Honeywell R4795A User Manual
The R4795A Protectorelay™ Primary Control
60-2285-7
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.
R4795A
Flame Safeguard
Primary Controls
■ 120V models meet the requirements of Underwriters 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 prepurge timer is used.
■ Selection of solid state, plug-in prepurge timers provides 7, 10, 30, 60, or 90 second prepurge time.
■ Includes terminals for connection of air flow switch
to prove airflow before prepurge period starts, during purge, and during the entire Run period.
■ Choice of interchangeable, color-coded, solid state,
plug-in flame signal amplifiers allows use with rectification 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 reestablished, safety switch trips and locks out system.
■ A tripped safety switch must be manually reset to
restore operation.
■ Push-to-reset safety switch is dust-resistant enclosed.
■ 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 replacement and increases resistance to vibration. Application 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.
CONTENTS
Specifications ................................................. 2
Ordering Information ..................................... 2
Installation ..................................................... 4
Checkout.........................................................8
Operation ..................................................... 11
Troubleshooting ........................................... 11
Service ..........................................................13
S.Y. • Rev. 12-94 • ©Honeywell Inc. 1994
1 60-2285—7
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, rectifying 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
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
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
60-2285—7 2
®
catalog or price sheets for complete ordering number, or specify:
or R7290A Ultraviolet Amplifier. and timing (7, 10, 30, 60, or 90 seconds).
Specify flame failure response time. 4. Q270A1024 Mounting Subbase.
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.
TERMINAL RATINGS:
Terminal Load Rating
3 Pilot Valve 125 VA pilot duty.
Intermittent Ignitiona360 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
Alarm 3A at 24 volts, or 1A at 120 volts, in a suitable wiring enclosure.
Terminals (Optional)
a
When ignition is connected to terminal 3, terminal 4 cannot be used.
R4795A
SPECIFICATIONS
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 Ultraviolet 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.
Ultraviolet Type (Purple Backplate): For use with C7027A,
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.
Recommended Limits: 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.
3 60-2285—7
R4795A
INSTALLATION
Installation
CAUTION
1. Installer must be a trained, experienced, flame
safeguard control service technician.
2. Disconnect power supply before beginning installation to prevent electrical shock and equipment 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 Component Recognized by authorities having jurisdiction 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 installation is complete.
Follow the burner manufacturer’s instructions, if sup-
plied. Otherwise proceed as follows.
Vibration
Do not install the R4795A where it could be subject to
excessive vibration. Vibration shortens the life of the electronic 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).
HORIZONTAL
VERTICAL
(73.0)
2-7/8
45 DEGREES
MAXIMUM LEAN
CAUTION
Ultraviolet sensing tubes have a life expectancy of
40,000 hours of continuous use within the ambient
temperature and voltage ratings. Worn out ultraviolet sensing tubes can result in failure of the
sensing tube to properly discriminate between flame
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. Appliances 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.
4-1/8 (104.8)
KNOCKOUTS (9) FOR
1/2 IN. (13) CONDUIT
M8681
WIRING TO SUBBASE
1. All wiring must comply with applicable codes, ordinances, 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.
60-2285—7 4
R4795A
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
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 complete. 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.
MAIN FUEL
BURNER
MOTOR
8
2K3
5
VALVE(S)
Fig. 3—Wiring hookup of oil system with
interrupted ignition.
AIR FLOW
SWITCH
TO FLAME
DETECTOR
(FLAME ROD
OR UV
DETECTOR)
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2
FOR INTERMITTENT IGNITION, CONNECT IGNITION TO TERMINAL 3.
3
REFER TO SPECIFICATIONS SECTION FOR RECOMMENDED LIMITS.
7
6
F
G
FLAME
AMPLIFIER
R4795A
2K2
1K4
3K2
4
IGNITION
3
1
2
PILOT
VALVE
CONTROLLER
LIMIT(S)
2
Retrofitting R4795
3
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
1
L2
L1
(HOT)
subbase.
Observe the following when retrofitting the R4795:
1. Requires a line voltage controller capable of switching
M8682
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.
5 60-2285—7
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