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www.desatech.com

119344-01B

3

sPeCIFICATIoNs

WMN20A, GWN20TA

•  Btu (Variable): 10,000/20,000 Btu/Hr
•  Type Gas: Natural Only
•  Ignition: Piezo
•  Pressure Regulator Setting: 3" W.C.
•  Inlet Gas Pressure (in. of water):
  Maximum - 10.5", Minimum - 4"

GWN30TA

•  Btu (Variable): 15,000/30,000 Btu/Hr
•  Type Gas: Natural Only
•  Ignition: Piezo
•  Pressure Regulator Setting: 3" W.C.
•  Inlet Gas Pressure (in. of water):
  Maximum - 10.5", Minimum - 4"

WMP20A, GWP20TA

•  Btu (Variable): 10,000/20,000 Btu/Hr
•  Type Gas: Propane/LP Only
•  Ignition: Piezo
•  Pressure Regulator Setting: 8" W.C.
•  Inlet Gas Pressure (in. of water):
  Maximum - 14", Minimum - 11"

GWP30TA

•  Btu (Variable): 15,000/30,000 Btu/Hr
•  Type Gas: Propane/LP Only
•  Ignition: Piezo
•  Pressure Regulator Setting: 8" W.C.
•  Inlet Gas Pressure (in. of water):
  Maximum - 14", Minimum - 11"

seRVICe HINTs

When Gas Pressure Is Too Low

•  pilot will not stay lit
•  burner will have delayed ignition
•  heater will not produce specified heat
•  propane/LP gas supply may be low
You may feel your gas pressure is too low. If 
so, contact your local natural or propane/LP 
gas supplier.

RePlACeMeNT PARTs

Note:

  Use  only  original  replacement  parts. 

This will protect your warranty coverage for 
parts replaced under warranty.

PARTS UNDER WARRANTY

Contact authorized dealers of this product. If 
they can’t supply original replacement part(s), 
call DESA Heating Products’ Technical Ser

-

vice Department at 1-866-672-6040.
When calling DESA Heating Products, have 

ready

•  your name
•  your address
•  model and serial numbers of your heater
•  how heater was malfunctioning
•  type  of  gas  used  (propane/LP  or  natural 

gas)

•  purchase date
Usually, we will ask you to return the part to 
the factory.

PARTS NOT UNDER WARRANTY

Contact authorized dealers of this product. If 
they can’t supply original replacement part(s), 
either contact your nearest 

Parts Central

 (see 

page 27) or call DESA Heating Products at 1-
866-672-6040 for referral information.
When calling DESA Heating Products, have 

ready

•  model number of your heater
•  the replacement part number

TeCHNICAl seRVICe

You may have further questions about instal

-

lation,  operation  or  troubleshooting.  If  so, 
contact  DESA  Heating  Products’  Technical 
Service  Department  at  1-866-672-6040. 
When  calling  please  have  your  model  and 
serial numbers of your heater ready.
You can also visit DESA Heating Products’ tech

-

nical service web site at 

www.desatech.com

.

seRVICe PUBlICATIoNs

You can purchase a service manual from the 
address listed on the back page of this manual. 
Send a check for $5.00 payable to DESA Heat

-

ing Products.

Summary of Contents for WMN20A

Page 1: ...her flammable vapors and liquids in the vicinity of this or any other appliance WHAT TO DO IF YOU SMELL GAS Do not try to light any appliance Do not touch any electrical switch do not use any phone in...

Page 2: ...er or birth defects or other reproductive harm IMPORTANT Read this owner s manualcarefullyandcompletely before trying to assemble operate or service this heater Improper use of this heater can cause s...

Page 3: ...th other gases 2 Do not place propane LP supply tank s inside any structure Locate propane LP supply tank s outdoors 3 This heater shall not be installed in a bedroom or bathroom 4 If you smell gas sh...

Page 4: ...f the unit Vent free gas products are prohibited for bedroom and bathroom installation in the Commonwealth of Massachusetts Unpacking 1 Remove heater from carton 2 Remove all protective packaging appl...

Page 5: ...The air that leaks around doors and windows may provide enough fresh air for combustion and ventilation However in buildings of un usually tight construction you must provide additional fresh air Unus...

Page 6: ...ppliances Direct vent draws combustion air from the outdoors and vents to the outdoors Example Gas water heater _ ____________ Btu Hr Vent free heater _ ___________ Btu Hr Total _ ___________ Btu Hr 4...

Page 7: ...lheatingsystem youmay run system s circulating blower whileusingheater Thiswillhelp circulatetheheatthroughoutthe house In the event of a power outage you can use this heater as your primary heat sour...

