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U.S. Patent Numbers
5,318,007 - 5,228,618
5,201,307 - 4,595,825
If you do not follow these instructions exactly, a fire or explosion may result,
causing property damage, personal injury or loss of life.
Improper installation, adjustment, alteration, service or maintenance can cause
property damage, personal injury or death. Installation and service must be
performed by a qualified installer, service agency or the gas supplier.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity
of this heater or other appliances.
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.
For additional free copies of this manual; call (800) 831-7133.
Rev. D 12-22-04
Pool & Spa Heaters
Pentair Water Pool and Spa, Inc.
1620 Hawkins Ave., Sanford, NC 27330
10951 W. Los Angeles Ave., Moorpark, CA 93021
NT Series
(919) 566-8000
(805) 523-2400
1 1
Retain For
P/N 472235



   Summary of Contents for Pentair Pool Products MiniMax NT Series

  • Page 1

    MiniMax NT Series ® Pool & Spa Heaters OPERATION & INSTALLATION MANUAL Consumer Retain For Future Reference U.S. Patent Numbers 6,295,980 5,318,007 - 5,228,618 5,201,307 - 4,595,825 WARNING FOR YOUR SAFETY - READ BEFORE OPERATING • If you do not follow these instructions exactly, a fire or explosion may result, causing property damage, personal injury or loss of life.

  • Page 2

    All rights reserved. Information in this document is subject to change without notice. Trademarks and Disclaimers. MiniMax and the Pentair Pool Products logo are registered trademarks of Pentair Water Pool and Spa, Inc. Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products.

  • Page 3: Table Of Contents

    Table of Contents Section I. Heater Identification Information ............Section II. Introduction .................... Important Notices ..................................Warranty Information ................................. Code Requirements ................................... Consumer Information and Safety ............................. Section III. Installation ....................Specifications .................................... Plumbing Connections ................................Valves ......................................Manual By-Pass ..................................Below Pool Installation ................................

  • Page 4: Section I. Heater Identification Information

    1) HTR : Heater 2) (200, 250, 300 or 400) : Input rating (Btu/hr) X 1000 3) NT : MiniMax NT Series 4) STD or TSI : Series Character 5) NH or PH: Gas type (Natural gas or Propane gas) and ignition system (Hot Surface Ignition)

  • Page 5: Section Ii. Introduction

    Pentair Pool Products’ high standards of excellence include a policy of continuous product improvement resulting in your state-of-the-art heater. We reserve the right to make improvements which change the specifications of the heater without incurring an obligation to update the current heater equipment.

  • Page 6: Code Requirements

    Section II. Introduction 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. 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;...

  • Page 7: Section Iii. Installation

    Section III. Installation Installation Instructions SPECIFICATIONS These installation instructions are designed for use by qualified personnel only, trained especially for installation of this type of heating equipment and related components. Some states require installation and repair by licensed personnel. If this applies in your state, be sure your contractor bears the appropriate license.

  • Page 8: Plumbing Connections

    Section III. Installation 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. See Figure 2. PUMP POOL POOL FILTER MANUAL...

  • Page 9: Water Connections

    Section III. Installation WATER CONNECTIONS Reversing Headers — Reversible Inlet/Outlet Connection The MiniMax NT Series heater is factory assembled NOTE with right side inlet/outlet water connections. The Do NOT remove the high-limit and pressure inlet/outlet header can be reversed for left side water switches or the thermistor from the front header connections without removing the heat exchanger.

  • Page 10

    Reversible Inlet/Outlet Connection, cont’d. 9. Install the temperature sensing probe by passing On the MiniMax NT Series heater there is insulation the wires through the hole provided on the left installed by the factory on the return head side of the side of the brace panel.

  • Page 11: Gas Connections

    Section III. Installation GAS CONNECTIONS 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.

  • Page 12: Gas Pipe Sizing

    Section III. Installation GAS PIPE SIZING Table 2. ) . t l a r c i b c i b ” 2 ” 4 ” 1 / 1 - ” 4 / 1 - ” 2 ” 2 / 1 - ”...

