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119344-01B

7

Figure 3 - Ventilation Air from Outdoors

vENTILATION AIR

Ventilation Air From Inside Building

This fresh air would come from an adjoining 
unconfined  space.  When  ventilating  to  an 
adjoining unconfined space, you must provide 
two permanent openings: one within 12" of the 
ceiling and one within 12" of the floor on the 
wall connecting the two spaces (see options 
1 and 2, Figure 2). You can also remove door 
into adjoining room (see option 3, Figure 2). 
Follow  the 

National  Fuel  Gas  Code, ANSI 

Z223.1/NFPA  54,  Section  5.3, Air  for  Com-
bustion  and  Ventilation

  for  required  size  of 

ventilation grills or ducts.

Figure 2 - Ventilation Air from Inside 

Building

Or  

Remove  

Door into  

Adjoining  

Room,  

Option 3 

Ventilation Grills  

Into Adjoining Room, 

Option 2 

12" 

12" 

Ventilation

Grills into

Adjoining

Room, 

Option 1

Outlet

Air

Ventilated

Attic 

Outlet

Air

Inlet

Air

Inlet Air

Ventilated 

Crawl Space

To 

Crawl

Space

To Attic

AIR FoR CoMBUsTIoN 

ANd VeNTIlATIoN

Continued

INsTAllATIoN

NOTICE: This heater is intended 

for  use  as  supplemental  heat. 

Use this heater along with your 

primary heating system. Do not 

install  this  heater  as  your  pri

-

mary heat source. If you have a 

central heating system, you may 

run system’s circulating blower 

while using heater. This will help 

circulate the heat throughout the 

house. In the event of a power 

outage, you can use this heater 

as your primary heat source.

 WARNING: A qualified ser

-

vice person must install heater. 

Follow all local codes.

CHECK GAS TYPE

Use only the correct type of gas (natural or 
propane/LP).  If  your  gas  supply  is  not  the 
correct  gas  type,  do  not  install  heater.  Call 
dealer  where  you  bought  heater  for  proper 
type heater.

This  appliance  is  only  for  use 

with the type of gas indicated on 

the rating plate. This appliance 

is  not  convertible  for  use  with 

other gases.

  WARNING:  This  appliance 

is equipped for natural or pro

-

pane/LP  gas.  Field  conversion 

is not permitted.

ventilation Air From Outdoors

Provide  extra  fresh  air  by  using  ventilation 
grills or ducts. You must provide two perma

-

nent openings: one within 12" of the ceiling 
and one within 12" of the floor. Connect these 
items directly to the outdoors or spaces open 
to the outdoors. These spaces include attics 
and crawl spaces. Follow the 

National Fuel 

Gas  Code, ANSI  Z223.1/NFPA  54,  Section 
5.3, Air  for  Combustion  and  Ventilation 

for 

required size of ventilation grills or ducts.

IMPORTANT:

  Do  not  provide  openings  for 

inlet or outlet air into attic if attic has a thermo

-

stat-controlled power vent. Heated air entering 
the attic will activate the power vent.

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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