Pentair Pool Products MiniMax NT Series User manual

Rev. B 2-11-04 P/N NTSM03
1
1
FOR YOUR SAFETY - READ BEFORE OPERATING
Warning: If you do not follow these instructions exactly, a fire or explosion may
result, causing property damage, personal injury or loss of life.
For additional free copies of this manual; call [phone].
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or other appliances.
For Your
Safety
Warning: Improper installation, adjustment, alteration, service or maintenance can
cause property damage, personal injury or death. Installation and service must be
performed by a licensed qualified installer, service agency or the gas supplier.
MiniMax®NT Series
POOL & SPA HEATERS
SERVICE MANUAL
WARNING
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.
WARNING
Pentair Pool Products, Inc.
1620 Hawkins Ave., Sanford, NC 27330 •[phone]
10951 W. Los Angeles Ave., Moorpark, CA 93021 •[phone]
1

P/N NTSM03 Rev. B 2-11-04
2
Table of Contents
Introduction ............................................................................................................................. 3
Important Notice .......................................................................................................................................................................... 3
Code Requirements ..................................................................................................................................................................... 3
Safety Rules ................................................................................................................................................................................ 4
Installation Tips ........................................................................................................................ 4
Dimensions ............................................................................................................................... 5
Installation Outdoors/Indoors ................................................................................................. 6
Installation on Floors Constructed of Combustible Materials ....................................................................................................... 6
Gas Requirements ................................................................................................................... 7-8
Gas Line Installations .................................................................................................................................................................. 7
Sediment Traps ........................................................................................................................................................................... 7
Pipe Sizing for Gas Line Installations .......................................................................................................................................... 8
Residential Propane 2 Stage Regulation ..................................................................................................................................... 8
Residential natural Gas 2 Stage Regulation ................................................................................................................................ 8
Testing Gas Pressure .............................................................................................................. 9
Gas Pressure Requirements ....................................................................................................................................................... 9
Water Connections................................................................................................................... 10-11
Plumbing Connections ................................................................................................................................................................. 10
Manual By-Pass .......................................................................................................................................................................... 10
Valves .......................................................................................................................................................................................... 11
Below Pool Installation ................................................................................................................................................................ 11
Pressure Switch Adjustment ........................................................................................................................................................ 11
Reversing Headers ................................................................................................................... 12-13
Air Requirements ..................................................................................................................... 14-17
Venting — Indoor Installations ..................................................................................................................................................... 14 - 16
Venting — Outdoor Installations .................................................................................................................................................. 17
Electrical Wiring ....................................................................................................................... 18-21
Wiring Schematic for all Dual Voltage Blowers ............................................................................................................................ 19
Wiring Diagram ............................................................................................................................................................................ 20
Schematic for Remote Controls (2 and 3 Wire) ........................................................................................................................... 21
Basic System Operation .......................................................................................................... 22-24
Heater Operation — Firing Sequence — Ignition Failure — Hard Lock Out ................................................................................ 22
Starting Operation — HSI Electronic Ignition Lighting/Operation ................................................................................................. 23
Chemical Balance ........................................................................................................................................................................ 24
Maintenance ............................................................................................................................. 25-28
Pressure Relief Valve .................................................................................................................................................................. 25
Spring and Fall Operation — Winter Operation ........................................................................................................................... 25
Burner Tray Removal ................................................................................................................................................................... 26
Desooting .................................................................................................................................................................................... 27
Reinstalling Heat Exchanger ....................................................................................................................................................... 28
Troubleshooting ....................................................................................................................... 29-46
Glossary .................................................................................................................................... 47
MiniMax NT (Standard) Parts List & Exploded View (Dual Voltage) ........................................... 48-49
MiniMax NT Low NOx Parts List & Exploded View (Dual Voltage) ............................................ 50-51
Warranty Information ............................................................................................................... Back Cover

