Honeywell R4795A User manual

160-2285—7
R4795A
Flame Safeguard
Primary Controls
The R4795A Protectorelay™ Primary Control
provides solid state electronic flame safeguard
protection for commercial and industrial gas or oil
burners. It provides a prepurge period before each
start, and intermittent pilot.
■120V models meet the requirements of Underwrit-
ers Laboratories Inc. Standard 795 for mechanical
draft and atmospheric burner inputs from 400,000 to
2,500,000 Btu.
■Meets Underwriters Laboratories Inc. requirements
for oil burner group 8 when 30, 60, or 90 second pre-
purge timer is used.
■Selection of solid state, plug-in prepurge timers pro-
vides 7, 10, 30, 60, or 90 second prepurge time.
■Includes terminals for connection of air flow switch
to prove airflow before prepurge period starts, dur-
ing purge, and during the entire Run period.
■Choice of interchangeable, color-coded, solid state,
plug-in flame signal amplifiers allows use with rec-
tification or ultraviolet type flame detectors.
■Safe-start feature prevents start when flame or flame
simulating condition is present.
■Recycles through prepurge if the flame goes out
while burner is running. If pilot flame is not re-
established, safety switch trips and locks out system.
■A tripped safety switch must be manually reset to
restore operation.
■Push-to-resetsafetyswitchisdust-resistantenclosed.
■Optional spdt alarm contacts operate external alarm
on safety switch lockout.
■Ignition interference circuit (rectification amplifier
only) protects electronic network from high voltage
ignition crossover and provides visual indication
when interference occurs.
■Solid state circuitry eliminates vacuum tube replace-
ment and increases resistance to vibration. Applica-
tion of power not required during Off cycle; no tube
warmup before starting.
■Easy-to-replace plug-in components result in faster
service and reduced inventory.
■Flame current jack, located on the amplifier, provides
means of plugging in a microammeter to measure the
flame signal with system operating.
■Easy mounting and removal through use of captive
mounting screws, which also serve as electrical
connections.
■Durable thermoplastic mounting base.
■Models available with -40°F (-40°C) temperature
rating.
S.Y. • Rev. 12-94 • ©Honeywell Inc. 1994
60-2285-7
CONTENTS
Specifications ................................................. 2
Ordering Information ..................................... 2
Installation ..................................................... 4
Checkout ......................................................... 8
Operation ..................................................... 11
Troubleshooting ........................................... 11
Service .......................................................... 13

60-2285—7 2
R4795A
SPECIFICATIONS • ORDERING INFORMATION
Specifications
R4795A Flame Safeguard Primary Control recycles once
after flame failure to try to re-establish pilot before lockout.
Use with R7289A Amplifier and rectifying flame rod, recti-
fying photocell, or C7012A,C Purple Peeper Ultraviolet
Flame Detector; or with R7290A Amplifier and C7027A,
C7035A, or C7044A Minipeeper Ultraviolet Flame Detector.
AMBIENT TEMPERATURE RATINGS:
Minimum: -20°F (-29°C). Special models to -40°F (-40°C).
Maximum: +125°F (52°C) at 60 Hz; +115°F (46°C) at
50 Hz. -40°F (-40°C) models have maximum ambient
of +115°F (46°C) at 60 Hz, +105°F (40°C) at 50 Hz.
Subtract 10°F (6°C) when optional alarm contacts are
included.
ELECTRICAL RATINGS:
Voltage and Frequency: Single voltage models only:
100V, 120V, 200V, 220V, 50/60 Hz. As ordered.
Power Consumption (at 60 Hz):
6.0W max using rectifying flame rod or photocell.
8.0W max using ultraviolet flame detector.
FLAME FAILURE RESPONSE TIME: 0.8 or 3 seconds
nominal, as ordered.
SAFETY SWITCH TIMING (LOCKOUT TIMING): 15 sec-
onds nominal.
RECYCLE TIME: Almost immediate after Flame Failure
Response Time.
FLAME ESTABLISHING PERIOD: May last up to safety
switch lockout time or until flame is recognized by
device.
