INSTALLATION & MAINTENANCE MANUAL FOR
MAXIM
INTEGRATED WATER HEATING SYSTEM
TABLE OF CONTENTS
Start-up Procedures
2
Maintenance & Safety Inspections
Wiring Diagrams
3-5
6,7
Burner
8
Burner Start-up
9-12
Burner Troubleshooting
MXG Burner Manual
MXO Burner Manual
13.14
Refer to PV500-21A
Refer to PV500-22A
FOR YOUR SAFETY
WHAT TO DO WHEN 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
phone outside the
building. Follow the gas
supplier’s instructions.
If you cannot reach
your gas supplier, CALL
THE FIRE DEPARTMENT.
FOR YOUR SAFETY
DO NOT store or use gasoline or
other flammable vapors and
liquids in the vicinity of this or
any other appliance.
FOR YOUR SAFETY
WARNING: Improper
installation, adjustment,
alteration, service, or
maintenance can cause injury or
property damage. Refer to this
manual for assistance, or
consult a qualified installer,
service agency, or the gas
supplier.
TYPICAL CONSTRUCTION
FIGURE 17-1
1. VENT STACK *
8. HANDHOLE CLEANOUT
2. TEMPERATURE LIMITING DEVICE (set at 200°F)
3. OPERATING THERMOSTAT (set at 120°F)
4. CONTROL SWITCH(es) AND FUSE(s)
5. GAS VALVE
9. UPPER OPERATING THERMOSTAT (set at 130°F)
10. COLD WATER INLET & RETURN CONNECTION
11. DRAIN
12. RELIEF VALVE
6. GAS INLET
13. PRIMARY SAFETY CONTROL
14. DIFFERENTIAL AIR PROVING SWITCH
7. BURNER
(* NOT FURNISHED BY PVI)
CAUTION: Temperatures higher than 130°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.
MAXIM
1
PV500-17 05-2000
Section 17
MAXIM
MAINTENANCE AND SAFETY INSPECTIONS
1. Establish a preventive maintenance program to
more fresh water containing scale-forming
chemicals is brought into the tank. As the
temperature of water increases, the rate of
scale deposition will be increased.
assure a longer water heater life.
2. The tank should be flushed at two- or three-
month intervals depending on water conditions
in your location. To flush, turn off electrical 4. The tank will have a handhole for inspection
disconnect switch to prevent the burner from
operating. Open the drain valve and allow
water to flow through the tank until it runs clear.
Close the drain valve and turn the electrical
switch back on. Draining two or three 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 which will settle out
and form a layer of sediment on the bottom of
the tank.
and cleaning. (See Figure 17-1, page 1.) To
inspect tank for scale buildup, remove the
handhole cover. If scale is present, it can be
loosened with a high pressure 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 is recommended.
5. If a firetube leaks for any reason, consult
factory for instructions.
3. A scale of lime will normally form during
operation and will accumulate on the bottom of
the tank. Lime is formed from the natural
chemicals in the water which 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
NOTE: 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 SCALEGUARDÒ 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.
3
PV500-17 05-2000
Section 17
MAXIM
MAINTENANCE AND SAFETY INSPECTIONS (continued)
Periodic Inspection of Operation Components (continued)
CAUTION: THE RELIEF VALVE IS A PRIMARY SAFETY DEVICE.
heater designs vary, only some of these
listed inspections may be appropriate for
your particular model.
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 kind or one meeting the
requirements stated on the rating decal
located adjacent to the relief valve.
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 5 for
sample of Inspection Record.)
3.
A table of periodic safety inspections
is an attachment of this manual for ease of
reference by the building service technician
or licensed equipment operator. Since
water
CALL YOUR PVI CUSTOMER SERVICE
REPRESENTATIVE IF YOU HAVE ANY
QUESTIONS. (1-800-433-5654)
Instructions for Taking Water Heater Out of Service
Extended shutdown of the appliance and
restarting are as follows:
C. Tag power switch(es) that fuel is off and
tank is empty.
A. Turn off all power and fuel supplies.
D. Refill tank with water and turn fuel and
power switch(es) on to restart. Reset all
controls and conduct start-up of the
appliance as discussed in the previous
pages.
B. Drain and flush tank as previously
discussed.