Rev. B 2-11-04 P/N NTSM03
3
MiniMax®NT Series
Pool and Spa Heaters
....For the installer and operator of the MiniMax NT Series pool and spa heaters. The manufacturer’s
warranty may be void if, for any reason, the heater is improperly installed and/or operated. Be sure to follow
the instructions set forth in this manual. If you need any more information, or if you have any questions
regarding to this pool heater, please contact Pentair Pool Products, Inc. at [phone].
These heaters are designed for the heating of swimming pools and spas, and should never be
employed for use as space heating boilers, general purpose water heaters, in non-stationary
installations, or for the heating of salt water.
CAUTION
OPERATING THIS HEATER CONTINUOUSLY AT WATER TEMPERATURE BELOW 68° F. WILL CAUSE
HARMFUL CONDENSATION AND WILL DAMAGE THE HEATER AND WILL VOID THE WARRANTY.
Do not use the heater to protect pools or spas from freezing if the final maintenance temperature desired is
below 68° F. as this will cause condensation related problems.
CODE REQUIREMENTS
The installation must conform with local codes or, in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane Installation Codes. If an
external electrical source is utilized, the heater, when installed, must be electrically grounded and bonded in
accordance with local codes or, in the absence of local codes, in the USA, with the National Electrical
Code, ANSI/NFPA 7; in Canada, with Canadian Electric Code, CSA C22.1-98.
Important Notice

P/N NTSM03 Rev. B 2-11-04
4
Installation Tips
CAUTION
DO NOT INSTALL HEATER
UNDER ANY ROOF
OVERHANG NOT HAVING A
PROPER RAIN GUTTER.
Safety Rules
1. Spa or hot tub water temperatures should never exceed
104° F. A temperature of 100° F. is considered safe for
a healthy adult. Special caution is suggested for young
children.
2. Drinking of alcoholic beverages before or during spa
or hot tub use can cause drowsiness which could lead
to unconsciousness and subsequently result in
drowning.
3. Pregnant women beware! Soaking in water above 100°
F. can cause fetal damage during the first three months
of pregnancy (resulting in the birth of a brain-damaged
or deformed child). Pregnant women should stick to
the 100° F. maximum rule.
4. Before entering the spa or hot tub, the user should
check the water temperature with an accurate
thermometer. Spa or hot tub thermostats may err in
regulating water temperatures by as much as 4° F.
5. Persons with a medical history of heart disease,
circulatory problems, diabetes or blood pressure
problems should obtain their physician's advice before
using spas or hot tubs.
6. Persons taking medication which induce drowsiness,
such as tranquilizers, antihistamines or anticoagulants
should not use spas or hot tubs.
Should overheating occur or the gas supply fail to shut off, turn off the manual gas control valve to the heater.
Do not use this heater if any part has been under water. Immediately call a qualified service technician to
inspect the heater and to replace any part of control system and gas control which has been under water.
WARNING
DO NOT INSTALL the heater under an overhang
of less than three (3) feet from the top of the heater.
The area under the overhang must be open on three
sides. Overhangs must be such that flue products
are not diverted into living spaces. Heaters installed
under overhangs must be protected from direct roof
water drainage by gutters and the like.
DO NOT INSTALL the heater in locations which
will permit the accumulation of leaves or other
combustible material on or around the base of the
heater.
DO NOT INSTALL the heater in a location that
will allow sprinklers to operate near the heater
equipment since the water may cause damage to the
controls and/or electronics.
DO NOT PLACE GAS
SUPPLY LINE UNION
COUPLING INSIDE OF
HEATER JACKET.
(Follow Recommendations of
National Fuel Gas Code NFPA 54.)
CAUTION
DO NOT RESTRICT
ACCESS TO HEATER
WITH PIPING.

Rev. B 2-11-04 P/N NTSM03
5
Dimensions
24.05
2 in. SOCKET
"A" DIM.
8.84
30.63
LEG
LEG
14.50
4.88
MODEL
200
250 24.63
21.63
"A" DIM.
15.50
300
400 34.13
27.63
7.35
24.05
"A" DIM.
8.84
30.63
LEG
LEG
14.50
4.88
INDOOR VENT ADAPTOR
4 in. Kit
P/N 460506
5 in. Kit
P/N 460507
15.50
7.35
2.00
2 in. SOCKET
MODEL
200
250 24.63
21.63
"A" DIM.
300
400 34.13
27.63
OUTDOOR VENTILATION
INDOOR VENTILATION
DIMENSIONS IN INCHES

