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Mascot ST Tankless Water Heater
4.9 Gas Supply and Piping
Gas piping should be supported by suitable hangers or
floor stands, not the appliance.
Review the following instructions before proceeding with
the installation.
1. V erify that the appliance is fitted for the proper type
of gas by checking the rating plate. Mascot ST will
function properly at elevations up to 10,000 feet
(3050 m). Refer to Section 4.12 for High Altitude
Settings.
2. T he maximum inlet gas pressure must not exceed
13" W.C. (3.2kPa). The minimum inlet gas pressure
is 3.5" W.C. (1.0kPa).
3. R efer to Table 8, Table 7 and Table 9 to size piping.
4. R un gas supply line in accordance with all
applicable codes.
5. L ocate and install manual shutoff valves in
accordance with state and local requirements.
6. A sediment trap must be provided upstream of the
gas controls.
7. A ll threaded joints should be coated with piping
compound resistant to action of liquefied petroleum
gas.
8. T he appliance and its individual shutoff valve
must be disconnected from the gas supply piping
during any pressure testing of that system at test
pressures in excess of 1/2 PSIG (3.45kPa).
9. T he unit must be isolated from the gas supply
system by closing its individual manual shutoff valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2
PSIG (3.45kPa).
10. T he appliance and its gas connection must be leak
tested before placing it in operation.
11. Purge all air from gas lines.
PRV (included) must be installed immediately at
water heater outlet with no valves between.
__________________________________________
ATTENTION
PRV (inclus) doit être installé immédiatement à sortie
chaudière avec pas de vannes entre.
_____________________________________
CAUTION
WARNING:
Open flame can cause gas to ignite and result in
property damage, severe injury, or loss of life.
NOTE: The Mascot ST appliance and all other gas
appliances sharing the gas supply line must be firing at
maximum capacity to properly measure the inlet supply
pressure. The pressure can be measured at the supply
pressure port on the gas valve. Low gas pressure could
be an indication of an undersized gas meter, undersized
gas supply lines and/or an obstructed gas supply line.
SCHED 40 METAL PIPE CAPACITY FOR 1.50 SPECIFIC GRAVITY
UNDILUTED PROPANE
NOMINAL PIPE SIZE
11" W.C. INLET AND 0.5" W.C. PRESSURE DROP
@
1/2"
SIZE
LENGTH MAXIMUM CAPACITY IN THOUSANDS OF BTU PER
HOUR
20
200
40
-
60
-
80
-
100
-
NOTES: 1. Follow all local and national propane gas codes for line sizing and
equipment requirements. 2. Verify that inlet gas pressure remains between
4 and 13 inches of water column before and during operation.
Source: ANSI Z223.1-80 National Fuel Gas Code.
Table 7.
Nominal Pipe Size, Propane
SCH 40 METAL PIPE CAPACITY FOR 0.60 SPECIFIC GRAVITY NATURAL GAS
NOMINAL PIPE SIZE
3/4"
LENGTH
FT CUBIC FEET OF GAS PER HOUR
20
190
40
130
60
105
80
90
100
Table 8.
Nominal Pipe Size, Natural Gas
EQUIVALENT LENGTHS OF STRAIGHT PIPE FOR TYPICAL SCH 40 FITTINGS
NOMINAL PIPE SIZE
1/2"
FITTING
LINEAR FEET
3.6
90° ELBOW
4.2
TEE
Table 9.
Equivalent Pipe Lengths
Page 23
3/4"
1"
418
787
287
541
231
434
197
372
175
330
0.30" W.C. PRESSURE DROP
@
1"
350
245
195
170
3/4"
1"
4.4
5.2
5.3
6.6
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