Bryant 108-451 - Manual (Page 6)

4. Check indoor fan operation by turning thermo­
stat fan switch to ‘on’ for continuous fan operation.
Move thermostat above room temperature and observe
that the indoor fan remains on.
5. To place the system in operation, open the main
manual gas valve, replace all panels, and set the
thermostat at the desired temperature.
High Temperature Cut-Off
The high temperature circuit includes two high
temperature controls - one located on the front of
each generator plus a high temperature relay (lockout
relay) located in the front control box. If either
generator becomes overheated the contacts in its
high temp control open, causing the high temp relay
to go ¿nto lockout position. The gas valves close,
the fan and pump stop, and will not recycle until
the lockout relay is reset. To reset lockout relay
turn electric power off and then back on. Be sure
to locate and correct cause of high temp cut-out.
Example: Natural Gas
1025 BTU
0.63 specific Gravity
1. From Table III manifold pressure is 3.2 inches
w.c.
2. With manometer connected to manifold ‘A’ set
pressure at 3.2 inches by adjusting gas pressure
regulator.
3. With manometer connected to-manifold ‘B’ set
pressure at 3.2 inches by adjusting gas pressure
regulator.
^
Table III-Manifold Pressure
(Inches w.c.)
ca
Specific Gravity
0.59 0.61 0.63 0.65 0.67
900 ■ 3.9" 4.0" 4.1" 4.2" 4.3"
950 3.5" 3.6" 3.7" 3.8" 3.9"
1000 3.1" 3.2" 3.3" , 3.4" 3.5"
1025 3.0" 3.1" 3.2" 3.3" 3.4"
1050 2.8" 2.9" 3.0" 3.1" 3.2"
1100 2.6" 2.7" 2.8" 2.9" 3.0"
VII. ADJUST GAS INPUT VIII. BALANCE THE SYSTEM
The gas input of the Model 108-451 is 330,000 BTUH
or 165,000 BTUH for each of the two generators.
For operation on natural gas the burners are equip­
ped with fixed orifices drilled #39. The adjustable
gas pressure regulator is set at the factory for 3.0
inches w.c. manifold pressure.
It is necessary to check manifold pressures with a
manometer, whether the gas is measured at the meter
or the input is set by manifold pressure according
to Table III.
When measuring gas at the meter also check pres­
sures at both generator manifolds with a manometer.
The pressures at both manifolds must read the same
to insure equal input to each generator. A 1/4 inch
pressure tap is located on each manifold for con­
necting the manometer.
If it is not possible to, measure the gas input at the
meter refer to Table III to procure the manifold
pressure required for the btu value and specific
gravity of the gas to be supplied to the unit. With
the manometer connected to one manifold set the
pressure by adjusting the gas pressure regulator.
Repeat the same procedure to set the pressure at
the manifold of the second generator.
After the unit is in operating and the input has been
measured and adjusted to agree with the rating
plate requirements, balance the system.
Any approved method of checking the air flow over
the water coil may be utilized. Reference is made
to the Bryant Service Manual on Gas Air Condi­
tioners for a review of standard methods.
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