P/N NTSM03 Rev. B 2-11-04
6
Installation - Outdoors/Indoors
The heater should not be installed closer than 6 inches to any
fences, walls or shrubs at any side or back, nor closer than 18
inches at the plumbing side. A minimum clearance of 24 inches
must be maintained at the front of the heater. The heater should
be installed at least 5 feet away from the pool or spa.
IMPORTANT!
Under certain conditions, “heavy rains or unusually high winds”,
it may be necessary to install an outdoors vent. In this situation,
use vent adaptor P/N 460507 and outdoor vent P/N 471357.
NOTE
From the point where the flue products leave the heater, that point
MUST be a minimum of (4) feet below, and (4) feet horizontally from
or (1) foot above any door, window or gravity inlet to a building.
DOOR
6"
6"
24"
18"
OUTDOOR INSTALLATION
VENTING GUIDELINES
4'
3'
4' Minimum
(Horizontal)
Clearance
4' Min. Below
CAUTION
Chemicals should not be stored near the heater installation.
Combustion air can be contaminated by corrosive chemical
fumes which can void the warranty.
BASE FOR USE ON COMBUSTIBLE FLOORS
24 GA. (MIN.) GALVANIZED SHEET METAL.
FOR AIR CIRCULATION). COVER BLOCKS WITH
(LAID WITH ENDS UNSEALED AND JOINTS MATCHED
HOLLOW MASONARY BLOCKS, NOT LESS THAN 4" THICK
SHEET METAL
BLOCKS
6" Min.
6" Min.
I NSTALLATION ON FLOORS CONSTRUCTED
OF COMBUSTIBLE MATERIALS
The heater may be placed on a “combustible floor”
using the method listed below:
a) The heater must be installed on a non-combustible floor
and at least six inches from any combustible material or
wall. Construct a non-combustible base from masonry
blocks as illustrated in Figure 2.
INDOOR INSTALLATIONS
The heater must be placed in a suitable room on a non-combustible
floor or on a non-combustible base and in an area where leakage
from heat exchanger or water connections will not result in
damage to the area adjacent to the heater or the structure. When
such locations cannot be avoided, it is recommended that a
suitable drain pan with adequate drainage, be installed under the
heater. The pan must not restrict air flow.
Installations in basements, garages, or underground structures
where flammable liquids may be stored must have the heater
elevated 18 inches from the floor using a non-combustible base.
The following minimum clearances from combustible materials
must be provided.
Side Front Back Top
Water Connection 18 in. 24 in. - -
Remaining 6 in. - 6 in. -
Ceiling Clearance - - - 18 in.*
*To ceiling or roof.
Figure 1.
Figure 2.
Figure 3.

Rev. B 2-11-04 P/N NTSM03
7
GAS LINE INSTALLATIONS
Before installing the gas line, be sure to check which
gas the heater has been designed to burn. This is
important because different types of gas require
different gas pipe sizes. The rating plate on the heater
will indicate which gas the heater is designed to burn.
Tables 1-5, shown on page 8, shows which size pipe
is required for the distance from the gas meter to the
heater. The table is for natural gas at a specific gravity
of .65 and propane at a specific gravity of 1.5.
When sizing gas lines, calculate three (3) additional
feet of straight pipe for every elbow used.
When installing the gas line, avoid getting dirt, grease
or other foreign material in the pipe as this may cause
damage to the gas valve, which may result in heater
failure.
The gas meter should be checked to make sure that it
will supply enough gas to the heater and any other
appliances that may be used on the same meter.
The gas line from the meter will usually be of a larger
size than the gas valve supplied with the heater.
Therefore a reduction of the connecting gas pipe will
be necessary. Make this reduction as close to the
heater as possible.
HEATER CABINET
UNION
TEE
FITTING
GAS
SUPPLY
3 INCHES
MINIMUM
MANUAL
SHUT OFF
VALVE
NIPPLE
CAP
GAS
VALVE
Gas Requirements
CAUTION
The heater and any other gas appliances must be
disconnected from the gas supply piping system
during any pressure testing on that system, (greater
than ½ PSIG).
The heater and its gas connection must be leak
tested before placing the heater in operation. Do not
use flame to test the gas line. Use soapy water or
another nonflammable method.
A manual main shut-off valve must be installed
externally to the heater. See Figure 4.
SEDIMENT TRAPS
Install a sediment in front of the gas controls.
The sediment trap shall be either a tee fitting with
a capped nipple in the bottom outlet which can be
removed for cleaning, as illustrated below, or a
other device recognized as an effective sediment
trap. All gas piping should be tested after installation
in accordance with local codes. See Figure 4.
WARNING
Do not install the gas line union inside the heater
cabinet. This will void your warranty.
Figure 4.

