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MORTEX

 

PRODUCTS

 

INC

 

501

 

TERMINAL

 

RD

 

FORT

 

WORTH,

 

TX

 

76106

 

Page

 

10

 

1.

 

Cut a rectangular opening in the plenum base. A sheet metal 
plate can be made that completely covers the opening in the 
base. 

2.

 

The plate must be secured with screws and sealed to prevent 
leaks. 

3.

 

The coil cabinet doors can be removed to inspect the heat 
exchanger on most Manufactured (Mobile) Home Downflow 
Appliances. 

 

Closet Installation 

This furnace is approved for use in an alcove with both the heating 
only (without an air conditioning coil) and the A/C ready models. A 
minimum of 6” front clearance to a face wall or partition is needed 
for service access and return air clearances. 

Air filter Size – All Models take two (2) - 16” x 20” x 1”. 

 

Prior to installing the furnace make sure the holes are cut into the 
floor for the refrigerant tubing, the electrical wiring is in place, the 
thermostat wiring and the condenser control wiring is in place. 
Follow the sixteen steps above for installing the furnace. 

 

FILTERS 

Alcove Installations 

All applications require the use of an internal filter. All filters 
mounting provisions are factory supplied as part of the louvered 
return grille door. 

 

Closet Installations 

All furnaces are shipped with air filters located in the return air 
louvered door. It is permissible to remove the filters from the return 
air louvered door and use a return filter grille that has been installed 
into the wall above the furnace and has a sufficient size so it does 
not restrict the return airflow. The recommended filter sizes for the 
return air filter grille are shown below for throwaway filters that are 
rated for a velocity of 300 feet/minute (91.44 m/minute): 
1,200 CFM requires a 20 inch x 30 inch filter size. 
1,600 CFM requires a 20 inch x 40 inch filter size. 
1,800 CFM requires a 25 inch x 30 inch filter size. 
2,000 CFM requires a 25 inch x 40 inch filter size. 

 

The recommended filter sizes for the return air filter grille are 
shown below for pleated air filters that are rated for a velocity of 
500 feet/minute (152.4 m/minute): 
1,200 CFM requires a 20 inch x 20 inch filter size. 
1,600 CFM requires a 20 inch x 25 inch filter size. 
1,800 CFM requires a 20 inch x 30 inch filter size. 
2,000 CFM requires a 16 inch x 40 inch filter size. 

 

IMPORTANT:

 Throw away air filters with a rated velocity of 300 

feet per minute (91.44 m/minute) cannot be used on the furnace 
return air louvered door because the air velocity is too high and will 
destroy the filter. The filter velocity with this furnace is 400 feet per 
minute (121.92 m/ minute). Do not use a filter that is rated for less 
than 400 ft/min (121.92 m/minute). 
Never use a filter deeper that 1 inch (2.54 cm) or a filter that has a 
large pressure drop. This pressure drop will cause the appliance 
airflow to be reduced causing the appliance temperature rise to 
increase causing reduced efficiency and higher heat exchanger 
temperatures. If the appliance does not operate within the specified 
rise range on the name plate or the limit is cycling, then you must 
change the air filter to a bigger size or reduce the thickness in order 
to reduce the pressure drop across the air filter. 

 

DOWNFLOW COOLING COIL CABINET

 

The cooling coil cabinet is supplied with the A/C Ready models. 
The cabinet is 25.5 inches (64.77 cm) tall. The base of the cooling 
coil cabinet can be mounted directly to the duct connector and 
attached with screws. Make sure all of the openings in the furnace 
base matchup with the openings in the duct connector, especially 
the supply air opening. You can remove the coil cabinet doors in 
order to confirm that all the holes in the base line up with the holes 
in the duct connector. A combustible floor base is not required 
when using a cooling coil cabinet. 

Line up the duct openings and secure the coil cabinet to the 
floor before installing the cooling coil. 

