Desa RLP155AT User manual

35/40,000 BTU/HR HEATER
PROPANE CONSTRUCTION FORCED AIR HEATER
OWNER’S MANUAL
IMPORTANT: Read and understand this manual before
assembling, starting or servicing heater. Improper use
of heater can cause serious injury. Keep this manual for
future reference.
GENERAL HAZARD WARNING:
Failure to comply with the precautions and instructions
provided with this heater, can result in death, serious
bodily injury and property loss or damage from hazards
of fire, explosion, burn, asphyxiation, carbon monoxide
poisoning, and/or elctrical shock.
Only persons who can understand and follow the instruc-
tions should use or service this heater.
If you need assistance or heater information such as an in-
structions manual, labels, etc. contact the manufacturer.
Save this manual for future reference.
For more information, visit www.desatech.com
TABLE OF CONTENTS
Safety Information ............................................... 2
Unpacking ........................................................... 3
Product Identification ........................................... 3
Theory of Operation ............................................ 4
Propane Supply ................................................... 4
Installation ........................................................... 4
Ventilation ........................................................... 5
Operation ............................................................. 5
Storage ................................................................ 6
Maintenance ........................................................ 7
Service Procedures ............................................. 7
Specifications ..................................................... 9
Troubleshooting ................................................. 10
Accessories ........................................................11
Technical Services ..............................................11
Replacement Parts .............................................11
Illlustrated Parts Breakdown and Parts List ....... 12
Warranty and Repair Service ..............Back Cover

www.desatech.com 113855-01A
2
SAFETY INFORMATION
WARNING: This product
contains and/or generates
chemicals known to the State
of California to cause cancer or
birth defects, or other reproduc-
tive harm.
WARNING: Fire, burn, inha-
lation, and explosion hazard.
Keep solid combustibles, such
as building materials, paper or
cardboard, a safe distance away
from the heater as recommend-
ed by the instructions. Never
use the heater in spaces which
do or may contain volatile or
airborne combustibles, or prod-
ucts such as gasoline, solvents,
paint thinner, dust particles or
unknown chemicals.
WARNING: Not for home or
recreational vehicle use.
The heater is designed for use as a construction heater
in accordance with ANSI Z83.7•CGA2.14-2000.
Other standards govern the use of fuel gases and
heating products for specific uses. Your local author-
ity can advise you about these. The primary purpose
of construction heaters is to provide temporary
heating of buildings under construction, alteration
or repair. Properly used, the heater provides safe
economical heating. Products of combustion are
vented into the area being heated.
We cannot foresee every use which may be made
of our heaters. Check with your local fire safety
authority if you have questions about heater use.
Other standards govern the use of fuel gases and
heat producing products for specific uses. Your
local authorities can advise you about these.
Carbon Monoxide Poisoning: Some people are
more affected by carbon monoxide than others.
Early signs of carbon monoxide poisoning re-
semble the flu, with headaches, dizziness, and/or
nausea. If you have these signs, the heater may not
be working properly. Get fresh air at once! Check
for proper ventilation and have heater serviced.
Propane Gas: Propane gas is odorless. An odor-
making agent is added to propane gas. The odor
helps you detect a propane gas leak. However, the
odor added to propane gas can fade. Propane gas
may be present even though no odor exists.
Make certain you read and understand all warn-
ings. Keep this manual for reference. It is your
guide to safe and proper operation of this heater.
1. Install and use heater with care. Follow all
local ordinances and codes. In the absence
of local ordinances and codes, refer to the
Standard for Storage and Handling of Lique-
fied Petroleum Gas, ANSI/NFPA 58 and the
Propane Gas Installation Code, CAN/CGA
B149.2. This instructs on the safe storage and
handling of propane gases.
2. Use only the electrical voltage and frequency
specified on model plate. The electrical con-
nections and grounding of the heater shall fol-
low the National Electric Code, ANSI/NFPA
70 or the Canadian Electrical Code, Part 1.