P/N NTSM03 Rev. B 2-11-04
8
“RESIDENTIAL” PROPANE 2 STAGE REGULATION
In many Propane gas line installations, the gas supplier and/or installer will utilize a two stage regulation process
where by at the supply tank they will install the first stage gas regulator, which would be at a higher pressure, usually
10 psi. This higher pressure allows for a much longer distance and in a much smaller pipe size. Then within a short
distance of the pool heater, usually around 24 inches, they will install a second regulator, which is the second stage,
and this would be set at the required inlet pressure of the heater.
See “Gas Pressure Requirement Charts”
Table 2. Table 3.
Installation (Gas Line)
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In many Natural gas line installations, the gas supplier and/or installer may utilize a two stage regulation process
where by at the streets main gas supply they will install the first stage gas regulator, which would be at a higher
pressure. This higher pressure is usually set at 2 psi or 5 psi and can be for long distances and in a much smaller pipe
size. Then within a short distance of the pool heater, generally around 24 inches, they will install a second regulator,
which is the second stage. This second stage regulator would be set at the minimum operating pressure for the heater.
For “Natural Gas Pentair Pool Heaters” the minimum is 7 inches W.C.
See “Gas Pressure Requirement Charts”
Table 4. Table 5.
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Rev. B 2-11-04 P/N NTSM03
9
1. Push the power switch to “OFF”.
2. Turn the gas valve knob to “OFF”.
3. Remove 1/8 in. NPT plug on the
outlet side of the valve and screw in
the fitting from the Manometer kit.
4. Connect the Manometer hose to the
fitting.
5. Turn the gas valve knob to “ON”.
6. Turn on the heater and read the
Manometer.
7. The Manometer must read
4 in. W.C. for natural gas or
11 in. W.C. for propane, on
manifold side of the gas valve,
while operating.
8. If reading is below specified; check
the inlet pressure while the heater is
running to make sure of proper
supply before attempting adjustments.
9. For adjustment, remove the Regulator
Adjustment Cap and using a screwdriver
turn the screw clockwise to increase -
counterclockwise to decrease gas pressure.
CAUTION
The use of Flexible Connectors (FLEX) is NOT
recommended as they cause excessive high gas
pressure drops.
Natural
Maximum inlet gas pressure 10 in. WC 14 in. WC
Minimum inlet gas pressure **5 in. WC 12 in. WC
Normal manifold pressure 4 in. WC 11 in. WC
*All Readings are taken with the heater fired. Any adjustments
or readings made with heater off will give incorrect readings.
** 6 in. WC for 400 model
Propane
Testing Gas Pressure
GAS PRESSURE REQUIREMENTS*
OFF
ON
REGULATOR
GAS VALVE
PRESS
TAP
Figure 5.
Inlet Manifold

P/N NTSM03 Rev. B 2-11-04
10
PUMP
FILTER
POOL
HEATER
CHECK
VALVE
MANUAL
BY-PASS
TO
POOL
GATE
VALVE
CHECK
VALVE
FROM
POOL
PLUMBING CONNECTIONS
The MiniMax NT Series heater has the
unique capability of direct schedule 40
PVC plumbing connections. A set of
bulkhead fittings is included with the
MiniMax NT Series to insure
conformity with Pentair’s
recommended PVC plumbing
procedure.
CAUTION
Before operating the heater on a new
installation, turn on the circulation
pump and bleed all the air from the
filter using the air relief valve on top
of the filter. If a Manual By-Pass is
installed; temporarily close it to insure
that all air is purged from the heater.
Water should flow freely through the
heater.
Do not operate the heater unless water in the pool/spa is at the proper level.
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Water Connections
Heater
To
Pool
Valve
In
Out
From
Pump
MANUAL BY-PASS
Where the flow rate exceeds the maximum 120 GPM,
a manual bypass should be installed and adjusted.
After adjustments are made, the valve handle should
be removed to avoid tampering.
Adjust By-Pass until a Delta T of 28° - 32° F. is
reached.
Figure 6.
Figure 7.
Table 6.

