Desa 35-R User Manual

PROPANE GAS-FIRED RADIANT CONSTRUCTION HEATER

OWNER’S MANUAL

MODEL 35-R

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 electrical shock.

Only persons who can understand and follow the in­structions should use or service this heater.

If you need assistance or heater information such as an in­structions manual, labels, etc. contact the manufacturer.

Save this manual for future reference.

For more information, visit www.desatech.com

Safety Information ............................................... 2

TABLE OF CONTENTS

Product Identification ........................................... 3

Unpacking ........................................................... 3

Theory of Operation ............................................ 3

Propane Gas Supply ........................................... 4

Ventilation ............................................................

Installation Instructions ........................................ 4

Locating Heater ................................................... 4

Operating Instructions ......................................... 5

Cleaning and Maintenance .................................. 6

Troubleshooting ................................................... 7

Illustrated Parts Breakdown and Parts List ......... 8

Specifications ....................................................

4

Replacement Parts ............................................ 10

Warranty and Repair Service ............................ 12

10

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, in­halation and explosion hazard.
Keep solid combustibles, such
as building materials, paper or
cardboard, a safe distance away
from the heater as recommended
by the instructions. Never use
the heater in spaces which do or
may contain volatile or airborne
combustibles or products 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/CGA 2.14. Other
standards govern the use of fuel gases and heating
products for specific uses. Your local authority
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 au

thority if you have questions about heater use.

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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 may 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 Liq
uefied Petroleum Gas, ANSI/NFPA 58 and
the Propane Installation Code, CAN/CGA
B149.2. This instructs on the safe storage and

handling of propane gases.

2. Use only the hose and factory preset regulator
provided with the heater.

3. Use only propane gas set up for vapor with
drawal.

4. Provide adequate ventilation. Before using
heater, provide at least a 3 ft
ing of fresh, outside air for each 100,000
Btu/hr of rating.

5. Do not use heater in occupied dwellings or in
living or sleeping quarters.

6. Do not use heater in basement or below ground
level.

7. Keep appliance area clear and free from com
bustible materials, gasoline, paint thinner and
other flammable vapors and liquids. Dust is

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combustible. Do not use heater in areas with
high dust content.

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(0.28 m2) open-

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SAFETY INFORMATION

Continued

8. Minimum heater clearances from combusti­bles: Sides 20" (50.8 cm), Top 40" (101.6 cm),
Front 54" (137.2 cm).

9. Keep heater at least 6 m (20 ft) from propane
tank(s).

10. Keep propane tank(s) below 38° C (100° F).

11. Check heater for damage before each use. Do
not use a damaged heater.

12. Check hose before each use of heater. If highly
worn or cut, replace with hose specified by the
manufacturer before using heater.

13. Locate heater on stable and level surface if
heater is hot or operating.

14. Not intended for use on finished floors.

15. Never block any air inlet or air outlet openings
of heater.

16. Keep heater away from strong drafts, wind,
water spray, rain or dripping water.

17. Do not leave heater unattended.

18. Keep children and animals away from
heater.

19. Never move, handle or service a hot or operat
ing heater. Severe burns may result. Wait 15
minutes after turning heater off.

20. To prevent injury, wear gloves when handling
heater.

21. Never attach duct work to heater.

22. Do not alter heater. Keep heater in its original
state.

23. Do not use heater if altered.

24. Turn off gas supply to heater when not in
use.

25. 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.

PRODUCT

IDENTIFICATION

Expanded
Metal
Screen

Burner
Face

Reflector

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Figure 1 - Product Identification

UNPACKING

1. Remove all packing items applied to heater for
shipment. Keep plastic cover caps (attached to
valve inlet 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.

THEORY OF OPERATION

The Fuel System: For propane units, the hose/

regulator assembly attaches to the propane gas
supply. For natural gas units, the gas supply at
taches to the heater through user supplied hose or
pipe. This provides fuel to the heater.

The Ignition System: The piezo ignitor lights the

burner fuel supply.

The Automatic Control System: This system causes

the heater to shut down if the flame goes out.

