Thermal Solutions EVCA SERIES, Инструкция по установке, эксплуатации и обслуживанию

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21
E.
GAS PIPING
WARNING
Failure to properly pipe gas supply to boiler may
result in improper operation and damage to the
boiler or structure. Always assure gas piping is
absolutely leak free and of the proper size and
type for the connected load.
An additional gas pressure regulator may be
needed. Consult gas supplier.
1. Size gas piping. Design system to provide adequate
gas supply to boiler. Consider these factors.
a. Allowable pressure drop from point of delivery
to boiler. Refer to Table 2 for minimum and
maximum boiler gas train inlet pressure. If gas
supply pressure is higher than maximum as listed
in Table 2, an additional field supplied pressure
regulator will be required.
TABLE 2 - BOILER GAS TRAIN
INLET PRESSURE
BOILER
MODEL
MODULATION
MIN ("w.c.) MAX (psig)
EVCA-750 7.0 5
EVCA-1000 7.0 5
EVCA-1500 7.0 5
EVCA-2000 9.0 5
EVCA-3000 6.0 5
b. If a lower minimum gas pressure is needed,
the low gas pressure build can be used. The
minimum gas pressure on all of the low gas
pressure builds is 4.0 in. w.c. Consult factory if
this option is desired. This option is not available
on the EVCA-3000.
c. Maximum gas demand. Table 6 lists boiler input
rate. Also consider existing and expected future
gas utilization equipment (i.e., water heater,
cooking equipment).
d. Length of piping and number of fittings. Refer
to Table 3 for maximum capacity of schedule
40 pipe. Table 5 lists equivalent pipe length for
standard fittings.
i. Given the specific gravity of gas at your
location, a correction factor can be found on
Table 4 and multiplied by the "Capacity in
Cubic Feet of gas Per Hour" on Table 3.
ii. For gas piping material other than schedule
40 pipe, refer to the National Fuel Gas Code,
NFPA 54/ANSI Z223.1 and/or CAN/CGA
B149 Installation codes.
2. If step down regulator is required, it must be used in
conjunction with the factory supplied regulator and
be located as far away from the boiler as possible to
prevent nuisance shutdowns.
a. The minimum and maximum inlet gas pressure
must not exceed the value specified in Table 2.
3. Install field supplied sediment trap, ground-joint
union and manual non-displaceable shut-off valve
upstream of factory supplied shut-off valve outside
the boiler jacket. Use methods and materials in
accordance with Local Codes and requirements of
gas supplier. In absence of such requirements, follow
National Fuel Gas Code, NFPA 54/ANSI Z223.1
and/or CAN/CGA B149 Installation Codes.
4. Use thread joint compound resistant to the action of
liquefied petroleum gas.
WARNING
Failure use proper thread compounds on all gas
connectors may result in leaks of flammable gas.
5. All above ground gas piping upstream from field
supplied manual gas valve must be electrically
continuous and bonded to a grounding electrode.
Do not use gas piping as grounding electrode. Refer
to National Electrical Code, ANSI/NFPA 70 and /or
CSA C22.1 Electrical Codes.
WARNING
Gas supply to boiler and system must be
absolutely shut off prior to installing or servicing
boiler gas piping.
WARNING
Use an additional gas pressure regulator where
the gas pressure is greater than 5 psig. Using
one additional regulator for multiple boilers
may result in unsafe boiler operation. The
additional regulator must be able to properly
regulate gas pressure flow at the lowest input of
a single boiler. If the regulator cannot do this,
two or more additional regulators are required.
Consult regulator manufacturer's instructions for
minimum gas flow rate.
NOTICE
The EVCA-3000 is shipped with the gas line
regulator in the downward position. During
installation loosen the union behind the regulator
and rotate gas inlet to horizontal orientation.
Remove cap and reattach 1/4" regulator tubing to
regulator.