Conspec Controls P2621-NO2/VC User manual

Conspec Controls, Inc.
P2621-NO2/VC
Nitrogen Dioxide Ventilation Fan
Controller
Operations Manual
Conspec Controls, Inc.: 1 - 800 - 487 -8450

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I) SYSTEM DESCRIPTION
Conspec’s P2621 - NO2/VC Nitrogen Dioxide (NO2) Monitor / Ventilat ion Controller is
designed for use where ventilation fans are installed to prevent the accumulation of
dangerous levels of Nitrogen Dioxide. Nitrogen Dioxide is a toxic byproduct of
combustion and is contained in the exhaust of internal combustion engines. The P2621 -
NO2/VC utilizes a programmable micro -Controller combined with a high- quality electro -
chemical Nitrogen Dioxide sensor to measure the NO2 level from 0 - 20ppm. The P2621 -
NO2/VC displays the NO2 level on the built - in LCD display, and activates a f an relay to
ventilate the area when elevated concentrations (1 ppm) of NO2 are detected. The
P2621 - NO2/VC’s audible alarm sounds if the NO2 level remains at an elevated level (3
ppm) for more than 15 minutes to signal nearby persons to leave the area. The P2621 -
NO2/VC continually self - tests the internal electronic circuitry and the sensor, and signals
if a fault is detected. Front- panel LED indicators are provided for “Power”, “Fan (ON)”,
“Alarm”, and “Fail”. The P2621 - NO2/VC is factory tested and calib rated prior to
shipment. Field calibrations are possible with the optional P1879 - NO2 Calibration Kit
and P2621 - H handheld programmer module. The P2621 - NO2/VC operate on 24VAC
power and consumes less than .15W max.
The P2621 - NO2/VC’s “Fan” relay is opera ted in the failsafe mode where the relay coil
is energized whenever the P2621- NO2/VC is in a non - alarm condition and the normally -
open contact (terminal connections K1 & K2) is held closed. When any fault occurs the
“Fan” relay is de - energized and the nor mally -open contact (terminal connections K1 &
K2) falls open. The “Fan” relay is de - energized at start - up, when the NO2 level rises
above 1ppm, when the internal diagnostics program detects a fault or when AC power to
the unit is lost. The “Fan” relay is re - energized when the fault is cleared. The P2621 -
NO2/VC’s programming holds the “Fan” relay de - energized for a minimum of three
minutes once activated to prevent short - cycling of the exhaust fans.
The P2621 - NO2/VC’s optional “Alarm” relay (terminal co nnections K3 & K4)
operates on the same principle as the internal audible alarm. The audible alarm is
activated only after the NO2 level has exceeded 3ppm for 15 minutes. The audible alarm
(and optional “Alarm” relay) deactivate when the NO2 level drops below 3ppm.
II) POWER REQUIREMENTS
Warning: The use of the P2621- NO2/VC unit with higher or lower voltages can
damage the unit and cause improper operation or a hazardous condition.
The P2621 - NO2/VC was engineered to be used with 24VAC power supply and a 24
VAC relay control circuit. The relay contacts are rated 5A@ 24VAC for use with an
inductive load. If the installation requires a higher voltage or greater load capacity,
replace the relay unit with an appropriately rated relay (or use a second rela y between the
control relay and the load). Power requirements for each P2621 - NO2/VC are 24 VAC at
0.5 amps.