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PROPANE GAS SUPPLY

Propane gas and propane tank(s) are to be fur­nished 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 liquid 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.
Use a 100 pound (45 kg) tank for longer operation
or in very cold weather. Less gas is vaporized at
lower temperatures. Your local propane gas dealer
will help you select the proper supply system. The
minimum surrounding air temperature rating for
each heater is -20° F (-29° C).

Average Temperature Number Of Tanks

At Tank Location 100 lb (45 kg)

above 0° F (-18° C) 1
below 0° F (-18° C) 2

Smaller tanks can be used for limited run times
but it is recommended to use larger tanks for
optimum performance.

VENTILATION

WARNING: Provide at least
a 3 ft2 (0.28 m2) 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 ventilation
before running heater.

INSTALLATION

INSTRUCTIONS

Read these instructions care­fully. Read and adhere to these
instructions. Do not allow any­one who has not read these
instructions to assemble, light,
adjust or operate this heater.

Do not attempt to operate the
heater with any gas other than
that indicated on the heater
nameplate.

For the U.S. and/or Canada, the installation of this
appliance must comply with local and/or Provin
cial codes or, in the absence of these codes, with
the (U.S.) National Fuel Gas Code, ANSI Z223.1
– Latest Edition (for natural and propane/LP gas
operation) and with the (U.S) Standard for the

Storage and Handling of Liquefied Petroleum
Gases, ANSI/NFPA 58 (for propane/LP gas opera-

tion) or with the current (Canadian) CAN/CGA
B149.1 and B149.2 installation codes.

This heater (including hose and regulator assembly
if applicable) must be inspected before each use
and at least annually by a qualified service person.
If the hose shows evidence of excessive abrasion
or wear or if the hose is cut, it must be replaced
prior to the heater being put into operation. The
replacement hose assembly shall be that specified
by the manufacturer.

Tip Over Switch

This heater incorporates a tip over switch which
automatically shuts off the burner in the event of
tipping. Ensure that this switch is in the vertical po­sition and is secured with the screws provided.

LOCATING HEATER

Although this heater incorporates a tip over switch,
the heater and propane/LP gas supply cylinder must
be located on a hard, flat, level surface to minimize
the risk of accidental tipping. The propane/LP gas
supply cylinder should be adequately restrained to
prevent accidental tipping. DO NOT operate this

heater with the supply cylinder in any other than
the upright position.

This appliance must be installed only in locations
where the potential for physical damage to the
appliance (i.e., due to physical contact) is reduced
to a minimum.

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LOCATING HEATER

Continued

The installer must inform the owner/operator of
this appliance that precautions must be taken to
protect the appliance from physical damage.

This appliance produces radiant heat. Therefore,
it must be located at least 6 feet away from
any propane/LP gas container and must not be
directed toward any propane/LP gas container
within 20 feet.

The heater must be installed in a location such that
it will not be exposed directly to water spray, rain
and/or dripping water.

Use of this heater in a draft/windy area decreases
its efficiency. If possible, operate the unit in a
draft free area.

CONNECTING TO GAS SUPPLY

This model may be connected to a self-contained
propane/LP gas supply system using the hose and
regulator assembly supplied with the appliance
OR, it may be connected to a permanently installed
propane/LP gas supply system.

If connected to a self-contained propane/LP
gas supply system, the hose assembly must be
inspected prior to each use of the heater. If it is
evident that there is excessive abrasion or wear or
if the hose is cut, it must be replaced prior to the
heater being put into operation.

WARNING: Never use a fork
lift truck type cylinder.

The connection to a propane/LP cylinder must be
made in a well ventilated area using the regulator
and hose assembly supplied with the appliance.
DO NOT attempt to adjust this regulator. It has
been preset at the factory to provide safe and
proper operation of the appliance. Use a 7/8" open
end wrench to connect the POL fitting (supplied
with the propane/LP regulator) to the propane/LP
cylinder. Turn the POL nut in a counterclockwise
direction (left hand thread) until tight. DO NOT
use pipe compound on POL threads.

The heater must be located at least 6 feet away
from any propane/LP cylinder and must not be
directed toward any propane/LP cylinder within
20 feet. If more than one heater is used, they
and the supply cylinders must be separated by at
least 20 feet.

