Fenwal 35-61 Series User manual

SERIES 35-61
24 VAC Microprocessor Based Direct Spark
Ignition Control with Combustion Blower Relay
FEATURES
n 24 VAC Microprocessor Based DSI Control
n System Diagnostic LED
n Automatic reset 1 hour after lockout
n Custom prepurge and interpurge timings
n Flame sense test pins
DESCRIPTION
The Series 35-61 is a 24 VAC Microprocessor Based Direct Spark
Ignition Control designed for use in all types of heating applications.
The control utilizes a microprocessor to continually and safely
monitor, analyze and control the proper operation of the gas burner.
Value added features such as combustion blower control, LED
diagnostics, automatic one hour reset, and flame current test pins
highlight the controls benefits.
®
35.61.02
Input Power Control: 18-30 VAC 50/60 Hz
(Class 2 Transformer)
Line: 120/240 VAC
(L1, IND contacts only)
Input Current Drain 300 mA @ 24 VAC, combustion
blower relay and gas valve relay
energized (control only)
Gas Valve Rating 2.0A @ 24 VAC
Combustion Blower 3.0 FLA @ 120 VAC (6.0 LRA)
Rating 1.5 FLA @ 240 VAC (3.0 LRA)
1/4 H.P. Motor
Operating Temperature -40ºF to +160ºF
-40ºC to +71ºC
Flame Sensitivity .7µA minimum
Spark Rate Line frequency (50/60 sparks/ sec.)
Enclosure Gray (Noryl N-190) fire
retardent plastic
Moisture Resistance Conformal coated to operate
to 95% R.H. Care must be
taken to protect module from
direct exposure to water
Tries for Ignition One or three try versions
available
Trial for Ignition Periods 4.0,7.0,10.0, or 15.0 seconds
available
Prepurge & Interpurge None, 15, or 30 seconds
depending on model. Without
prepurge there is a 3.5
second delay before the first
try for ignition.
SPECIFICATIONS
APPLICATIONS
n Gas Furnaces
n Boilers
n Water Heaters
n Other Similar Appliances
Agency Certifications
Software conforms to UL 1998 requirements
Design certified to ANSI Z21.20, CAN/CSA C22.2
No. 199-M89
35-61, 24 VAC DSI Control with Blower Relay Page 1
www.fenwalcontrols.com 1-800-FENWAL-1

MOUNTING AND WIRING
The Series 35-61 is not position sensitive and can be mounted
vertically or horizontally. The case may be mounted on any surface
with #6 sheet metal screws. All wiring must be done in accordance
with both local and national electrical code.
Power Up / Stand By
Upon applying power (24 volts) to 24VAC/R, the control will
reset, perform a self check routine, initiate full time flame
sensing, flash the diagnostic LED for up to four seconds,
and enter the thermostat scan state.
Heat Mode
When a call for heat is received from the thermostat supplying
24 volts to TH/W, the control will check the pressure switch for
normally open contacts. The combustion blower is then
energized and once th pressure switch contacts close, a pre
purge delay begins. Following the pre-purge period the gas
valve is energized and sparks commence for the trial for
ignition period.
When flame is detected during the trial for ignition, sparks are
shutoff immediately and the gas valve combustion blower remains
energized. The thermostat, pressure switch, and main burner
flame are constantly monitored to assure the system continues
to operate properly. When the thermostat is satisfied and the
demand for heat ends, the main valve is de-energized immed-
iately, the control senses the loss of flame signal and initiates
a post-purge period (optional) before de-energizing the
combustion blower.
Failure to Light - Lockout
SINGLE TRIAL MODEL
Should the main burner fail to light, or flame is not detected
during the trial for ignition period, the control will go into lockout.
The valve will be turned off immediately, and the combustion
blower will be turned off following the optional post purge period.
MULTI TRIAL MODEL
Multi-try Models will attempt two additional ignition trials before
going into lockout. The valve relay will be de-energized immed-
iately, and the combustion blower will be turned off following the
optional post purge period.