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III) LOCATION & MOUNTING
The P2621 - NO2/VC can be used to monitor up to 10,000 square feet of undivided area.
It can be used as a self - containe d, stand -alone control or as part of a multi sensor Control
system. If the airflow is not uniform or if the area to be monitored is unusual, then the
area by each unit should be appropriately reduced.
Select an appropriate mounting location in an area of heavy traffic flow, away from drafts
and where the vent holes on the bottom of the unit will not be blocked. Mount the unit
with four (4) screws using the external mounting feet provided. The unit should be at a
convenient height, typically five (5) fee t above the floor.
IV) INSTALLATION & WIRING
After mounting the unit(s) as described above, connect the power and relay wires as
shown in INSTALLATION DIAGRAM page 9 of this manual. The power circuit and
Control circuit of the unit(s) must be wired with 18 AWG or heavier copper wire. A
multiple sensor installation requires only a simple series Connection of the fan Control
relays. This feature allows for maximum flexibility in system design and installation.
Zoned systems are easily created when sever al sets of fans need to be controlled
independently.
1. Be sure to turn OFF power to fan Control system and 24 VAC power supply
before wiring and Connections are made.
2. Open the enclosure using the provided hex - key. The Control card is mounted on
the inside of the enclosure door. A terminal block for electrical Connections is
located on the back panel of the monitor. The terminals are marked for power
input and relay Connections.
3. The wiring must enter the P2621 -NO2/VC enclosure through the two (2 )
electrical openings provided on the unit with conduit fittings.
4. Connect 24 VAC power supply to terminals T1 and T2 of the terminal block.
Each P2621 unit requires 12 watts of power for proper operation.
5. Connect the relay (Control) Contacts K1 and K2 in series with the coil of the
ventilation fan control, intermediate relay, or K1 and K2 of the next unit (for
multiple units configuration). NOTE: the P2621 - NO2/VC must be wired so
that the fans are ON when the relay contacts K1 and K2 are open.
6. OPTIONAL ALARM RELAY - Connect the optional relay (alarm relay) Contacts
K3 and K4, if so equipped, as shown in Installation Diagram page 9 of this
manual.
7. Verify that the wiring to each unit is correct.

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V) POWER UP & TESTING
1. Close the enclosure d oor and secure screws on the front panel.
2. Make sure power supply to the fan Control system is OFF. Turn ON the 24 VAC
power to the P2621- NO2/VC unit.
3. The green POWER light should turn ON. The word – FAN - should appear in the
LCD display. After se veral minutes the LCD display will display the current
Nitrogen Dioxide (NO2) reading in parts per million (ppm).
NOTE: After the P2621 -NO2/VC has been OFF, when power is restored to the
unit, - FAN - will appear in the LCD display and the unit will run ve ntilation fan
for several minutes to clear the air of accumulated Nitrogen Dioxide (NO2) and
then return to normal operation.
4. Turn OFF the power to the P2621- NO2/VC. Turn ON the power to the
ventilation fan Control system. Then turn on the power to t he P2621 - NO2/VC.
The green POWER light should turn ON. The word – FAN - should appear in the
LCD display. After several minutes, the LCD will display the current Nitrogen
Dioxide (NO2) reading in ppm.
VI) Regular Maintenance
To ensure the sensor is oper ating correctly and performing proper gas detection, it is
extremely important for the user to verify the sensor is responding correctly to the NO2
gas at a regular interval. Conspec stipulates a gas injection into the sensor and verify the
response of the sensor for every THREE MONTHS of operation.
To perform an actual gas verification, simply inject a known concentration of certified
NO2 test gas (recommended 10 PPM of NO2 gas balance with Air) into the sensor. After
injecting the test gas into the senso r for FOUR minutes, verify the reading displayed on
the 3 - digit LCD. If the reading displayed on the LCD is within 2% of the NO2 gas
injected (if 10 PPM of NO2 Gas is used, then the reading should read between 8 to 12
PPM), then the sensor is operating cor rectly and no further calibration will be required.
The user can also verify that the Controller is performing its Control function correctly by
noticing the ventilation fan is turned ON when the gas reading exceeds 1 PPM. (If the 10
PPM NO2 test gas is maintained into the sensor for more than 15 minutes, an audible
piezo horn will be sounded). At the end of verification, if the user wishes to clear the
alarm NO2ndition faster, zero gas can be injected into the sensor for 2 minutes to purge
the sensor.
At the end of four minutes after the test gas was injected into the sensor, if the reading on
the 3 - digit LCD deviates from the actual concentration of the test gas by more than 2%,
then proper calibration of the sensor will be required. The user can purchase a calibration

