodes out of the nozzle assembly
through the holes in the pressure plate.
8. Inspect the electrodes for cracked ceramic
or loose retaining studs that hold the wire
within the ceramic. Select the proper
pressure plate hole to place each electrode
and insert the electrode through the hole,
retaining stud end first.
9. Tighten electrode mounting clamp slightly
until electrode ceramics are seated firmly
and completely in the mounting bracket
without gaps between ceramics and
mounting bracket at the bearing faces.
10. Measure and set electrodes according to
Figure 17-3, page 10. After the gaps and
setting are complete, fully tighten the
electrode mounting clamp. Do not
overtighten or the insulation may crack.
11. Replace nozzle assembly; be sure to
connect the flame and spark rod wires
before installing nozzle assembly fully into
blasttube. Check connectors on theendsof
the flame and spark rod wires for good
contact. Look for properly stripped wire
ends. Be sure connectors are firmly
attached to the flame and ignition rod ends.
Insulating boots can give a false feeling of
proper seating. DO NOT MOVE
ELECTRODES. Be careful not to bump
electrodes. Check fan wheel for free
rotation.
12. Reinstall orifices in unions (if required).
Reinstall gas nozzle assembly.

PV500-17 07/13 Section 17
10
MAXIM
AXIAL FLOW GAS BURNER START-UP (continued)
PRESSURE PLATE
Set up and Tolerances
Figure 17-3
13. Connect a test meter to the control for
reading the flame response signal.
IMPORTANT
Some controls read the flame signal in
micro amps and some in volts DC. The TFM
or MEC120 series control has two terminals
marked for reading volts DC. The S89
control uses a micro amp signal for
measuring flame strength. For this control, a
meter must be hooked in series with the
flame rod wire. Disconnect the leadwire at
the S89 sensor terminal. Connect the
positive lead of the meter to the quick-
connect sensor terminal on the S89 and the
negative lead to the free end of the sensor
leadwire.
14. Be sure the tank is filled with water. Once
the burner is reassembled, two devices will
be needed to read gas pressures,
preferably U-tube manometers. Connect
one to read the inlet pressure of the burner.
This is the pressure measured before all
components in the gas train. The
manometer must stay connected
throughout the testing as the inlet pressure
must be monitored during the firing of the
burner.
Record static pressure; it must not exceed
14" W.C. Pressures above this could cause
damage to the diaphragm inthe gasvalve or
pressure regulator.
15. Burners with pilot; inputs over 400,000
Btu/h (See wiring diagram.)
16. Connect a manometer to the manifold test
port at the shutoff valve closest to the
burner. Turn off the main gas shutoff valve.
Set the air shutter as shown on the tag
attached to gas train. This may not be the
exact setting you end up with, but it is a
good starting point. Turn the unit on using
the rocker switch on the side of the control
enclosureassembly. If the operatingcontrol
switches are closed, the burner blower
should come on and pre-purge begin.
If nothing happens, check the control to be
sure it is not in the tripped position and
reset it by pushing the flame safeguard
reset button. The burner should pre-purge
for no longer than thirty seconds.

PV500-17 07/13 Section 17
11
MAXIM
AXIAL FLOW GAS BURNER START-UP (continued)
This section pertains to MEC120 control only.
When the blower motor starts, the air proving
light on the MEC120 should be on. This
indicates a positive airflow condition. If the air
proving light is not on, turn air proving switch
adjustment screw counter-clockwise until the
air proving light comes on, then turn screwone
turn counter-clockwise. If the gas valves open
and close intermittently during normal
operation, turn screw one half turn counter-
clockwise until this condition ceases. This
procedure should be followed with every
burner.
After purging is complete, terminal 3 energizes
the pilot valve and terminal 4 energizes the
ignition transformer on the control. The pilot is
then established. The VDC reading on the
meter should read a steady 14-17 VDC. Each
different control will have the required flame
response signal stamped on it. This is the
minimum for it to properly operate. If the pilot
fails to light during the initial period, it is
probably due to air in the line. The control will
lock out. Wait one minute and push the flame
safeguard reset button to restart burner and
begin the purge cycle again.
Once the flame is established, set the pilot
pressure(measured downstream of gas valve)
at pressure shown on the tag attached to gas
train. Next, open the main gas valve slowly.
Set manifold pressure at pressure shown on
the tag attached to gas train. Do not screw the
adjusting nut of the regulator in past the point
where no further increase inmanifold pressure
is noted. Check theincoming pressure with the
burner running. This is recorded as inlet flow
pressure.
Our standard flow pressure requirement on
these burners is 8" W.C. flow. If the required
manifold cannot be reached, check the inlet
pressure. It should be a minimum of that
shown on the heater decal with the burner
running on full input. It is important that the
incoming pressure does not fall below these
minimums or nuisance control lockouts could
occur.
IMPORTANT
Where low gas pressure is a problem, special
arrangements may have been made to fire the
burner with reduced pressure. The appliance
data decal will reflect this information.
17. Direct Spark Ignition - (DSI) Burners - No
pilot. (See wiring diagram.)
Connect manometer to the manifold test port.
Set the air shutter as shown on the tag
attached to gas train. This may not be the
exact setting you end up with, but it is a good
starting point.
Turn the unit on, usingthe rockerswitch onthe
side of the control enclosure assembly. The
burner should come on and ignition occur. If
the burner fails to ignite, there may have been
air in the line. To reset the control, turn the
switch off for 60 seconds (S89 controls only)
and it should automatically reset, or push the
reset button on the control. If after the
appropriate prepurge, ignition does not occur,
turn air proving switch adjustment screw
counter-clockwise until TFI (try for ignition)
occurs. Now in order to more precisely adjust
the air failure set point, slowly turn screw
clockwise until the burner shuts off. Then turn
screw counter-clockwise one turn. If the gas
valves open and close intermittently during
normal operation, turn screw one half turn
counter-clockwise until this condition ceases.
Once the burner fires, set manifold pressure at
pressure shown on the tag attached to gas
train. There will be a tap on the downstream
side of the valve to measure pressure. The
manifold pressure must be taken downstream
of the gas valve. Check the incoming pressure
with the burner running. This recorded flow
pressure must be the minimum specified on
the heater decal.