 

OUTDOOR AIR ACCESSORY

 

A replacement furnace may have a blend air accessory that supplies 
fresh air from outside through a 4 inch (10.16 cm) pipe that attaches 
to the top cover of the appliance. There is a knockout and four 
screw holes are located in the top cover of the appliance for the 
attachment of a blend air damper or tube assembly. Refer to Figure 
10 for knockout and screw hole locations. 

 

 

Figure 9: Outdoor Fresh Air Intake Knockout 

 

SECTION IV: GAS SUPPLY AND VALVE 
CONNECTIONS 

 

 

 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

All field installed gas piping must be pressure tested for 
leaks prior to operation of the appliance. Never test for gas 
leaks with an open flame. Use a commercially available 
soap solution made specifically for detection of leaks. Be 
sure to check all connections. 
Failure to properly check all connections for leaks or failure 
to check any connections for leaks may result in a fire or 
explosion causing property damage, personal injury or loss 
of life. 

Summary of Contents for G18D SERIES

Page 1: ...30 Reading the Inlet Supply Gas Pressure INP 29 14 Separate T stat furnace Cooling Unit Trans W D 17 31 Reading the Outlet Manifold Gas Pressure 29 15 Same T stat Separate Furnace Cooling Unit Trans W...

Page 2: ...enting system Verify the furnace is operating according to the manufacturer s instructions 11 When installed in a Manufactured Mobile Home The combustion air shall not be supplied from occupied spaces...

Page 3: ...he voltage exceeds 132 VAC This furnace must be installed so the components are protected from water Installing and servicing heating equipment can be hazardous due to the electrical and gas fired com...

Page 4: ...btain the model and serial numbers so the correct parts can be ordered The furnace supply air blower is designed for correct performance with this furnace Do not attempt alter or use a different type...

Page 5: ...rom gas supply line should be performed as described in ANSI Z223 1 latest edition National Fuel Gas Code or in Canada in CAN CGA B149 1 or B149 2 codes 5 Do not attempt to reuse any mechanical or ele...

Page 6: ...OR ACCESS Ample clearances should be provided to permit easy access to the appliance The following minimum clearances are recommended 1 Twenty four 24 inches 61 cm between the front of the furnace and...

Page 7: ...hat the requirements of this subdivision cannot be met at the time of completion of the installation the owner shall have thirty 30 days to comply with the above 48 requirements provided that during t...

Page 8: ...mper is full heating or full cooling position Figure 2 Duct Connector Dimensions Floor Base Installation and Duct Connection Downflow combustible floor base is used for installations on combustible ma...

Page 9: ...g the furnace be sure you have enough clearance to install the furnace and clearance for the return air Refer to Table 1 CLEARANCES 2 Remove the top shipping cover and corner posts 3 Remove the upper...

Page 10: ...d velocity of 300 feet per minute 91 44 m minute cannot be used on the furnace return air louvered door because the air velocity is too high and will destroy the filter The filter velocity with this f...

Page 11: ...2 1 27 cm Table 4 allows for a 0 3 W C 0 075 kPa pressure drop in the ON OFF Pressure Convertable OUT P IN P VENT Manifold Pressure Tap Electrical Terminals Gas Supply Line Pressure Tap GAS FLOW Switc...

Page 12: ...natural gas orifice into the bag and hang it on the gas valve 11 Place the gas valve mounting bracket on the burner mounting plate and secure with the screws you removed in step 5 12 Reconnect the el...

Page 13: ...48 72AG 081 0 081 46 72AG 082 0 082 45 72AG 089 0 089 43 10 000 72AG 073 0 073 49 72AG 078 0 078 47 72AG 081 0 082 46 72AG 089 0 089 43 60 00 BTU FURNACE 70 00 BTU FURNACE 77 00 BTU FURNACE 90 00 BTU...

Page 14: ...ized Proper methods for field installing electrical wiring i Between the furnace and devices not attached to the furnace ii Between the separate devices that are field installed and located iii Exteri...

Page 15: ...Current 60 HZ 0 49 0 49 0 49 0 49 Total Unit Amps 2 54 2 54 2 54 2 54 Model G18D060CA3BA G18D070CA3BA G18D077CA3BA G18D090CA3BA Blower Motor HP 1 3 1 3 1 3 1 3 Blower Mortor SPD 5 5 5 5 Blower Motor...

