54
Figure 25: Gas Inlet Pressure Tap
and Pressure Switch Location
VII. Gas Piping
(continued)
C. Pressure test.
See Table 19 for Apex Min./Max.
Pressure Ratings. The boiler and its gas connection
must be leak tested before placing boiler in operation.
1. Protect boiler gas control valve.
For all testing
over ½ psig (3.4 kPa), boiler and its individual
shutoff valve must be disconnected from gas supply
piping. For testing at ½ psig (3.4 kPa) or less, isolate
boiler from gas supply piping by closing boiler’s
individual manual shutoff valve.
2. Locate leaks
using approved combustible gas non-
corrosive leak detector solution.
DANGER
Explosion Hazard. Do not use matches, candles,
open flames or other ignition source to check for
leaks.
D. Apex Models APX525, APX625, APX725
and APX825
(if equipped with optional low and
high gas pressure switches):
1. Verify low and high gas pressure switch
settings
are within the range shown in Table 19.
The switches are preset for natural gas. For LP gas,
the low gas pressure switch setting must be adjusted.
2. The low gas pressure switch
must be reset after
the boiler is piped to the gas supply and before it is
fired.
3. For the low and high gas pressure switches
proper operation, the boiler inlet gas pressure must
be within the range shown in Table 19.
3. The gas pressure can be measured
at the gas
valve inlet pressure port. Refer to Figure 25 “Gas
Inlet Pressure Tap and Pressure Switch Location “.
4. If either pressure switch is tripped,
it must be
manually reset before the boiler can be restarted.
E. Gas Piping for Multiple Boiler Installation
1. Individual module (boiler) gas pipe sizing
specific details
- see Paragraph A.
2. Individual module (boiler) recommended gas
piping detail
- see Figure 24.
3. An additional gas pressure regulator(s)
may need
to be installed to properly regulate inlet gas pressure
at the smallest individual module (boiler).
CAUTION
If gas pressure in the building is above ½ psig
(3.4 kPa), an additional gas pressure regulator
is required. Using one additional regulator
for multiple boilers may result in unsafe boiler
operation. The additional regulator must be able
to properly regulate gas pressure at the input
of the smallest boiler. If the regulator cannot
do this, two or more additional regulators are
required. Consult regulator manufacturer and/or
local gas supplier for instructions and equipment
ratings.
Summary of Contents for APEX
Page 57: ...57 VIII Electrical continued Figure 26 Ladder Diagram ...
Page 58: ...58 VIII Electrical continued ...
Page 59: ...59 Figure 27 Wiring Connections Diagram VIII Electrical continued ...
Page 105: ...105 ...
Page 109: ...109 XIII Repair Parts continued APX625 APX725 and APX825 APX825 shown ...
Page 112: ...112 XIII Repair Parts continued APX425 and APX525 ...
Page 114: ...114 XIII Repair Parts continued APX625 APX725 and APX825 ...
Page 122: ...122 ...
Page 123: ...123 ...