Page 8: ...affic areas in windy or drafty areas Figure 4 Mounting Clearances As Viewed From Front of Heater INSTALLATION Continued CAUTION This heater cre ates warm air currents These currents move heat to wall...

Page 9: ...of front panel forward then out 3 Remove any remaining packaging ma terials Methods For Attaching Mounting Bracket To Wall Only use last hole on each end of mounting bracket to attach bracket to wall...

Page 10: ...cm 5 6 cm 18 3 4 47 6 cm Min 18 3 4 47 6 cm Min Figure 10 Popping Open Anchor Wings For Thin Walls Mounting Bracket attached to wall Horizontal Slots Attaching To Wall Anchor Method For attaching moun...

Page 11: ...lace front panel at this time Replace front panel after making gas connections and checking for leaks see pages 12 through 14 INSTALLATION Continued Mounting heater to floor With optional floor kit Mo...

Page 12: ...ure 14 External Regulator With Vent Pointing Down External Regulator Propane LP Supply Tank Vent Pointing Down CAUTION Use only new black iron or steel pipe Inter nally tinned copper tubing may be use...

Page 13: ...ernal regula tor has been installed between propane LP supply and heater See guidelines under Connect ing to Gas Supply page 12 Pressure Testing Gas Supply Piping System Test Pressures In Excess Of 1...

Page 14: ...tank valve 3 Make sure control knob of heater is in the OFF position 4 Check all joints from equipment shutoff valve to thermostat gas valve see Figure 17 or 18 Apply a noncorrosive leak de tection f...

Page 15: ...losion may result causing property damage per sonal injury or loss of life A This appliance has a pilot which must be lighted by hand When lighting the pi lot follow these instructions exactly B BEFOR...

Page 16: ...temperatures etc Frequent use of your heater will let you determine your own comfort levels MANUAL LIGHTING PROCEDURE 1 Remove front panel see Figure 7 page 9 2 Follow steps 1 through 7 under Lighting...

Page 17: ...eck pilot flame pattern and burner flame pattern often PILOT FLAME PATTERN Figure 22 shows a correct pilot flame pattern Figure 23 shows an incorrect pilot flame pat tern The incorrect pilot flame is...

Page 18: ...ommend that you keep the burner tube and pilot assembly clean and free of dust and dirt To clean these parts we recommend using compressed air no greater than 30 PSI Your local computer store hardware...

Page 19: ...position 4 Air in gas lines when in stalled 5 Depleted gas supply pro pane LP gas only 6 ODS pilot is clogged 7 Gas regulator setting is not correct OBSERVED PROBLEM Whenignitorbuttonispressed there...

Page 20: ...ane LP gas company 1 Contact local natural or propane LP gas company 2 Clean burner see Cleaning and Maintenance page 18 or replace burner orifice 1 Clean burner see Cleaning and Maintenance page 18 o...

Page 21: ...s from furniture polish wax carpet cleaners etc may turn into white powder residue 1 Metal expanding while heat ing or contracting while cooling REMEDY 1 Check burner for dirt and debris If found clea...

Page 22: ...partially clogged 1 Gas leak See Warning statement above 2 Control valve defective 1 Foreign matter between control valve and burner 2 Gas leak See Warning statement above 1 Not enough combustion vent...

Page 23: ...ced under warranty Parts Under Warranty Contact authorized dealers of this product If they can t supply original replacement part s call DESA Heating Products Technical Ser vice Department at 1 866 67...

Page 24: ...119344 01B 24 4 20 4 17 18 19 2 3 5 6 8 16 9 10 11 12 13 14 18 Manual Control Models Only Thermostat Models Only 19 7 1 21 22 15 9 Illustrated Parts Breakdown Models WMN20A WMP20A GWN20TA GWP20TA GWN...

Page 25: ...bly 1 107894 15 Deflector Assembly 1 9 098271 09 Ignitor Cable 1 10 098249 01 Nut 2 11 110803 01 ODS Pilot Assembly 1 110803 02 ODS Pilot Assembly 1 12 103446 02 Burner 1 103447 06 Burner 1 13 099387...

Page 26: ...GA5010 For all models Equipment shutoff valve with 1 8 NPT tap FAN KITS PP100 For all models Provides better heat distri bution Makes heater more efficient Com plete installation and operating instru...

Page 27: ...1 0505 1 800 446 1446 www nbmc com Parts Centrals These Parts Centrals are privately owned businesses They have agreed to support our customer s needs by providing original replacement parts and acces...

Page 28: ...Heating Products who will provide original factory replacement parts Failure to use original factory replacement parts voids this warranty The heater MUST be installed by a qualified installer in acc...

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