3. Electrical grounding instructions — This
appliance is equipped with a three-prong
(grounding) plug for your protection against
shock hazard and should be plugged directly
into a properly grounded three-prong recep-
tacle or extension cord.
4. This product has been approved for use in the
Commonwealth of Massachusetts.
5. Use only a three-prong, grounded extension
cord.
6. Use only the hose and factory preset regulator
provided with the heater.
7. Use only propane gas set up for vapor with-
drawal.
8. Provide adequate ventilation. Before using
heater, provide at least a 1 1/2 square-foot
(1400 cm2) opening of fresh, outside air.
9. For indoor use only. Do not use heater
outdoors.
10. Do not use heater in occupied dwellings or in
living or sleeping quarters.
11. Do not use heater in basement or below ground
level. Propane gas is heavier than air. If a leak
occurs, propane gas will sink to the lowest
possible level.
12. Keep appliance area clear and free from com-
bustible materials, gasoline, paint thinner, and
other flammable vapors and liquids.
13. Do not use heater in areas with high dust
content. Dust is combustible.

www.desatech.com
113855-01A 3
SAFETY INFORMATION
Continued
Hot Air Outlet
(Front) Outer Shell
Motor
Power
Cord
Ignitor
Button
Automatic
Control Valve
Button
Hose/Regulator
Assembly
Handle
Figure 1 - 35,000 Btu/Hr Model Shown
14. Minimum heater clearances from combus-
tibles:
Outlet: 6 Ft. (1.83 m) Sides: 2 Ft. (0.61 m)
Top: 6 Ft. (1.83 m) Rear: 2 Ft. (0.61 m)
15. Keep heater at least six feet from propane
tank(s). Do not point heater at propane tank(s)
within 20 feet.
16. Keep propane tank(s) below 100° F (37.8° C).
17. Check heater for damage before each use. Do
not use a damaged heater.
18. Check hose before each use of heater. If highly
worn or cut, replace with hose specified by
manufacturer before using heater.
19. Locate heater on stable and level surface if
heater is hot or operating.
20. Not intended for use on finished floors.
21. Never block air inlet (rear) or air outlet (front)
of heater.
22. Keep heater away from strong drafts, water
spray, rain, or dripping water.
23. Do not leave heater unattended.
24. Keep children and animals away from
heater.
25. Never move, handle, or service a hot, operat-
ing, or plugged-in heater. Severe burns may
result. You must wait 15 minutes after turning
heater off.
26. To prevent injury, wear gloves when handling
heater.
27. Never attach duct work to front or rear of
heater.
28. Do not alter heater. Keep heater in its original
state.
29. Do not use heater if altered.
30. Turn off propane supply and unplug heater
when not in use.
31. Use only original replacement parts. This
heater must use design-specific parts. Do
not substitute or use generic parts. Improper
replacement parts could cause serious or fatal
injuries.
UNPACKING
1. Remove all packing items applied to heater for
shipment. Keep plastic cover caps (attached to
inlet connector and hose/regulator assembly)
for storage.
2. Remove all items from carton.
3. Check all items for shipping damage. If heater
is damaged, promptly inform dealer where you
bought heater.
PRODUCT
IDENTIFICATION

www.desatech.com 113855-01A
4
INSTALLATION
WARNING: Review and under-
stand the warnings in the Safety
Information section, page 2. They
are needed to safely operate this
heater. Follow all local codes
when using this heater.
WARNING: Test all gas piping
and connections for leaks after
installation or servicing. Never
use an open flame to check for
a leak. Apply a mixture of liquid
soap and water to all joints.
Bubbles forming show a leak.
Correct all leaks at once.
1. Provide propane supply system (see Propane
Supply).
2. Connect POL fitting on hose/regulator as-
sembly to propane tank(s). Turn POL fitting
counterclockwise into threads on tank. Tighten
firmly using wrench. IMPORTANT: Position
regulator so that hose leaving the regulator is
in a horizontal position (see Figure 3, page 5).