ALARM CONTACTS (Optional): Isolated spdt contacts.
Male quick-connect terminals (female quick-connects
included). See Terminal Ratings. –40°F (–40°C) models
have isolated spdt alarm contacts.
Ordering Information
When purchasing replacement and modernization products from your TRADELINE®wholesaler or your distributor, refer to the
TRADELINE®catalog or price sheets for complete ordering number, or specify:
1. Order number. 3. Flame failure response time.
2. Voltage and frequency. 4. Alarm contacts, if desired (included with -40°F [-40°C] models.)
Order separately:
1. R7289A Rectification Amplifier, 3. Plug-in prepurge timer model number
or R7290A Ultraviolet Amplifier. and timing (7, 10, 30, 60, or 90 seconds).
Specify flame failure response time. 4. Q270A1024 Mounting Subbase.
2. Flame detector to match amplifier. 5. Accessories, if desired.
If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:
1. Your local Honeywell Home and Building Control sales office (check white pages of phone directory).
2. Home and Building Control Customer Logistics
Honeywell Inc., 1985 Douglas Drive North
Minneapolis, Minnesota 55422-4386
In Canada—Honeywell Controls Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9. International
sales and service offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan,
Mexico, Netherlands, Taiwan, United Kingdom, U.S.A.

360-2285—7
R4795A
SPECIFICATIONS
TERMINAL RATINGS:
Terminal Load Rating
3 Pilot Valve 125 VA pilot duty.
Intermittent Ignition
a
360 VA.
4 Interrupted Ignition 360 VA.
5 Main Fuel Valve(s) 125 VA pilot duty, or 25 VA pilot duty plus one or more motorized
valves with total rating up to 400 VA opening, 200 VA holding.
6-7 Airflow Switch 0.6A at 30 Vdc.
8 Fan or Burner Motor 9.8A full load, 58.8A locked rotor (inrush) at 120 Vac. 4.9A full
load, 29.4A locked rotor (inrush at 220 and 240 Vac.
Isolated Spdt Alarm
Terminals (Optional) Alarm 3A at 24 volts, or 1A at 120 volts, in a suitable wiring enclosure.
aWhen ignition is connected to terminal 3, terminal 4 cannot be used.
NOTE: Allowable inrush can be up to ten times the pilot
duty rating.
Example:
Pilot duty rating = 125 VA.
At 120V, running current is 125/120 = 1.05A.
Maximum allowable inrush is 10 times 1.05 = 10.5A.
DIMENSIONS (Includes Cover and Subbase): Approxi-
mately 5 x 5 x 5 in. (127 x 127 x 127 mm).
MOUNTING: Q270A1024 Subbase. Ordered separately.
APPROVALS:
Underwriters Laboratories Inc Listed: 120V models us-
ing 30, 60, or 90 second prepurge timers including –
40°F (–40°C) rated models; file no. MP268, guide
no. MCCZ.
Underwriters Laboratories Inc. Component Recognized:
120 volt models using 7 or 10 second prepurge timers
including -40°F (-40°C) rated models; file no. MP268,
guide no. MCCZ2.
Canadian Standards Association Certified: 120V mod-
els only, including -40°F (-40°C) rated models; file
no. LR95329.
Factory Mutual Approved: R4795A 120V models; re-
port no. 18774. -40°F (-40°C) rated models; report
no. 19608.1.
American Gas Association Design Certified: File no. 21-6
(F and F1).
ACCESSORIES:
W136A Test Meter (includes 117053 Meter Connector
Plug).
Flame Simulator:
203659 Ultraviolet
121708 Rectification
123514B Ultraviolet
117053 Meter Connector Plug
FSP1535 Tester for operational check
Q624 Solid State Spark Generator
118702E Remote Reset Cover, 120 Vac, 60 Hz
202471C Reset Cover for R4795A
ADDITIONAL CONTROLS:
Order all additional controls separately:
Q270A1024 Mounting Subbase.
