Munchkin MUNCHKIN HIGH EFFICIENCY HEATER with the "925" Controller Part 1. General Information

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GENERAL INFORMATION

PART 1. GENERAL INFORMATION

A. HOW IT OPERATES

When the room thermostat calls for heat, the Munchkin control board will start the circulator and start to monitor the return temperature of the system before the heater will begin to heat the water. Once the controller has sensed a drop in the return water temperature below the temperature set point minus the differential set point, the heater will start to heat the water. This eliminates the Munchkin starting every time the thermostat calls for heat. This feature keeps the system from short cycling.

Once the system has sensed the temperature difference, the Munchkin will activate the blower motor for 5 seconds to pre-purge the system before starting the Munchkin. The Munchkin controller will now start to modulate the pre-mix burner based on analyzing the return temperature, supply water temperature and the set point temperature. By compiling this information, the controller utilizes an algorithm to fully adjust the firing rate while maintaining the desired output temperature. The pre-mix burner fan has a direct drive current low-voltage motor with a pulse relay counting. This system allows precise control over the fan speed and combustion air volumes. Coupled with the Honeywell gas valve and the Venturi system which are set to provide a one-to-one ratio of precisely measured volumes of fuel to air, an accurate and instant burner output is achieved. This keeps the Munchkin running at the highest efficiency.

When the thermostat is satisfied, the Munchkin will then go through a 4 second post-purge cycle before shutting off. Every Munchkin heater is equipped with a display which will read the outlet temperature of the heater and then will illuminate a green light showing flame on. If a problem occurs, the front indicator light will turn red and the display will read a fault code; see Part 7, Section B/C.

B. MUNCHKIN RATINGS AND DIMENSIONS

PERFORMANCE RATINGS

Model

Input Modulation

DOE Heating

AFUE

Shipping Weight

*IBR

T50M

18,000 to 50,000

16,000 to 46,000

92%

58 lbs.

40,000

T80M

19,000 to 80,000

17,000 to 74,000

92%

58 lbs.

64,000

80M

27,000 to 80,000

25,000 to 74,000

92%

75 lbs.

64,000

140M

46,000 to 140,000

43,000 to 129,000

92%

101 lbs.

112,000

199M

66,000 to 199,000

61,000 to 183,000

92%

111 lbs.

159,000

*Net water

CONNECTION SIZES

 

Supply/Return

 

 

Model

Connection

Gas Connection Size

Vent Dia.

T50M

1 1/4" NPT

3/4"

2"

T80M

1 1/4" NPT

3/4"

2"

80M

1 1/4" NPT

3/4"

3"

140M

1 1/4" NPT

3/4"

3"

199M

1 1/4" NPT

3/4"

3"

4

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Contents Munchkin High Efficiency Heater With the 925 ControllerUsing this Manual Special Attention BoxesTable of Contents Part 1. General Information Munchkin Ratings and DimensionsHOW IT Operates Recommended Service Clearances Dimensions 80M 140M/199M PRE-INSTALLATION Requirement GeneralPressure Relief Valve Part 2. ElectricalElectrical Connection Electrical Connection Wiring Directly to Central Heating Circulator Part 3. GAS Connection GAS ConnectionGAS Piping GAS TableDungs GAS Valve Part 4. Venting Approved Venting MaterialsVenting the Munchkin Direct vent terminal clearance Minimum clearance, C Longer Vent Runs Vented ApplianceHeater Removal from a Common Vent System Condensate RemovalDiagrams for Sidewall Venting Venting Diagrams for Vertical Venting Part 5. Piping Hydronic Piping with Circulators or Zone ValvesCirculator Sizing Munchkin T50M Munchkin T80M/80M Munchkin 140M Munchkin 199MFill and Purge Heating System Piping Symbol Legend Piping IllustrationsOFF Zone valves Piping Zone valves Make-up water Piping Space heating zone circuit Zone Circulators Make-up water PB1 PB2 PB1 PB2 Sequence of Operation Part 6. START-UP ProceduresItems to be Checked Before Lighting the Munchkin Lighting Instructions Operating InstructionsAdjusting the Temperature on the Munchkin Display Status MenuTest Mode To Turn OFF GAS to AppliancePart 7. Troubleshooting Munchkin Error Code925 Control Board Error Codes Resistance Tables Part 8. Maintenance Maintenance ProceduresCondensate Cleaning Instructions Before Each Heating SeasonMaintenance Control Wiring Layout Munchkin ControllerMaintenance Maintenance Page Page Munchkin R1

MUNCHKIN HIGH EFFICIENCY HEATER with the "925" Controller specifications

The Munchkin High Efficiency Heater, equipped with the advanced "925" Controller, represents a significant advancement in heating technology for both residential and commercial applications. Known for its reliability and exceptional performance, this heater is designed to provide efficient heating while minimizing energy costs and environmental impact.

The Munchkin High Efficiency Heater operates on a condensing technology that extracts heat from exhaust gases. This process allows for higher efficiency rates, often exceeding 95%. By recovering heat that would otherwise be lost, the heater maximizes energy utilization, making it an eco-friendly choice for homeowners and businesses alike.

One of the standout features of the Munchkin 925 Controller is its user-friendly interface, which allows for effortless operation and monitoring of the heating system. The controller comes with advanced diagnostic capabilities that provide real-time feedback on system performance. Users can easily adjust settings, program schedules, and monitor energy consumption, ensuring optimal comfort and efficiency.

Furthermore, the Munchkin High Efficiency Heater is equipped with a variety of features that enhance its performance and user experience. The unit is designed with a durable heat exchanger made from stainless steel, which not only improves heat transfer but also ensures longevity and resistance to corrosion.

The heater operates quietly, making it suitable for installation in residential settings, including bedrooms and living spaces. Additionally, its compact design allows for flexible installation options, even in constrained spaces. The Munchkin unit is also compatible with multiple venting options, providing further versatility in installation configuration.

Safety features are a priority in the design of the Munchkin Heater. It includes built-in freeze protection, ensuring that the system operates effectively even in low temperatures. The unit also has an array of safety sensors that monitor for conditions such as flue blockage and overheating, triggering automatic shut-off mechanisms to prevent potential hazards.

In conclusion, the Munchkin High Efficiency Heater with the "925" Controller is a cutting-edge solution for efficient heating. With its superior performance, advanced controller system, durable construction, and comprehensive safety features, it remains a top choice for those looking to improve their heating efficiency while reducing energy consumption. Whether it's for residential or commercial use, the Munchkin heater promises reliability and comfort in any environment.
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