This places the regulator vent in the proper
position to protect it from the weather.
Figure 2 - Cross Section Operational View
Air For Combustion
Air For Heating
Clean Heated
Air Out (Front)
Fan Motor
Cool
Air In
(Back)
Combustion
Chamber
Hose/Regulator
Assembly
THEORY OF OPERATION
The Fuel System: The hose/regulator assembly
attaches to the propane gas supply. This provides
fuel to the heater.
The Air System: The motor turns the fan. The
fan pushes air into and around the combustion
chamber. This air is heated and provides a stream
of clean, hot air.
The Ignition System: The piezo ignitor lights
the burner.
The Automatic Control System: This system causes
the heater to shut down if the flame goes out.
PROPANE SUPPLY
Propane gas and propane tank(s) are to be fur-
nished by the user.
Use this heater only with a propane vapor
withdrawal supply system. See Chapter 5 of the
Standard for Storage and Handling of Liquefied
Petroleum Gas, ANSI/NFPA 58 and/or CAN/CGA
B149.2. Your local library or fire department will
have this booklet.
The amount of propane gas ready for use from
propane tanks varies. Two factors decide this
amount:
1. The amount of propane gas in tank(s)
2. The temperature of tank(s)
This heater is designed to operate with a minimum
20-pound (9 kg) propane tank. You may need two
or more tanks or one larger tank in colder weather.
It is recommended you use a 100-pound (45 kg)
tank for longer operation. See chart below. Less
gas is vaporized at lower temperatures. Your local
propane gas dealer will help you select the proper
supply system. The minimum surrounding air tem-
perature rating for each heater is -0°F (-18°C).
Average Temp °F (°C) No. Of Tanks
At Tank Location 100-pound (45 kg)
0°(-18°) to 40°(4°) 1
Below 0°(-18°) 2

www.desatech.com
113855-01A 5
VENTILATION
WARNING: Provide at least
a 1 1/2 square foot (1400 cm2)
opening of fresh, outside air
while running heater. If proper
fresh, outside air ventilation is
not provided, carbon monoxide
poisoning can occur. Provide
proper fresh, outside air ventila-
tion before running heater.
OPERATION
WARNING: Review and under-
stand the warnings in the Safety
Information section, page 2. They
are needed to safely operate this
heater. Follow all local codes
when using this heater.
TO START HEATER
1. Follow all installation, ventilation, and safety
information.
2. Locate heater on stable and level surface.
Make sure strong drafts do not blow into front
or rear of heater.
3. Plug power cord of heater into a three-prong,
grounded extension cord. Extension cord must
be at least six feet long. Extension cord must
be UL listed.
Extension Cord Wire Size Requirements
• Up to 50 ft (15.24 m) long, use 18 AWG rated
cord.
• 51 to 100 ft (15.54 to 30.48 m) long,
use 16 AWG rated cord.
• 101 to 200 ft (30.78 to 60.96 m) long,
use 14 AWG rated cord.
4. Plug extension cord into a 120 volt/60 hertz,
3-hole, grounded outlet. Motor will start. Fan
will turn, forcing air out front of heater.
5. Open propane supply valve on propane
tank(s) slowly. Note: If not opened slowly,
excess-flow check valve on propane tank will
stop gas flow. You may hear a click from the
excess-flow check valve closing. If this hap-
pens, reset the excess-flow check valve by
closing propane supply valve and open again
slowly.
3. Connect hose to valve inlet (see Figure 4).
Tighten firmly using a wrench.
IMPORTANT: Use extra hose or piping if
needed. Install extra hose or piping between
hose/regulator assembly and propane tank. You
must use the regulator supplied with heater.
4. Open propane supply valve on propane tank(s)
slowly. Note: If not opened slowly, excess-flow
check valve on propane tank will stop gas flow.
You may hear a click from the excess-flow
check valve closing. If this happens, reset the
excess-flow check valve by closing propane
supply valve and open again slowly.