Recovery from lockout requires a manual reset by either
resetting the thermostat or removing 24 volts for aperiod of
5 seconds.
If the thermostat is still calling for heat after one hour the control
will automatically reset and attempt to ignite the burner again.
Flame Failure - Re-Ignition
If the established flame signal is lost while the burner is
operating, the control will respond within 0.8 seconds. The HV
spark will be energized for a trial ignition period in an attempt to
relight the burner. If the burner does not light the control will de-
energize the gas valve. Multi-try models will make two more
attempts to relight the burner. If the burner does not relight the
control will go into lock out as noted above in “Failure to Light”.
If flame is re-established, normal operation resumes.
Combustion Airflow Problems - Lockout
Combustion air flow is continually monitored during an ignition
sequence by the air flow switch (PSW). If during the initial call for
heat the pressure contacts are in the closed position for 30 sec
onds without an output to the Combustion Blower, an air flow
fault will be declared and the control will remain in this mode with
the combustion blower off.
If the air flow switch remains open for more than 30 seconds
after the combustion blower output (L1 & IND) is energized, an
air flow fault will be declared and the control will stay in this
mode with the combustion blower on, waiting for the air flow
switch to close.
When proper air flow is detected from the air flow switch input
(PSW) the control begins the prepurge period with a normal
ignition sequence following.
If the air flow signal is lost while the burner is firing, the control
will immediately de-energize the gas valve and the combustion
blower will remain on. If the call for heat remains, the control will
wait for proper air flow to return. If proper air flow is not detected
after 30 seconds an air flow fault signal will be declared. If proper
air flow is detected at any time, a normal sequence will begin
with the prepurge period.
Flame Fault
If at any time the main valve fails to close completely and
maintains a flame, the full time flame sense cir cuit will detect
it and energize the combustion blower. Should the main valve
later close completely removing the flame signal, the combustion
blower will power off following the optional post purge period.
Fault Conditions
The LED will flash on for 1/4 second, then off for 1/4 second during
a fault condition. The pause between fault codes is 3 seconds.
SEQUENCE OF OPERATION / FLAME RECOVERY / SAFETY LOCKOUT
Error Mode
Internal Control Failure
Air Flow Fault
Flame with No Call for heat
Ignition Lockout
LED Indication
Steady on
1 flash
2 flashes
3 flashes
Page 2 35-61, 24 VAC DSI Control with Blower Relay www.fenwalcontrols.com 1-800-FENWAL-1
WARNING:
The Series 35-61 uses voltages of shock hazard potential. Wiring
and initial operation must be done by a qualified service tech-nician.
The control must be secured in an area that will experience a
minimum of vibration and remain below the operating temperature of
160ºF. All connections should be made with UL approved 105ºC rated
18 gauge, stranded, .054 thick insulated wire. Refer to wire diagram when
connecting the Series 35-61 to other components in the system.

PROPER ELECTRODE LOCATION
Proper location of the electrode assembly is important for optimum
system performance. It is recommended that electrode assembly be
mounted temporarily using clamps or other suitable means so that
the system can be checked before permanently mounting the
assembly. The electrode assembly should be located so that the
tips are inside the flame envelope and about 1/2 inch (1 cm) above
the base of the flame. See Figure 3 below.
TERMINAL DESIGNATIONS
CAUTION:
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation.
A functional checkout of a replacement control is recommended.
CAUTIONS:
1. Ceramic insulators should not be in or close to the flame.
2. Electrode assemblies should not be adjusted or disassembled.
Electrodes should have a gap spacing of 0.125± 0.031 in
(3.12± 0.81 mm). If this spacing is not correct, the assembly
must be replaced. Electrodes are NOT field adjustable.
3. Exceeding the temperature limits can cause nuisance lockouts
and premature electrode failure.
WARNING:
Operation outside specifications could result in failure of the Fenwal
product and other equipment with injury to people and property.