Plug-In Flame Signal Amplifiers, Rectification Type
(Green Backplate): For use with C7004B C7005A,
and B, C7008A, or Q179A,C Rectifying Flame Rods
(for gas); C7003A, C7010A, C7013A or C7014A
Photocells (for oil); or C7012A,C Purple Peeper Ul-
traviolet Flame Detectors (for gas or oil).
R7289A1004 Amplifier: 3 sec nominal flame failure
response.
R7289A1012 Amplifier: 0.8 sec nominal flame failure
response.
R7289A1020 Amplifier: 3 sec nominal flame failure
response, -40°F (-40°C) ambient temperature.
UltravioletType(PurpleBackplate): Foruse withC7027A,
C7035A or C7044A Minipeeper Ultraviolet Flame
Detectors (for gas or oil).
R7290A1001 Amplifier: 3 sec nominal flame failure
response.
R7290A1019 Amplifier: 0.8 sec nominal flame failure
response.
R7290A1027 Amplifier: 3 sec nominal flame failure
response, -40°F (-40°C) ambient temperature.
ST71A Plug-In Prepurge Timer (ordered separately):
Minimum Timings: 7, 10, 30, 60, and 90 seconds (as
ordered).
Maximum Timings: 8.4, 12, 36, 72, and 108 seconds
at room ambient temperature.
RecommendedLimits: L404A;L604A,L;L4006A,C,E;
L4008A,E,F; L6006A,B: These controllers were
Underwriters Laboratories Inc. tested for breaking
loads only, at 120 Vac, for the total rating of 9.8A
full load, plus 360VA ignition, plus 250 VA pilot
duty.
Flame Detector: As specified in Plug-In Flame Signal
Amplifiers listed above.

60-2285—7 4
R4795A
INSTALLATION
Installation
Vibration
Do not install the R4795A where it could be subject to
excessive vibration. Vibration shortens the life of the elec-
tronic and mechanical components.
Weather
The R4795A is not designed to be weathertight. If it is
installed outdoors, use a suitable weathertight enclosure.
Mounting The Subbase
Locate the subbase where ambient temperature is within
the specified rating.
Mount the subbase so the top and bottom are horizontal
and the back is vertical. The subbase can lean backward as
much as 45 degrees when necessary. See Fig. 1.
Fig. 1—Subbase mounting dimensions in in.
(mm).
CAUTION
1. Installer must be a trained, experienced, flame
safeguard control service technician.
2. Disconnect power supply before beginning in-
stallation to prevent electrical shock and equip-
ment damage.
3. All wiring must comply with applicable local
electrical codes, ordinances, and regulations.
4. Voltage and frequency of the power supply
connected to this control must agree with those
marked on the device.
5. Loads connected to the control terminals must
not exceed those listed in the Specifications
section.
6. All external timers must be Listed or Compo-
nent Recognized by authorities having jurisdic-
tion for the specific purpose for which they are
used.
7. Some authorities having jurisdiction prohibit
the wiring of any limit or operating contacts in
series with the main fuel valve(s).
8. Perform all required checkout tests after instal-
lation is complete.
Follow the burner manufacturer’s instructions, if sup-
plied. Otherwise proceed as follows.
CAUTION
Ultraviolet sensing tubes have a life expectancy of
40,000 hours of continuous use within the ambient
temperature and voltage ratings. Worn out ultra-
violet sensing tubes can result in failure of the
sensingtube toproperlydiscriminate betweenflame
conditions.
For systems using R4795A with R7290 Amplifiers, use
C7027, C7035 and C7044 Flame Detectors only on burners
that cycle On and Off at least once every 24 hours. Appli-
ances with burners that remain on for 24 hours continuously
or longer should use the C7012E Flame Detector with the
R7247C Amplifier or the C7076A Flame Detector with the
R7476A Amplifier as the ultraviolet flame detection system.
LOCATION
Temperature
Install the R4795A where the surrounding temperatures
remain within the Ambient Operating Temperature Ratings
listed in the Specifications section.
Humidity
Install the R4795A where the relative humidity never
reaches the saturation point. Condensation of moisture on
the R4795A may cause enough leakage to short the flame
signal to ground and prevent the burner from starting.
