Instruction/ maintenance manual of the product WMP20A Desa
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MODELS GWN20T A, GWP20T A, GWN30T A, GWP30T A, WMN20A, WMP20A UNVENTED (VENT -FREE) BL UE FLAME GAS HEA TER SAFETY INFORMA TION AND INST ALLA TION MANU AL For more information, visit www .
www .desatech.com 1 19344-01B 2 SAFETY INFORMA TION W ARNIN G: Im prope r in - st al l a t i on , ad ju s t m e nt , al - te ra t i o n , se rv i c e or mai nt e - na nc e ca n ca us e in j u r y or pr op e r t y da m ag e. Re f e r to th is ma nu a l fo r co rr e c t in - st al l a t i on an d o p e r a ti on a l p r o ce du re s.
www .desatech.com 1 19344-01B 3 Natural and Propane/LP Gas: Natural and pro - pane/ LP gases are fuel gases. Fuel gases are odorless. An odor-making agent is added to fuel gases. The odor helps you detect a fuel gas leak. However , the odor added to fuel gas can fade.
www .desatech.com 1 19344-01B 4 12 . Operating heater above elevations of 4,500 feet could cause pilot outage. 13. To prevent performance problems, do not use propane/LP fuel tank of less than 100 lbs. capacity. 14. Provide adequate clearances around air openings.
www .desatech.com 1 19344-01B 5 AIR FOR COMB USTION AND VENTILA TION WARNING: This heater shall not be installed in a conned space or unusually tight con - struction unless provisions are pro vide d fo r ad equ ate com bus - tion and ventilation air.
www .desatech.com 1 19344-01B 6 AIR FOR COMB USTION AND VENTILA TION Continued DETERMINING FRESH-AIR FLOW FOR HEA TER LOCA TION Determining if Y ou Have a Conned or Unconned Space Use this work sheet to determine if you have a conned or unconned space.
www .desatech.com 1 19344-01B 7 Figure 3 - V entilation Air from Outdoors VENTILA TION AIR V entilation Air From Inside Building This fresh air would come from an adjoining unconned space.
www .desatech.com 1 19344-01B 8 INST ALLA TION ITEMS Before installing heater, make sure you have the items listed below . • for propane/LP gas, external regulator (supplied by installer) • piping.
www .desatech.com 1 19344-01B 9 INST ALLA TION Continued THERMOST A T SENSING BULB (Thermostat Models Only) The thermosta t sensing bulb has been placed below the heater . 1. Place clamp on thermostat sensing bulb as shown in Figure 5. Clamp is provided in hardware package.
www .desatech.com 1 19344-01B 10 INST ALLA TION Continued 30,000 Btu/Hr Models 20,000 Btu/Hr Models Figure 8 - Mounting Bracket Clearances Attaching Mounting Bracket T o W all Note: Wall anchors, mounting screws and spacers are in hardware package. The hard - ware package is provided with heater .
www .desatech.com 1 19344-01B 1 1 Figure 12 - Installing Bottom Mounting Screws Side View Front View W all Spacer Heater Installing Bottom Mounting Screws 1. Loca te two bottom mount ing holes. These holes are near bottom on back panel of heater (see Figure 12).
www .desatech.com 1 19344-01B 12 CONNECTING TO GAS SUPPL Y W ARNING: This appliance requires a 3/8" NPT (National Pipe Thread) inlet connection to the pressure regulator . W ARNING: A qualied ser - vic e pers on mus t conne ct h eat er to gas supply .
www .desatech.com 1 19344-01B 13 * A CSA design-certied equipment shutoff valve with 1/8" NPT tap is an acceptable al - ternative to test gauge connection. Purchase the optional CSA design-certied equipment shutoff valve from your dealer . See Acces- sories , page 26.
www .desatech.com 1 19344-01B 14 3. Check all joints from gas meter for natural gas (see Figure 17) or propane/LP supply tank for propane/LP gas, to equipment shutoff valve (see Figure 18). Apply a noncorrosive leak detection uid to all joints. Bubbles forming show a leak.
www .desatech.com 1 19344-01B 15 6. Th e r m os t a t M o d el s : Tur n co n t r o l k n o b counterclockwise to the PILOT position. Press in control knob for ve (5) seconds. Manual Models: Press in and turn control knob counterclockwise to the PI - LOT position.