ELECTRICAL
1. Wiring to the unit should conform to the
National Electrical Code or the code
legally authorized in your locality. A fused
disconnect switch should be used for
water heater control. Service wiring
connections of 120V, 1 phase, 60 Hz. are
located in the enclosure on the water
heater.
NOTE: 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.
4
PV500-17 05-2000
Section17
MAINTENANCE & SAFETY INSPECTION REPORT
BURNER
INSPECTION
COMBUSTION
ANALYSIS
TANK
TANK FLUSH TANK FITTING
VENT
THERMOSTAT GAS TRAIN
LEAK TEST
DATE
INSPECTION & CLEANOUT INSPECTION INSPECTION INSPECTION
Recommended
Inspection
YEARLY
6 MONTHS
6 MONTHS
3 MONTHS
6 MONTHS
YEARLY
YEARLY
YEARLY
Intervals
TABLE 17-1
NOTE: Burner Inspection and Combustion Analysis should be done by a factory authorized service person.
5
PV500-17 05-2000
Section 17
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
FIGURE 17-2
1. FAN HOUSING
9. AIR PROVING SWITCH
2. AIR DAMPER
10. DAMPER ADJUSTMENT KNOB
11. MANUAL SHUTOFF VALVES
12. GAS PRESSURE REGULATOR
13. GAS VALVE
3. GAS NOZZLE ASSEMBLY
4. PRESSURE PLATE
5. BLAST TUBE & BURNER HOUSING JUNCTION
6. IGNITION TRANSFORMER
7. IGNITION ELECTRODE
8. FLAME SENSING ROD
14. AUXILIARY GAS VALVE
15. MAIN GAS TRAIN
16. ELECTRODE CLAMP
6
PV500-17 05-2000
Section 17
MAXIM
AXIAL FLOW GAS BURNER START-UP
(Refer to Figure 17-2, page 6 to identify burner parts)
1.
Remove the enclosure panel cover on
7. With the electrodes exposed, check them
for the proper settings as called for in
Figure 17-3, page 8. Check for any 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.
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.
3.
4.
Visually check that all components are
intact and no damage has occurred during
transit.
Check all connections within the control
cabinet. A loose connection could cause
intermittent shutdowns.
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.
Some burners will use direct 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.
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.
NOTE: 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.
10. Measure and set electrodes according to
Figure 17-3, page 8. After the gaps and
setting are complete, fully tighten the
electrode mounting clamp. Do not
overtighten or the insulation may crack.
5.
Remove the flame safeguard control
from its base. Check the connections in
control mounting base; loose connections
can cause nuisance shutdowns. Check the
time card or programmer, when applicable,
for good connection.
11. Replace nozzle assembly; be sure to
connect the flame and spark rod wires
before installing nozzle assembly fully into
blast tube. Check connectors on the ends
of 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.
NOTE: 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.
12. Reinstall orifices in unions (if required).
Reinstall gas nozzle assembly.
7
PV500-17 05-2000
Section 17
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
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 in the gas
valve or pressure regulator.
reading the flame response signal.
NOTE: Some controls read the flame signal
in micro amps and some in volts DC.
The TFM or MC120 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.
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
enclosure assembly. If the operating control
switches are closed, the burner blower
should come on and pre-purge begin.
14. Be sure the tank is filled with water. Once
the burner is reassembled, two devices to
read
pressure,
preferably
U-tube
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.
manometers, will be needed to read gas
pressures. 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
8
PV500-17 05-2000
Section 17
MAXIM
AXIAL FLOW GAS BURNER START-UP (continued)
This section pertains to MC120 control only.
NOTE: 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.
When the blower motor starts, the air proving
light on the MC-120 should be on. This
indicates a positive air flow 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 screw one
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.
16.
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.
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.
Turn the unit on, using the rocker switch on
the 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 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 in manifold pressure
is noted. Check the incoming pressure with the
burner running. This is recorded as inlet flow
pressure.
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.
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.
9
PV500-17 05-2000
Section 17
MAXIM
AXIAL FLOW GAS BURNER START-UP (continued)
17. Check flue gases with a flue analyzer to make
i. Make sure the air shutter is locked
securely in place.
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.