M8681
HORIZONTAL
VERTICAL
2-7/8
(73.0)
4-1/8 (104.8)
KNOCKOUTS (9) FOR
1/2 IN. (13) CONDUIT
45 DEGREES
MAXIMUM LEAN
WIRING TO SUBBASE
1. All wiring must comply with applicable codes, ordi-
nances, and regulations. All wiring to the Q270A Universal
Mounting subbase must be NEC Class 1.
2. When wiring the Q270A for use with the R4795A, use
the terminal designations 8, 7, and 6 (printed in yellow).
3. For normal installations, use moisture-resistant No. 14
wire suitable for at least 167°F (75°C).
4. For high temperature installations, use moisture-re-
sistant No. 14 wire selected for a temperature rating above
the maximum operating temperature for all but the ignition
and flame detector F leadwires.
a. For the ignition, use Honeywell Specification no.
R1061012 Ignition Cable or equivalent. This wire is
rated at 350°F (175°C) for continuous duty, and up to
500°F (260°C) for intermittent use.
b. For the flame detector F leadwire, use Honeywell
Specification no. R1298020 or equivalent. This wire
is rated up to 400°F (205°C) for continuous duty. It is
tested for operation up to 600V and breakdown up
to 7500V.

560-2285—7
R4795A
INSTALLATION
IMPORTANT: Do not run high voltage ignition trans-
former wires in the same conduit with the flame
detector wiring.
5. For ignition installations in a contaminating environ-
ment, use Honeywell Specification no. R1239001 High Ten-
sion Ignition Cable or equivalent. This wire is very resistant
to severe conditions of oil, heat, and corona, and is tested to
withstand high voltages up to 25,000V rms in a salt bath for
one minute without breakdown. It is rated at 200°F (93°C)
for continuous duty and up to 350°F (75°C) for intermittent
use.
Wiring Hookups
The typical wiring hookups in Fig. 2 and 3 show the
internal line voltage schematic. Contact 3K2 closes when the
controller calls for heat. 1K4 closes when prepurge is com-
plete. 2K2 breaks and 2K3 makes when flame is proven.
Also see the Operation section.
Fig. 2—Wiring hookup of gas system with
interrupted ignition and intermittent pilot.
M8682
L1
(HOT)
L2
1
1
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR INTERMITTENT IGNITION, CONNECT IGNITION TO TERMINAL 3.
REFER TO SPECIFICATIONS SECTION FOR RECOMMENDED LIMITS.
BURNER
MOTOR
AIR FLOW
SWITCH
TO FLAME
DETECTOR
(FLAME ROD
OR UV
DETECTOR)
FLAME
AMPLIFIER
1K4
3K2
2K2
2K3
MAIN FUEL
VALVE(S)
IGNITION
PILOT
VALVE
CONTROLLER
LIMIT(S)
R4795A
8
7
6
F
G
5
4
3
1
2
2
3
Fig. 3—Wiring hookup of oil system with
interrupted ignition.
M8683
L1
(HOT)
L2
1
1
2
3
4
5
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
FOR INTERMITTENT IGNITION,CONNECT IGNITION TO TERMINAL 3.
IMMEDIATE OPENING OIL VALVE V4046B.
OPTIONAL DELAYED OPENING OIL VALVE V4046A OR V4046B WITH
ST70A ELECTRONIC TIME DELAY.
REFER TO SPECIFICATIONS SECTION FOR RECOMMENDED LIMITS.
BURNER
MOTOR
AIR FLOW
SWITCH
TO FLAME
DETECTOR
(PHOTOCELL
OR UV)
FLAME
AMPLIFIER
1K4
3K2
2K2
2K3
2ND STAGE
OIL VALVE(S)
IGNITION
1ST STAGE
OIL VALVE(S)
CONTROLLER
LIMIT(S)
R4795A
8
7
6
F
G
5
4
3
1
2
2
5
3
4
Retrofitting R4795
CAUTION
Make wiring connections as specified in Fig. 2, 3,
or 4. Do not simply plug the R4795 into the old
subbase without first changing the wiring at the
subbase.
