MrCool MHWH199NC U Series Installation Manual Download Page 56

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Wiring Connections

Wiring Diagram

CN1

FAN

POWER CORD

* Thermostat

Anti-freezer for certain models

Pulse igniter

lgnition pin

Feedback needle

Ground wire

Feedback wire

Pulse igniter

Display

Air pressure

sensor

Heat exc

nge

outlet temp.

Cold water temp

Main water

ﬂow

Hot water temp.

Flue gas temp sensor

FAN

control

FAN control

Flue gas temp

Main Board

(PCB)

L=520

L=480

L=540

Thermostat

water ﬂow sensor

* Thermostat

Heat

exchanger

water ﬂow proportional

valve

gas proportional valve

Air pressure

sensor

Summary of Contents for MHWH199NC U Series

Page 1: ...Thank you for choosing MRCOOL Please read this manual carefully before installation and keep it for future reference Due to updates and constantly improving performance the information and instruction...

Page 2: ...e Vent 18 Connecting the Power Supply 19 Operation 20 General Maintenance 21 Troubleshooting 22 Wiring Connection 23 Installation Checklist 24 Parts List 2 6 7 9 10 11 16 20 22 24 26 27 30 32 34 35 36...

Page 3: ...these could create a re hazard which could result in personal injury and property damage DO NOT use or store aerosol products such as hair sprays spray paints etc or any other compressed gases near t...

Page 4: ...al switch DO NOT use any phone within the building where you smell gas EXIT the building IMMEDIATELY and CALL your GAS SUPPLIER Follow the gas supplier s instructions If you CANNOT reach the gas suppl...

Page 5: ...l However this adjustment should only be performed by a quali ed technician If this adjustment is not made or performed incorrectly it could cause improper operation of the unit Improper operation cou...

Page 6: ...er than its intended purpose as described within this manual DO NOT remove the front cover unless the power to the water heater is turned o or disconnected Failure to follow this warning could result...

Page 7: ...at 140 F 60 C Shipping Storage Temperature Range 4 F 176 F 20 C 80 C Flue High Limit Switch 158 F 70 C Water Temperature High Limit Switch 185 F 85 C Freeze Protection Ceramic Heater Turns on at 41 F...

Page 8: ...mrcool com 3 Product Overview Accessories 7 Fig 3 1 1 5 3 6 4 2 7 8 10 9...

Page 9: ...future reference For more info visit www mrcool com Version 061020 Tankless Water Heater 2 2 pieces each Bird Screens Wall Mounting Screw Kit Wall Mounting Bracket lower bottom Wall Mounting Bracket...

Page 10: ...nents Units inch millimeter Units inch millimeter Appliance Dimensions 1 83 in 46 5 mm 26 77 in 680 mm 2 74 in 69 5 mm 1 77 in 45 mm 17 32 in 440 mm 4 13 in 105 mm 4 84 in 123 mm 1 57 in 40 mm 4 35 in...

Page 11: ...witch the information displayed when Info button is pressed Refer to Chapter 17 Display more operation information Refer to Chapter 17 Units Preserved Preserved Preserved Preserved Wi Fi Common Chimne...

Page 12: ...n installation location you must ensure that the location will provide adequate clearance for the water heater as well as adequate options for venting and drainage and su cient access to gas water and...

Page 13: ...ructure When such a location cannot be found it is highly recommended that a drain pan that can drain adequately be installed beneath the unit refer to Fig 6 1 When installing the drain pan ensure tha...

Page 14: ...water supply as possible For more information regarding the water supply refer to Chapter 10 Install the water heater in an area that will allow for service maintenance as well as access to the utili...

Page 15: ...noises while operating To mount the water heater to the wall 1 Make 4 holes in the wall with the drill A x the upper bracket securely to the wall with the expanded screws ensure that it is level and e...

Page 16: ...Align the grooves on the back of the water heater with the convex on the upper bracket Then hang the unit on the bracket See Fig 6 4 4 Secure the lower bracket installed on the water heater in a previ...

Page 17: ...ors on the water heater use two wrenches when tightening piping to the water heater Use one wrench to prevent the connector at the water heater from turning and the other wrench to tighten the connect...

Page 18: ...water heater This will facilitate any future maintenance or service required Check with the local jurisdiction to verify the use of 1 2 in 12 7 mm gas pipe is allowed approved in the area where the wa...

Page 19: ...iping Example 1 2 Stage System with Multiple Regulators Recommended 18 Gas Tank High Pressure Regulator 2 Stage Gas Regulators Gas Supply Low Pressure Regulator Located before entering home or buildin...

Page 20: ...mrcool com Connecting the Gas Supply Typical Gas Piping Example 2 Single Regulator System 19 Gas Tank Gas Supply To other gas appliances Full Size Gas Pipe Gas Regulator 12 in W C Fig 7 4...

