Raypak HI DELTA HD101 Installation & Operating Instructions Manual page 18

CAUTION: Do not use Teflon tape on gas line pipe
thread. A pipe compound rated for use with gas
systems is recommended. Apply sparingly only on
male pipe ends.
CAUTION: Support gas supply piping with
hangers, not by the heater or its accessories. Ensure
the gas piping is protected from physical damage
and freezing where required.
Gas Supply Pressure
A minimum of 4 in. WC and a maximum of 10.5 in. WC
upstream gas pressure is required under load and no
load conditions for natural gas. A minimum of 11 in.
WC and a maximum of 13 in. WC is required for
propane gas. The gas pressure regulator supplied on
the heater is for low pressure service. If upstream
Fig. 13: Sediment Trap Orientation
Input 3/4"
Model
No.
(KBTUH) N
HD101 100 105
HD151 150 50
HD201 199 30
HD251 250 20
HD301 299 15
HD401 399 5
Natural gas – 1,000 BTUH per ft
Propane gas – 2,500 BTUH per ft
Table G: Maximum Equivalent Pipe Length
pressure exceeds 14 in. WC, an intermediate gas
pressure regulator, of the lockup type, must be
installed.
When connecting additional gas utilization equipment
to the gas piping system, the existing piping must be
checked to determine if it has adequate capacity.
Gas Pressure Regulator
The gas valve pressure regulator(s) on the heater are
nominally preset at 3 in. WC for natural gas, and 10.0
in. WC for propane gas manifold pressure. The pres-
sure at the gas valve outlet tap, measured with a
manometer, while in operation should be 3.0 in. ± 0.3
in. WC (HI), and 1.0 in. ± 0.1 WC (LO) for natural gas
and 10.0 in. ± 0.1 in. WC (HI), and 3.5 in. ± 0.1 in. WC
(LO) for propane gas. If an adjustment is needed, turn
the adjustment screw clockwise to increase pressure
or counter-clockwise to decrease pressure.
1" 1-1/4"
P N P N
385 340
180 160 530 600
95 95 355 360
50 60 230 240
35 45 170 170
20 25 80 100
3
, .60 specific gravity at 0.5 in. WC pressure drop
3
, 1.50 specific gravity at 0.5 in. WC pressure drop
18
1-1/2"
P N P
550 360
365 210