Table 1A
First Stage Piping at High Pressure_10 PSI
DO NOT adjust or attempt to measure gas
valve outlet pressure. Attempting to alter
or measure the gas valve outlet pressure
could result in damage to the valve, causing
potential severe personal injury, death, or
substantial property damage.
⚠
WARNING
Check inlet gas supply
1
Gas connections
Dual Fuel Supplemental Manual
The Dual Fuel Crest is equipped with two
(2) inlet gas connections. Each connection
must be checked to ensure proper operation.
NOTICE
Table 1B
Second Stage Piping at Low Pressure_1/2 PSI
10
20
30
40
50
60
70
80
90
100
125
150
1/2
2442 1885 1580 1382 1240 1133 1048
979
921
872
775
703
Pipe
3/4
4831 3812 3230 2842 2561 2346 2175 2035 1917 1816 1618 1470
Size
1
8531 6916 5939 5270 4776 4392 4083 3829 3614 3429 3063 2789
(I.D.)
1 1/4 16626 13771 11963 10691 9736 8987 8378 7872 7443 7074 6336 5779
1 1/2 23670 19957 17510 15749 14407 13341 12470 11740 11119 10581 9501 8682
2
42521 36514 32398 29359 27001 25104 23538 22216 21082 20097 18104 16580
Nominal Iron Pipe
Size Inches
Length of pipe or tubing, feet
Maximum Capacities of Pipe in KBTUH/Hr
Notice: Capacities show n are for Natural Gas. Please consult supplier for proper gas pipe sizing for propane.
10
20
30
40
50
60
70
80
90
100
125
150
1 1/4
2205 1496 1212 1039
913
834
771
724
677
630
567
511
Pipe
1 1/2
3307 2299 1858 1559 1417 1275 1181 1086 1023
976
866
787
Size
2
6221 4331 3465 2992 2646 2394 2205 2047 1921 1811 1606 1496
(I.D.)
2 1/2 10140 7046 5695 4778 4343 3908 3618 3329 3160 2991 2654 2412
3
17990 12510 10110 8481 7708 6936 6422 5908 5608 5309 4711 4281
4
36710 25520 20620 17300 15730 14150 13100 12050 11440 10830 9613 8736
Nominal Iron Pipe
Size Inches
Length of pipe or tubing, feet
Maximum Capacities of Pipe in KBTUH/Hr
Notice: Capacities show n are for Natural Gas. Please consult supplier for proper gas pipe sizing for propane.
Ensure that the high gas pressure regulator
is at least 10 feet (3 m) upstream of the
appliance.
NOTICE
The gas inlet size has been designed to allow
the minimum of 10 feet between the boiler
and regulator and for a maximum pressure
drop of 1
"
w.c.
NOTICE
The gas piping must be sized for the proper flow and length
of pipe, to avoid excessive pressure drop. Both the gas meter
and the gas regulator must be properly sized for the total gas
load.
If you experience a pressure drop greater than 1 inch w.c.
(249 Pa), the meter, regulator, or gas line is undersized or
in need of service. Perform the steps below when checking
inlet gas supply:
1.
Turn the main power switch to the “OFF” position.
2.
Shut off gas supply at the manual gas valve in the gas
piping to the appliance.
3.
For Crest models 751-2001: Remove the 1/8
"
pipe
plug on the gas manifold before the gas valve, and
install a suitable 1/8
"
fitting (field supplied) for
the manometer tubing. Place the tubing of the
manometer over the tap once the 1/8
"
fitting is
installed as shown in FIG. 1-1, 1-2, 1-3, and 1-4.
For Crest models 2501-6001: Remove the 1/8
"
pipe
plug on the large gas valve flange before the gas valve,
and install a suitable 1/8
"
fitting (field supplied)
for the manometer tubing. Place the tubing of the
manometer over the tap once the 1/8
"
fitting is
installed as shown in FIG. 1-1, 1-2, 1-3, and 1-4.
4.
Slowly turn on the gas supply at the factory installed
manual gas valve.
5.
Turn the power switch to the “ON” position.
6.
Adjust the temperature set point on the control
panel of the SMART TOUCH control module to call
for heat or utilize Service Mode, see page 10 of this
manual.
7.
Observe the gas supply pressure as the burner fires at
100% of rated input. Percent of burner input will be
displayed on the Modulation Screen.
8.
Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified in this section of the manual.
9.
If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
