Wessington Cryogenics Limited

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1

Wessington Cryogenics

Limited

Philadelphia Complex, Houghton le Spring, Tyne & Wear, DH4 4UG

England


TELEPHONE

NUMBER +44 (0) 191 512 0677

FAX
NUMBER: +44 (0) 191 512 0745



QFM440R

CARBON DIOXIDE GAS MONITOR AND ALARM


Installation and Operating

Instructions


Doc: OP
\
QFM440R V1.0 (2/00)


SAFETY WARNINGS


These instructions must be read thoroughly before attempting to install or
operate this unit.


Any electrical installation must be undertaken only by suitably qualified and
competent personnel.


No voltage above 30V is to be connected to or into the main QFM440R unit.


The QFM440R must be used only for the purposes and in the manner described in
these instructions. If used for other purposes or in a manner not specified
protection provided by thi
s equipment may be impaired.


Description and Application


The QFM440R continually monitors the air surrounding the sensor filter on its base and
provides visual and audible alarms when the monitored concentration of carbon dioxide
exceeds pre
-
set `Alarm’
levels. A typical response time is less than two minutes.


Information Specific to This Unit


Serial number






QFM440R
-


Pre
-
set `High Carbon Dioxide Alarm’ threshold



1.5%


Pre
-
set `Critically High Carbon Dioxide Alarm’ threshold


3.0%


Installation an
d Positioning


The QFM440R is supplied fitted with a wall mounting bracket which should be used for
securing the QFM440R firmly to a clean, dry, vertical surface.


When deciding where to position the monitor, consideration should be given to


2

[i] whether t
he alarm lights and audible alarm can be easily seen and heard and

[ii] whether the unit is placed so that it is monitoring the required area adequately.


The QFM440R monitors the surrounding air by natural convection and diffusion into the
carbon dioxide
sensor through the sensor filter in its base.
IT IS IMPORTANT TO
ENSURE THAT THE SENSOR FILTER IS NEITHER COVERED NOR BLOCKED

and
that AIR CAN CIRCULATE FREELY AROUND THIS FILTER AND THE BASE OF THE
UNIT.


The QFM440R is not waterproof and
must not

be expo
sed to, immersed in, sprayed or
washed with water, rain, solutions or other solvents.


Do not introduce, or allow foreign objects to enter, the sensor or sensor filter in
the base of the unit. Foreign objects entering the sensor may cause the unit to fail

Connection to Relay Terminals


Before opening the QFM440 it must be isolated from the electrical supply.


The top panel of the QFM440 should be carefully removed (four black coloured corner
screws) taking particular care not to pull on the cable which goes

through one of the
cable glands and connects into the `POWER INPUT’ terminals.


The top section of the front panel (on which is printed `Quantum QFM440 Carbon
Dioxide Monitor and Alarm’ ) can then be removed by sliding it upwards, out of the slot.


Connec
tions to the contacts of the internal relay of the QFM440R can be made at the
terminals labelled `
ALARM RELAY

1NO
,
1NC

and
1C
’. 1C is the Common terminal ;
1NO is the Normally Open terminal ; 1NC is the Normally Closed terminal of these `volt
-
free’ cont
acts.


The maximum rating for the terminals of this relay is 1 A at 30V D.C. This rating must
not be exceeded.


Wiring to these terminals must be undertaken only by suitably qualified personnel to the
appropriate international regulatory standards and wir
es and cables must be suitably
rated and comply with BS6500.


The cable must pass into the unit only through the black cable gland mounted in the top
panel (refer to the Sketch of the QFM440R shown later in these instructions) and should
be properly secure
d therein. Cable diameter should be 3 to 6.5 mm.


After making these connections the top section of the front panel should be replaced
correctly and then the top panel replaced.


Only then may the QFM440 be reconnected to the electrical supply.






3

Operat
ion


The QFM440R is powered by a compact `mains adapter’ Power Supply Unit which plugs
into a standard `UK’ mains 13A wall socket. A 2 metre long low voltage cable connects
the power supply to the main QFM440R unit which operates continually and has no ON
/
OFF switch.


Allow a `warm
-
up’ period of at least 5 minutes for the QFM440R

after connecting
the Power Supply Unit to the electrical supply before taking any readings. During the
early part of the `warm
-
up’ both `High’ and `Critically High’ indications s
hould be active.
As the `warm
-
up’ progresses (assuming a normal carbon dioxide level in the air) the
`Critically High’ indications should cancel and then later, the `High’ indications should
also cancel.


