Weil-McLain AHE Series, Manual

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Part number 550-141-887/0800 18
AHE Series 4 Direct Vent Wall-Mounted Boilers — Boiler Manual
Natural gas piping
1. Refer to Table 4 for pipe length and diameter. Base
on rated boiler input (divide by 1,000 to obtain
cubic feet per hour). Table 4 is only for gas with
specific gravity, 0.06, with a pressure drop through
the gas piping of 0.03" w.c. For additional gas pipe
sizing information, refer to ANSI Z223.1 (or B149.1
or B149.2 for Canadian installations).
2. Inlet gas pressure:
•maximum: 13" w.c.
•minimum: 5" w.c.
•manifold pressure: 3½" w.c.
3. Install 100% lockup gas pressure regulator in supply
line if inlet pressure exceeds 13" w.c. Adjust for 13"
w.c. maximum.
Propane gas piping
1. Contact gas supplier to size pipes, tanks and 100%
lockup gas pressure regulator.
2. Adjust propane supply regulator provided by gas
supplier for 13" w.c. maximum pressure.
2. Inlet gas pressure:
•maximum: 13" w.c.
•minimum: 11" w.c.
•manifold pressure: 10" w.c.
3. Install 100% lockup gas pressure regulator in supply
line if inlet pressure exceeds 13" w.c. Adjust for 13"
w.c. maximum.
Connecting gas piping to boiler
1. Refer to Figure 15 for recommended gas piping.
2. Use pipe dope compatible with propane gases.
Apply sparingly only to male threads of pipe joints
so that pipe dope does not block gas flow.
Failure to apply pipe dope as
detailed above can result in severe
personal injury, death or substantial
property damage.
3. Install drip leg at inlet of gas connection to boiler.
See Figure 15. Where local utility requires drip leg
to be extended to the floor, use appropriate length
of pipe between cap and tee.
4. Install manual main shutoff gas valve and ground
joint union in gas piping according to local utility
requirements.
5. In Canada, when using manual main shutoff gas
valve, it must be identified by the installer.
6. Support piping with hangers, not by boiler or its
accessories.
7. Purge all air from gas supply piping.
8. Before placing boiler in operation, check boiler and
its gas connection for leaks.
Do not check for gas leaks with open
flame — use bubble test. Failure to
use bubble test or check for gas leaks
can cause severe personal injury,
death or substantial property
damage.
a. Close manual main shutoff valve during any
pressure test less than 13" w.c.
b. Disconnect boiler and gas valve from supply
piping during any pressure test greater than
13" w.c.
5
Gas piping
Table 4
Pipe capacity for 0.60 specific gravity natural gas
Figure 15 Gas supply piping
Length of
pipe
(feet)
Capacity of pipe
(in cubic feet of gas per hour)
½"
¾" 1"
10 132 278 520
20 92 190 350
30 73 152 285
40 63 130 245
50 56 115 215
75 45 93 175
100 38 79 150
150 31 64 120
Boiler
Nipple
Nipple
Manual main shutoff
gas valve
Tee
Ground joint union
Nipple
Drip leg
Cap
Gas supply
88715
Supply Return