Detroit Radiant Products Re-Verber-Ray DTH Series User manual

TUBE HEATER
TROUBLESHOOTING GUIDE
MODELS: DTH(S) Series Tube Heaterer
Detroit Radiant Products Company
21400 Hoover Road • Warren • Michigan • 48089 • [phone] • Fax: [phone]
website: www.reverberray.com email: [email protected]
THESE HEATERS MUST BE INSTALLED AND SERVICED BY TRAINED GAS
INSTALLATION AND SERVICE PERSONNEL ONLY. READ AND UNDERSTAND ALL
INSTRUCTIONS THOROUGHLY BEFORE ATTEMPTING TO INSTALL, OPERATE OR
SERVICE THE DETROIT RADIANT PRODUCTS COMPANY HEATER. FAILURE TO
COMPLY WITH THESE WARNINGS AND INSTRUCTIONS, AND THOSE ON THE
HEATER, COULD RESULT IN PERSONAL INJURY, DEATH, FIRE, ASPHYXIATION AND/
OR PROPERTY DAMAGE. RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE.
CAUTION! Heater may be hot. Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other appliance. Note presence of
flammable gas and electrical shock hazard.
WARNING! Extinguish open flame while servicing heaters. Test for gas leaks with
soap and water solution only. Wear safety glasses while servicing unit.
Approval Standards and Certifications
Detroit Radiant Products units comply with or are certified by the following Organizations
or Standards:
- American National Standards (ANSI Z83.6)
- Occupational Safety and Health Act (OSHA)
- American Gas Association (AGA)
- International Approval Services (IAS)
FOR YOUR SAFETY!
IF YOU SMELL GAS:
1. Open windows.
2. Do not touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
SHUTDOWN INSTRUCTIONS!
1. Open electrical circuit.
2. Rotate heater’s manual gas
valve knob to “OFF” position.
IMPORTANT:Any alteration of the system or of the factory-authorized components specified
either in this manual or by Detroit Radiant Products Company voids all certification and warranties.

Table of Contents
Tools Recommended To Troubleshoot Heaters
DTHS-2 Wiring Diagram & Theory of Operation
DTHS-3 Wiring Diagram & Theory of Operation
Burner Photographs -2 & -3 Series Heaters
Component Photographs
Troubleshooting Flow Chart
General Troubleshooting Reference & Solution Chart
Troubleshooting Solutions
Component History Chart
How To... (For Trouble Shooting Procedures)
2
3
4
5
6
7, 8
9, 10
11-19
20
21-23
1
This symbol appears when directions indicate the presence of flammable gas.
This symbol appears when directions indicate the presence an electrical shock hazard.

-Digital Multimeter - Used for troubleshooting & testing electrical circuits.
(Part 1A783 from Grainger)
-Flame Rectification Meter - Used for testing rectification of flame with the digital multimeter.
(Channel Products)
-Digital Manometer Kit - Used for taking gas pressure, digitally.
(Part 100281-21 from Dwyer Instruments)
-Liquid Manometer Kit - Used for taking gas pressure, via a liquid manometer.
(Part 115010-00 from Dwyer Instruments)
-Digital Hygro-Thermometer (Amprobe #TH-2) - Reads temperature from -10 to 50OC and relative humidity from
5-95%. (Part 1P124 from Grainger)
-Incline Manometer - Used for measuring pressure inside burner box. Provides data for pressure
switch. (Cat# 172 from Dwyer Instruments)
-1/4” Nut Driver - Can be used to remove screws holding top on.
(Part 5X509 from Grainger)
-Pliers 8” - Tool for burner box access.
(Part 6C183 from Grainger)
-Pipe Wrench 8” - Can be used to disassemble gas train assembly.
(Part 4A497 from Grainger)
-Ratcheting Box Wrench - Can be used to remove orifice and bolts. (size 7/16” and 3/8”)
(Part 1AMW9 from Grainger)
-6” Steel Rule - Used for measuring air orifice size.
(Part 6C289 from Grainger)
-Terminals 1/4” Female - Extra female spade terminals.
-Barb Fitting - Fitting to take gas pressure at the valve.
-Vinyl Tubing - Tubing for pressure measurements. (size 5/16” x 3’)
-Jumpers/Connectors - Used to jump out the pressure switches.
-Self Tapping Screws - Extra screws.
-Drill Bits 1-60, A-Z - Drill Bits 1-60, A-Z, for measuring gas orifice size (DMS).
-Manuals - DX, DX-2 or XTS Series Installation, Operation & Maintenance manuals (IOM’s).
Tools Recommended to Troubleshoot Heaters
2

