[2.14.2
Differential Thermostat
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NOTE: Use this only in large systems, generally not
residential. It is recommended that the
differential thermostat be 4.40 degrees C 8 degrees F
turn on and 1.70 to 2.80 degrees C 3 to 5 degrees F
turn off.
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Provide UL-listed differential thermostat for controlling the magnetic
starter, not in the same circuit as pump motor. [For integral collector
freeze protection, provide two independent contact relays [, rated ten
amperes at 120 Vac].] [Provide a switch with ON, OFF, and AUTO positions.]
Provide weathertight enclosures.
][2.14.3
Sensors
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NOTE: Delete this paragraph if solar collectors are
unglazed.
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Construct sensors to withstand stagnation temperatures of glazed solar
collectors. Provide primary and alternate collector sensors attached to an
absorber plate. Provide [copper] [brass] wells which can be inserted into
the collector tube, storage tank, or [_____]. Sensors may be strapped onto
pipes and covered with insulation.
]2.14.4
Pressure Gages
ASME B40.1, brass body, and minimum 90 mm 3 1/2 inch diameter dial face.
2.14.5
Tank Gages
FS A-A-50568; Type [I, buoyant force;] [II, diaphragm;] [or] [III, purge,
bubble-pipe].
2.14.6
Thermometers
ASTM E 1, [liquid-in-glass type] [dial type, liquid-filled tube and bulb].
For pipe and tank applications, provide separate sockets fabricated of
brass, copper, or stainless steel and rated for 862 kPa 125 psi working
pressure.
2.14.7
Test Ports
Solid brass, 6 mm 1/4 inch fitting to receive either a temperature or
pressure probe 3 mm 1/8 inch outside diameter, two valve cores of neoprene,
fitted with color coded and marked cap with gasket, and rated for 6894 kPa
(gage) 1,000 psig.
[2.14.8
Monitoring System
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NOTE: For small systems such as family housing, do
not use monitoring system, due to high initial cost
and the labor to maintain it.
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SECTION 13610N
Page 21
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