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kit (P1879 - NO2/VC) from Conspec and follow the instructions to perform a calibration.
The user may also send the unit to the distributor or directly to the factory for calibration.
VII) CALIBRATION PROCEDURE
NOTE: All Conspec Smart Gas Mo nitors are fully tested and calibrated before
shipment. Calibration is the process of setting two distinct points for the Nitrogen
Dioxide monitor to reference. All NO2 readings are derived from these two
reference points. The first reference point is re ferred to as “ZERO GAS”
representing a total absence of NO2 and is obtained by injecting zero air into the
sensor. The seNO2nd reference point is referred to as “SCALED GAS” and can
be either half -scaled (½ of full range or 10ppm) or full scaled (full ran ge or
20ppm) NO2 and is obtained by injecting a known concentration of NO2 into the
sensor. The proper application of the calibration gases is essential to the correct
operation of the P2621 - NO2/VC.
Place the strap of the P1879 - NO2 Calibration Kit over th e P2621 -NO2/VC so that
the case hangs below the monitor. Use the supplied hex- key to loosen the tamper -
proof screw in the lower left - hand corner of the P2621 - NO2/VC’s door. Use a
standard flat blade screwdriver to loosen the remaining three door retaining
screws. Open the door of the P2621 - NO2/VC and locate the 20 header - pin
Connector marked “J2" in the middle of the left edge of the P2065 Smart Monitor
Card. Plug the P2621 -P programmer into the “J2" Connector on the P2065 card
so that the “J2" graphic on the P2621 - P plug is located uppermost. Open the top
half- door of the P1879 - NO2 calibration kit and locate the P3013 calibration
adapter. Insert the P3013 calibration adapter into the bottom of the P2057 NO2
sensor by pushing upward while twisting. In stall a 0.5 liter per minute regulator
on each gas cylinder. Connect a 3' section of flexible tubing onto the barb of each
regulator. Follow instructions under “Manual Calibration.”
MANUAL CALIBRATION (This is Function “011" in CONFIGure Mode).
NOTE: DO NOT ENTER FUNCTION 11 UNLESS A GAS CALIBRATION IS TO BE
PERFORMED . STEPPING THROUGH FUNCTION 11 WITHOUT APPLYING
THE CALIBRATION GASES WILL ERASE THE PREVIOUS CALIBRATION
SETTINGS RENDERING THE MONITOR INOPERATIVE UNTIL A PROPER
CALIBRATION IS PERFORME D.
1. Depress the “CONFIG/4" Key for 2 seNO2nds. The message “ENTER ACCESS
CODE” will scroll across the 3 digit LCD .Press Key “4" once to remove the
prompt. The LCD will read “000" (Waiting for operator to key in access CODE).
2. Press Key 3 once. The L CD will read “001" (Access CODE factory set.)
3. Press Key “4" twice to enter the Access CODE of “001". The message “CONSPEC
Ver#” will scroll across the LCD (Software Version Number).

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4. Press Key “4" once to remove the prompt. The LCD will read “000" (Waitin g for
operator to key in function number to go to).
5. Press Key “2" once and Key “3" once. The LCD will read “011" ( function number
11, Manual Calibration).
6. Press Key “4" twice to enter function 11. The message “ZERO INPUT” will scroll
across the 3 digit LCD .
7. Press Key “4" once to remove the prompt.
*The LCD of the P2621 - NO2/VC Monitor will display the 3 digit A nalog to D igital
NO2 unt ( ADC ). The ADC has a possible range of 0 - 999 with typical values of
“050" with ZERO AIR applied, “400 - 500" with 25 0ppm (Half - scale) NO2 GAS
applied, or “800 - 999" with 500ppm (full scale) NO2 gas applied.
8. Inject ZERO -AIR into the sensor. Wait approximately 2 minutes. The ADC should
read approximately “050" with ZERO AIR flowing through the sensor. Press Key
“4" once to accept the ZERO GAS calibration. (If the reading on LCD is outside the
range of 25 – 100, the monitor should be sent back to the factory for in - house
calibration)
The message “SCALED INPUT” will scroll across the LCD followed by the
message “FULL S CALE INPUT” .
9. Press the Key “CONFIG/4" once WHILE either message is scrolling depending on
whether you are using Full (20ppm) or Scaled (10ppm) NO2 Cal -Gas.
*The LCD of the P2621 - NO2/VC Monitor will display the 3 digit A nalog to D igital
C ount (ADC ).
10. Rem ove the ZERO AIR and inject the NO2 CAL - GAS into the sensor. The ADC
should climb as the sensor responds to the Cal - Gas (typically ~ 450 with 10ppm, or
~ 850 with 20ppm, if the reading is differed by more than 50%, sent the monitor
back to the factory for in -house calibration). Wait approximately 2 minutes for the
ADC to stabilize.
11. Press Key “4" once to accept the SCALED GAS calibration.
*The message “CONSPEC Ver#” will scroll across the LCD (Software Version
Number).