3
2. Theory of Operation
2.1 DTHS-2 Models: 40,000 BTU/H through 100,000 BTU/H
• Starting Circuit (Figure 2.1)
When voltage is applied to L1 and L2, a circuit is completed from L1 via the blower motor to L2. The
blower fan is mounted in the control box and rated to supply sufficient air combustion.
Air pressure generated by the blower will cause the normally open burner pressure switch No. 1 to close.
The burner pressure switch is factory preset to ensure that a minimum of 2/3 the normal rate of combustion
air is passed into the combustion chamber. Any air flow restriction resulting in less than 2/3 normal rate
will cause the pressure switch to open and shut down the entire system.
Current will pass through the burner pressure switch to the normally closed exhaust pressure switch No. 2.
The exhaust pressure switch is factory preset to ensure that a minimum of 1/2 the normal rate will cause the
pressure switch to open and shut down the entire system.
NOTE: Pressure switches are nonadjustable.
Another circuit is completed from L1 to the radiant sensor and glo-bar back to L2. Simultaneously, the
safety and booster coils of the first of two redundant valves are energized through the contact of the radiant
sensor. This causes the first valve to open and the glo-bar to heat up. No gas flows however, until the
second redundant valve is energized and opened.
• Running Circuit
When the glo-bar reaches ignition temperature, the radiant sensor is heated and opens (maximum 60 seconds).
The radiant sensor is a heat sensitive bimetal switch with a single throw contact that is normally in the
closed position and calibrated to open when the glo-bar has attained ignition temperature.
The second redundant valve, now in series with the glo-bar, is energized and opened. Gas flows through
the burner and is ignited by the glo-bar. The second coil remaining in series with the glo-bar causes the
glo-bar to cool down. The radiant sensor is held open by radiant heat emitted from the gas flame. The
booster coil of the first valve is now placed in series with the secondary coil, and very low current flows
through the coil. The safety coil power is sufficient to hold only the first valve open. If a momentary
power failure occurs, the first valve will shut down the gas supply to the burner. When power is restored,
the safety coil alone does not have the power to pull the valve open, therefore, the radiant sensor cools
down, the contacts close and the unit cycles (maximum 60 seconds).
Note: Warranty is void if wire nuts are removed.
PRESSURE SWITCHES
BLOWER
BURNER
N.O.
EXHAUST
N.C.
RADIANT SENSOR
SECONDARY
COIL
SAFETY
COIL
BOOSTER
COIL
GLO-BAR
IGNITOR
BK
BK
BK
BK
BK
BK
BK
BK
WW
W
W
W
W
R
RR
R
R
W
120V
L2
L1
BK W
BLOWER
PRESSURE SWITCHES
RADIANT SENSOR
GLO-BAR
IGNITOR
GAS
VALVE
BURNER
N.O.
EXHAUST
N.C.
W
W
W
R
W
W
W
W
BK BK
BK
BK BK
BK
BK
BK
L1
L2
120V
R
R
R
BK
W
Figure 2.1

4
Theory of Operation
2.2 DTHS-3 Models: 125,000 BTU/H and 150,000 BTU/H
• Starting Circuit (Figure 2.2)
When voltage is applied to L1 and L2, a circuit is completed from L1 via the blower motor to L2.
The blower fan is mounted in the control box and rated to supply sufficient air for combustion.
Air pressure generated by the blower will cause the normally-open burner pressure switch No. 1
to close. The control completes another circuit from L1 to the hot surface ignition control and
back to L2. There is a five-second delay, then the glo-bar is powered. After the glo-bar
has been powered for 45 seconds, the control causes the gas valve to open and initiates
the ignition trial. Power to the glo-bar is shut off during the last two or three seconds of the
ignition trial.
• Starting Circuit
When power is removed from the glo-bar, the glo-bar is utilized as a flame probe. As long as a
flame is present, the valve is held open. If the flame is lost, the control acts to close the valve
within one second, and a new trial sequence identical to that at start-up is initiated. If proof of
flame is not established within 8 seconds, the unit will lock out. If lockout occurs, the control can
be reset by briefly interrupting the power source.
PRESSURE SWITCHES
BLOWER
BURNER
N.O.
EXHAUST
N.C.
GLO-BAR
IGNITOR
BK
BK
BK
BK
BK
W
R
W
120V
L2
L1
BK
W
GAS
VALVE
CIRCUIT
BOARD
W
W
BK
BK
BLOWER
PRESSURE SWITCHES
GLO-BAR
IGNITOR
GAS VALVE
BURNER
N.O.
EXHAUST
N.C.
W
W
W
W
BK BK
BK
BK BK
BK
L1
L2
120V
R
CIRCUIT
BOARD
BURNER
Figure 2.2
PRESSURE SWITCHES
BLOWER
BURNER
N.O.
EXHAUST
N.C.
RADIANT SENSOR
SECONDARY
BOOSTER COIL
SAFETY COIL
GLO-BAR
IGNITOR
BK
BK
BK
BK
BK
BK
W
W
W
120V
L2
L1
V1
V2 L1
FS
L2IGFS
WW
4
3
21
BK BK
BK BK
BK BK
DTHS-2 Models: 125,000 BTU/H and 150,000 BTU/H
Please consult the factory when
troubleshooting the DTH(S)-2 125,000 &
150,000.
Follow the adjasent diagram for proper
wiring of the DTH(S)-2 125,000 &150,000.