The gas supply must be turned off at the propane/
LP supply cylinder when the heater is not in use.

When the heater is to be stored indoors, the con
nection between the propane/LP supply cylinder
and the heater must be disconnected and the
cylinder removed from the heater and stored in
accordance with Chapter 5 of the Standard for

the Storage and Handling of Liquefied Petroleum
Gases ANSI/NFPA 58

If connected to a permanently installed propane/
LP supply system, the system requires the use
of a two-stage gas regulator assembly which is
normally provided by your propane/LP dealer as
part of the propane/LP supply system. Consult with
your local propane/LP dealer for details concern
ing proper equipment and installation.

Piping must be clean and free from scale or
burrs.

.

WARNING: Never use a flame

for gas leak testing.

OPERATING

INSTRUCTIONS

WARNING: If you do not fol­low these instructions exactly,
a fire or explosion may result
causing property damage, per
sonal injury or loss of life.

CAUTION: This appliance
is hot during normal operation,
avoid physical contact.

CAUTION: Do not place
clothing or other combustible
materials on this appliance.

DO NOT operate this heater if any part has been
under water. Call a qualified service technician to
inspect the appliance and to replace any part of
the control system or gas control valve which has
been under water.

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OPERATING

INSTRUCTIONS

Continued

LIGHTING HEATER

1. Before attempting to light the heater check
for gas leaks. Turn on the gas supply to the

appliance and check all fittings and connec­tions for gas leaks using a mild soap and water
solution. NEVER use a match to check for gas
leaks. Should a gas leak occur, shut off the gas
supply to the appliance immediately. Correct
all leaks at once.

2. Use only the fuel intended for this appliance.
Check the appliance rating plate for the correct
fuel information.

3. Turn on the main gas supply.

4. Press and hold button on control valve.

5. Press button on piezo ignitor 6 to 8 times.
Burner should light.

Thermocouple

Figure 2 - Heater Parts

To Match Light the Pilot

Hold a lit match to the burner face while pressing
and holding the control valve button. After the
burner ignites, keep button pressed for one (1)
minute or until the burner stays lit after releasing
button. DO NOT light gas at the burner orifice. DO
NOT face heater when attempting to light. Always
stand to the side of the unit when lighting.

CAUTION: When lighting
burner with a match or taper,
light at bottom of screen. Not
at orifice.

Burner

Ignitor
Electrode

Piezo
Ignitor
Button

Control
Valve Button

Note: In cases where long runs of gas supply lines
have been installed ahead of the appliance, it may
be necessary to bleed trapped air out of supply lines
before lighting pilot. New installations generally
require bleed of supply lines. Wait a minimum of
five minutes after bleeding supply lines before
attempting to light heater.

IMPORTANT: DO NOT attempt to adjust the
main burner input using the main gas supply valve.
This may cause the pilot and thermocouple to shut
down the burner.

SHUTTING OFF HEATER

1. Close propane gas supply cylinder valve.

2. Observe the burner until flame is extin
guished.

3. Listen for closure of the safety valve.

IMPORTANT: DO NOT reopen the propane gas
supply cylinder valve before the safety valve
closes.

CLEANING AND

MAINTENANCE

WARNING: Never attempt
to service heater while it is
connected to propane supply,
operating or hot. Severe burns
can occur.

1. Turn heater off and let cool at least 20 minutes
before cleaning.

2. 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.

3. 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.

4. Clean inside of heater using compressed
air. Blow air back and forth along the entire
burner face until all dust has been dislodged
from surface of reverberator and screen. Blow
air through venturi from the control end of
heater.

5. Inspect hose/regulator assembly before each
use. If hose is highly worn or cut, replace.

6. Have heater inspected yearly by a qualified
service agency.

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TROUBLESHOOTING

WARNING: Never attempt to service heater while it is connected

to propane supply, operating or hot. Severe burns can occur.

