LAARS Mini-Therm II JVT (Sizes 50-225) - Install and Operating Manual - Manual (Page 11)

Mini-Therm II Hydronic Boiler Page 11
NOTE: The boiler and all other gas appliances
sharing the boiler gas supply line must be firing at
maximum capacity to properly measure the inlet
supply pressure. Low gas pressure could be an
indication of an undersize gas meter and/or
obstructed gas supply line.
8. The correct high fire burner manifold gas
pressure is stamped on the rating plate. The
regulator is pre-set at the factory, and normally
requires no further adjustment. For two-stage
units (JVS100-225) be sure unit is able to fire at
both high and low fire.
9. Before operating the boiler, the complete gas
supply system and all connections must be tested
for leaks using a leak detector solution. Do not
use an open flame.
Caution
Some leak test solutions (including soap and water)
may cause corrosion or stress cracking. Rinse the
piping with water after testing.
Attention
Certaines solultions d’essai d’étanchéité (y compris
l’eau et le savon) peuvent causer de la corrosion ou
de la fissuration. Rincez les tuyaux à l’eau apprès
l’essai d’étanchéité.
4.2 Special Precautions for LP Gas
LP Gas is heavier than air and can therefore
more readily collect or “pool” in enclosed areas if
provision for proper ventilation is not made. Be sure
to pay special attention to proper ventilation for LP
gas. Locate boilers a safe distance from LP gas
cylinders and filling equipment. In the United States,
consult the “National Fuel Gas Code” (NFPA 54 /
ANSI Z223.1, latest edition) or in Canada, the
Propane Installation Code (CSA-B149.1), any local
codes and fire protection authorities about specific
installation restrictions in your area.
4. A sediment trap (drip leg) must be installed
ahead of the gas controls (see Figure 5). Fit the
trap with a threaded cap which can be removed
for cleaning.
5. Install a manual gas shutoff valve for service and
safety. Do not use a restrictive gas cock. Flexible
gas connectors, if used, must be CSA rated for
the total input rating of the boiler.
6. Disconnect the boiler and its individual shutoff
valve from the gas supply system during pressure
testing of the system at pressures higher than 1/2
pounds per square inch (psi) (3.45 kilopascals
[kPa]). If the test pressure is equal to or less than
1/2 psi (3.45 kPa), close the manual shutoff
valve on the heater during the piping pressure
test.
7. If the gas supply pressure is less than required,
check for undersized pipe between the meter and
the boiler, a restrictive fitting, or an undersized
gas meter. Gas supply pressures to the heater are
listed in Table 5.
NOTE: The maximum inlet gas pressure must not
exceed the specified value. The minimum value
listed is for the purpose of input adjustment. Refer
to Table 5.
Distance
From Gas
Meter
Boiler Size
50 75 100 125 160 225
Pipe Size
0-50'
1/2 3/4 3/4 3/4 1 1
0-15m
50-100'
3/4 3/4 3/4 1 1 1-1/4
15-30m
100-200'
3/4 1 1 1 1-1/4 1-1/4
30-60m
Table 4. Natural Gas Pipe Size Requirements*
*Note: These figures are for Natural Gas (.65 Sp. Gr.), and are
based on 1/2" water column pressure drop. Check supply
pressure with a manometer, and local code requirements for
variations. For LPG, reduce pipe diameter one size, but
maintain a 1/2" minimum diameter. A 'normal' number of Tees
and elbows have been taken into allowance.
Figure 5. Typical design for a sediment trap/drip leg.
Supply Pressure Minimum Maximum
Natural Gas 5.5 Inches WC 10.5 Inches WC
(1.3 kPa) (2.5 kPa)
LP Gas 10.0 Inches WC 13.0 Inches WC
(2.4 kPa) (3.1 kPa)
Table 5. Gas Supply Pressure Requirements.
Gas Supply
Inlet
Tee
Fitting
3 in.
(76mm) Min.
Cap
Nipple
To Equipment
Inlet