DTHS-3
Series Heater
DTHS-2
Series Heater
5
Burner Unit Photographs

Burner Pressure Switch Gas Burner & Burner Housing Circuit Board
Fan
Exhaust Pressure Switch
PICTURE 1 PICTURE 3PICTURE 2
PICTURE 4 PICTURE 6PICTURE 5
This symbol appears when directions indicate the presence of flammable gas.
This symbol appears when directions indicate the presence an electrical shock hazard.
Gas Cock & Regulator
Air Intake Collar & Orifice
Glo-Bar
PICTURE 7 PICTURE 9PICTURE 8
6
-3 Gas Valve
-2 Gas Valve
Manifold Tap
Manifold Tap
Inlet Tap
Radiant Sensor
Component Photographs
-3 Gas Valve

DTH (S) Trouble Shooting Flow Chart
Continued on the
following page.
7
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
NO
Does the fan
blower turn on?
NO
Check the thermostat and
wiring. Is the power going to
the heater 115V?
Find the source of
the electrical problem.
Replace the blower.
Check the voltage to the
blower. Is it 115V? Check wiring and correct.
Remove the obstuction.
Is the blower obstructed?
Turn up T-Stat
YES
YES
NO
YES
NO
Replace the ignitor.Is the ignitor damaged?
Is the inlet or outlet of the
unit obstucted? i.e. ice,
birds nest dirt ect.
Check voltage at ignitorduring
the ignition sequence. Is it
115V?
Is the resistance through the
ignitor(OHMS) 40-500?
Does the ignitor warm
up and glow red?
Check for loose wiring or
restrictions in hose connections to
the pressure switch(s). Are they ok?
Repair wiring or hose
connections.
Remove obstruction.
Is the model in question
equipped w/ 2 switches? Replace the door switch.
Temporarily place jumpers on
switch. Does ignitor glow red?
If the model does not have two pressure
switches, then it should have a single
pressure switch and a door switch.
Depress the door switch . Is it 115V?
If heater in question has a circuit board Model #
Mark 17X-117, Mark 17 HSI or 5001A-1, then
replace board. Note: If heater contains circuit
board 5001A-1 consult facory for proper parts.
Replace the switch after verifying that
none of the following is occuring. If one
of the following is occuring, then this is a
possible cause for pressure switch failure.
Address the problem.
-Baffle is not in the tube(s) farthest from
the burner.
-Significant build up of contaminants on
the squirrel cage. Clean each blade.
-The 4” air intake pipe exceeds 20 ft. and
or 2 elbows.
-There is a negative pressure experianced.
Temporarily place jumpers across
both terminals of radiant sensor.
Did the ignitor glow red?
Temporarily place jumpers across the
terminals of each switch one at a
time. Does the ignitor glow red?
Replace radiant sensor.
YES
YES
NO
NO
NO
NO
YES
YES
NO
YES
NO
YES
NO NO
YES
YESYESNO NO
YES NO