5. Check all connections for leaks. Apply mix-
ture of liquid soap and water to gas joints.
Bubbles forming show a leak that must be
corrected.
6. Close propane supply valve.
Figure 4 - Hose and Inlet Connector
Figure 3 - Regulator Position
Propane
Tank
Propane
Supply
Valve
Regulator
Hose
POL
Fitting
Hose
Inlet Connector
INSTALLATION
Continued

www.desatech.com 113855-01A
6
Piezo
Ignitor
Automatic Control
Valve Button
OPERATION
Continued
Figure 5 - Automatic Control Valve
Button and Piezo Ignitor
WARNING: Be sure motor and
fan are running before pushing in
automatic control valve button.
Flames could flash outside heater
if motor and fan are not running.
6. Push in and hold automatic control valve but-
ton (see Figure 5). Push piezo ignitor button
(see Figure 5). Keep pushing ignitor button
until the burner lights. When burner lights,
keep automatic control valve button pushed in.
Release button after 30 seconds. This activates
the automatic control system.
Note: If heater fails to ignite, hose may have
air in it. If so, keep automatic control valve
button pressed and wait 20 seconds. Release
automatic control valve button and wait 20
seconds for unburned fuel to exit heater.
Repeat this step.
NOTICE: If heater is unplugged
or power outage occurs while
heater is running, the thermal
limit device will stop fuel flow.
A few seconds occur before the
thermal limit device activates.
During this short time, flames
may appear outside the heater.
This is normal. The flames will
go out when thermal limit device
activates.
TO STOP HEATER
1. Tightly close propane supply valve on propane
tank(s).
2. Wait a few seconds. Heater will burn gas left
in supply hose.
3. Unplug heater.
TO RESTART HEATER
1. Wait five minutes after stopping heater.
2. Repeat steps under To Start Heater, page 5.
STORAGE
CAUTION: Disconnect heater
from propane supply tank(s).
1. Store propane tank(s) in safe manner. See
Chapter 5 of Standard for Storage and Han-
dling of Liquefied Petroleum Gases, ANSI/
NFPA 58. Follow all local codes. Always store
propane tanks outdoors.
2. Place plastic cover caps over brass fittings on
inlet connector and hose/regulator assembly.
3. Store in dry, clean, and safe place. Do not
store hose/regulator assembly inside heater
combustion chamber.
4. When taking heater out of storage, always
check inside of heater. Insects and small
animals may place foreign objects in heater.
Remove motor and other internal parts if
needed to remove foreign objects (see Service
Procedures, page 7).

www.desatech.com
113855-01A 7
MAINTENANCE
WARNINGS
• Never service heater while it
is plugged in, connected to
propane supply, operating, or
hot. Severe burns and electri-
cal shock can occur.
• Keep heater clear and free
from combustible materials,
gasoline, and other flammable
vapors and liquids.
• Do not block the flow of com-
bustion or ventilation air.
1. Keep heater clean. Clean heater annually or as
needed to remove dust and debris. If heater is
dirty or dusty, clean heater with a damp cloth.
Use household cleaners on difficult spots.
2. Inspect heater before each use. Check connec-
tions for leaks. Apply mixture of liquid soap
and water to connections. Bubbles forming
show a leak. Correct all leaks at once.
3. Inspect hose/regulator assembly before each
use. If hose is highly worn or cut, replace with
hose specified by manufacturer.
4. Have heater inspected yearly by a qualified
service agency.
5. Keep inside of heater free from combustible
and foreign objects. Remove motor and other
internal parts if needed to clean inside of
heater (see Service Procedures).
6. Clean fan blades each season or as needed (see
Fan, page 8).
SERVICE PROCEDURES
WARNING: Never service
heater while it is plugged in,
connected to propane supply,
operating, or hot. Severe burns
and electrical shock can occur.
ELECTRICAL SYSTEM
The entire electrical system for this heater is con-
tained within the motor. If any part of the electrical
system is damaged, you must replace motor.