TROUBLESHOOTING GUIDE
SYMPTOM RECOMMEDED ACTIONS
FLAME SENSOR CURRENT CHECK
SERVICE CHECKS
Flame current is the current which passes through the flame from
the sensor to ground. The minimum flame current necessary to keep
the system from lockout is .7 microamps. To measure flame current,
connect ananalog DC microammeter to the FC-FC+ terminals per
figure. Meter should read .7 uA or higher. If the meter reads below
“0” on scale, meter leads are reversed. Disconnect power and
reconnect meter leads for proper polarity.
24 VAC Supply to Processor
Thermostat Input
Pressure Switch Input
System Ground
Valve Power
Valve Ground
120/240 VAC Input (Hot)
Inducer Blower Output
Alarm
Remote Flame Sensor
24VAC/R
TH/W
PS/W
GND
V1
V2
L1
IND
NC
S1
1. Dead
2. Thermostat on - no
blower output
3. Pressure switch
input okay but no
Trial-for-Ignition
after purge delay
4. Valve on, no spark
5. Spark on, no valve
6. Flame ok during TFI,
no flame sense
(after TFI
A. Miswired
B. Transformer bad
C. Fuse/Circuit breaker bad
D. Bad control (check LED for
steady on)
A. Miswired
B. Bad thermostat no voltage @ terminal W
C. Bad control (check LED for steady on)
A. Miswired (check psw terminal voltage)
B. Flame sense problem(existing flame-check
LED -2 flashes)
C. Bad control (check voltage between L1 & IND)
A. Shorted electrode
B. Open HV cable
C. Bad control
A. Valve coil open
B. Open valve wire
C. Bad control (check voltage between V1 & V2)
A. Bad electrode
B. Bad S1 or HV wire
C. Poor ground at burner
D. Poor flame (check flame current)
Series 35-61 Module
35-61, 24 VAC DSI Control with Blower Relay Page 3www.fenwalcontrols.com 1-800-FENWAL-1
Figure 3

SERIES 35-61 X X X - X X X
Trial for Ignition Time (TFI)
1= 4 Seconds
3= 7 Seconds
5= 10 Seconds
7= 15 Seconds
Inter-PurgeTime
0= NONE (SINGLE TRY MODELS ONLY)
1= 15 Seconds
2= 30 Seconds
Pre-Purge Time
0= NONE
1= 15 Seconds
2= 30 Seconds
Number of Ignition Tries and
Methods of Flame Sensing
0= Single Try - Local Sense
1= Single Try - Remote Sense
5= Three Tries - Local Sense
6= Three Tries - Remote Sense
Inducer Control
0= No Post-Purge (w/input only)
1= No Post-Purge
2= 30 Second Post-Purge
3= 60 Second Post-Purge
Product Designation
5= Standard
8= Aftermartet Kit (may consist of control,
high voltage ignition wire,electrode and harness)
9= *Non-Standard Configuration
Special Options
nNo Cover
nNo Diagnostics
nRecycle after Loss of Flame
DIMENSIONS
CONTROL CONFIGURATION
Description
Page 4 35-61, 24 VAC DSI Control with Blower Relay www.fenwalcontrols.com 1-800-FENWAL-1
*Non-Standard Configurations
9 = Non Standard Configuration
A 9 in this location of the part number
(i.e. 35-61 5 -113) identifies this
configuration as a non-standard design.
The part number does not follow the part
numbering system. The 9XX is a sequential
part number assigned by Fenwal. Consult
factory for operating characteristics of this
control.
901
FENWAL
400 MAIN STREET, ASHLAND, MA 01721
TEL: [phone] FAX: [phone]
www.fenwalcontrols.com
© 2003 Fenwal Printed in U.S.A. TAG
These instructions do not purport to cover all the details or variations in the equipment
described, nor do they provide for every possible contingency to be met in connection with
installation, operation and maintenance. All specifications subject to change without notice.
Should further information be desired or should particular problems arise which are not covered
sufficiently for the purchaser’s purposes, the matter should be referred to KIDDE-FENWAL,
Inc., Ashland, Massachusetts.
P/N 35.61.02 6/20/03
®