Flow Chart Continued
8
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Does the heater have a circuit board part
numbers: 5001A-1, Mark17X-117 or
MarkX-HSI?
After the ignitor is warmed up,
does the gas valve open? Does the ignitor stay on continuosly?
Replace circuit board.
Note: If heater contains
board # 5001A-1 consult
the factory for parts.
Test for 115V at valve during valve
opening period usually 30 to 45 seconds
after power to the heater.
Fix
Problem.
Check to make sure that the
radiant sensor is not
misaligned or that the mica
glass is not dirty.
Correct
problem.
Check to make sure gas pressure is within
minimum and maximum inputs as indicated on
AGA burner rating label. Is gas pressure ok?
Replace gas valve.
Disconnect the four incomming wires
and the ignitor plug on the vlave.
Connect an ohn meter to the black and
red wire on valve. Is the reading
between 610 and 734 ohms?
Check to make sure that the gas
pressure is within minimum and
maximum inputs as indicated on
AGA burner rating label. Is gas
pressure ok?
Replace
valve.
Replace radiant snesor.
Does the burner stay on? Is the L1 and L2 reversed?
This can be checked by
testing voltage between L1
and ground. If voltage is
between L2 and ground
then wires are reversed.
(-3 Series only)
Correct
wiring.
Does heater stay on until
call for heat ends?
The following can cause
the heater to shut down:
-Improper grounding.
-High winds.
-Taking combustion air
from the attic.
-Baffle is not in the
tube(s) farthest from the
burner.
-Fluctuating gas pressure.
Trouble shooting
ends.
Temporarily place jumpers on
pressure and door switches.
Does this eliminate the problem?
If the heater has a circuit board,
then replace the board, otherwise
consult the factory.
Replace the switch after verifying that
none of the following is occuring. If one
of the following is occuring, then this is a
possible cause for pressure switch failure.
Address the problem.
-Baffle is not in the tube(s) farthest from
the burner.
-Significant build up of contaminants on
the squirrel cage. Clean each blade.
-The 4” air intake pipe exceeds 20 ft. and
or 2 elbows.
-There is a negative pressure experianced.
YES
NO
NO
NO
YES
YES
YES
NO
YES
NO
YES
NO
YES NO
NO YES
YES
NO
YES NO
YES
NO

Thermostat closed, fan does not
operate.
Thermostat closed. Fan operates.
No glo-bar energization.
Thermostat Closed. Fan and glo-bar
operate. Glo-bar does not shut off
and valve does not open.
Thermostat closed. Fan and glo-bar
operate. After 45 second glo-bar
shuts off. No ignition.
Thermostat closed, fan & glo-bar
operate. Ignition occurs, burner
cycles off after 35 to 55 seconds &
glo-bar starts to glo immediately.
Thermostat closed. Fan and glo-bar
operate. Ignition occurs. Burner
cycles off and will not recycle.
Thermostat closed. Fan & glo-bar
operate. Ignition occurs. Burner
cycles off. Burner recycles.
SYMPTOM EXPLANATION SOLUTION
1. Blown fuse.
2. Faulty thermostat.
3. Loose or disconnected wire.
4. Faulty fan.
1. Loose or disconnected wire.
2. Box lid or gasket not in place.
3. Plugged pressure switch lines.
4. Plugged inlet or restricted exhaust vent.
5. Baffle location incorrect.
6. Faulty pressure switches.
7. Faulty circuit control.
8. Faulty glo-bar.
1. Radiant sensor stuck close.
2. Dirty radiant sensor mica.
3. Dirty radiant sensor glass.
1. Closed gas supply.
2. Dirty or restricted gas orifice.
3. Faulty valve. Disconnected valve wire.
4. Inlet pressure too high - (max pressure = 14”).
1. Closed gas supply.
2. Dirty or restricted gas orifice.
3. Faulty radiant sensor.
4. Low gas pressure.
1. Polarity reversed.
2. No electrical ground.
3. Faulty circuit control.
4. Low gas pressure.
5. Glo-bar faulty.
6. Faulty exhaust switch.
1. Polarity reversed.
2. No electrical ground.
3. Faulty circuit control.
4. Low gas pressure.
5. Glo-bar faulty.
6. Faulty exhaust switch.
1. Replace.
2. Replace.
3. Repair as required.
4. Lubricate, repair or replace.
1. Repair as required.
2. Put in place.
3. Clean as necessary.
4. Remove foreign matter.
5. Reposition baffle.
6. Replace only - do not adjust.
7. Replace circuit control.
8. Replace glo-bar.
1. Replace.
2. Clean as necessary.
3. Clean as necessary.
1. Open all gas connections.
2. Remove and clean with a soft cloth.
3. Replace valve or reconnect wires.
4. Adjust pressure.
1. Open.
2. Remove & clean with soft cloth.
3. Replace radiant sensor.
4. Adjust pressure.
1. Correct polarity.
2. Connect electrical ground to junction box.
3. Replace.
4. Provide required gas pressure.
5. Replace.
6. Replace.
1. Correct polarity.
2. Connect electrical ground to junction box.
3. Replace.
4. Provide required gas pressure.
5. Replace.
6. Replace.
Page 11Page 12-13Page 14Page 15
Page 16
Page 16Page 17
GENERAL TROUBLESHOOTING CHART
1
2
5
3
4
7
6
9
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.