Observe the following when retrofitting the R4795:
1. Requires a line voltage controller capable of switching
the entire connected electrical load.
2. Delayed opening oil valve may be retained but its
delay is not necessary. Integral ST71A Purge Timer meets
the intent of a delayed opening valve.
3. Refer to Fig. 2, 3 or 4 for proper wiring connections.

60-2285—7 6
R4795A
INSTALLATION
Replacing RA890E,F,G with R4795A
1. Disconnect all wires from terminal 1, and splice with
solderless connector. (If RA890 has no terminal 1 wiring,
disregard this step.)
2. Remove line voltage controller wire from terminal 6
and connect to terminal 1.
3. Move burner motor connection from terminal 3 to ter-
minal 6 on subbase.
4. Remove jumper from T and T and install air switch. If
low voltage control was wired to RA890 T-T, remove low
voltage control and install line voltage control as shown in
Fig. 4.
5. If R482D Relay was used with RA890E, remove it.
The R482D is redundant when R4795D is used.
6. Checkforproper operation through atleasttwocycles.
Fig. 4—Replacing RA890E,F,G with R4795A on
gas or oil burner.
L1
(HOT)
L2
REPLACING RA890 WITH R4795 ON GAS OR OIL BURNER
CONTROLLER HIGH LIMIT MAIN GAS
VALVE OR
2ND STAGE
OIL VALVE
IGNITION
TRANSFORMER
BURNER
MOTOR
PILOT OR
OIL VALVE
RA890 WITH Q270
BEFORE
FLAME
DETECTOR
6
T
T
F
G2
1
3
4
5
L1
(HOT)
L2
CONTROLLER HIGH LIMIT MAIN GAS
VALVE OR
2ND STAGE
OIL VALVE
IGNITION
TRANSFORMER
BURNER
MOTOR
PILOT OR
OIL VALVE
RA4795 WITH Q270
AFTER
FLAME
DETECTOR
68
7
6
T
T
F
G
2
1
3
4
5
AIR FLOW
SWITCH
SODERLESS
CONNECTION
120V
120V
M8684
R4795C Replacement
In most cases, the R4795A can directly replace the
R4795C. For standing pilot applications where the pilot
flame was detected during the off cycle, install a relay as
shown in Fig. 5.
Flame Detector Wiring
See Fig. 6.
Alarm Contacts
Models with alarm contacts have three male quick-con-
nect terminals. Three female quick-connect terminals are
provided for field installation. To connect leadwires to the
female quick-connects, strip 1/4 inch (6.4 mm) insulation
from end of leadwire; insert into the quick-connect, and
crimp securely with a crimping tool. Fig. 7 shows proper
alarm terminal connections.
If a line voltage alarm is used with the R4795, mount the
entire control in a suitable enclosure.
Fig. 5—When R4795A replaces R4795C in a
standing pilot application, install relay 1R to
prevent detection of pilot flame during burner
off cycle.
M8685
L1
(HOT)
L2
1
1
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
REFER TO SPECIFICATIONS SECTION FOR RECOMMENDED LIMITS.
LOW VOLTAGE CIRCUIT OMITTED.
BURNER
MOTOR
AIR FLOW
SWITCH
TO FLAME
DETECTOR
(FLAME ROD
OR UV
DETECTOR)
FLAME
AMPLIFIER
1K4
3K2
1R1
2K2
2K3
MIAN FUEL
VALVES
CONTROLLER
LIMIT(S)
8
7
6
F
G
5
4
3
1
2
2
3
1R
R4795A

760-2285—7
R4795A
INSTALLATION
Fig. 6—Flame detector wiring.