18. 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.
b. Insert draft gauge into the 1/4" test
opening in the stack. Draft in stack should
read -.02" to -.06" W.C. Adjust draft
regulator, if installed.
19. 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.
c. When water in the tank is above 120? F,
insert analyzer or O2 tester in 1/4" test
opening and take O2 reading in
percentage.
NOTE: 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.
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.
20. Record the following information for future
use:
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.
A. Air shutter position________________
B. Manifold gas pressure________"W.C.
C. Stack draft_________________"W.C.
D. O2 reading_______________%(4-6%)
E. CO2 reading______________%(8-9%)
F. CO reading________%(less than .03%)
G. Stack temperature:
f. If air shutter was changed during CO test,
take a final O2 reading.
g. Insert CO2 tester 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.
Gross _______________________°F.
Less ambient__________________°F.
Net__________________________°F.
H. Combustion efficiency___________%
10
PV500-17 05-2000
Section 17
MAXIM
TROUBLESHOOTING SUGGESTIONS
AXIAL FLOW GAS BURNER
1. BURNER FAILS TO START
D. Occasional low voltage supply. Have local
utility correct. Make certain the burner control
circuit transformer (if supplied) is correct for
the voltage and power (VAC) being supplied.
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.
E. Occasional low gas supply pressure.
Have local utility correct.
B. Bad fuse or switch open on incoming
3. BURNER MOTOR RUNS, BUT PILOT DOES
power source. Correct as required.
NOT LIGHT
C. Flame safeguard control safety switch
tripped out. Reset and determine cause for
apparent flame failure.
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.
D. Loose connections or faulty wiring.
Tighten all terminals screws and consult
wiring diagram furnished with the burner.
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.
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.
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.
F. Defective blower motor. Check for free
rotation of fan wheel. Repair or replace.
G. Air proving switch is not properly
E. Defective ignition transformer. Replace.
Incorrect ignition electrode settings.
Readjust as required.
adjusted. See Section 15, page 11.
2. OCCASIONAL
LOCKOUTS
FOR
NO
APPARENT REASON
F. Defective flame safeguard control or plug
in purge timing card. Replace as required.
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 pressure gauge to make certain that
pressure is as recommended.
G. Air flow switch not making circuit. Check
out electrically. Defective air flow switch-
replace. Air switch negative pressure
sensing tube out of position-reposition as
necessary.
B. Loose or broken wires. Check all wire nut
connections and tighten all terminal screw
connections in panel and elsewhere as
appropriate.
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.
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 opening of the air switch
contacts.
B. Pilot flame signal reading too low to pull in
flame safeguard relay. Readjust as required.
11
PV500-17 05-2000
Section 17
MAXIM
TROUBLESHOOTING SUGGESTIONS
AXIAL FLOW GAS BURNER (continued)
C. Gas line obstructed. Check and correct.
C. Defective automatic main or auxiliary gas
shut off valves. Check electrical circuitry to
valves. Replace valves or correct circuitry as
required.
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
supply pressure at meter, determine pressure
drop and increase line size as required, or raise
supply pressure to compensate for small line. Do
not raise pressure so high that under static (no
flow) conditions the pressure exceeds the
maximum allowable pressure to the gas train
components on the burner.
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.
F. Burner gas train components sized too small
for supply pressure. Increase component size
as appropriate or consult factory.
G. Defective main gas pressure regulator.
Replace. Misadjusted main gas pressure
regulator. Readjust to meet required
operational values.
G. Automatic gas valve not opening fully due to
defective operation. Replace gas valve.
H. Polarity reversed on incoming power. (S89
control only)
H. Orifice (if supplied) too small. Replace with
correct size.
5. CARBON MONOXIDE READINGS ON GAS FIRING
I. Defective main gas pressure regulator.
A. Flame impingement on "cold" heat transfer
surfaces caused by excessive firing rate.
Reduce firing rate to correct input volume.
Replace.
J. Incorrect spring in main gas pressure
regulator. Replace as required.
B. Incorrect gas/air ratios. Readjust burner to
correct CO2/O2 levels, eliminated all CO
formation.
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 when
automatic valves are open. Replace vent valve,
if not closing fully.
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.
Additional troubleshooting information can be found in the Flame Safeguard bulletin supplied with the burner.
12
PV500-17 05-2000
Section 17
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