Loss of heater efficiency.
Radiant tube leaking burnt gases.
Condensation.
Tube bowing.
Tube corroding.
Visual inspection of burner
operation not possible.
Stack sooting.
Odor or fumes in space.
1. Low gas pressure.
2. Dirty or restricted orifice.
3. Foreign matter inside burner assembly.
4. Reflector is sooted and has lost its
reflective ability.
5. Clogged fan blower.
1. Loose tube connections.
2. Holes or cracks in radiant tubes.
1. Stack length too long.
2. Light gauge flue stack used.
3. Contaminated combustion air.
1. Insufficient combustion air.
2. Contaminated combustion air.
3. Overfired.
4. Heater’s tubes are unable to expand.
1. Contaminated combustion air.
1. Dirty or sooted sight glass.
2. Unit mounted upside down.
1. Insufficient combustion air.
2. Improper gas.
1. Vaporized solvents decomposing when
contacting radiant tubes.
2. Evaporation of oils/solvents at floor level.
3. Fork lifts.
4. Loose tube connections.
1. Provide required gas pressure.
2. Remove and clean with a soft cloth.
3. Clean as necessary.
4. Clean with aluminum cleaner and
soft cloth.
5. Clean.
1. Assure that tube is fully inserted into
flared end and properly clamped.
2. Replace.
1. Shorten stack.
2. Minimum of 26 gauge vent pipe is required.
3. Provide fresh air inlet duct.
1. Provide 2 sq. in. of free air per
5000 BTU/H of input.
2. Provide fresh air inlet duct.
3. Check gas pressure and orifice size.
4. Remount heater with 16” section of flex.
1. Provide fresh air inlet duct.
1. Remove and clean or replace.
2. Mount correctly.
1. Provide 1 sq. in. of free air for every
5000 BTU/H of input.
2. Correct with proper gas input.
1. Address ventilation concerns.
2. Address ventilation concerns.
3. Address ventilation concerns/repair.
4. Tighten tube clamps to 50-100 ft. lb.
SYMPTOM EXPLANATION SOLUTION
Page 17
Page 17Page 18Page 18Page 19
Page 19
GENERAL TROUBLESHOOTING CHART
Page 18
Page 19
8
9
10
11
12
13
14
15
Page 20
“How To” Instructions Inlet pressure, manifold reading, proper polarity,
positive ground, negative pressure, bypass pressure switches.
10
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.

Thermostat Closed, Fan Does Not Operate
If the thermostat is closed (on) and heater does not operate, check the following:
1.1
Check the building’s main circuit breaker or fuse box. The problem may be a blown fuse or circuit.
1.2
Thermostat Operation: Verify the thermostat is allowing power to be sent to the heater. Confirm
by measuring the voltage to the heater using a volt meter (See picture below). If there is no power,
the problem is in the thermostat and it should be replaced. If power is at the heater, continue on to
the next step.
1.3
Check the electrical connections leading to the fan. Be sure that the wire nuts are tight.
1.4
Using the voltmeter, check to be sure power is going to the fan (pg. 6, pic. 5). If there is power, try
cleaning and oiling (SAE-20 oil) the motor. If the fan is still not working, it is faulty.
Picture 1.2
2 x 4 Junction Box
11
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 1