Rev. B 2-11-04 P/N NTSM03
11
CAUTION
BELOW OR ABOVE POOL INSTALLATION
The water pressure switch is set in the factory at
1½ PSI. This setting is for a heater installed at pool
level or within 3’ above or 3’ below. If the heater is to
be installed more that 3’ above or 3’ below, the water
pressure switch must be adjusted by a qualified
service technician.
FLOW SWITCH
If the heater is installed more the 10’ above the pool
or more than 10’ below the pool level, you will be
beyond the limits of the pressure switch and a flow
switch must be installed. Locate and install the flow
switch externally on the outlet piping from the heater,
as close as possible to the heater. Connect the flow
switch wires in place of the water pressure switch wires.
VALVES
When any equipment is located below the surface of
the pool or spa, valves should be placed in the
circulation piping system to isolate the equipment
from the pool or spa. Check valves are recommended
to prevent back siphon.
Periodically check the operation of the valve to
insure proper operation.
MICRO SWITCH
Counter-ClockwiseClockwise
1. Backwash filter and clean the pump hair and
lint basket before making any adjustment to the
pressure switch.
2. Switch the circulation pump on and make sure
it is primed.
3. Push the heater power switch on and set the
thermostats to their highest temperature
settings.
4. Turn the adjustment knob clockwise or away
from the micro-switch, until the heater shuts
down.
5. Turn the adjustment knob counter-clockwise
1/2 turn and the heater should refire.
6. Turn the pump off and the heater should shut
down. If heater does not shut down, repeat
procedure.
7. Switch pump off and on several times to assure
proper adjustment.
CAUTION
Exercise care when installing chemical feeders so
as to not allow back siphoning of chemicals into the
heater, filters or pump. When chemical feeders are
installed in the circulation of the piping system, make
sure the feeder outlet line is down stream of the
heater, and is equipped with a positive seal
noncorrosive “Check Valve”, (P/N R172288), between
the feeder and heater.
BELOW POOL INSTALLATION
If the heater is below water level, the pressure
switch must be adjusted. This adjustment must be
done by a qualified service technician.
See following CAUTION before installation.
Water Connections, cont’d.
PRESSURE SWITCH ADJUSTMENT
Figure 8.

P/N NTSM03 Rev. B 2-11-04
12
Reversible Inlet/Outlet Connection
The MiniMax NT Series heater is factory assembled
with right side inlet/outlet water connections. The
inlet/outlet header can be reversed for left side water
connections without removing the heat exchanger.
Reversing Water Connections
Tools required:
Phillips Screw Driver
9/16 in. Socket and Wrench
1/2 in. & 9/16 in. Open Wrench
1. Remove the right and left large inspection plates.
It is not necessary to remove the top of the
heater to gain access to the headers.
2. Disconnect all wires from the high-limit
switches except the short jumper wire.
NOTE
Do NOT remove the high-limit and pressure
switches or the thermistor from the front header
during the reversing procedure, as they will be in
the proper location when installed on the left side.
3. Disconnect the pressure switch wiring.
4. Disconnect the temperature sensor wires from
the circuit board and feed them back to the
header.
Reversing Headers
5. Remove the 8 bolts holding the main inlet/outlet
head.

Rev. B 2-11-04 P/N NTSM03
13
7. When heads are removed, replace the heat
exchanger tube seal gaskets.
8. Exchange the inlet/outlet header with the return
header. Lift the insulation to allow the main head
to be installed. Align header with the heat
exchanger. When head is placed into position,
release the insulation; it will now shield the high
limits from the heat produced by the flue collector.
Install header bolts, and tighten snugly by hand.
(This will help avoid cross threading.) When
tightening, use a cross pattern starting from the
center of the header. DO NOT over tighten.
9. Install the temperature sensing probe by passing
the wires through the hole provided on the left
side of the brace panel. Route wires through the
support bracket.
10. Reconnect all the high limit wires and the
pressure switch wiring, routing the wires
through the same hole as the thermostat sensor
wires.
11. Pump and bleed system to check the head for
leaks.
12. Reinstall the two large inspection plates on the
appropriate side.
Reversible Inlet/Outlet Connection,
On the MiniMax NT Series heater there is insulation
installed by the factory on the return head side of the
heaters. This insulation is there so that if the heads
are reversed in the field, during initial installation of
the heater, the high limits will be insulated from the
heat radiating from the flue collector.
6. Return head in position before removal. This view
shows the insulation installed by the factory.
Remove the 8 bolts holding the return head in place.
Remember: The inlet and outlet markings
on the header are still correct.
Do not plumb the heater backwards.
Reversing Headers (Return Head)
cont’d.

