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14

MAINTENANCE INSTRUCTIONS

As with all fuel burning appliances, it is important to conduct periodic maintenance functions that will allow for continued

safe, efficient operation of the unit. We suggest that before every heating season, or at least once a year, conduct

the following minimum service functions.

STEP 1:

 The gas supply should be turned OFF at the shutoff valve in the supply line leading to the appliance or at the

gas source. The gas to the unit should then be disconnected so the unit can be removed from the wall.

STEP 2:

 Remove the front cover by removing the control knob and the two(2) screws on the top of the front. Then slide

the front upwards.

STEP 3:

 Carefully examine the interior of the vent pipe. If you notice any blockages or obstruction that was not part of

the unit when it was installed. Clean the pipes and prepare them for reattachment to the unit.

The vent system should be inspected periodically, or at least once a year and cleaned if necessary. If removal of the

venting is required, follow the instructions in the “Ventilation Installation” section of this manual for reassembly.

STEP 4: 

Look inside the openings of the rear of the unit and check for foreign materials. Remove any objects which 

may block or obstruct the free flow of combustion and ventilation air.

STEP 5:

 Visually check the pilot and the main burner for signs of excessive dirt or debris through the heat exchanger

front glass. If you find any of these, follow the directions below to reach the components to clean, otherwise continue

to the next step.

To Remove Pilot:

 Find the pilot. Loosen the head of thermocouple, disconnect the pilot gas supply line, (only on the 

side of the pilot, not on the valve side). Remove the two (2) M4 screws that hold the pilot in place. Clean with a vacuum 

cleaner or use a can of compressed air.

To Remove Burner: 

Loosen the gas line from the burner (on the right side of the unit). On the left side of the unit,

unscrew the nut that holds the burner in place. Then remove the burner. Clean with a vacuum cleaner or use a can of

compressed air. 

Note: You can remove the main burner-pilot assembly if you don’t unscrew the M4 screws that hold the pilot to the burner.

Before reinstalling the assembly, check the ceramic fiber sealing gasket. If it is damaged or worn, replace with a new 

gasket available from your dealer.

STEP 6: 

Reassemble the unit back to its original state and mount the unit to the wall. Properly reassemble and reseal

the vent-air intake system.

STEP 7:

 Reconnect the gas supply and check for leaks using a soapy water solution that you apply to all gas connections.

Bubbles on any of the joints indicate a leak is present and must be repaired. Turn off the gas when making such repairs. 

Check to make sure that the piezo ignitor still lights the pilot.

STEP 8:

 While the main burner is ON, Check the flames to verify that they are burning a clean blue color. 

(See Fig. 5, 6 & 7 on next page).

Note: After maintenance, the first few minutes of the heater operation will probably have some yellowish flying traces in

the flame due to the burning of particles left behind during the cleaning operation.

** Liquid Propane will have some evidence of yellow tips on the flame.

Any safety screen or guard removed for servicing an appliance must be replaced prior to operating the appliance.

Before completing your periodic maintenance check, ensure the heater area is kept clean 

and free from combustible materials, gasoline and other flammable vapors and liquids. 

Also,check to see that the flow of combustion and ventilation air around the vent cap on the

outside of the structure is not obstructed.

Summary of Contents for MDV12N

Page 1: ...other gases WARNING If the information in these instructions are not followed exactly a fire or explosion may result causing property damage personal injury loss of life INSTALLER Leave this manual wi...

Page 2: ...ly durable products for your maximum comfort and satisfaction Install and use the heater with care The installation must conform with local codes or in the absence of local codes use the latest editio...

Page 3: ...t and hot air outlet 12 Do not spill water over the heater as it may cause corrosion 13 Allow heater to thoroughly cool before servicing 14 Input ratings are shown in BTU per hour and are rated for el...

Page 4: ...MDV8 2 cm 25 32 in MDV12 20 3 cm 1 3 16 in 61 cm 24 in 15 cm 6 in Clearances to combustible surfaces Rear MDV8 2 cm 25 32 in MDV12 20 3cm 1 3 16 in Sides 15 cm 6 in Above 61 cm 24 in From floor 18 cm...

Page 5: ...ible wall in both indoor and outdoor Floor level Fold here 5 The following diagrams serve as a reference for the installation of your heater with the ventilation provided with the unit The template th...

Page 6: ...s inlet 3 8 NPT 380 mm 15 230 mm 9 1 16 190mm 7 1 2 40mm 1 9 16 112mm 4 7 16 180mm 7 1 8 115m m 4 1 2 25mm 1 390mm 15 3 8 575mm 22 5 8 92mm 3 5 8 92mm 3 5 8 92mm 3 5 8 92mm 3 5 8 490mm 19 5 16 215mm 8...

Page 7: ...inlet 3 8 NPT 660 mm 26 270 mm 10 5 8 300mm 11 13 16 110mm 4 5 16 390mm 15 3 8 40mm 1 9 16 112mm 4 7 16 180mm 7 1 8 160m m 4 1 2 25mm 1 390mm 15 3 8 118mm 4 5 8 118mm 4 5 8 118mm 4 5 8 118mm 4 5 8 490...

Page 8: ...unting plates with screws provided MDV12 MDV20 heaters only Assemble the wall thimble 4 Prepare the rear spacers with mounting screws The wall s thickness cannot be less than 4 1 2 11 5 cm nor can it...

Page 9: ...g 4 IMPORTANT The appliance s vent cap should be at least 24 in 61 cm from any outside adjacent or intersecting wall IMPORTANT The appliance s venting system should be inspected at least once a year a...

Page 10: ...Gas connection Mounting Details Gas valve 18 cm 7 41 cm 16 1 8 MDV20 24 cm 9 7 16 MDV12 21 cm 8 1 4 MDV8 20 cm 7 7 8 See mounting details Putty 11 cm 4 5 16 Thimble only for models MDV12 MDV20 Drywall...

Page 11: ...appliance 10 000 BTU hr 3kW and 100 000 BTU hr 30 kW 36 inches 91 cm for appliance 100 000 BTU hr 30 kW 6 feet 1 83 m 7 feet 2 13 m 12 inches 30 cm 12 inches 30 cm 6 inches 15 cm for appliance 10 000...

Page 12: ...reater diameter to allow full gas volume to heater Excessive pressure loss will occur if the pipe is too small A manual shutoff valve union and plugged 1 8 NPT pressure tapping point must be installed...

Page 13: ...o the next step Find the pilot by looking through the viewing window on the front of the unit Press the knob down lightly and turn counterclockwise to the t o l i P t o l i P Position Press down and h...

Page 14: ...ve the two 2 M4 screws that hold the pilot in place Clean with a vacuum cleaner or use a can of compressed air To Remove Burner Loosen the gas line from the burner on the right side of the unit On the...

Page 15: ...15 Fig 5 Fig 7 Fig 6 Correct Flame Pattern Correct Flame Pattern Incorrect Flame Pattern...

Page 16: ...16 PARTS LIST MDV8 NATURAL 118 PROPANE 85 P ITEM DESCRIPTION QTY...

Page 17: ...17 PARTS LIST MDV12 MDV12V View NATURAL 137 PROPANE 104 P DESCRIPTION ITEM QTY...

Page 18: ...NATURAL 178 PROPANE 131 P ITEM DESCRIPTION QTY PARTS LIST MDV20 MDV20V View 18...

Page 19: ...rranties except as set forth herein and any implied warranties of merchantability and fitness in duration to the period of coverage of this expressed written Limited Warranty Bismar will not be liable...

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