The normal operation of the QFM440R is summarised i
n the table below :


Condition

Power

Green
LED

Relay


Audible
Alarm

High
Carbon
Dioxide
Red LED

Critically
High
Carbon
Dioxide

Red LED

Service
Yellow
LED

Normal

(Monitored

carbon dioxide
level below the
`High Carbon
Dioxide’
threshold.)

On

Energised

Off

Off

Off

Off

High Carbon
Dioxide Alarm

(Monitored carbon
dioxide level above
the `High Carbon
Dioxide’ but below
the `Critically High
Carbon Dioxide’
thresholds.)

On

De
-

energised

Bleeping
Slow

(On : Off
time = 1:3)

Flashing

Slow

(On : Off
time = 1:3)

Of
f

Off

Critically High
Carbon Dioxide
Alarm

(Monitored
carbon dioxide
level above the
`Critically High
Carbon Dioxide’
threshold.)

On

De
-

energised

Bleeping
Fast

(On : Off
time = 1:1)

Flashing

Slow

(On : Off
time = 1:3)

Flashing

Fast

(On : Off

time =1:1)

Off

Service

On

De
-

energised

Constant
tone

Off

Off

On
Constant

Test Switch
pressed

On

De
-

energised

Bleeping
Fast

Flashing
Slow

Flashing
Fast

Off

Mains Power
disconnected or
failed

Off

De
-

energised

Off

Off

Off

Off



4

If the Service condition is observe
d the QFM440R should be withdrawn from
service immediately and re
-
calibrated
as it is no longer operates correctly. Refer to
Testing and Calibration section below.
If re
-
calibration can not be performed or does
not return the unit to the `Normal’ condition

the unit MUST be withdrawn from
service.
Wessington Cryogenics

Limited should then be contacted
.


Response Time


The response of the QFM440R when a high concentration of carbon dioxide enters its
sensor is
not

instantaneous. The time taken for the QFM440R

to exhibit alarms (the
response time) depends on the concentration of carbon dioxide to which it is exposed.
When the QFM440R is correctly calibrated and the sensor is exposed to 4% carbon
dioxide test gas the response time is typically less than 2 minute
s for both the `High’ and
`Critically High’ alarms to become activated.


Testing and Calibration


Using Test Gases

Test gases must be administered to the carbon dioxide sensor through the filter in the
bottom panel of the QFM440R at a flow rate of between
0.2 and 0.5 litres per minute for
a duration of between 2 and 4 minutes. The filter holder allows an appropriately sized
tube or adapter to make a suitable seal.


Functionality Testing

The QFM440R must be tested for functionality on a regular and frequent

basis. If
the QFM440R fails a properly constituted functionality test it should be withdrawn
from service immediately.


A functionality test involves admitting gas having a carbon dioxide concentration
marginally above the `Critically High Alarm’ threshol
d to the sensor and checking that
both the `High’ and ‘Critically High Carbon Dioxide’ red LEDs flash and that the audible
alarm bleeps (and, if fitted and used, the relay becomes de
-
energised). A test gas of 4%
carbon dioxide is appropriate for a Critical
ly High Alarm threshold of 3%.


The QFM440R should return to the normal (non
-
alarm) state within 90 seconds of fresh
air being readmitted to the sensor.


Alarm Test Switch

The Alarm Test Switch is located to the left hand side of the bottom panel of the
QF
M440R. When this switch is pressed in all of the `High’ and `Critically High’
indications should be activated (as shown in the table above). This switch only tests the
functioning of the LEDs and Audible Alarm
-

it does NOT test that the whole unit
functio
ns correctly.


Calibration Checking and Recalibration

The calibration of the QFM440R should be checked at least once every six months

either [A] by admitting test gases having carbon dioxide concentrations marginally
higher and marginally lower than both t
he pre
-
set alarm levels



5

or [B] by measuring the analogue output voltage first in fresh air and second with a test
gas having a carbon dioxide concentration marginally higher than that of the `Critically
High’ alarm level.


If a check shows the calibration

to be unsatisfactory the unit must be taken out of
service immediately and then either recalibrated, rechecked and tested or
Wessington
Cryogenics

Ltd. contacted.