Thermostat Closed, Fan Operates, No Glo-Bar Energization
(This step is applicable for all models)
2.1
Locate any disconnected or loose wires and repair.
2.2
The normally open Burner Pressure Switch is located on the fan side of the heater (pg. 6, pic. 1 ). This switch
must be closed before the glo-bar can be energized. *Bypass this switch (pg. 21, #6) to check for proper function.
Once bypassed, reinstall the cover and test the heater. If it works, there is a problem with the burner pressure
switch or what it is sensing, and you should continue with step 2.2.1. If bypassing this pressure switch does not
make the heater work, continue with step 2.3.
2.2a
Be sure the lid is on correctly and the gasket is intact.
2.2b
Make sure the clear vinyl tube that bleeds pressure to the outside of the heater is clean and clear of
obstructions.
2.2c
Make sure the heater’s vent cap is in place and in good condition. Also, check for obstructions within the
cap.
NOTE: Excessive winds may cause properly operating safety pressure switches to shut down the heater. Heaters ducted
through (on either the intake or exhaust sides) the roof may be deprived of the air necessary to pressurize the burner box. This
“chimney effect” will typically not allow the burner pressure switch to close. Heaters vented through a sidewall may see too
much back-pressure, thus opening the exhaust pressure switch. In either case, the caps need to be shielded to lessen the effects
of high winds.
2.2d
Make sure the heater’s baffle is located properly. It should be found at the exhaust end of the emitter tube.
2.2e
The fan may not be accurately pressurizing the heater. Clean obstructions from the air-intake connection
and cap (pg. 6, pic. 8). Clean the squirrel cage. Oil the motor (SAE-20). Examine and clean the fan blades
(pg. 6, pic. 5). Once the fan is completely clean, retry the heater, without bypassing the Burner Pressure
Switch. If the glo-bar is still not energizing, continue with Step 2.2f.
2.2f
If steps 2.2a - 2.2f were performed and the heater still won’t properly function, the burner pressure switch
is faulty.
12
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 2

Thermostat Closed, Fan Operates, No Glo-Bar Energization (cont.)
(This step is applicable for all models)
2.3
The Exhaust Pressure Switch is located on the valve side of the heater (pg. 6, pic. 4). *Bypass this switch
(pg. 21, #6). If the heater works with the exhaust pressure switch bypassed, the problem is with this switch or what
it is sensing and you should continue with step 2.3.1. If bypassing this switch does not cause the heater to work,
continue with step 2.4.
2.3a
Be sure the lid is on correctly and tightly, and the gasket is in intact.
2.3b
Check to make sure the clear vinyl or aluminum tube that bleeds pressure to the outside of the heater is
clean and clear of obstructions.
2.3c
Clean any obstructions from the emitter tube, exhaust tube and vent cap.
2.3d
Check to make sure the heater’s baffle is located properly. It should be found at the exhaust end of the
emitter tube.
NOTE: Excessive winds may cause properly operating safety pressure switches to shut down the heater. Heaters ducted
through (on either the intake or exhaust sides) the roof may be deprived of the air necessary to pressurize the burner box. This
“chimney effect” will typically not allow the burner pressure switch to close. Heaters vented through a sidewall may see too
much back-pressure, thus opening the exhaust pressure switch. In either case, the caps need to be shielded to lessen the effects
of high winds.
2.3e
Check to make sure the sensing tube pointed in the outlet of the fan is at the bottom of the opening (pg 5,
pic. 4)
2.3f
If steps 2.3a - 2.3e were performed and the heater still won’t properly function, the exhaust pressure switch
is faulty.
2.4(-2) (This step is applicable for non-DTHS-2 & DTHS-2 model heaters 40-100 MBTU/H).
Check the normally closed radiant sensor to see if it is stuck in the open position. See how to (pg. 22, #8). If stuck
open, the radiant sensor can be bypassed. See “How To” (pg. 22, #7) to confirm that there are no other failures.
2.4(-3) (This step is applicable for DTHS-3 models only)
Check the Circuit Board (pg. 6, pic. 3). Use a volt meter to ensure that power is actually entering the circuit
board. Turn off the gas to the heater and *bypass both pressure switches (pg. 21, #6), as a heater with no cover will
not allow pressure switches to function properly. 120 volts exiting the circuit board indicates that the glo-bar is
faulty. If no voltage exits the circuit board, it is faulty.
13
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 2

Thermostat Closed, Fan & Glo-bar Operate, Glo-bar does not shut off and
Valve does not open
(This step is applicable for all models)
3.1
The normally closed radiant sensor, located on the side of the tube in the sensor box, may be stuck in the open
position. This can be confirmed by bypassing it. See how to (pg. 22, #7).
If the heater operates with the switch bypassed, the problem is with the radiant sensor or what it is sensing,
therefore you should continue with step 3.1a. If bypassing the radiant sensor does not work, the valve is faulty and
must be replaced.
3.1a
Be sure the radiant sensor MICA is clean and intact.
3.1b
Check to make sure the glass on the underside of the radiant sensor is clear and not cracked or broken.
3.1c
Reconnect the radiant sensor into the system. If steps 3.1a - 3.1b were performed and the heater will not
properly function, The radiant sensor is faulty and must be replaced.
14
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 3