Page 16: ...e routed through side of furnace and connect to the pig tail wires located above the control box The thermostat wires should also be no smaller than 22 gauges Refer to Table 9 for recommended wire gau...

Page 17: ...use located on the left side of the control board that protects the 24 VAC circuit Replace the fuse only with the equivalent 3 Amp Automotive type fuse Separate Heating and Cooling Thermostats If the...

Page 18: ...ypical Single Stage Heating Cooling Digital Thermostat with Two Stage Furnace Figure 19 Typical Two Stage Heating Cooling Digital Thermostat Connections Typical Heat Pump Heating Cooling Thermostat Wi...

Page 19: ...not less than 17 percent The combustion system is fan assisted This Category I direct vent furnace is designed for Manufactured Home and Modular Home applications It may be installed without modifica...

Page 20: ...rews or rivets Figure 20 Roof Jack Mounting Collars Top of Furnace VENTING INTO AN EXISTING ROOF JACK The furnace shall not be connected to another manufacturers factory built roof jack vent system If...

Page 21: ...per installation of the roof jack requires that openings in the roof and ceiling be on the same vertical center line as the furnace flue collar 2 Once the hole has been cut into the roof insert the ro...

Page 22: ...1000 BTU hr The calculation would be the 50 cubic ft per 1000 BTU hr by the 80 000 BTU Input of all appliances 50 x 80 4000 ft 7 Determine ratio of the available volume to the required volume 2400 ft...

Page 23: ...ply with local codes and requirements NOTE The Roof Jack venting system is considered a special venting system Important Consideration must be given for degradation of building materials by flue gases...

Page 24: ...window or door that may be opened 12 inches 30 cm for models 100 000 BTUH 30 kW 36 inches 91 cm for models 100 000 BTUH 30 kW 4 Feet 1 22 m C Clearance to permanently closed window 12 inches 30 cm 12...

Page 25: ...enting systems are permitted and must be installed in accordance with the National Fuel Gas Code ANSI Z223 1 NFPA 54 and or the CSA B149 1 Natural Gas and Propane Installation Codes local codes and th...

Page 26: ...T C ADJUSTIBLE HEIGHT 90 RJF1729 AL 17 29 FLAT 73 85 94 5 106 5 90 RJF2551 AL 25 51 FLAT 81 107 102 5 128 5 90 RJS1729 AL 17 29 3 12 73 85 94 5 106 5 90 RJS2551 AL 25 51 3 12 81 107 102 5 128 5 90 RJS...

Page 27: ...liance connected to the venting system being placed into operation while all other appliances connected to the venting system are not in operation 1 Seal any unused openings in the venting system 2 In...

Page 28: ...for a CU FT Gas Meter The formula for the input calculation of the appliance if you re heating value is in Mj m you using a cubic meter gas meter Example calculating the input for an appliance operati...

Page 29: ...the gas valve Follow the procedure to shut off the furnace located in the Users Information Manual 5 Turn the switch on the gas valve to the OFF position 6 Turn off the gas supply at the ball valve o...

Page 30: ...als HEAT 120 VAC Blower speed tap connection for heating speed COOL 120 VAC Blower speed tap connection for cooling speed XFMR 120 VAC connection to the transformer L1 120 VAC incoming power supply to...

Page 31: ...try If flame is not established on the first trial for ignition period the gas valve is de energized and the inducer remains energized for an inter purge period of 25 seconds The ignitor is then re e...

Page 32: ...ndoor blower motor on heat speed the other outputs will be kept off and the control will display a LED fault code of 5 When flame is no longer sensed the induced draft motor will run through post purg...

Page 33: ...t be per the following A National Electrical Code NEC and or B Canadian Electrical Code CEC and or C State County Local Regional or City Codes 2 If any origional Factory wire must be replaced then rep...

Page 34: ...ys are integrated into the control board Notes 1 All field wiring must be per the following A National Electrical Code NEC and or B Canadian Electrical Code CEC and or C State County Local Regional or...

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