19
Installation
CNA-Series Tankless Heater
Keltech •
215-1814 Rev. C; ECN 150010
7/13/2015
IS Installation continued…
All quarter turn latches in the door of the PE must be fully latched for proper operation . Power to the PE must be
turned off before opening the enclosure .
WARNING This Pressurized Enclosure shall not be opened unless the area is known to be free of
flammable materials or unless all devices within have been de-energized.
Power shall not be restored after the enclosure has been opened until the enclosure has been purged for allotted
time (See table below) . Time begins when pressure indicator turns green after the door of the enclosure has been
closed and fully latched .
WARNING Ignition of potentially explosive gas/air mixtures may result if power is turned on before the
allotted purge time!
Expo Technologies CF systems have a Minimum Pressure Sensor set to a pressure of at lease 0 .1" WC (0 .25bars) . When
the PE pressure is above this set point the sensor produces a positive Pressurized signal . This is displayed on the Red/
Green indicator located on the Purge System . This signal can be used to operate an electrical contact for a remote Alarm .
This signal may be supplied to the pressure operated switch suitable for Intrinsically Safe circuit in accordance . When the
enclosure pressure falls below the set point of the sensor, the Pressurized signal is removed, and the Alarm conditions
occurs . This Alarm must be located where it can be readily observed according to NFPA496 requirements .
No valves may
be fitted between the Expo Technologies system and the alarm switch.
WARNING Never turn on the power without purging first, unless you have proved the interior of the PE is gas
free and checked that the “Pressurized” indicator is green!
Commissioning Test
Commissioning Continuous Flow Keltech Option EXP2CFPM System:
1 . Open the air or gas supply shutoff valve .
2 . Adjust the Flow Control Valve (FCV) so that the enclosure pressure rises to the point where the "Pressurized"
indicator turns green .
3 . Lower the PE pressure until the Pressurized indicator turns Red .
4 . Open the FCV again and set the PE pressure to a level somewhere between the Minimum Pressure
Sensorset point and the RLV opening pressures . This working pressure is not critical . Enough pressure to keep
the“Pressurized” indicator Green is sufficient .
5 . On EXP2CFPM Purge System the timing function if performed by the user . The user must ensure that the time
delay between the indicator turning Yellow and the application of power to the PE is not less than the minimum
time required to purge the PE as shown in the table below .
Normal Operation:
Turn the air supply valve ON to start or OFF to stop the system . The user must close the Power
Switch only after the enclosure has been pressurized and purged sufficiently to ensure that the interior of the enclosure
is gas free . It is the operator’s responsibility to shut off the power as soon as possible after a pressure failure .
PURGE TIME CHART - EXP2CFPM Option
for use with EXPO Mini Z Purge 1ZCF/pm/IS
Model/Enclosure
Group Size
Cubic
Feet
Volume
Exchanges
X 4
Orifice
Size
Orifice
No .
Purge
Time
(Minutes)
CNA-36-54
10
40
0 .9
#2
44
CNA-63
12 .5
50
0 .9
#2
55
CNA-72-108
10
40
0 .9
#2
44
CNA-126-144
12 .5
50
0 .9
#2
55