Screw
Screw
Motor and
Fan Guard
MOTOR
1. Remove three screws that attach fan guard to
heater shell.
2. Remove motor and fan guard from heater shell
(see Figure 6).
3. Use hex wrench to loosen set screw which
holds fan to motor shaft (see Figure 7). Re-
move fan. Be careful not to damage the fan
blade pitch.
4. Remove two nuts and two screws that attach
fan guard to motor using nut-driver. Remove
fan guard from motor (see Figure 8).
Figure 6 - Removing Motor and Fan
Guard from Heater
Figure 7 - Setscrew Location
Setscrew
Figure 8 - Removing or Attaching Fan
Guard from Motor
Fan Guard
Motor
Screw

www.desatech.com 113855-01A
8
Figure 9 - Replacing Motor and Fan
Guard Into Heater
SERVICE PROCEDURES
Continued
Figure 11 - Removing Ignitor Mounting
Screw and Ignitor
Figure 10 - Removing Ignitor Wire from
Piezo Ignitor
Ignitor
Mounting
Screw
Ignitor Wire
Piezo Ignitor
Underside
of Heater
Motor and
Fan Guard
Screw
Screw
5
Disconnect the green power cord wire from motor
and remove black and white wire terminals.
6. Discard old motor.
7. Attach green power cord wire to motor.
8. Attach fan guard to new motor with two nuts
and two screws.
9. Replace black and white terminals.
10. Place fan onto motor shaft of new motor. Make
sure set screw contacts flat surface on motor
shaft. Tighten set screw firmly (40-50 inch-
pounds [46.08-57.60 kilogram-centimeters]).
11. Place motor and fan guard into rear of heater
shell. Make sure power cord is properly lo-
cated (see Figure 9).
12. Insert three screws through heater shell and
into fan guard (see Figure 9). Tighten screws
firmly.
FAN
1. Remove three screws that attach fan guard to
heater shell.
2. Remove motor and fan guard from heater shell
(see Figure 6, page 7).
3. Use hex wrench to loosen set screw that holds
fan to motor shaft (see Figure 7, page 7).
4. Remove fan. Be careful not to damage the fan
blade pitch.
5a. If replacing fan, remove old fan and discard.
Go to step 7, column 2.
5b. If cleaning fan, use soft cloth moistened with
kerosene or solvent.
6. Dry fan thoroughly.
7. Place fan onto motor shaft. Make sure set
screw contacts flat surface on motor shaft.
Tighten set screw firmly (40-50 inch-pounds
[46.08-57.60 kilogram-centimeters]).
8. Place motor and fan guard into rear of heater
shell. Make sure power cord is properly lo-
cated (see Figure 9).
9. Insert three screws through heater shell and
into fan guard. Tighten screws firmly.
IGNITOR
1. Remove motor and fan guard from heater (see
Motor, page 7, steps 1 and 2).
2. Remove black ignitor wire from piezo ignitor.
Access ignitor wire through underside of
heater base (see Figure 10). Push wire up
through notch in filler panel.
3. Remove ignitor mounting screw from rear
head using nut-driver or standard screwdriver
(see Figure 11).