P/N NTSM03 Rev. B 2-11-04
14
INDOOR VENTING—General Requirements
The vent pipe must be the same size or larger than specified adaptor. The MiniMax NT Series heaters are capable of a
360-degree discharge rotation and operate with a positive vent static pressure and with a vent gas temperature less than 400° F.
Please note the allowable vent runs for each stack pipe diameter are different and can not be exceeded. The total
length of the horizontal run must not exceed the length that is listed below in the tables.
Note that each 90-degree elbow reduces the maximum horizontal vent run by 8 feet and each 45-degree elbow in the vent
run reduces the maximum vent run by 4 feet. See the tables below for the maximum vent lengths using a 90-degree and
45-degree elbows.
The MiniMax NT Series is a “Category III” Appliance and is an induced-draft pool and spa heater which uses positive
pressure to push flue gases through the vent pipe to the outside. This requires a completely sealed vent system—single
wall vent pipe with sealed-seams and joints. Flue gases under positive pressure may escape into the dwelling with any
cracks or loose joints in the vent pipe, or improper vent installation. The vent pipe must be of a sealed-seam construction
such as those listed for use with “Category III Appliances” and for operating temperatures above 350°. The use of listed
thimbles, roof jacks and/or side vent terminals are required; and the proper clearances to combustible materials must be
maintained in accordance with type of vent pipe employed—in the absence of a clearance recommendation by the vent
pipe manufacturer, the requirements of the Uniform Mechanical Code should be met. The ventilation air requirements
for the MiniMax NT Series heater can be found on page 15. It is recommended that vent runs over 18 feet be insulated
to reduce condensation related problems and/or the use of a condensate trap in the vent run close to the heater may be
necessary in certain installations such as cold climates. The MiniMax NT Series is suitable for through-the-wall venting,
see table and dimensions below.
Recommended sources for Side-wall vent hood terminals include: The Field Controls Co. (2308 Airport Road,
Kingston, NC 28501, [phone]) and Tjernlund Products Inc. (1601 Ninth Street, White Bear Lake, MN
55110, [phone])—consult manufacturer for model information and availability.
CAUTION
Do NOT combine exhaust vent pipes to a common exhaust vent in multiple unit installations. Run separate vent pipes.
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)latot4(3—)latot4(—
SRETAEHROFSTIKTNEVLLAWHGUORHT
traP
rebmuN A.miDB.miDC.miDD.miDE.miDF.miD
235174.aiD.ni4.aiD.ni6.ni½8.ni61/56.ni8/521.ni8/501
345174.aiD.ni5.aiD.ni8.ni½8.ni8.ni8/521.ni8/501
F
E
C
BA
D
Air Requirements
Figure 9.
Table 9.
Table 7. Table 8.

Rev. B 2-11-04 P/N NTSM03
15
INDOOR INSTALLATION (USA ONLY)
OUTDOOR SHELTER INSTALLATION (CANADA)
See below for Vent Adaptors
All products of combustion and vent gases must be completely
removed to the outside atmosphere through a vent pipe which is
connected to the stack adaptor. A vent pipe extension of the same
size must be connected to the vent adaptor and extended at least
2 feet higher than highest point of the roof within a 10 foot
horizontal radius, and at least 3 feet higher than the point at which
it passes through the roof, or as permitted by local code; see
Figures 10, 11 and Detail “H” of Figure 13. The vent should
terminate with an approved vent cap (weather cap) for protection
against rain or blockage by snow.
vent terminated at least 24"
above any object within 10 ft.
;;;
;;;
Vent Cap
Ridge
Chimney
3 ft. min.
2 ft. min.
Roof
Jack
More Than10 ft.
Air Requirements (Indoor)
Chimney or GasVent
Vent Cap and
Riser Furnished
by Installer
Optional
Side
Wall Vant
Heater
Outlet Air
Opening
Inlet Air
Opening
Chimney or GasVent
Vent Cap and
Riser Furnished
by Installer
Optional
Side
Wall Vant
Heater
Outlet Air Opening
Inlet Air Opening
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ledoM noitsubmoCrofriA
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NOTE
• The heater requires two uninterrupted air
supply openings; one for ventilation and one to
supply air for proper gas combustion. The air
supply openings should be sized according to
Table 10.
• The openings listed in Table 10. are free open vent
area—if the vents incorporate restrictive louvers, the
vent openings must be increased to compensate
for the area blocked by the louvers (or grills).
Air supply requirements below apply to all
MiniMax NT Series heaters
VENT ADAPTORS (ALL MODELS)
The proper draft hood and adapter must be installed on
the heater as shown below and on page 14:
Vent
Adaptor
The heater must be located as close as practical to a chimney or
gas vent.
Figure 10.
Figure 11.
Table 10. Figure 12.