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12. Press Key “4" once to remove the prompt.
*The LCD will read “000" (Waiting for operator to key in function number to go to).
NOTE: If the operator wishes to check the alarms, leave NO2 calibration gas
flowing into the sensor, otherwise turn off the flow of NO2 calibration ga s and inject
Zero Air into the sensor for 1 minute to purge the sensor of NO2 before proceeding.
13. Press Key “3" once to enter function number “001" (Exit CONFIG mode). The LCD
will read “001" .
14. Press Key “4" twice to NO2nfirm function 1 (Exit CO NFIG mode).
15. The P2621 - NO2/VC returns to “Gas Monitoring Mode” with the LCD displaying the
current NO2 NO2ncentration.
VIII) SENSOR REPLACEMENT
The P2057 NO2 sensor should be replaced when the displayed readings on the P2621 -
NO2/VC become erratic or the unit can no longer be calibrated. Conspec recommends
replacing all P2057 NO2 sensors in service for 5 years as their continued operation is no
longer assured. Use the supplied hex - key to loosen the tamper - proof screw in the lower
left - hand corner of the P2621 - NO2/VC’s door. Use a standard flat blade screwdriver to
loosen the remaining three door retaining screws. Open the door of the P2621- NO2/VC
and unplug the P2057's 4- wire cable from the “J4” Connector on the P2065 Smart
Monitor Card. Clip the wire tie securing the cable to the lower left - hand corner of the
P2065 Smart Monitor Card and discard. Grasp the ring protruding from the bottom of the
P2621 - NO2/VC and twist counter clockwise (as viewed from below) while holding the
body of the P2057 inside the enclosure. Unscrew the outer ring (Note: the outer ring
holds the dust screen in place inside the diffusion tube. When the outer ring is removed
care should be taken to retain the dust screen if the P2057 is to be returned for sensor
replaceme nt) and remove the P2057 NO2 sensor from the P2621 - NO2/VC enclosure.
Installation of a new P2057 NO2 sensor is accomplished in the reverse order.
NOTE: When a new P2057 NO2 sensor is installed allow 10 minutes for the sensor
to warm up.
IX) TROUBLE SHO OTING
1. No Lights On The Front Panel
Turn OFF the power to the P2621- NO2/VC and to the fan Control system. Open the
enclosure and check that the 24 VAC power supply wiring is securely attached to the
terminals T1 and T2, and that the wiring from the Conn ector terminals to the circuit
board is securely attached. Turn ON the 24 VAC power to the P2621 - NO2/VC. If the
power light is OFF, using a voltmeter, measure the voltage between T1 and T2. The
voltage should read close to 24 VAC. If it does not, the prob lem is in the power supply
and not in the P2621 - NO2/VC. If there is 24 VAC across the T1 and T2 terminals and