Using method [A], for the standard settings of 1.5% for `High Alarm’ and 3.0% for
`Critical
ly High Alarm’, test gases of 1%, 2% and 4% would be appropriate. The test
gases must be used as described in the section `Using Test Gases’ above. The 1% test
gas should not cause any alarms to be activated. The 2% test gas should activate only
the `High
Carbon Dioxide Alarm’. The 4% test gas should activate both the `High’ and
the `Critically High Carbon Dioxide Alarm’. (Refer to the table in the `Operation’ section
for the correct indications which should be observed for each alarm state.) If the correct

indications are not observed the unit must be taken out of service immediately then
should be recalibrated (refer to Appendix 1) or
Wessington Cryogenics

Ltd. contacted.


Using method [B] the dedicated calibration check lead is fitted to the interconnecti
on
socket on the bottom plate of the QFM440R and the red and black plugs connected into
the voltage measuring inputs a high impedance digital voltmeter set on a range to
measure up to 3V d.c. First, with the QFM440R standing in fresh air (i.e. air with the

normal atmospheric concentration of carbon dioxide) the voltage reading should be
within the range of +0.41V to +0.71V. Note that office, laboratory or workshop air may
not be `fresh’ and may have a significantly higher carbon dioxide concentration than t
he
normal atmospheric level. A test gas of normal air (approx. 330ppm CO2) or pure
nitrogen gas may be used to replace `fresh’ air for this part of the check.


If the measured voltage in fresh air lies outside of these limits the check must be
stopped and
the QFM440R must be taken out of service until it has been successfully
recalibrated and retested. The recalibration procedure is given in Appendix 1.


Second, a test gas marginally higher in carbon dioxide concentration than the `Critically
High Alarm’ th
reshold must be admitted to the sensor as described in the section `Using
Test Gases’ above. (Where the Critically High Alarm threshold is 3%, a test gas of 4%
carbon dioxide would be appropriate.)


Both the `High’ and `Critically High Carbon Dioxide Alarm
’ states should be activated
(refer to table under `Operation’ section). If they are not the QFM440R should be taken
out of service immediately and
Wessington Cryogenics

Ltd. contacted.


Connection to other Units


The QFM440R can be linked to a number of a
ncillary units by means of an
interconnecting cable which plugs into the socket on the bottom face of the unit. This
allows repeat alarms, displays and the switching of external electrical circuits to be
controlled by the QFM440R. The unit may also be fitt
ed with an internal relay allowing it
to switch low voltage circuits directly.

A brief summary of these ancillary units is given in Appendix B.



6

Maintenance


There are no operator serviceable or replaceable parts. Important maintenance
practices are the te
sting and recalibration procedures described in the section above.


The socket on the bottom face of the QFM440R is fitted with a black plastic dust cover.
This cover should only be removed when the interconnecting cable is fitted to the
socket.


Technical

Specification


Operating conditions


Temperature

-
5 to + 45
o
C.





Humidity 0 to 99% RH non
-
condensing





Pressure range atmospheric +/
-
10%

Main Unit


No voltage above 30V is to be connected to or into the main QFM440R unit.

Case material



Black anodis
ed aluminium with GRP front panel.

Dimensions (excl. bracket)

165 (H) x 90 (W) x 55 (D) mm.

Weight




Approx. 550 gms (0.55 Kg).

Environment



For INDOOR use only (refer to installation section).


Indications



4 LEDs and Audible Alarm





Refer to table i
n operating section


Electrical Connection


Socket on bottom face for connection only to approved





dedicated units.


Relay Contacts


Maximum rating 1A at 30 V. D.C. (Volt
-
free contacts)





Connection at terminals 1NO,1NC and 1C on circuit board





Fo
r relay operation refer to table in `Operation’ section.


Standard Alarm Thresholds

High Carbon Dioxide



1.5% carbon dioxide

(Special thresholds


Critically High Carbon Dioxide


3% carbon dioxide

available on request)


Response time (for correctly


Typica
lly less than 2 minutes for alarms to activate
calibrated QFM440R)



when sensor subject to 4% carbon dioxide test gas


Power Supply Unit


Power requirement


230 V., 50 Hz, 50 mA.

Electrical Class/Category

Class II. Double insulated.

Dimensions



90 (H)
x 54 (W) x 70 (D)

Weight



260 gms

Environment



For INDOOR use only. IP40.

7





Sketch of QFM440R Carbon Dioxide Gas Monitor and Alarm for Identification Purposes







Fixing hole separation 127mm





Cable gland





To mains a
dapter




for relay






power supply




connection




cable



Wall

mounting

bracket












`Power’ green LED

Blanking plug for

calibration adjustment










Position of audible alarm

`Critically High Carbon

Dioxide Alarm’

red LED



`High Carbon Dioxide

Alarm’ red LED


`Service’ yellow LED









Alarm Test switch


Sensor filter


Interconnection socket




8

Appendix A


Recalibration of the QFM440R



1]

Connect the Yellow plug of the calibration test lead into the c
ommon measuring
input (usually marked ) of a digital electronic voltmeter.