  • Page 13: Testing Gas Pressure/gas Pressure Requirements

    Section III. Installation TESTING GAS PRESSURE Inlet Manifold 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 Manifold Inlet fitting from the Manometer kit.

  • Page 14: Indoor Venting-general Requirements

    Section III. Installation INDOOR VENTING — General Requirements The vent pipe must be the same size or larger. The MiniMax NT 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. The total length of the horizontal run must not exceed the length that is listed below in the tables.

  • Page 15: Indoor (usa) / Outdoor (canada) Installations

    Section III. Installation INDOOR INSTALLATION (USA ONLY) Chimney or Gas Vent Vent Cap and Riser Furnished OUTDOOR SHELTER INSTALLATION (CANADA) by Installer page 16 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.

  • Page 16: Combustion Air Supply

    Section III. Installation Air Supply Requirements Guide COMBUSTION AIR SUPPLY for MiniMax NT Heaters For indoor installation, the heater location must provide sufficient air supply for proper combustion and ventilation of the surrounding area. The requirements for the air supply specify that the room in which a heater is installed should be provided with two permanent air supply openings;...

  • Page 17: Indoor Installations -venting Guidelines

    Section III. Installation Rev. D 12-22-04 P/N 472235...

  • Page 18: Outdoor Installations -venting Guidelines

    Section III. Installation OUTDOOR INSTALLATION (Outdoor Shelter Installation in Canada, see page 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.

  • Page 19: Electrical Connections

    Section III. Installation ELECTRICAL CONNECTIONS Electrical Rating 60 Hz 120 / 240 Volts AC, single phase CAUTION This heater is designed to operate at 120 or 240 VAC. It is not recommended to be connected to OR operate on a 208 VAC. NOTE •...

  • Page 20: Wiring Diagram-nt Std & Tsi With Ddtc

    Section III. Installation WIRING DIAGRAM–NT STD & TSI WITH DDTC THERMISTER 24VAC POOL P/N 472235 Rev. D 12-22-04...

  • Page 21: Section Iv. Operation

    Section IV. Operation Operation Instruction BASIC SYSTEM OPERATION Start pump, make sure the pump is running and is primed, to close the water pressure switch and supply power to heater. Be sure the pool and/or spa is properly filled with water. Follow the Lighting/Operating instructions below. MINIMAX NT HSI ELECTRONIC IGNITION LIGHTING/OPERATION FOR YOUR SAFETY: READ BEFORE LIGHTING WARNING...

  • Page 22: Safety Controls

    Section IV. Operation SAFETY CONTROLS Figure 21. VACUUM AIR PRESSURE (FAN) SWITCH The air pressure switch, (see Figure 21), is a safety device used to insure that the combustion air blower (fan) is operating and has been designed to monitor the vacuum (negative) pressure within the blower housing.

  • Page 23: Operation Of Ignition Module

    Section IV. Operation SAFETY CONTROLS, (cont’d.) Flame Current Diagnostic LED Check Point 1 Flash - Air Flow Fault HIGH LIMITS 2 Flashes - Flame no Call for Heat 3 Flashes - Lock Out A “High Limit”, is a safety device that opens the electrical circuit and shuts off the heater based on a water temperature set point within the “High Limit Device”.

  • Page 24: Digital Display Temperature Controller (ddtc)


  • Page 25

    Section IV. Operation Figure 27. Rev. D 12-22-04 P/N 472235...

  • Page 26

    Section IV. Operation SET UP The MiniMax NT Heater comes from the factory preset with a pool temperature setting of 78° F. and a preset spa temperature of 100° F., and in the off mode setting. Once the power is turned on, the DDTC board will do a self diagnostic internal check, during this time the display will first read “888”, then the display will switch to three dashes “- - -“, this process takes approximately ten (10) seconds.

