Page 17
Gas Supply
Inlet
Tee
Fitting
3 in.
(76mm) Min.
Cap
Nipple
To Equipment
Inlet
Figure 8. Typical design for a sediment
trap/drip leg.
M
INI-
T
HERM
JX
Residential Boilers
®
2. Check the gas supply to be sure that it is the same
as the gas indicated on the boiler’s plate. This boiler,
as shipped from the factory, is certified to operate
within the altitude range indicated on the rating plate.
If a field conversion to a different altitude range or
different gas should be necessary, conversion parts
are available.
See Section 12.C on page 50 for part numbers.
3. Use the figures in Table 4 to size the gas inlet piping
from the gas meter to the heater. Check all local
codes for compliance before i
nstalling the heater.
4. A sediment trap (drip leg) must be installed ahead
of the gas controls
(see Figure 8)
. 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 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 3 on page 17.
SECTION 4
Gas Connections
4.A Gas Supply and Piping
1. Gas piping installation must be in accordance
with the latest edition of ANSI Z223.1 and all local
codes. In Canada, the installation must be in
accordance with CSA-B149.1 and all local codes
that apply.
CAUTION
Permanent damage to the gas valve will occur if the
following procedures are not followed.
ATTENTION
Vous endommagerez la soupape de gaz si vous ne
respectez pas les procédures suivantes.
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 4
Table 3. Gas Supply Pressure Requirements
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 4. Gas Pipe Size Requirements*
Boiler Size
50
75
100
125
150
200
Needed Pipe Size
0-50ft
0-15m
1/2
3/4
3/4
3/4
3/4
1
50-100ft
15-30m
1/2
3/4
3/4
1
1
1-1/4
100-200ft
30-60m
3/4
1
1
1
1-1/4
1-1/4
*
Note:
These figures are for
Natural Gas (.65 Sp. Gr.),
and are based on 1/2" water column pressure drop.
For LP (1.5 Sp. 11” wc) and 1/2” water column drop.
Check supply pressure with a manometer, and local code
requirements for variations. Pipe fittings must be consid-
ered when determining gas pipe size. See National Fuel
Gas Code or local code requirements for complete pipe
sizing requirements.
Equivalent
Distance
From Gas
Meter
1/2”
1/2”
1/2”
1/2”
1/2”
1/2”
3/4”
3/4”
3/4”
3/4”
3/4”
3/4”
3/4”
3/4”
3/4”
1”
1”
1”
continued on next page.