PV500-17 07/13 Section 17
12
MAXIM
AXIAL FLOW GAS BURNER START-UP (continued)
18. Check flue gases with a flue analyzer to
make final settings of the air shutter.
a. The readings need to be taken from a
hole in the vent several inches above the
heater vent connection, but before draft
regulator.
b. Insert draft gauge into the 1/4" test
openingin the stack. Draft instack should
read -.02" to -.06" W.C. Adjust draft
regulator, if installed.
c. When water in the tank is above 120°F,
insert analyzer or O2tester in 1/4" test
opening and take O2reading in
percentage.
d. Gradually close air shutter, taking O2
reading at each adjustment of air shutter
until optimum O2% (4-6%) is reached. If
O2% decreases, open air shutter to last
reading where the greatest reading is
achieved.
e. Insert CO tester in 1/4" test opening and
take CO reading. CO should not exceed
.03%. A reading greater than .03%
indicates lack of air. Open air shutter
slightly and take readings until CO is
within proper range. Optimum reading is
no CO.
f. If air shutter was changed during CO test,
take a final O2reading.
g. Insert CO2tester in 1/4" test opening;
record in percentage.
h. Insert stack temperature gauge in 1/4"
test opening and read gross stack
temperature; maximum gross stack is to
be 450°F, minimum net stack is to be
300°F. (NOTE: net temperature is the
total stack temperature, less room
temperature.) If an excessively high
gross stack temperature is recorded,
check the flue tubes for turbulators.
i. Make sure the air shutter is locked
securely in place.
19. On burners with pilots, recheck pilot to make
sure its operation has not deteriorated if
adjustments are made to the air shutter. To
do this, shut off the main valve, check the
flame response signal by cycling the burner
through several lightoffs.
20. Check each operating and limit control to be
sure they function properly by lowering and
raising the temperature setting on each
control, causing the burner to cycle on and
off.
IMPORTANT
During the initial firing of the burner, smoke
that is not related to the burner will be
emitted from the heater. This is normal during
"burn in" and could possibly continue for
several hours.
21. Record the following information for future
use:
A. Air shutter position________________
B. Manifold gas pressure________"W.C.
C. Stack draft_________________"W.C.
D. O2reading_______________%(4-6%)
E. CO2reading______________%(8-9%)
F. CO reading________%(less than .03%)
G. Stack temperature:
Gross _______________________°F.
Less ambient__________________°F.
Net__________________________°F.
H. Combustion efficiency___________%

