Enerco MHU 45, MHU 75 owner manual Adjustments

Page 11

ROBERTSHAW 2000DER GAS VALVE

GAS VALVE KNOB SHOWN

MANIFOLD

IN OFF POSITION

PRESSURE TAP

INLET PRESSURE TAP

MANIFOLD PRESSURE ADJUSTMENT

SCREW UNDER CAP

FIGURE 10

13.If appliance still will not operate, follow the instructions “TO TURN OFF GAS TO UNIT” and call your service technician or gas supplier.

TO TURN OFF GAS TO UNIT

1.Set thermostat to lowest level.

2.Turn off all electrical power to unit if service is to be performed.

3.Depress knob on gas valve; knob will snap to OFF.

HEATING SEQUENCE OF OPERATION

1.When the thermostat calls for heat, the combustion air blower starts immediately.

2.Combustion air pressure switch proves blower operation before allowing power to the ignition controller. This switch is factory set and no adjustment is necessary.

3.After prepurge of approximately 30 seconds, the spark ignition is energized and the solenoid valves open in the gas valve.

4.The spark then ignites the gas, the ignition sensor proves the flame and the combustion process continues.

5.In the event that the flame is not detected after the first 10- second trial for ignition, the controller will repeat steps 3 and 4 an additional two times before locking out the gas valve.

Ignition control will then automatically repeat steps 3, 4, and 5 after 60 minutes.

To interrupt the 60-minute lockout period, move thermostat from “Heat” to “OFF” then back to “HEAT.” Heating sequence then restarts at step 1.

6.The burners shall light without noticeable crossover delay. There shall be no flame lifting from the burner heads, flashback or burning within the burner. The flames shall be predominantly blue in color and shall be approximately centered in the tubes with no apparent impingement taking place.

7.The ignition control will energize the fan approximately 45 seconds after ignition is established.

8.After the thermostat demand is satisfied the gas valve is closed; 5 seconds after the demand is satisfied the combustion air blower is shut off.

9.The control center shall shut off the system fan approximately 150 seconds after the gas valve is denergized.

IGNITION CONTROL LED

The ignition control board contains a green LED which indicates the following:

 

TABLE 3

 

IGNITION CONTROL LED

LED

UNIT OPERATION

Slow Flash*

Normal Operation - No call for heat

Fast Flash

Normal Operation - Call for heat

 

Current signal at FLAME terminal 0.6 to 1.0 microamps

2 Flashes

System lockout - failed to detect or sustain flame

 

Current signal at FLAME terminal <0.6 microamps

3 Flashes

Pressure switch failed closed before CAB is energized

 

or failed open after CAB is energized

4 Flashes

High limit or rollout switch open

5 Flashes

Flame sensed and gas valve not energized

Steady Off

Loss of power

Steady On

Ignition control failure

*When thermostat is placed in continuous fan mode LED will slowly flash.

GAS CONVERSION KIT OPTIONAL

Can be purchased at any Enerco / Mr. Heater dealer or direct from the factory under the following numbers

45NG--

TO--

LP-----

60067

75NG--

TO--

LP-----

60069

45LP---

TO--

NG-----

60066

75LP---

TO--

NG-----

60071

ADJUSTMENTS

HIGH ALTITUDE

Units may be fired at full input up to 2000 ft. (610m) above sea level. Above 2000 ft. (610m), manifold pressure must be adjusted on some units. Adjust pressure regulator to pressure shown in table 4 for natural gas and table 5 for LP/propane gas.

GAS FLOW

To check for proper gas flow to the combustion chamber, determine the Btu input from the appliance rating plate. Divide this input rating by the Btu per cubic feet of available gas. Result is the required number of cubic feet per hour. Determine the flow of gas through the gas meter for two minutes and multiply by 30 to get the hourly flow of gas.

GAS PRESSURE

1.Check gas line pressure with unit firing at maximum rate. A

Enerco Compact Unit Heater

11

Operating Instructions and Owner’s Manual

Page 10 Page 12
Image 11
Page 10 Page 12
Contents MR. Heater General Hazard Warning ContentsSide View START-UP and Performance Check List MHU45/MHU75 and HSU45/HSU75 Unit DimensionsTOP View Back ViewRequirements CSA in Canada Garage InstallationsShipping Requirements CSA in the USAVenting Unit Heater InstallationInstall Unit Heater Combustion and Ventilation AIRVent Termination on Single Wall Vent Horizontal Venting GeneralCondensate Drain Through TEE Pipe and Drain Loop Horizontal Venting CommercialHorizontal Venting Residential Removal of Unit from Common Vent Venting Using a Masonry ChimneyHorizontal Venting Residential Installation GAS Supply to Unit Heater Line Voltage Field WiringElectrical Connections GAS Supply ConnectionUnit START-UP GAS ConnectionLeak Check Start UP and OperationAdjustments Service Wire Diagram Ladder DiagramParts List Enerco Compact Unit Heater Parts Ordering Information For Information Regarding ServiceLimited Warranty

MHU 45, MHU 75 specifications

Enerco is a renowned name in the heating industry, particularly famous for its innovative line of forced air propane heaters. The Enerco MHU 45 and MHU 75 models are among the top choices for both residential and commercial heating needs, showcasing a range of advanced features and technologies designed for efficient performance and user convenience.

The MHU 45 and MHU 75, as their names suggest, deliver heating outputs of 45,000 BTU and 75,000 BTU respectively, making them suitable for a variety of applications, from small workshops to larger industrial spaces. Both models are equipped with a powerful fan that ensures even heat distribution, rapidly warming up an area while maintaining energy efficiency.

One of the standout features of the MHU series is their lightweight and portable design, allowing users to easily move the heaters from one location to another. This is particularly beneficial in a work environment where heating needs may vary based on project demands. The integrated handle and rubber feet add to the convenience, ensuring stability during operation.

The MHU series also incorporates safety technologies that have been meticulously designed to protect both the unit and the user. Both models are equipped with a built-in safety shut-off valve that automatically turns the heater off in the event of a tip-over or overheating, providing peace of mind for users.

Efficiency is a key characteristic of the Enerco MHU heaters. They utilize propane fuel for combustion, which tends to burn cleaner than other fossil fuels. This not only contributes to a reduced environmental impact but also translates to savings on energy costs for users. The MHU 45 and MHU 75 feature adjustable heat settings, which allow for customized heating to match specific needs, further enhancing their efficiency.

In terms of runtime, the MHU series offers impressive performance. The fuel consumption is optimized to ensure users can rely on these heaters for extended periods without frequent refueling interruptions.

In summary, the Enerco MHU 45 and MHU 75 are powerful, portable, and efficient propane heaters designed to deliver excellent performance in a variety of settings. With their robust safety features, lightweight design, and ability to provide rapid heat distribution, they stand out as exceptional choices for those seeking reliable heating solutions. Whether for industrial, commercial, or residential use, these models underline Enerco's dedication to quality and innovation in heating technology.
Top Page Image Contents