P/N NTSM03 Rev. B 2-11-04
16
Detail H
INDOOR INSTALLATIONS
MINIMAX NTVENTING GUIDELINES
4'
7'
4'
Air Supply Ventilation
Air Supply Combustion
Vent Hood
Walkway
3'
1' min. 1' min.
1' min. above grade
Vent Hood
Vent Hood
E
H
D
F
G G
F
BC
A
must extend at least 3 ft. higher than the point at which it passes through the roof, or as permitted by local code. must use a double-wall vent pipe through the roof penetration. must terminate with an approved (listed) roof jack, storm collar, and vent/weather cap.
must be not less than 7 ft.above public walkways. must be at least 3 ft.above any outside air intake located within a 10 ft.radius. must NOT be within 3 ft. of an inside corner of the structure. must be at least 1 ft.above grade. must be located the following distances away from any door, window, or gravity air inlet:
4 ft. below 4 ft. horizontally 1 ft. above
Air Supply See Air Supply Requirements Table.
B
A
D E
F
J
K
L
C
G
Vent termination for side wall installations:
must be the same diameter as the vent connector. must be suitable for use with category III appliances which have flue gas temperatures of less than 400 deg. F. may use a single wall vent pipe with permanently sealed seams and joints.
Vent pipe extension:
Vent for roof penetration installations:
Recommended sources for side wall Vent Hood; see page 17, Section Venting.
vent terminated at least 24" above any object within 10 ft.
L
J
K
;;; ;;;
Vent Cap
Ridge
Chimney
3 ft. min.
2 ft. min.
Roof Jack
More Than10 ft.
(Table 10. on page 15.)
Figure 13.
Air Requirements (Indoor)

Rev. B 2-11-04 P/N NTSM03
17
OUTDOOR INSTALLATION ONLY (Outdoor Shelter Installation in Canada, see page 15)
For outdoor installation with an exhaust grill, the heater must be placed in a suitable area on a level, noncombustible
surface. Do not install the heater under an overhang with clearances less than 3 feet from the top of the heater. The
area under an overhang must be open on three sides.
IMPORTANT!
• For an outdoor installation it is important to ensure water is diverted from overhanging eves
with a proper gutter/drainage system. The heater must be set on a level foundation for proper
drainage.
• Under certain conditions, “heavy rains or unusually high winds”, it may be necessary to install
an outdoors vent. In this situation, use vent adaptor P/N 460507 and outdoor vent P/N 471357.
Maintain minimum clearances as indicated below. Install a minimum of 4 feet below, and 4 feet horizontally from
any opening to a building, see Figure 14.
Air Requirements (Outdoor)
MINIMAX NT VENTING GUIDELINES
OUTDOOR INSTALLATION
B
C
D
Must be not less than 7 ft. above public walkways.
Must be at least 3 ft. above any forced
air inlet located within a 10 ft. radius.
A
B
C
D
E
VentTermination:
Check local building codes
for setback requirements.
Property Line
4'
1'
4'
4'
Walkway
3'
A
Must be located the following distances away
from any door, window, or gravity air inlet:
4 ft. below, or
4 ft. horizontally, or
1 ft. above
E
Figure 14.

P/N NTSM03 Rev. B 2-11-04
18
Electrical Rating 60 Hz 120 / 240 Volts AC, single phase
NOTE
•The MiniMax NT Series heater is prewired for 240 volt AC connection using the “RED/BROWN” female connector and the
“WHITE” common male connector; see below, Figure 15. If you require the heater to be connected to 120 volts AC,
remove the “RED/BROWN” female connector from the “WHITE” common connector; now locate the “BLUE” female
connector and plug it into the “WHITE” common connector. When connecting the home wiring to the “Line Terminal
Block” inside the junction box, follow the polarity as shown below. Connecting to 120 VAC, make sure that you connect
the positive wire to the positive terminal (L), the neutral wire is connected to the neutral terminal (N) and the ground is
connected to the ground terminal (GND); see below, Figure 16.
•If any of the original wiring supplied with this heater must be replaced, installer must supply (No. 18 AWG, 600V, 105° C.
U.L. approved AWM low energy stranded) copper wire or it’s equivalent. Thermal fuse wiring must be replaced with
18 AWG, 600V, 150° C temperature rating. Interconnecting wiring to appliance must conform to the National Electrical
Code or supercede local (wiring) codes.
WARNING
The installation must conform with local codes or, in the absence of local codes, with the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane Installation Codes. If an
external electrical source is utilized, the heater, when installed, must be electrically grounded and
bonded in accordance with local codes or, in the absence of local codes, in the USA, with the National
Electrical Code, ANSI/NFPA 7; in Canada, with Canadian Electric Code, CSA C22.1-98.
•Always use crimp type connectors when connecting two wires.
LINE TERMINAL BLOCK
RED/BROWN
FM CONNECTOR
FOR USE WITH
240 VOLT AC
BLUE
FM CONNECTOR
FOR USE WITH
120 VOLT AC
WHITE
COMMON MALE
CONNECTOR
TERMINAL BLOCK
FOR AC INPUT
120 / 240 VOLT SINGLE
PHASE "See Figure Below"
L
N
GREEN WIRE
WHITE WIRE
BLACK WIRE
GROUND
CONNECTION
NEUTRAL / WHITE 120VAC
LINE #1 FOR 240 VOLT AC
POSITIVE LINE FOR 120 VOLTS AC
LINE #2 FOR 240 VOLT AC
INTERNAL
FACTORY WIRES
Figure 15.
Figure 16.
You might need
to open the jacket
(upper panel)
for servicing the
Line Terminal
Block as shown in
Figures 15 & 16.
Electrical Wiring