Thermostat Closed, Fan & Glo-Bar Operate.
After 45 Seconds Glo-Bar Shuts Off, No Ignition.
4.1
Be sure that the gas valves inside (DTHS-3 Series) and outside of the heater are turned to the ON position.
4.2
Locate and confirm that the gas orifice is not plugged with dirt, spider webs or rust.
4.3
(DTHS-3 models) Turn off the gas to the heater and *bypass both the Burner & Exhaust Pressure Switches
(pg. 21, #6). Test the voltage coming from the Circuit Board to the Gas Valve (pg. 6, pic. 6) using a volt
meter. If there is 120 volts, the gas valve is faulty. If there is less than 102 volts or no voltage at all, the circuit
board is faulty.
(DTHS-2 models) One of the three (3) coils on the gas valve may be faulty. This can be confirmed by ohming
out the valve. See how to (pg. 22, #9). If one or more coils are bad the valve is faulty and must be replaced.
4.4
The inlet pressure entering the system may be too high. The maximum value for both natural and propane is
14” W.C.P. Correct this problem by either adjusting the building’s regulator down to 14” W.C.P. or by using
step-down regulators in the building’s piping system.
NOTE: THE GAS VALVE (DTHS-3) OR EXTERNAL REGULATOR (DTHS-2) ARE ONLY RATED
FOR 1/2 POUND (14 INCHES) OF PRESSURE. IF USING A HIGH-PRESSURE REGULATOR, BE
SURE IT IS LOCKING UP PRIOR TO THE INLET PRESSURE REACHING 1/2 POUND.
NOTE: THE EXTERNAL REGULATOR CAN STICK CLOSED IF HIGH PRESSURE IS PUT TO IT.
TO CONFIRM THIS, LOOK INTO THE INLET OF THE REGULATOR. IF YOU CAN SEE THE
POPPET HANGING FROM THE TOP OF IT, IT IS NOT LOCKED UP. IF YOU CANNOT, IT IS
LOCKED UP FROM HIGH PRESSURE AND MUST BE REPLACED.
15
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 4

Thermostat Closed. Fan & Glo-Bar Operate. Ignition Occurs.
Burner Cycles Off after 35 to 55 seconds & Glo-bar starts to glo immediately.
(DTHS-2 models) The glo-bar is hot enough to open the radiant sensor, but the flame is not hot enough to hold
it open (see 3.1).
Take a manifold pressure to verify proper gas supply (see 4.4) (pg. 21, #2).
Solution 6
Thermostat Closed. Fan & Glo-Bar Operate. Ignition Occurs.
Burner Cycles Off & will not Recycle.
There are two possibilities:
1) The Burner cycles for 8 seconds and shuts off (DTHS-3 Models).
6.1
The polarity could be incorrect. Check the systems wiring (pg. 21, #3) (See installation-operation
manual wiring diagram).
6.2
The heater senses flame through ground. Therefore, the unit might not be properly grounded. The
wiring should be inspected (pg. 21, #4).
6.3
There may be loose connections somewhere within the heater, or, the circuit board may be faulty.
6.4
The gas pressure is too low. Check the manifold pressure (pg. 6, pic. 6 & pg. 21, #2) for appropriate
pressure.
6.5
The glo-bar may be cracked. (pg. 6, pic. 7). Check for visible damage.
2) The Burner cycles for more or less than 8 seconds and shuts off (DTHS-2 & -3).
6.6
Follow steps 6.1 - 6.5.
6.7
The Exhaust Pressure Switch is located on the valve side of the heater (pg. 6, pic. 4). *Bypass this switch
(pg. 21, #6). If the heater works with the exhaust pressure switch bypassed, the problem is with this switch
or what it is sensing and you should continue with step 2.3.1 (located on page 13). If bypassing this switch
does not cause the heater to work, continue with step 2.4 (located on page 13).
16
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 5