Page 21: ...0 7 280 5 840 5 000 4 430 4 020 3 690 3 440 3 230 3 050 2 700 16 900 11 600 9 310 7 970 7 060 6 400 5 890 5 480 5 140 4 860 4 300 29 800 20 500 16 500 14 100 12 500 11 300 10 400 9 690 9 090 8 580 7 6...

Page 22: ...2 420 1 940 1 660 1 480 1 340 1 230 1 140 1 070 1 010 899 814 749 6 790 4 660 3 750 3 210 2 840 2 570 2 370 2 200 2 070 1 950 1 730 1 570 1 440 1 2 in 3 4 in 1 in 1 1 4 in 1 1 2 in 2 in Pipe Size Leng...

Page 23: ...ve high ow rates such as bathtub and shower faucets to ramp the water heater up to its maximum ring rate 11 When the water heater reaches its maximum ring rate check the inlet gas pressure reading on...

Page 24: ...23 Measuring The Inlet Gas Pressure Fig 9 1 Fig 9 2 Fig 9 4 mrcool com Fig 9 5 Fig 9 3...

Page 25: ...10 1 represents a typical water piping example Fig 10 1 10 Condensate Drain Gas Supply Hot Water Out Cold Water In Gas Check Valve Pressure Relief Valve Hot Water Valve Cold Water Valve Neutralizing A...

Page 26: ...ite only has 1 2 in plumbing throughout it is not necessary to up size the water lines to 3 4 in if you are installing a single water heater When connecting the water supply follow these guidelines Us...

Page 27: ...elief valve and the water heater Figure 10 1 on the previous pages represents a typical water heater with a pressure relief valve When installing the pressure relief valve follow these guidelines DO N...

Page 28: ...r heater directly into an external drain From the water heater through a neutralizing agent and then into an external drain From the water heater into a laundry tub From the water heater into a conden...

Page 29: ...xide DO NOT connect more than one appliance to the neutralizer To avoid damaging the appliance the neutralizer inlet and discharge must be lower than the condensate drain The connection between the ap...

Page 30: ...rease An increased pH level will prevent corrosion of the installation s drainage system and the public sewer system Neutralizer Installation Guidelines The inlet of the neutralizer has a center conne...

Page 31: ...ent pipe and reduce the open cross sectional area of the vent According to NFPA 720 carbon monoxide detectors should be installed outside each sleeping area WARNING This appliance is certi ed as a Cat...

Page 32: ...oid moisture and frost build up and to maintain clearances on adjacent homes 45 90 elbows and tees may be attached to the end of the termination vent pipe to direct the exhaust plumes away from buildi...

Page 33: ...ired combustion air directly from the outdoors The manufacturer recommends direct air vent installations whenever possible to avoid the back drafting of cold air through the water heater If you cannot...

Page 34: ...cm 36 in 91 cm above if within 10 ft 12 in 30 cm Clearance to service regulator vent outlet Clearance to non mechanical air supply inlet to building or the combustion air inlet to any other appliance...

Page 35: ...certi cation of the appliance PVC CPVC Schedule 40 or 80 Solid Core Approved Polypropylene PP Type BH Special Gas Vent Class IIA PVC Type BH Special Gas Vent Class IIB CPVC Type BH Special Gas Vent Cl...

Page 36: ...duct length may be identical to the exhaust duct length One foot straight pipe and an 90 elbow are not included in the vent length The maximum vent length is reduced by the number of elbows used as sh...

Page 37: ...ll also void the warranty of the water heater If the distance between the air inlet and exhaust vent terminations is less than 7 ft 2 1 m the water heater will draw in exhaust gases through the intake...

Page 38: ...mrcool com Terminating the Vent 37 Bird Screen Minimum 2 in 50 mm Minimum 1 ft 300 mm Minimum 5 5 in 140 mm Minimum 1 ft 300 mm Two Pipe Sidewall Venting Example 1 Fig 17 1 Fig 17 2...

Page 39: ...mrcool com Terminating the Vent 38 Minimum 1 ft 300 mm Two Pipe Sidewall Venting Example 2 Bird Screen Minimum 2 in 50 mm Minimum 5 5 in 140 mm Minimum 1 ft 300 mm Fig 17 3 Fig 17 4...

Page 40: ...00 mm External Wall Air intake Flue Exhaust Only the following orientations are allowed for twin pipe terminations IPEX and Centrotherm Low Pro le terminations ONLY Clearance above the highest anticip...

Page 41: ...d directly remove and discard the factory installed plug Install a power switch between the breaker and the water heater to facilitate any end user maintenance and servicing Connect the water heater t...

Page 42: ...ter heater at the manual gas valve and call a quali ed technician If any part of the water heater has been submerged in water do not use this appliance immediately cut o the power supply and call a qu...

Page 43: ...the range becomes 95 122 F 35 50 C To reset the default setting temperature press the ENTER button for 3 seconds until the set temperature on the display ashes while the power is on Then press the or...