M8686
BLUE
WHITE
F
G
C7027, C7035, OR C7044
ULTRAVIOLET FLAME DETECTOR
BLUE
YELLOW
BLACK
BLACK
F
G
C7012 ULTRAVIOLET DETECTOR
1
G
F
X
X
X
X
X
X
FLAME ROD
G
F
X
X
PHOTOCELL
1C7027, C7035, AND C7044 FLAME DETECTOR LEADS ARE COLOR
CODED BLUE AND WHITE. THE BLUE LEAD MUST BE CONNECTED
TO THE F TERMINAL AND THE WHITE LEAD MUST BE CONNECTED
TO THE G TERMINAL. THIS CIRCUIT IS DC AND THE UV SENSING
TUBE IS POLARITY SENSITIVE. REVERSING THE LEADS EVEN
MOMENTARILY CAN DAMAGE OR DESTROY THE UV TUBE.
POWER
SUPPLY
Fig. 7—Alarm terminal connections.
Mounting R4795 On Subbase
Make sure that the power supply is disconnected.
Loosen the thumbscrew and remove the cover (see Fig. 8).
Position the R4795 over the Q270 Subbase. Start all ten
mounting screws and tighten uniformly. These screws com-
plete electrical circuits (terminal 1 excepted) and hold the
R4795 to the subbase.
L1
(HOT)
L2
1
1
2
2
IF A LINE VOLTAGE ALARM IS USED, THE R4795 MUST BE
MOUNTED IN A SUITABLE ENCLOSURE.
POWER SUPPLY MUST MATCH THE ELECTRICAL RATINGS OF THE
ALARM. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
LINE OR
LOW VOLTAGE
ALARM
ALARM TERMINALS (OPTIONAL)
N.C. N.O. COM
M8687
R4795
ALARM
POWER
SUPPLY
CAUTION
Do not overtighten the mounting screws because
damage to the circuit board can result. Maximum
recommended torque is 10 lb-in. (1.13 N•m).
Replace cover and securely tighten thumbscrew.
Fig. 8—R4795 and Q270 Subbase.
TERMINAL
BLOCKS
PURGE TIMER
AMPLIFIER
COVER THUMBSCREW
SAFETY SWITCH
RESET BUTTON
IN COVER
CAPTIVE MOUNTING
SCREWS (10)
Q270
SUBBASE
M8688

60-2285—7 8
R4795A
CHECKOUT
Checkout
Fig. 10—Internal view showing amplifier and
test jack for flame current test.
CAUTION
Use extreme care while testing the R4795; line
voltage can be present on most terminals when the
power is On.
CHECKOUT SUMMARY
The following list summarizes the checkout tests re-
quired for each type of installation. Instructions for each test
are included in this section.
Preliminary Inspection: All installations.
Flame Current Check: All installations.
Pilot Turndown Test: If a pilot must be proved before the
main fuel valves can open.
Hot Refractory Hold-in Test: Photocell oil installations
only.
Ignition Spark Response Test: All ultraviolet detector
applications.
Safe Shutdown Tests: All installations.
Refer to Fig. 2 to 3 for terminal location, and to Fig. 9 and
10 for location of component parts. Loosen thumbscrew to
remove cover.
Fig. 9—Internal components of R4795A.
M8679
1K
UNDER
COVER
PLUG-IN
PURGE
TIMER
(ST71A)
SPRING
CLIP FOR
AMPLIFER
PLUG IN AMPLIFIER
(R7289–GREEN–RECTIFICATION)
(R7290–PURPLE–ULTRAVIOLET)
TRANSFORMER
SAFETY
SWITCH
RESET
BUTTON
CAPTIVE
MOUNTING
SCREWS
(10)
2K
3K
M8680
ST71A
PLUG-IN
PURGE
TIMER
PURGE TIMER
CONNECTORS
PLUG-IN
AMPLIFIER
OPTIONAL
ALARM TERMINALS
AMPLIFIER
CONNECTORS
TEST JACK
ARC-GAP IGNITION INTERFERENCE
PROTECTION (R7289 RECTIFICATION
AMPLIFIER ONLY)
PRELIMINARY INSPECTION
Make certain that:
1. Wiring connections are correct and all terminal screws
are tight. Use a meter to check the continuity of all circuits.
2. Flame detector is installed and positioned properly.
Consult the appropriate installation instructions.
