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P/N 471593

                     Rev. C  11-1-01

32

Possible Cause

Remedy

Heater will not come on

Automatic ignition system fails

Check if electrical connections are
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

Pump strainer clogged

Clean strainer

Defective wiring or connection

Repair or replace wires

Defective pressure switch

Replace switch

Defective gas controls

Call serviceperson

On-Off switch in "OFF" position

Turn switch to "ON"

Heater Short Cycling 

(Rapid On and Off Operation)

Insufficient water flow

Clean filter and pump strainer

Defective wiring

Repair or replace wiring

Defective flow valve or out of adjustment

Call serviceperson

Defective hi-limit and/or thermostat

Call serviceperson

Heater Makes Knocking Noises,
Make sure all valves on system are open

Heater operating after pump has shut off

Shut off gas supply and call serviceperson

Heater exchanger scaled

Shut off gas supply and call serviceperson

Troubleshooting - General

CAUTION

Please consult the latest edition of the “MiniMax NT Low NOx Service Manual” for complete service and
repair instructions. Repairs should only be attempted by properly trained service personnel.

Summary of Contents for MiniMax 250

Page 1: ...th Installation and service must be performed by a qualified installer service agency or the gas supplier MiniMax NT Low NOx Series POOL SPA HEATERS OPERATION INSTALLATION MANUAL WARNING WHAT TO DO IF...

Page 2: ...ents 14 Regulated Manifold Pressure Test 14 Venting Indoor Installations 15 18 Venting Outdoor Installations 19 Basic Operation General Description 20 Basic Operation Safety Controls 21 22 Basic Opera...

Page 3: ...r of the MiniMax NT Low NOx pool and spa heater 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 fort...

Page 4: ...re 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...

Page 5: ...TING OPERATION NATURAL GAS 1 STOP Read the safety information above 2 Set the thermostat to the lowest setting 3 Turn off electric power to the heater 4 This heater is equipped with an ignition device...

Page 6: ...this applies in your state be sure your contractor bears the appropriate license SPECIFICATIONS 24 05 2 in SOCKET A DIM 8 84 6 64 30 63 LEG LEG 14 50 3 50 4 875 MODEL 200 250 24 63 21 63 A DIM 15 50...

Page 7: ...replaced installer must supply No 18 AWG 105 C U L approved AWM low energy stranded copper wire or it s equivalent In Canada wires must be CSA approved WARNING The heater must be electrically grounded...

Page 8: ...ntroller then the second wire to either the SPA or POOL tab b Now return power to the heater but leaving the temperature controller in the OFF position see Page 24 Note If you used the main power swit...

Page 9: ...erate NOTE The heater factory settings are 78 F for the pool and 104 F for the spa When connecting a remote control to the MiniMax you must install the low voltage thermostat wires in separate conduit...

Page 10: ...ATE SUPPLY SAFETY GROUND WIRE GREEN HERE CHASSIS BOND LUG EXTERNAL ORG WHT GRN 2 1 3 2 1 4 3 2 5 1 4 3 6 2 1 W2 W1 F2 F1 P11 P10 P7 P4 ORG RED THERMAL FUSE WHT BLU RED SWITCH WATER PRESSURE THERMAL SW...

Page 11: ...L WIRING CODES SHEET METAL GROUND SCREW WITH PAINT CUTTING WASHER TERMINATE SUPPLY SAFETY GROUND WIRE GREEN HERE CHASSIS BOND LUG EXTERNAL ORG WHT GRN 2 1 3 2 1 4 3 2 5 1 4 3 6 2 1 W2 W1 F2 F1 P11 PI0...

Page 12: ...G WASHER TERMINATE SUPPLY SAFETY GROUND WIRE GREEN HERE CHASSIS BOND LUG EXTERNAL ORG WHT GRN 2 1 3 2 1 4 3 2 5 1 4 3 6 2 1 F2 F1 P11 P10 P7 P4 ORG RED THERMAL FUSE WHT BLU RED SWITCH WATER PRESSURE T...

Page 13: ...mperature sensing bulb from the inlet outlet header Note If needed you may cut the wire ties holding them together 5 Remove the 16 bolts holding the main inlet outlet head and return head in place exc...

Page 14: ...ot 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 Pipe Sized For Length Of Run In Equivalent Feet...

Page 15: ...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 Mechan...

Page 16: ...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 W...

Page 17: ...be contaminated by corrosive chemical fumes which can void the warranty NOTE The openings listed in Table 2 are free open vent area if the vents incorporate restrictive louvers the vent openings must...