www .desatech.com 1 19344-01B 16 OPERA TING HEA TER Continued THERMOST A T CONTROL OPERA TION The thermostatic control used on these models differs from standard thermostats. Standard thermostats simply turn on and off the burner . The therm ost at used on this heate r sens es the room temp erat ure .
www .desatech.com 1 19344-01B 17 BURNER FLAME P A TTERN W ARNING: If yellow tipping occurs, your heater could pro - duce increased levels of carbon monoxide. NOTICE: Do not mistake orange ames with yellow tipping. Dirt or other ne particles enter the heater and burn causing brief patches of orange ame.
www .desatech.com 1 19344-01B 18 CLEANING AND MAINTENANCE W ARNING: T urn off heater and let cool before cleaning. CAUTION: Y ou must keep control areas, burner and circu - lating air passageways of heater clean. Inspect the se areas of heater before each use.
www .desatech.com 1 19344-01B 19 TROUBLESHOO TING WAR NI NG : T ur n off and unp lu g he at er and le t co ol be fo re ser vi cing . Onl y a q ual i ed ser vi ce per so n s ho uld se rv ice an d rep ai r h eat er . CAUTION: Never use a wire, needle or similar object to clean ODS/pilot.
www .desatech.com 1 19344-01B 20 OBSERVED PROBLEM ODS/pilot lights but flame goes out when control knob is released Burner does not light after ODS/pilot is lit Delayed ignition of burner Burner backring during com - bustion REMEDY 1. Press in control knob fully 2.
www .desatech.com 1 19344-01B 21 TROUBLESHOO TING Continued OBSERVED PROBLEM Y ellow ame during burner combustion Slight smoke or odor during initial operation Heater produces a whistling noise whe.
www .desatech.com 1 19344-01B 22 W ARNING: If you smell gas • Shut off gas supply . • Do not try to light any appliance. • Do not touch any electrical switch; do not use any phone in your building. • Immediately call your gas supplier from a neighbor’s phone.
www .desatech.com 1 19344-01B 23 SPECIFICA TIONS WMN20A, GWN20T A • Btu (V ariable): 10,000/20,000 Btu/Hr • T ype Gas: Natural Only • Ignition: Piezo • Pressure Regulator Setting: 3" W .C. • Inlet Gas Pressure (in. of water): Maximum - 10.
www .desatech.com 1 19344-01B 24 4* 20 4** 17 18** 19** 2 3 5 6 8 16 9 10 1 1 12 13 14 18* *Manual Control Models Only **Thermostat Models Only 19* 7 1 21* 22* 15 9 ILL USTRA TED P ARTS BREAKDOWN MODE.
www .desatech.com 1 19344-01B 25 P ARTS LIST This list contains replaceable parts used in your heater . When ordering parts, follow the instructions listed under Replacement Parts on page 23 of this manual.
www .desatech.com 1 19344-01B 26 ACCESSORIES Pu rc ha se the se hea te r ac ce ss or ies fr om you r lo ca l de aler . If the y ca n no t su pply the se acc es - so ri e s , e ith er co nt a ct you r ne ar e st Parts Cent ral (see page 27) or call DESA Heating Products at 1-866-672-6040 for referral information.
www .desatech.com 1 19344-01B 27 T ool & Equipment Co. 5 Manila Ave Hamden, CT 06514-0322 1-800-397-7553 203-248-7553 Portable Heater Parts 342 N. County Rd. 400 East V alparaiso, IN 46383-9704 219-462-7441 1-888-619-7060 www .portableheaterparts.
Always specify model and serial numbers when communicating with the factory . We reserve the right to amend these specications at any time without notice. The only warranty applicable is our standard written warranty . We make no other warranty , expressed or implied.
An important point after buying a device Desa WMP20A (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Desa WMP20A yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Desa WMP20A - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Desa WMP20A you will learn all the available features of the product, as well as information on its operation. The information that you get Desa WMP20A will certainly help you make a decision on the purchase.
If you already are a holder of Desa WMP20A, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Desa WMP20A.
However, one of the most important roles played by the user manual is to help in solving problems with Desa WMP20A. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Desa WMP20A along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