PV500-17 07/13 Section 17
13
MAXIM
TROUBLESHOOTING SUGGESTIONS
AXIAL FLOW GAS BURNER
1. BURNER FAILS TO START
Defective On/Off switch. Replace switch.
A. Control circuit has an open control contact.
Check limits, low water cutoff, proof of closure
switch and others as applicable.
B. Bad fuse or switch open on incoming power
source. Correct as required.
C. Flame safeguard control safety switch
tripped out. Reset and determine cause for
apparent flame failure.
D. Loose connections or faulty wiring. Tightenall
terminals screws and consult wiring diagram
furnished with the burner.
E. Flame safeguard control starting circuit
blocked due to flame relay being energized.
Possible defective scanner or flame rod -
replace. Possible defective amplifier - replace.
Scanner actually sighting flame due to leaking
fuel valve - correct unwanted flame cause.
Defective flame safeguard control - replace.
F. Defective blower motor. Check forfree rotation
of fan wheel. Repair or replace.
G. Air proving switch is not properly adjusted.
Adjust per instructions; page 11 of this manual.
2. OCCASIONAL LOCKOUTS FOR NO APPARENT
REASON
A. Gas pilot ignition failure. Check to see that
ignition is instant and that flame signal readings
are stable and above minimum values. Use a
manometer or 0 to 10" W.C. gas pressuregauge
to make certain that pressure is as
recommended.
B. Loose or broken wires. Check all wire nut
connections and tighten all terminal screw
connections in panel and elsewhere as
appropriate.
C. With flame safeguard controls that
incorporate the air flow switch in the non-
recycling circuit, ensure that when main flame
lights, the air flow switch is not so critically set as
to allow occasional momentary openingof theair
switch contacts.
D. Occasional low voltage supply. Have local
utility correct. Make certain the burner control
circuittransformer (if supplied) is correctforthe
voltage and power (VAC) being supplied.
E. Occasional low gas supply pressure. Have
local utility correct.
3. BURNER MOTOR RUNS, BUT PILOT DOES NOT
LIGHT
A. Gas supply to burner shut off. Make sure all
manual gas supply valves are open. Automatic
high pressure valve at meter such as "Sentry"
type tripped shut due to high gas pressure.
Reset valve and correct cause for trip out.
B. Pilot solenoid valve not opening. Listen and
feel for valve actuation. Solenoid valve not
being powered. Check electrical circuitry.
Replace coil or entire valve if coil is burned out.
C. Defective gas pilot regulator. Replace.
D. Gas pressure too high or too low at pilot
orifice (if supplied). Check orifice size in gas
pilot assembly. Replace if incorrect. Readjust
pressure as required.
E. Defective ignition transformer. Replace.
Incorrect ignition electrode settings.
Readjust as required.
F. Defective flame safeguard control orplug in
purge timing card. Replace as required.
G. Air flow switch not making circuit. Checkout
electrically. Defective air flow switch- replace.
Air switch negative pressure sensing tube out
of position-reposition as necessary.
4. BURNER MOTOR RUNS & PILOT LIGHTS, BUT
MAIN GAS FLAME IS NOT ESTABLISHED.
A. Main shut off or test cock closed. Check to
make certain fully open.
B. Pilot flame signal reading too low to pull in
flame safeguard relay. Readjust as required.

PV500-17 07/13 Section 17
14
MAXIM
TROUBLESHOOTING SUGGESTIONS
AXIAL FLOW GAS BURNER (continued)
C. Defective automatic main or auxiliary gas shut
off valves. Check electrical circuitry to valves.
Replace valves or correct circuitry as required.
D. Main diaphragm shut off valve opening too
slowly. Adjust bleed on valve.
E. Defective flame safeguard control or plug on
amplifier. Check and replace as required.
F. Main gas pressure regulator atmospheric vent
line obstructed. Correct.
G. Defective main gas pressure regulator. Replace.
Misadjusted main gas pressure regulator.
Readjust to meet required operational values.
H. Polarity reversed on incoming power. (S89 control
only)
5. CARBON MONOXIDE READINGS ON GAS FIRING
A. Flame impingement on "cold" heat transfer
surfaces caused by excessive firingrate. Reduce
firing rate to correct input volume.
B. Incorrect gas/air ratios. Readjust burner to correct
CO2/O2levels, eliminated all CO formation.
6. GAS HIGH FIRE INPUT CANNOT BE ACHIEVED
A. Gas company pressure regulator or meter
operating incorrectly, not allowing required gas
pressure at burner train inlet. Contact gas
company to correct.
B. Gas cock upstream of train inlet not fully open.
Check and correct.
C. Gas line obstructed. Check and correct.
D. Gas train main and/or lead test cocks not fully
open. Check and correct.
E. Gas supply line between gas company
regulator and burner inlet too small. Check
supplypressure at meter, determine pressuredrop
and increase line size as required, or raise supply
pressureto compensate for small line.Do notraise
pressure so high that under static (no flow)
conditions the pressure exceeds the maximum
allowable pressure to the gas train components on
the burner.
F. Burner gas train components sized too small
for supply pressure. Increase component size as
appropriate or consult factory.
G. Automatic gas valve not opening fully due to
defective operation. Replace gas valve.
H. Orifice (if supplied) too small. Replace with
correct size.
I. Defective main gas pressure regulator. Replace.
J. Incorrect spring in main gas pressure regulator.
Replace as required.
K. Main gas pressure regulator vent line
obstructed. Check and correct.
L. Normally open vent valve (if supplied) not
closing when automatic gas valves open.Check
to see if valve is fully closed whenautomatic valves
are open. Replace vent valve, if not closing fully.
Additional troubleshooting information can be found in the Flame Safeguard bulletin supplied with the burner.