Page 18: ...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 locate...

Page 19: ...RTANT When locating the heater consider that high winds can roll over or deflect off adjacent buildings and walls Normally placing the heater at least three feet from any wall will minimize downdraft...

Page 20: ...own arrow keys See page 24 3 Push the off key on the Pentair temperature controller 7800 the amber off led will illuminate See page 24 4 Open the access doors 5 Push in the gas control knob slightly a...

Page 21: ...he switch may remain closed with no water flow if there is more than a 3 ft elevation difference between the heater heat exchanger and the pool water line if this is the case the water pressure switch...

Page 22: ...e safety timing ignition sequence After the fan prepurge cycle the hot surface ignitor is activated for a heat up period followed by energization of the gas valve for the trial for ignition period Whe...

Page 23: ...NO REMOTE Each temperature setting in either POOL or SPA mode is settable independently If the Factory s presetting of 78 F for Pool and 104 F for Spa is not desirable you may adjust these settings S...

Page 24: ...ture is now set 4 You can leave the right window displaying the set Temperature or by pressing the MODE key you can return to the Time Mode NOTE To re set the Spa Temperature follow the above steps 1...

Page 25: ...per Minute setting then press the SET key The Day and Time are now set and the Day icon will be flashing 6 Press the SET and MODE keys at the same time to return to the Operational Mode SET MODE PROGR...

Page 26: ...determined tighten the thermostat knob stopper 5 Set time clock to start circulation system no earlier than daybreak The swimming pool loses less heat at this time 6 For pools that are only used on th...

Page 27: ...e Then test only once every month or so to be sure it is being maintained See your local pool dealer for help in properly balancing the water chemistry 7 2 6 8 7 0 7 4 7 6 7 8 8 0 8 2 8 4 Add Soda Ash...

Page 28: ...Temperature Controller 7800 will shut down and will display an ignition fault and luminate the red service light Please note that on initial firing of heater when gas supply piping is full of air or a...

Page 29: ...for POOL or SPA the heater will first acknowledge the new selection by flashing the new selection s corresponding selection LED POOL or SPA however the heater will first complete a safe shutdown sequ...

Page 30: ...in the cabinet The cause of the fault must be corrected and the one shot fuse replaced before icon can be cleared This fault icon displays whenever there is a failure of either the low gas pressure sw...

Page 31: ...p O B 2 V 1 V n e e w t e b e g a t l o v k c e h c l o r t n o c d a B C I F T g n i r u d y a k o e m a l F 5 I F T r e t f a e s n e s e m a l f o n r o t i n g i d a B A e r i w 1 S d a B B r e n...

Page 32: ...h to ON Heater Short Cycling Rapid On and Off Operation Insufficient water flow Clean filter and pump strainer Defective wiring Repair or replace wiring Defective flow valve or out of adjustment Call...

Page 33: ...NOx HEATER Single Voltage 1 4 3 5 6 8 9 10 12 26 28 33 34 36 48 47 46 49 44 42 43 38 37 18 17 16 15 21 14 32 39 24 25 2 7 11 22 23 20 19 29 31 30 35 45 41 40 50 13 27 MiniMAX NT Low NOx Single Voltage...

Page 34: ...Left 1 33 Jacket Corner 4 34 Jacket Divider 1 471651 471580 35 Jacket Lower Panel Left 1 36 Base 1 471645 471573 37 Jacket Back 1 471669 471574 38 Bracket Jacket Side 2 39 Jacket Upper Panel Right 1...

Page 35: ...T LOW NOx HEATER Dual Voltage 1 4 3 5 6 8 9 10 12 26 28 33 34 36 48 47 46 44 42 43 38 37 18 17 16 15 21 14 32 39 24 25 2 7 11 22 23 20 19 29 31 30 35 45 41 40 13 27 MiniMAX NT Low NOx Dual Voltage Man...

Page 36: ...72001 30 Burner 4 5 6 8 200 250 300 400 31 Face Plate 1 471871 471819 471873 471977 32 Jacket Upper Panel Left 1 33 Jacket Corner 4 34 Jacket Divider 1 471827 471651 471826 471580 35 Jacket Lower Pane...

Page 37: ...Rev C 11 1 01 P N 471593 37 NOTES...

Page 38: ...P N 471593 Rev C 11 1 01 38 NOTES...

Page 39: ...Rev C 11 1 01 P N 471593 39 NOTES...

Page 40: ...dent negligence alteration abuse misapplication or misuse The above warranty applies only if the heater is installed and operated in complete compliance with the installation and operation manual prov...

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