SYMPTOM

Burner fails to light

Pilot lights but goes out when
automatic control valve button
is released

Burn rate is low

Burner lights but goes out when
button is released

POSSIBLE CAUSE

1. Gas supply valve closed

2. Exce ss-flo w ch eck valve
closed

3. Blockage in burner orifice

4. Piezo ignition system not
sparking

1. Not enough warm-up time

2. Low gas pressure

3. Thermocouple loose or needs
to be replaced

4. Automatic control valve needs
to be replaced

1. Plugged gas orifices

2. Low gas pressure

3. Low fuel supply

1. Loose wi res on ti p over
switch

2. Loose or broken lead wire

3. Loose or mislocated thermo­couple wire

4. Defective thermocouple

5. Defective control

6. Defective tip over switch

REMEDY

1. Open gas supply valve slowly

2. Close propane supply valve
on propane tank and reopen
slowly

3. Replace burner orifice

4. Assure ignitor electrode gap is

5.0 mm (0.195 in). Check wire
lead for damage Replace piezo
ignitor and/or ignitor electrode
as necessary. Do not bend elec
trode, this may cause breakage

1. Relight, hold automatic control
valve button in 45 seconds

2. Check for proper gas supply

3. Tighten connection or replace
thermocouple

4. Replace automatic control
valve

1. Replace gas orifice

2. Check gas supply; check
regulator output

3. Consult gas supplier to deter­mine adequate supply. Tank
could be empty

1. Tighten wires on tip over
switch

2. Tighten or repair wire

3. Tighten thermocouple. Make
sure thermocouple is located
correctly between reverbera­tor and grid

4. Replace thermocouple

5. Replace control

6. Replace tip over switch

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MODEL 35-R

1

17

12

13

15

14

16

2

3

4

5

10

9

7

8

11

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ILLUSTRATED PARTS BREAKDOWN

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PARTS LIST

MODEL 35-R

This list contains replaceable parts used in your heater. When ordering parts, follow the instructions
listed under Replacement Parts on page 10 of this manual.

KEY
NO. PART NO. DESCRIPTION QTY.

1 115286-01 Burner 1
2 114121-01 Thermocouple 1
3 117384-01 Thermocouple Bracket 1
4 115291-01 Ignitor Electrode 1
5 117385-01 Ignitor Bracket 1
6 102445-01 Piezo Ignitor Kit 1
7 115287-01 Orifice 1
8 115285-01 Valve 1
9 115289-01 Junction Block 1
10 115288-01 Tip Switch 1
11 111090-02
12 115290-01 Hose/Regulator Assembly 1
13 115292-01 Wheel 2
14 114156-02 Axle Bracket 2
15 115294-01 Wheel Lock 2
16 117297-01 Main Frame Lower Assembly 1
17 117310-01 Reflector 1

114245-06 General Information Decal 1
115297-01 Warning Tag
114246-03

Brass Elbow 1

PARTS AVAILABLE - NOT SHOWN

1

Caution Decal 1

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SPECIFICATIONS

• Rating: 35,000 Btu/Hr

• Fuel: Propane Vapor Only

• Fuel Consumption per Hour:

0.38 gallon (1.5 liters), 1.6 lbs (1.74 kg)

• Supply Pressure To Regulator (for input adjust
ment): Maximum - 200 lbs or tank pressure

Minimum - 10 psi

• Manifold Pressure: 9.5" W.C. (2.3 kPa)

• Minimum Surrounding Air Temperature:

-20° F (-29° C)

REPLACEMENT PARTS

WARNING: Use only original
replacement parts. This heater
must use design-specific parts.
Do not substitute or use generic

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parts. Improper replacement
parts could cause serious or fa­tal injuries. This will also protect
your warranty coverage for parts
replaced under warranty.

PARTS UNDER WARRANTY

Contact authorized dealers of this product. If they
canʼt supply original replacement part(s), either call
DESA Heating Productsʼ at 1-866-672-6040 or
DESA Industries at 1-905-826-8010.

When calling DESA, have ready:

• your name and address

• model and serial numbers of your heater

• how heater was malfunctioning

• purchase date
In most cases, we will ask you to return the part

to the factory.

PARTS NOT UNDER WARRANTY

Contact authorized dealers of this product. If they
canʼt supply original replacement part(s), call DESA
Heating Productsʼ at 1-866-672-6040 or DESA
Industries at 1-905-826-8010.

When calling DESA, have ready:

• model and serial numbers of your heater

• the replacement part number

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NOTES

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