4. Remove ignitor from rear head.

www.desatech.com
113855-01A 9
Figure 12 - Clearance Between Ignitor
Electrode and Target Plate
Ignitor Electrode
Gap
Area
SPECIFICATIONS
Output Rating (BTU/Hr) 35,000 40,000
Fuel Propane Vapor Propane Vapor
Fuel Consumption
Gallons (liters)/Hour .38 (1.44) .44 (1.65)
Pounds (kg)/Hour 1.62 (0.74) 1.86 (0.84)
Supply Pressure To Regulator
Minimum (for purposes 20 psi 20 psi
of input adjustment)
Maximum Tank Pressure or 200 psi Tank Pressure or 200 psi
Regulator Outlet Pressure 10 PSI 10 PSI
Manifold Pressure 10 PSI 10 PSI
Hot Air Output
(CFM Approx) 100 100
Motor 3045 RPM, 1/40 HP 3045 RPM, 1/40 HP
Electric Input 120 volt/60 hertz 120 volt/60 hertz
Amperage .6 .6
Ignition Manual, Piezo Manual, Piezo
Temperature Range for
Heater Operation -0° F to 85° F * -0° F to 85° F *
(-17° C to 29.4° C)* (-17° C to 29.4° C)*
Weight
Heater 14 lbs. (6.35 kg) 14 lbs. (6.35 kg)
Shipping 15.3 lbs. (6.94 kg) 5.3 lbs. (6.94 kg)
Size - L x W x H
Carton 19.75" x 11.25" x 14" 19.75" x 11.25" x 14"
(50.16 x 28.57 x 35.56 cm) (50.16 x 28.57 x 35.56 cm)
Heater 18.5" x 7.7" x 12.8" 18.5" x 7.7" x 12.8"
(46.99 x 19.55 x 32.51 cm) (46.99 x 19.55 x 32.51 cm)
* When running heater in temperatures above 85° F (29.44° C), high internal temperatures may cause thermal limit
device to shut down heater.
5. Install new ignitor. Attach ignitor to rear head
with ignitor mounting screw.
6. Run ignitor wire from new ignitor through
notch in filler panel. Attach ignitor wire to
piezo ignitor.
7. Set gap between ignitor electrode and target
plate to .17" (43.18 cm) (see Figure 12).
WARNING: Make sure heater
is disconnected from propane
supply. Heater could ignite caus-
ing severe burns.
8. Test for spark. Push piezo ignitor button and
watch for spark between ignitor electrode and
target plate.
SERVICE PROCEDURES
Continued
9. Place motor and fan guard into rear of heater
shell (see Motor, page 8, steps 9 and 10).

www.desatech.com 113855-01A
10
TROUBLESHOOTING
WARNING: Never service heater while it is plugged in, connected
to propane supply, operating, or hot. Severe burns and electrical
shock can occur.
REMEDY
1. Check voltage to electrical
outlet. If voltage is good,
check heater power cord for
breaks
2. Adjust motor/fan guard to
keep fan from hitting inside of
heater shell. Bend fan guard if
necessary
3. Replace fan. See Fan, page 8
4. Replace motor. See Motor,
page 7
1. Repeat installation and opera-
tion instructions. See Installa-
tion and Operation, page 5
2. A) Check ignitor wire. Tighten
or reattach loose ignitor wire.
See Figure 11, page 8 for
ignitor wire location
B) Set gap between ignitor
electrode and target plate to
.17" (0.43 cm)
C) Tighten nut holding piezo
ignitor to base of heater
D) Replace ignitor electrode.
See Ignitor, page 8
1. This can happen when running
heater in temperatures above
85°F (29.44° C). Run heater
in cooler temperatures
2 Check heater inlet and outlet.
Remove any obstructions
3. Replace fan. See Fan, page 8
4. Clean heater. See Mainte-
nance, page 7
OBSERVED FAULT
Fan does not turn when heater is
plugged in
Heater will not ignite
Heater shuts down while run-
ning
POSSIBLE CAUSE
1. No electrical power to heater
2. Fan hitting inside of heater
shell
3. Fan blades bent
4. Defective motor
1. User did not follow installa-
tion or operation instructions
properly
2. No spark at ignitor. To test for
spark, follow step 8 under Ig-
nitor, page 9. If you see spark
at ignitor, have heater serviced
by qualified service person. If
no spark seen:
A) Loose or disconnected
ignitor wire
B) Wrong spark gap
C) Piezo ignitor loose
D) Bad ignitor electrode
1. High surrounding air tem-
perature causing thermal limit
device to shut down heater
2. Restricted air flow
3. Damaged fan
4. Excessive dust or debris in
surrounding area
WARNING: Use only in areas
free of high dust content.