Bryant 246 - Electric Limit Control; Gas Piping

FAX No. 317 240 5662
F. 014/018
SEP/04/2008/THU 09:18 AM UTC TECH PUB
open, the gas on top of the diaphragm is released. The
gas pressure on the bottom of the diaphragm forces
the diaphragm upward, opening the main valve.
The D6 gas controls are for a 750-millivolt self¬
generating system powered by a pilot burner-
generator only. NEVER connect it to line voltage or
to a transformer.
If the pilot should go out, no electric current would be
generated by the thermopile; therefore, the automatic
gas valve could not open.
Electric Limit Control
This control is furnished with water boilers, all gases.
It will shutoff the gas supply to the main burners
when the water temperature in the boiler reaches the
Cut-Out setting. When the water temperature drops to
the Cut-In temperature, the control allows gas flow to
the burners. Out-Out temperature is adjustable from
180 to 240° F, depending on the limit desired- .....
Gas Piping 1
•Use a ground-joint-type union to connect the control
assembly to the manifold header, then continue the
piping to the main gas supply. Follow all local codes
and ordinances. The following are pertinent recom¬
mendations. See Figure 28.
joint compound (pipe dope) which is resistant to the
action of propane should be applied sparingly and
only to the male threads of the joints. Consult local
supplier for type of compound to be used.
1. Run a spearate gas line direct as possible from gas
source to boiler. Size of pipe should be large as prac¬
tical to minimize pressure loss (consult local utility).
Pipe size should never be smaller .than inlet to main
manual gas shutoff valve supplied with boiler..
2. Mount., mam, manual gas shutoff valve ap¬
proximately 5 .feet above floor level. A tapping for
Figure 28
manu al pilot gas shutoff valve should be on inlet .(sup¬
ply) side of valve. See Figure 27.
• 3. Connect gas control, assembly to main supply line
with ground joint union and tee. • ■
4. Install drip leg from tee so it extends below control
assembly. ... ■ / ■ ".-
5. Support supply pipe with adequate hungers or
straps..•;..: : ■ ". ■■■ '■ :' ■ < • : ? '
Connect the pilot supply tubing from the various
pilots through the 100% pilot shutoff relay, if used, to
the manual pilot gas shutoff valve.
The escapement tube from the Bryant automatic
gas valve, or valve controller, should be installed
oh the pilot burner in the base closest to the control
end of the boiler. The escapement tube is mounted to
the top of the pilot mounting bracket with a clip and
one screw. On boiler sizes 17 through 33, natural gas
only, there are two escapement tubes; one each in the
first two bases from the control end of the boiler. See
Figure 29.
CONDENSATE
SHIELD
CUPS TO HOLD ,.
ESCAPEMENt TUBES
1/4 REGULATOR
BLEED ESCAPEMENT
VALVE ESCAPEMENT TUBE
Figure 29
D4 (Natural) Steam and Water Non-100% Shutoff,
D2 (Propane) D5 (Natural) Steam and Water.
Thermocouple Pilot - 100% Shutoff.
ACS439
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