3. Ambient temperature at flame detector does not ex-
ceed maximum rated temperature.
4. Correct combination of amplifier and flame detector is
used. Refer to Plug-In Flame Signal Amplifiers in Specifica-
tions section.
5. Burner is completely installed and ready to fire; fuel
lines are purged of air.
6. Combustion chamber and flues are clear of fuel.
7. Power is connected to system disconnect switch (mas-
ter switch).
8. Safety switch is reset; push in and then release the
green safety switch.
9. All limits and interlocks are reset.
IMPORTANT: Anytime you reset the safety switch, wait at
leastoneminuteafter it tripstoallowtheheater to cool
before pushing in the reset button.
CAUTION
Make initial pilot lightoff with manual main fuel
shutoff cock closed.

960-2285—7
R4795A
CHECKOUT
2. The flame current is at least two microamperes for
R7289A Rectification Amplifier (color-coded green), or at
least 1.5 microamperes for an R7290A Ultraviolet Amplifier
(color-coded violet).
IF A STEADY READING OF AT LEAST MINIMUM
STRENGTH CANNOT BE OBTAINED, ONE OR MORE
OF THE FOLLOWING CONDITIONS CAN EXIST:
•Improper supply voltage.
•Defective flame detector wiring including:
—Open circuits.
—Short circuits.
—High resistance shorts caused by moisture, accu-
mulated dirt, or an improper choice of detector lead-
wire for the particular installation.
•Impropersighting,improper viewing window, ordirty
viewing window for optical detectors.
•Improper application of a flame rod including:
—Insufficient ground area.
—Poor location of flame rod in flame.
—Excessive heat on flame rod insulator, greater than
600°F (316°C).
—Ignition interference.
•Improper application of a vacuum photocell including:
—Temperature over 165°F (74°C) at photocell.
—Dirty photocell envelope.
•Defective sensor.
PILOT TURNDOWN TEST
IMPORTANT: If the R4795 is used to prove a pilot flame,
perform the following Turndown Test to assure that
the main burner can be lit by the smallest pilot flame
that will hold in the 2K (flame) relay.
1. Shut off the fuel supply to the main burner only by
closing the manual main burner shutoff cock. Do not shut off
fuel supply to the pilot valve.
2. Start the system by raising the setpoint of the control-
ler (or pressing the START button). After prepurge is com-
pleted, the pilot will light and pull in the flame relay.
3. Reduce the size of the pilot flame to the turndown
condition by slowly closing the manual valve on the pilot gas
line. At the turndown condition, the pilot will be small
enough so it just barely holds in the flame relay (2K).
a. Slowly turn down the pilot until the flame relay drops
out.
b. Allow the control to complete prepurge.
c. As the control attempts to restart the pilot, turn the
pilot back up slowly just until relay 2K pulls back in.
You will have 15 seconds to complete this step before
lockout occurs.
d. Again turn the pilot down slightly but not enough so
the flame relay drops out. If the relay drops out, simply
allow the control to complete the purge period and
then turn the pilot back up to pull in the flame relay as
in step c. above. The closer the pilot is to the dropout
condition, the more conclusive the test will be.
FLAME CURRENT CHECK
The flame current check is the best indicator of proper
flame detector application. Perform the check at the time of
installation, and at any time service is done on the system,
and at least once a month, or more often, while the system is
in operation. This prevents shutdowns due to poor flame
signal.
Test by connecting a W136 (or equivalent) to the ampli-
fier and reading the flame current while the burner is operat-
ing. (Fig. 11).
Fig. 11—Connecting meter to read flame
current.
M8689
W136
117053 METER
CONNECTOR PLUG
(SUPPLIED WITH W136)
BLACK
BLACK
BLACK
RED
RED
FLAME
CURRENT
TEST JACK
PLUG-IN
AMPLIFIER
IF 117053 METER CONNECTOR PLUG IS NOT AVALIABLE
(R7289A RECTIFICATION AMPLIFER ONLY)
FLAME
DETECTOR
F LEAD
G LEAD
RED F
G
W136
R4795
-+
Insert a 117053 Meter Connector Plug, wired color-to-
color to the W136 leadwires, into the test jack on the ampli-
fier (Fig. 10). This automatically puts the microammeter in
series with the flame detector.
