14
SNA-Series Tankless Heater
Installation
10/17/2014
Keltech •
215-1815 Rev. B; ECN 130011
Special Installation and Operating Instructions
Tankless Water Heaters With Optional Class I Division 2 Purge EXP2 Option and
EXP2LC and EXP2LCPM
General Information
All Keltech Tankless Water Heaters with a model number suffix of – EXP2 and EXP2LC have been fitted with a Z
purge system to pressurize the enclosure suitable for use in Class I Division 2 Hazardous Locations .
A Continuous Flow (Model CF) or Leakage Compensation (Model LC) Mini-Z Pressurizing System has been fitted to
the bottom of the enclosure (See Figure 6) .
Outlet
18"
(458mm)
Max
Explosion proof
sealing fitting
supplied by others
Purge System
Relief Valve
Conduit Hub
Class 1 Div . 2
supplied by others
Inlet
5" (127mm)
1
1
2
3
4
5
6
3
5
6
Suggested region for power
entrance at left/bottom of enclosure .
Entrance hole and components to
be provided by installer .
All plumbing fittings are 1-1/4" NPT
female threaded .
Purge Control Panel
Class 1 Division 2
All installation egress from
panel must be sealed (electrical
conduit) for proper explosion proof
installation .
Spark arrestor with calibration orfice
is located behind the purge control
unit and through the bottom of the
enclosure .
Purge gas/compressed air inlet
fitting here .
FIGURE 6
EXP2 & EXP2LC Installation Notes
1 . Any tubing, conduit or fittings connected to the Pressurized Enclosure (PE) must conform to local codes for
flammability ratings .
2 . All egress into PE must be plugged and properly sealed to minimize leakage of purge air . Use hazardous
location sealing fittings suitable for Class I locations within 18" of enclosure (See Figure 6) .
3 . There are two types of purge systems:
EXP2
option is a continuous flow purge system and is calibrated to flow at .9 SCFM . To minimize waste, plug
and seal all openings and conduit .
EXP2LC
is a leakage compensation purge intended to have minimal flow after the initial purge time . The PE is
built as leak tight as possible and the LC system merely tops up for any enclosure leakage .
4 . The system is designed for use primarily with compressed air . The source of the compressed air must be
from a non-classified area . Purge air must be clean, dry and free of flammable gases . When inert compressed
gasses are used (Nitrogen, for example) the installer and facility manager must take suitable precautions
on-site so that buildup of the inert gas does not present a health hazard . Where risk of asphyxiation exists, a
warning label must be fitted to the Pressurized Enclosure (PE) .
5 . Adjustment of Purge System is not necessary . System is fully calibrated .
6 . Connect to Purge System where indicated in Figure 6 . Connection port is 1/4" NPT female . Supply pressure
must be regulated to 60–115 PSI .