2]

Connect the Red plug of the calibration test lead into the positive voltage
measuring input (usually marked V or V+ ) of the digital electronic voltmeter.


3]

Remove the b
lack plastic protection cover from the interconnection socket on the
base of the QFM440R (refer to sketch) and then insert the 9
-
pin `D’ plug of the
calibration test lead carefully into the socket. Do not force
-

it only goes one way round.


4]

Switch the
voltmeter on and set it to read in d.c. Volts with a resolution to at least
2 decimal places (usually this is the 2V scale).


5]

Ensure that the QFM440R has been exposed to fresh air (or test gas with a
carbon dioxide concentration of 330ppm or below) for
at least 6 minutes and ensure that
the sensor continues to be exposed to this throughout the duration of the recalibration.


6]

Remove the blanking plug on the front face of the QFM440R (refer to sketch)


7]

Identify a brass coloured screw adjustment which

can be seen directly behind the
hole in the panel. Carefully insert a fine blade instrument screwdriver or `trimtool’
through the hole in the panel. Take care to ensure that it locates correctly in the brass
coloured screw adjustment of the potentiometer
then carefully and slowly rotate
clockwise or anticlockwise until a reading of +0.56 V. is obtained on the voltmeter.


Note: The voltage reading may vary by +/
-
0.02 V. (e.g. expect the reading to vary from
+0.54 to +0.58 V when calibrated at +0.56 V). This

is a design feature of the QFM440R.


8]

Carefully replace the blanking plug into the hole on the front face of the
QFM440R


9]

Check the reading on the voltmeter. It should be between +0.50 V. and +0.60 V.


10]

The recalibration is now complete. Following

this recalibration the QFM440R
MUST

now be tested before being allowed back into service. Method [A] or [B]
described under `Calibration Checking and Recalibration’ in the `Testing and Calibration’
section of these instructions must be followed.

9

Appendix
B

Ancillary Units for Connection to QFM440R.




Part Number


Name

Functions

QRA440

Alarm Repeater
Module

Battery powered unit which `mimics’ the alarm
i湤i捡瑩c湳n t桥 n䙍㐴げ m潮it潲

`慮 扥 m潵湴敤n潵t獩摥 t桥 r潯m 扥i湧
m潮it潲敤o潲oi渠愠r敭潴攠汯捡瑩



QRD440


Alarm Repeater
and Display Module

Battery powered unit similar to the QRA440 but
also gives a continuous reading of the carbon
dioxide concentration monitored by the
QFM440R


QRL440/1

Alarm Repeater,
Display and Relay
Switching Module

Single

channel

Mains powered unit which `mimics’ the alarm
i湤i捡瑩c湳n t桥 n䙍㐴げI 灲潶i摥猠愠
捯cti湵潵猠r敡摩湧 潦 t桥 捡牢潮⁤c潸i摥
捯c捥ctr慴楯渠n潮it潲敤o批 t桥 n䙍㐴げ 慮搠
桯畳u猠tw漠楮摥灥湤敮t r敬慹猠f潲o獷it捨c湧 潲o
捯ctr潬li湧 數t敲湡e 敬散瑲i捡c c
ir捵ct献 T桩猠m潤敬
捯c湥捴猠t漠愠獩湧l攠e䙍㐴げ m潮it潲o


QRL440/4

Alarm Repeater,
Display and Relay
Switching Module
Two to Four
channel

Similar to the QRL440/1 above but can have up
to four QFM440R monitors connected to it. It
provides `mimic’ alarms o
f 慬l n䙍㐴げ 畮it猠
捯c湥捴敤 t漠楴o 慮搠d敬慹猠潰敲慴攠楦 慮y
n䙍㐴げ i湤i捡瑥猠t桥 灡rti捵c慲a慬慲a 獴慴攮 ft
has a single display with `channel select’ switch.


QM44CC


Interconnecting
cable

Used to link the QFM440R to the above units and
also for some

of the above units to one another.
Standard length 10 metres but other lengths to
order. Fitted with connectors at both ends.
Simply plugs in.


QR440B

Replacement Battery Pack for QRA440 or QRD440