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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.
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