Rev. B 2-11-04 P/N NTSM03
19
WIRING SCHEMATIC FOR ALL DUAL VOLTAGE BLOWERS
120 VOLTS AC 240 VOLTS AC
WHITE LINE # 1 WHITE LINE # 1
YELLOW YELLOW CAP OFF
JOINED
ORANGE ORANGE JOINED
BLACK BLACK
LINE # 2
PURPLE PURPLE LINE # 2
BROWN BROWN
=
CAPACITOR CAPACITOR
BROWN BROWN
NOTE FOR TEST OF THE BLOWER:
1. In reference to the above terms, "CAP OFF" means to no connection.
2. The term "JOINED" means the two wires are connected together and
no external connection.
=
Electrical Installation (Dual Voltage Blowers)

P/N NTSM03 Rev. B 2-11-04
20
Electrical Installation (Dual Voltage Wiring)
MiniMax NT Series HSI Electronic Ignition Wiring Diagram
(DUAL VOLTAGE w/6800 Control Board)
G
IGN MODULE
IGNITOR
HOT SURFACE
BURNER
GND VAL TH IGN L2 L1 IGN/240
MiniMax NT Dual Voltage W/6800 Control Board Wiring Diagram
O
W
G
O
R
THERMAL FUSE
WBL
R
SWITCH
WATER PRESSURE
SPST EXTERNAL SWITCH
GAS VALVE
R
W
BL
R
HIGH LIMIT
115˚F
1 2 3 4 5
3 2 1G
AIR PRESS. SW.
BL
R
W
BLOCK TERM BLOCK
TERM
W
W
BK
W
BK
O
O
W
W
WW
BLOWER
BK/W
BK
R/W R
PR
O
W
BK
W
IGN/120 FS
W
BK
120 VAC
OR
240 VAC
BK
W
BK
Y
CON-FEM(BL)
CON-MAL(W)
F1
F2
24 VAC
W
POOL
JUMPER REQUIRED
J6
THERMOSTAT
CIRCUIT BOARD
PROBE
TEMP.
VLV
TPROBE
J5
J8
24V
J4 J7
IGN MODULE
J10 J11
IND
(6800)
IF ORIGINAL FACTORY WIRING MUST BE REPLACED, INSTALLER MUST SUPPLY UL/CSA APPROVED WIRE
WITH 18 AWG, 600V, 105˚ C TEMP. RATING.
O
W
SW/HL/TFUSE
J9
POOLSPA COM
W W
O
BK
W
W
OFF SPA
J2 J3
THERMAL FUSE WIRING MUST BE REPLACED WITH
W
W
W
W
IF NO REMOTE SWITCH
R
R/W
BK
BK/W
W
W
W
BK Y
BL
O O
HIGH LIMIT
150˚F
18 AWG, 600V, 150˚ C TEMP. RATING.
FOR 120 VAC
CON-FEM(BR)
FOR 240 VAC ATTACH
GROUND WIRE HERE
G
(ON THE SIDE JACKET) BOND LOG
PR
O
Y
BK
W
FROM
TRANSFORMER
BK
WBK
W
W
BL
W
Y
472085C
MV MV
P4 P7 P10 P11
P1
P2
P9
W
W
FLAME
SENSOR
WIRE COLOR CODE
BK : BLACK BL : BLUE BR : BROWN R : RED O : ORANGE Y : YELLOW G : GREEN GY : GRAY PR : PURPLE W : WHITE R/W : RED W/WHITE TRACE BK/W : BLACK W/WHITE TRACE
COM NO
Figure 17.