Solution 7
Thermostat Closed. Fan & Glo-Bar Operate. Ignition Occurs.
Burner Cycles Off. Burner Recycles.
Refer to steps 6.6 - 6.7.
Solution 8
Heater’s Efficiency is Lacking
Usually, a heater lacking in efficiency has improper gas pressure, dirty parts or is a misapplication of the heater
itself.
8.1
If the manifold pressure is not high enough, ( 3.8” natural for 40-125 MBH, 6.0” natural for 150 MBH and 10”
for propane) the heater will not deliver the desired amount of heat. Check the Manifold Pressure (pg. 6, pic. 6)
and pg. 21, #1 & #2).
8.2
Locate and confirm the orifice is not plugged with dirt, spider webs or rust.
8.3
Check the burner assembly to make sure it is clear of any obstructions.
8.4
Be sure the reflector is in place and clean. Use a soft cloth and aluminum cleaner to clean the reflector.
8.5
Be sure the fan is clean and able to supply the appropriate amount of air to the heater. Clean any obstructions from
the air-intake pipe and cap. Clean the squirrel cage. Oil the motor (SAE-20). Examine and clean the fan blades.
17
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 9
Radiant Tube Leaking Burnt Gas
Obstructions in the heater may cause too much heat in a specific point, leading to holes or cracks. These
openings can cause burnt gas to leak out. If this problem is occurring, follow these steps:
Carefully inspect the length of all emitter tubes and clamps for any cracks, holes or loose connections. If any
part of the tube has an opening, it must be replaced immediately. Also check for blockages in the exhaust and
emitter tube.

Solution 10
Condensation is Forming
If condensation is forming anywhere along the length of the emitter or exhaust pipe, check to make sure that it
is not excessive in length. Be sure that the heater has the appropriate manifold pressure (Tow To part 2).
Confirm the use of adequate vent material (26 gauge minimum is required). Inspect the baffle location (it
should be found at the exhaust end of the emitter tube), insulate vent materials, and seal leaks around vent
openings. Chemicals burned through the combustion process can alter the exhaust by-products and
temperature. See your heater’s manual for air-intake specifications.
Solution 11
Emitter Tube is Bowing
Normal operation of the heater will often cause expansion of the emitter tube. If there is no room for this to
occur, the tube will bow. If this is happening, follow steps below.
11.1
Too little air will lead to shorter flame, causing it to burn hotter than normal. Be sure there is nothing blocking
the air intake and that the fan is clean (pg. 6, pics. 5 & 8).
11.2
Contaminated combustion air could alter the flame characteristics, overheating the tube and causing it to bow.
See your manual for air-intake specifications.
11.3
Too much gas may also overheat the tube and cause it to bow.Check the manifold (How To part 2) pressure (pg. 6,
pic. 6).
11.4
If the heater is mounted so that it cannot expand lengthwise (ie. it is cemented into the wall at both ends), add a
16” section of flex on the inlet side of the heater and allow the exhaust to move freely through the wall.
Solution 12
Tube is Corroding
The tube would corrode if the air entering the heating system was not clean. See your heater’s manual for
combustion air intake instructions.
18
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.

Solution 13
Visual Inspection of Burner Operation not Possible
From the ground, the burner inspection window should be visible. If it is not, the heater may be mounted upside
down. Confirm proper mounting and remount if necessary.
Solution 14
Stack Sooting
Soot accumulation can be caused by the following:
14.1
If the air entering the system is not clean (see solutions 6 & 8), soot will form.
14.2
Soot will form if there is not enough air entering the system. The air intake orifice and pipe must be clean and
clear of any obstructions (see 2.2e) (pg. 6 pic. 8).
14.3
Too much gas entering the system will cause soot to form. Check the manifold (section 6.1) pressure
(pg. 6, pic.6 and pg. 21, #2) for the appropriate pressure.
14.4
Check the atmospheric vents on both pressure switches to be sure they are clean and clear. (see 2.3b).
14.5
Be sure there is no excessive back pressure on the system. (Example - high winds, bird nest, snow, etc.)
Solution15
Odor or Fumes Present in Space
Odors present in the space being heated may be caused by a variety of products being used, stored or processed
in the space. These are usually cleaning solvents or sealers which are high in hydrocarbons (ie. parts cleaners,
transmission cleaners and floor sealers). In addition, propane burning forklifts can also add odors and carbon
monoxide to the space.
To cut down on these odors, a clean work environment has to be maintained. If it is necessary that these
solvents remain in the space, proper ventilation is required.
NOTE: If the heater is pulling intake air from the space, its integrity can be compromised by the
presence of these solvents, causing the same problems found in solutions 8-12 of this guide.
19
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.