  • Page 27

    Section IV. Operation • HEATING The heating light is on any time the thermostat has signaled a call for heat which initializes the ignition safety circuit — the light comes on indicating successful firing of the main burners and stays on until the pool/spa reach the water temperature setting.

  • Page 28: Section V. Troubleshooting

    Section V. Troubleshooting Troubleshooting Instruction TROUBLESHOOTING (DDTC) The DDTC temperature display contains three LED’s with a decimal point between the first and second, this display is also used to display an error code if for some reason there is a failure within the heater control system or a DDTC internal fault.

  • Page 29: Troubleshooting (general)

    Section V. Troubleshooting TROUBLESHOOTING (GENERAL) Possible Cause Remedy Heater will not come on Check if electrical connections are Automatic ignition system fails correct and securely fastened – If YES, call serviceperson. Pump not running Place pump in operation Pump air locked Check for leaks Filter dirty Clean filter...

  • Page 30: Section Vi. Maintenance

    1. Examine the venting system. Make sure there are no In some installations, a pressure relief valve (PRV) obstructions in the flow of combustion and is required on the MiniMax NT Series. To install a PRV, ventilation air. remove the access 2.

  • Page 31: Spring, Fall And Winter Operation

    Section VI. Maintenance SPRING AND FALL OPERATION If the pool is being used occasionally, do not turn the heater completely off. Set the thermostat down to 65° F. This will keep the pool and the surrounding ground warm enough to bring the pool up to a comfortable swimming temperature in a shorter period of time.

  • Page 32: Chemical Balance

    Table 15. POOL AND SPA WATER If pH becomes too high (over alkaline), it Your Pentair Pool Products pool heater was designed has these effects: specifically for your spa or pool and will give you many 1.

  • Page 33: Replacement Parts - Nt Std& Tsi W/ddtc

    REPLACEMENT PARTS NT STD w/DDTC — (all Models) NT TSI w/DDTC — (200, 250, 300 Models) FOR TSI FOR STD ONLY ONLY Rev. D 12-22-04 P/N 472235...

  • Page 34

    Replacement Parts—NT STD Item Description Quantity Exhaust Grill w/Gasket 472352 Gasket, Exhaust Grill 471701 Top Cover w/Posts 472353 472354 472355 472356 Exhaust Assembly 472373 472376 472373 Blower w/Gasket 472361 472362 472374 Gasket, Blower 471610 Flue Collector 472008 472007 472006 472005 Insulation, Header/Hi-Limit 472270 Return Header Assembly...

  • Page 35

    Replacement Parts—NT TSI Item Description Quantity Replacement 472352 Exhaust Grill w/Gasket Gasket, Exhaust Grill 471701 Parts for the Top Cover w/Posts 472353 472354 472355 472356 400 Model Series Exhaust Assembly 472357 472358 472359 472358 are for models 472361 472362 Blower w/Gasket manufactured 471610 Gasket, Blower...

  • Page 36: Nt /guide D'installation Et De Fonctionnement

    REPLACEMENT PARTS NT TSI w/DDTC — ( — 400 Model Starting w/Serial No. 12040039 42 41 P/N 472235 Rev. D 12-22-04...

  • Page 37

    Replacement Parts — NT TSI — (400 Models) Starting with Serial Number 12040039 Item Description Part No. Exhaust Grill w/Gasket 472352 Gasket, Exhaust Grill 471701 Top Cover w/Posts 472356 Exhaust Assembly 472144 Exhaust Duct 472259 Blower w/Gasket 472480 Gasket, Blower 471610 Flue Collector 472005...

  • Page 38

    NOTES P/N 472235 Rev. D 12-22-04...

  • Page 39

    NOTES Rev. D 12-22-04 P/N 472235...

  • Page 40: Save These Instructions

    40 40 SAVE THESE INSTRUCTIONS Pentair Water Pool and Spa, Inc. 1620 Hawkins Ave., Sanford, NC 27330 (919) 566-8000 • 10951 W. Los Angeles Ave., Moorpark, CA 93021 (805) 523-2400 • P/N 472235 Rev. D 12-22-04...

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