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66-2001 - R7795A,B,C,D Flame Safeguard Primary Controls 1
66-20012
B. M. Rev. 9-93 �Honeywell Inc. 1993 Form Number 66-20012
R7795A,B,C,D
Flame Safeguard
Primary Controls
The R7795 Flame Safeguard Primary Control
provides flameout protection plus automatic
control of commercial and industrial gas and
oil burners. Models provide intermittent pilot
or interrupted pilot with delayed main valve.
CONTENTS
Specifications ................................................. 2
Ordering Information ..................................... 2
Detailed Operating Sequence ........................ 4
Installation ..................................................... 8
Checkout ....................................................... 11
Troubleshooting ........................................... 17
Service .......................................................... 19
Field selectable ten or four second trial for pilot
flame ignition.
Powered alarm terminal to operate an external line
voltage alarm on safety lockout.
R7795 models are available with either intermittent
pilot (interrupted ignition) or interrupted pilot and
delayed main valve. See Table 2.
Run-Test switch on interrupted pilot/delayed main
valve models.
Safe-start feature prevents start-up with lockout if
flame or a flame simulating failure exists.
Recycle or lockout on flame failure is field selectable.
Safety switch must be manually reset after lockout.
Meets Underwriters Laboratories, Canadian Stan-
dards Association, and Factory Mutual Approved
standards.
Integral solid state color-coded flame amplifiers:
R7795A,C for ultraviolet detection systems (purple).
R795B,D for rectification detection systems (green).
See Table 1.
Solid state plug-in ST95A Purge Timers provide
prepurge timings of 1.5, 7, 10, 30, 60, or 90 seconds.
Includes terminals for connection of a line voltage
airflow switch to prove airflow from the start of
prepurge through the run period.
Mounts on a Q795A Subbase with two captive
screws. All electrical connections are automatically
provided between the device and subbase. Wiring
terminals are accessible for testing.
Meter jack on amplifier board for measuring flame
signal with system in operation.
Internal light-emitting diode (LED) indicates pres-
ence of flame signal. 2
TABLE 2R7795 MODELS AVAILABLE.
Flame
Flame Establishing
Flame Failure
Detection
Amplifier
Period (sec)
Nominal
Device
Run/Test
R7795
Type
Color
Pilot
a
Main
Response (sec)
Reaction
b
Switch
R7795A
UV
Purple
Intermittent
Intermittent
3
Recycle
No
Pilot
or Lockout
R7795B
Rectification
Green
R7795C
UV
Purple
10/4
10
Yes
R7795D
Rectification
Green
Interrupted
Seconds
a
Field selectable:
10 sec with the orange jumper wire unclipped.
4 sec with the orange jumper wire clipped.
b
Field selectable:
Recycle with the yellow jumper wire unclipped.
Lockout with the yellow jumper wire clipped.
R7795A,B,C,D
SPECIFICATIONS ORDERING INFORMATION
Specifications
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, TRADELINE, 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 Satisfaction
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 (612) 951-1000
In CanadaHoneywell Limited/Honeywell Limit�e, 740 Ellesmere Road, Scarborough, Ontario M1P 2V9. International
Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany,
Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
TABLE 1FLAME DETECTION SYSTEMS.
Flame Detection
Applicable Flame Detectors
Model
Amplifier Type
Fuel
Type
Models
R7795A,C
Ultraviolet (purple)
Gas, oil
UV (Minipeeper)
C7027, C7035, C7044
R7795B,D
Rectification (Green)
Gas
Rectifying flame rods
Holders:
a
C7004,
C7007, C7011
Complete Assy:
C7005, C7008,
C7009, Q179
Oil
Rectifying photo cells
b
C7003, C7010,
C7013, C7014
Gas, oil, coal
UV (Purple Peeper)
C7012A,C
a
Order flame rod separately.
b
Use Honeywell part no. 38316 Photocell only. 3
66-20012
ELECTRICAL RATINGS:
Voltage and Frequency: 120 Vac, (+10, -15%), 50/60 Hz.
Power Consumption:
R7795A,C: 17 VA (maximum).
R7795B,D: 15 VA (maximum).
TERMINAL RATINGS:
Maximum Rating
Terminal
Load
at 120 Vac
5
Pilot Valve
125 VA pilot duty.
18
Ignition
360 VA.
6, 7
Main Fuel
125 VA pilot duty or
Valve(s)
25 VA pilot duty plus
one or more motorized
valves with a total rating
of 500 VA opening,
250 VA holding.
8
Fan or
9.8A full load; 58.8A
burner motor locked rotor.
9
Alarm
1.0A.
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.
AMBIENT TEMPERATURE RANGES:
Operating: -40
� F [-40� C] to +135� F [+57� C].
FLAME FAILURE RESPONSE: 3 seconds nominal.
DIMENSIONS: Approximately 5 x 5 x 5-1/4 in. [127 x 127
x 133.5 mm].
WEIGHT: 2.0 lb [0.9 kg].