If an R7289A Rectification Type Amplifier is used and a
meter connector plug is not available, disconnect the flame
detector lead from the F terminal; then connect this lead to
the Black lead of the microammeter, and connect the Red
lead of the microammeter to the F terminal.
NOTE: If an R7290A Ultraviolet Type Amplifier is used, the
flame current cannot be read by connecting a micro-
ammeter in series with the F lead.
When reading the flame current, assure that the following
criteria are met:
1. The flame current is steady; meter does not vary more
than a needle width.

60-2285—7 10
R4795A
CHECKOUT
CAUTION
Do not manually push in the relays.
4. Check that the pilot is lit and relay 2K is pulled in.
5. Open the manual main burner shutoff cock. Main
flame should light within one second. If the burner does not
light within one second, close the shutoff cock and shut off
power to the relay. Proceed to step 7.
6. If the burner lights, repeat step 5 two or three times to
verify lightoff.
7. If the lightoff is unsatisfactory, readjust the flame
detector to require a larger pilot flame to hold in the flame
relay. This usually requires:
a. Resighting a photocell or UV type detector farther
out on the axis of a pilot flame, or
b. Adjusting a flame rod detector so that a larger mini-
mum pilot is required.
8. Repeat the entire turndown test until the flame is
established promptly in step 5.
9. Turn up the pilot to full flame at the test completion.
HOT REFRACTORY HOLD-IN TEST
(PHOTOCELL OIL INSTALLATIONS ONLY)
If hot refractory holds in the flame relay at the end of the
burner-on cycle, the system cannot restart until the relay
drops out. Check for hot refractory hold-in by observing the
flame relay for immediate dropout at the end of a long
burner-on period. If the relay does not drop out, resight the
photocell so it does not sight the refractory, or decrease
photocell sensitivity using aperture disks or filters.
IGNITION SPARK RESPONSE TEST
(UV DETECTORS)
The flame relay should not respond (pull in) to ignition
spark. To determine flame detector sensitivity to ignition
spark, perform the following test:
1. Shut the pilot and main fuel manual valves.
2. Start the system by raising the controller setpoint or
pressing the START button. This should energize the igni-
tion transformer so spark is produced between the electrode
and ground.
3. Check the flame relay 2K. The relay should not pull in.
The flame signal current should not be more than one-fourth
microampere.
4. If relay 2K does pull in, resight the detector farther out
from the spark, or away from possible reflection. It may be
necessary to construct a barrier to block the ignition spark
from the detector view. Continue adjustments until flame
detector does not respond to the ignition spark.
IMPORTANT: Repeat ALL required checkout tests after all
adjustments are complete. ALL tests must be satisfac-
tory when the flame detector is in its FINAL position.
SAFE SHUTDOWN CHECKS
Limit Action
With the burner operating, lower the high limit setting to
simulate an overheated boiler or furnace. Normal shutdown
should occur. Restore the normal limit setting; the burner
should go through a normal prepurge and start.
Using manual reset limits is desirable to prevent the
system from cycling off the high limit and to assure that the
condition that caused the limit action is detected as soon as
possible.
Flame Failure
Let burner operate five minutes; then manually shut off
fuel supply to simulate flame failure. Relay should drop out
and fuel valve(s) close. The system will purge and then lock
out on safety. Let the safety switch cool for one minute;
reopen manual fuel valve, and reset safety switch. Burner
should start.
Power Failure
Let the burner run five minutes. Then simulate power
failure by opening the line switch. All relays should drop out
and the fuel valves should close. After a minimum of five
seconds, close the line switch. The R4795 should go through
a normal cycle.
IMPORTANT: At the completion of all Checkout tests,
make sure that the R4795 is not on safety lockout, that
the pilot is turned up to its normal level, and that all
limit settings are correct. Operate the system through
one normal cycle. Replace cover and securely tighten
thumbscrew.