Page 44: ...nter the information query interface while the power is on IT displays as default 2 Press the or buttons to select the information item 3 Press ENTER to show details Step 2 Then press ENTER to see the...

Page 45: ...ep 2 Turn o the water heater by pressing the POWER button Step 3 Cut o the power supply Step 4 Connect the power supply and press the button for at least 5 seconds until PP is displayed on the screen...

Page 46: ...Step 7 Press the POWER button and then press the buttons to adjust the L2 value according to the table below Step 8 Press the POWER button again to exit the parameter code adjustment mode Altitude set...

Page 47: ...Air Pressure Historical Error Total Water Consumption Ignition Success Times Version Number of Main Board Version Number of Display Board Press and hold the ENTER INFO buttons together for 3 seconds t...

Page 48: ...CA Flash CF Flash A0 Flash A1 Flash A2 Flash A3 Flash A4 Flash A5 Flash N A N A E1 E2 Thermistor Failure Fake Flame Fan Failure Gas Valve Failure Main Water Valve Failure Overtime Failure Accidental F...

Page 49: ...solation valve on the cold water side to the outlet of the circulation pump 2 Connect the empty connection of the isolation valve on the hot water valve to the solution tank 3 Connect the inlet of the...

Page 50: ...Inlet Water Filter 1 Drain the water heater 2 Take out the lter by turning it counterclockwise See Fig 20 2 3 Rinse the lter with clean water brush or wipe it when necessary 4 Insert the cleaned lter...

Page 51: ...y pressure to the required value Replace the gas valve Replace the sensor Open circuit formed between ame sensor and the burner or the heat exchanger before ignition Unplug the ame sensor from the MAI...

Page 52: ...Gas Temperature Sensor Failure Exhaust gas temperature sensor is open or has short circuited Ensure the sensor is connected If the sensor is connected C9 persists change the sensor If C9 persists wit...

Page 53: ...ssible Causes Possible Remedies No water is available when the faucet is turned on or opened Is the water supply valve shut o at the meter are the cold water faucets still working Open the closed supp...

Page 54: ...about the water heater s operating condition at the time of the ten most recent faults or errors This information is available to view in the error code history when accessed in the After Sales Mode...

Page 55: ...isplay Check for loose connections and proper pin alignment engagement on the control s connector Correct wiring per wiring diagram including the connection of the transformer to the control Power the...

Page 56: ...Feedback wire Pulse igniter D N G M W P L L A H R E W O P 1 2 3 Display Air pressure sensor Heat exchanger outlet temp Cold water temp Main water ow Hot water temp Flue gas temp sensor FAN control FAN...

Page 57: ...15 CN13 CN14 CN8 F1 CN10 CN1 CN4 CN12 CN11 24V B B A 5V A OUT GND Main control board Bypass water flow Ignitor Flame sensor Flue temperature sensor CN18 A B C B D Area A T3 15A 250V Thermostat HEATER...

Page 58: ...ater temp Display board RS 485 connector preserved for cascade system M Main water valve Inlet water temp Main water flow Heat exchanger outlet water temp Air pressure B To air sampling tube CN2 CN1 C...

Page 59: ...58 Area C Area D 24V B B A 5V A OUT GND 24V B B A 5V A OUT GND CN7 M By pass water valve Flow2 AD5 Flame GND GND 5V Fire CN14 CN7 Flow2 AD5 Flame GND GND 5V Fire CN14 Bypass water flow Ignitor Flame s...

Page 60: ...ine pressure and all ttings for leaks 13 Has the gas company inspected the installation if required 14 Is the water supply pressure su cient greater than 40 PSI 15 Have you installed shut o valves on...

Page 61: ...odes and the guidelines in this manual 26 Have you ensured that PVC solid core pipe has not been used as venting for the water heater Venting the Water Heater continued Power Supply Water Heater in Op...

Page 62: ...play 2 Sealing Washer 3 Front Cover 4 Cover Plate 2 inch 3 inch adapted 5 Control Board Assembly 6 Controller Support 7 Power Cable 8 Case PCB box included 9 Mounting Bracket 10 Vent Seal 11 Vent Coll...

Page 63: ...Condensate collector gasket Condensate collector Flue Vent Flue temperature sensor Blower Igniter assembly Mixer assembly Blower gasket Burner assembly Blower bracket Mu er Gas pipe Gas valve No Descr...

Page 64: ...water inlet connector Clip Cold water pipe Thermistor Connector of water inlet Connecting pipe component Water ow sensor Water Ratio Valve Water outlet connection No Description Notes 1 2 3 4 5 6 7 8...

Page 65: ...Electrician and or HVAC Technician License Installation Date Installation location Serial number...

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MrCool MHWH199NC U Series, Installation Manual

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Summary of Contents for MHWH199NC U Series

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