MOUNTING: Two captive screws in device for mounting
onto Q795A Subbase (ordered separately).
R7795A,B,C,D
SPECIFICATIONS
APPROVALS:
Underwriters Laboratories Inc. listed: File No. MP268,
Guide No. MCCZ.
Canadian Standards Association certification: pending.
Factory Mutual approved: Report No. J.I. OR4A2.AF
ACCESSORIES (See Fig. 1):
W136A Test Meter (includes 196146 Meter Connector
Plug).
196146 Meter Connector Plug for older W136A Test
Meters.
123514A Flame Simulator for rectification systems.
123514B Flame Simulator for ultraviolet systems.
Q624A Solid State Spark Generator.
Q795A Wiring Subbase.
ST795A Plug-in Purge Timer (models available with
1.5, 7, 10, 30, 60, and 90 second timings).
FSP5004A with adapter for operational check of the
R7795.
R1061012 Ignition Cable for ignition installations in
high temperature environments; rated at 350
� F
[177
� C] for continuous duty, and up to 500� F
[260
� C] for intermittent use; tested to 20,000 Vrms.
R1239001 High Tension Ignition Cable for ignition
installations in a contaminating environment; very
resistant to severe conditions of oil, heat, and corona.
Tested to withstand high voltages up to 25,000 Vrms
in a salt bath for one minute without breakdown.
Rated at 200
� F [93� C] for continuous duty, and up
to 250
� F [177� C] for intermittent use.
R1298020 Cable for flame detector (F leadwire) instal-
lations in a high temperature environment; rated up
to 400
� F [204� C] for continuous duty; tested for
operation up to 600V and breakdown up to 7500V.
198365A Remote Reset Cover. Heavy duty cover with
remote reset assembly; 120 Vac, 50/60 Hz solenoid
will only fit R7795 with a series number of 1.
198365B Remote Reset Cover. Heavy duty cover with
remote reset assembly; 120 Vac, 50/60 Hz solenoid
will only fit R7795 with a series number of 2.
Fig. 1R7795 System components.
M12389
Q795A WIRING SUBBASE
COVER
ST795A
PREPURGE
TIMER 4
R7795A,B,C,D
DETAILED OPERATING SEQUENCE
Detailed Operating Sequence
Fig. 2Operating sequence for the R7795A,B, with intermittent pilot.
The R7795A,B provides the following operational se-
quence when used with the appropriate flame detector. (See
Figs. 2 and 3.)
STANDBY
The R7795 Primary Control is ready to start up when
the burner controller closes (limits are closed).
NORMAL START-UP
1. With power applied (limits and controller closed,
terminal L1 to 16, and no flame signal present) the 3K re-
lay pulls in and the burner motor (terminal 8) is energized.
2. As soon as the airflow switch closes (terminal 3 to
8), the ST795A Prepurge Timer starts to time out (pre-
purge begins).
NOTE: The ST795A Prepurge Timer returns to zero any
time the airflow switch opens. The prepurge restarts
when the airflow switch recloses.
3. PILOT FLAME ESTABLISHING PERIOD.
At the end of prepurge (ST795A timed out), the 1K
relay pulls in, energizing the ignition transformer (termi-
nal 18) and the intermittent pilot valve (terminal 5). This
starts the ten or four second pilot flame establishing
period. Safety shutdown and lockout will occur if pres-
ence of flame is not proven within:
Ten seconds if the ORANGE jumper is not clipped.
Four seconds if the ORANGE jumper is clipped.
4. MAIN FLAME IGNITION TRIAL
At the end of the pilot flame establishing period (ten or
four seconds), and with pilot flame present, the main valve
(terminal 6) is energized.
The R7795 is now in the normal burner run mode of
operation and will remain so until an external command
directs it to do otherwise.
5. NORMAL SHUTDOWN
When the burner controller opens, the pilot valve (ter-
minal 5), the main valve (terminal 6) and the burner/
blower motor (terminal 8) are immediately de-energized.
The R7795 goes into the standby mode, terminating the
operating cycle. 5
66-20012
R7795A,B,C,D
DETAILED OPERATING SEQUENCE
Fig. 3Internal schematic of the R7795A,B with intermittent pilot.
INTERRUPTED
PILOT VALVE
MAIN
FUEL VALVE
BURNER
MOTOR
IGNITION
TRANSFORMER
OPTO
ISOLATOR
BASIC DIAGRAM OF
THE R7795A
LINE VOLTAGE
ALARM
1
1
1
2
2
2
3
3
3
5
7
6
18
L1
L2
F
G
8
16
9
3
M11915
2K
ST795A
120 Vac
60 HZ
L1
(HOT)
L2
LINE VOLTAGE
AIRFLOW SWITCH
CONTROLLER
LIMIT(S)
FLAME AMPLIFIER
SOLID STATE
LOGIC CKT.
3K3
3K1
1K2
F1
S.SW
S.SW
3K
1K
1K
2K1
2K1
INTERRUPTED
PILOT