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the power light is off, return the P2621-NO2/VC to your supplier or CONSPEC factory
for repair or rep1acement.
2. The Fan Does Not Operate When Fan Light (yellow light) is ON or
The Fan Does Not Turn OFF When The Fan Light (yellow light) is OFF
Turn OFF the power to the P2621 and to the fan Control system. Check that the field
installed relay in the fan motor circuit is a (NC~ Normally Closed type .) Open the
enclosure and check that the ventilation fan wiring is securely attached to the terminals
K1 and K2, and that the wiring from the Connector terminals to the circuit board is
securely attached. Disconnect the ventilation fan wiring from terminal s K1 and K2. Using
an ohmmeter, measure the resistance between terminals K1 and K2. The circuit should be
open (high resistance). If the circuit is not open, return the P2621 to your supplier or
CONSPEC for repair or replacement. Turn on the 24 VAC power t o the P2621 - NO2/VC
and wait for - FAN - to appear in the display using an ohmmeter, measure the resistance
between terminals K1 and K2. The circuit should be open (high resistance). If the circuit
is not open, return the P2621 to your supplier or to CONSPEC for repair or replacement.
With the 24VAC power to the P2621 - NO2/VC turned OFF, wait for - FAN - to disappear
from the display. Using an ohmmeter, measure the resistance between terminals K1 and
K2. The circuit should be closed (low or zero resistance). If the circuit is not closed,
return the P2621 -NO2/VC to your supplier or CONSPEC for repair or replacement. If the
above resistance checks between terminals K1 and K2 are fine, turn OFF the 24 VAC
power to the P2621- NO2/VC and reconnect the fan Control wiri ng. Turn ON the 24 VAC
power to the unit and fan Control system. Check the fan operation. If the fan does not
operate properly the problem is in the ventilation fan Control system or the Connecting
wiring.
3. Fault Light Is ON
Turn OFF the 24 VAC power t o the P2621 - NO2/VC then turn it ON. If power cycling
does not remove the fault condition turn OFF the 24 VAC power and power to the
ventilation fan Control system. Open the enclosure and check that the connector from the
sensor is attached to the main boar d. Turn ON the 24 VAC power to the P2621 - NO2/VC.
If the above steps do not remove the fault condition, turn OFF the 24 VAC power to the
P2621 -NO2/VC and return the unit to your supplier or Conspec for repair or replacement.
The sensor is factory calibrated and the P2621 - NO2/VC is ready to install and use. An
optional field calibration kit is available when local regulations require periodic
calibration checks of the sensor. When the sensor is about to fail, the red fail LED will
light intermittently and wil l light steadily when the sensor fails. If the sensor is not
replaced the P2621 will turn on the fans and go into the fail mode. The plug - in sensor
module must be replaced before the unit can be reset.
Conspec Technical Services: 724 - 489 -8450

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VII) FIELD WIRING DIAGRAM
Analog Output (Optional)
Common ---------------------- TB1 (COM) ------- P2065 (J5 COM)
4- 20mA Signal --------------- TB1 (SIG) -------- P2065 (J5 SIG)
15- 30VDC -------------------- TB1 (+V) ---------- P2065 (J5 +V)
NOTE: The stan dard Configuration for the P2065 -1 includes a 110VAC power supply
with an output of .7A @ 15VDC to power the monitor and options. The positive terminal
of the power supply is Connected to TB1(+) and the negative terminal to TB1(NO2M).
The installer is not required to Connect an outside power source to TB1 on monitors
NO2ntaining a power supply. The Analog Output is a 4 - 20mA Current Source.
Control Outputs (Optional)
Strobe (+) --------------------- TB1 (+V)
Strobe ( - ) --------------------------------- ------------- P2065 J3 (OUT 4) / First Alarm
Piezo (+) ----------------------- TB1 (+V)
Piezo ( - ) ----------------------------------------------- P2065 J3 (OUT 3) / Second Alarm
NOTE:
The Control Outputs are open - collector transistors limited to 100mA @ 30VDC.
In use, the load’s positive terminal is connected to the P2065- 1's V+ terminal and
the load’s negative terminal is Connected to the J3 Connector on the P2065 card
(OUT 4 for the First Alarm or OUT 3 for the Second Alarm). When the P2065 -1
is in a n ormal condition the open collector transistors are turned off and the load
is inactive. When the programmed alarm level is reached the open collector
transistor is turned on providing a path to common, activating the load.
Conspec Technical Service s: 724 -489-8450