approval. The Contracting Officer will inspect the linen bag prior to
completion of flushing and approve the flushing operation. System shall be
drained prior to final filling.
3.2.4.4
System Filling
System shall be filled through indicated connections with [propylene-glycol
solution. Solution shall be mixed externally to the solar system and
consist of [30] [50] percent propylene-glycol and [70] [50] percent
distilled water by volume] [distilled water]. Air shall be vented from the
system after filling. System pressure at the high point on the roof shall
be 69 kPa 10 psig minimum.
3.2.4.5
Operational Test
Operational test shall occur over a period of 48 consecutive hours with
sufficient solar insolation to cause activation of the solar energy system
during daylight hours. With system fully charged so that pressure at the
high point on the roof or the lowest system pressure is a minimum of 69 kPa
10 psig and with fluid and pump[s] energized, [sight flow indicator must
indicate flow] [flowmeter must indicate flow as indicated]. Calibrated
balancing valves with pressure taps shall indicate bank flow rate as shown.
3.2.4.6
Control Logic
**************************************************************************
NOTE: The following on/off set differentials are
common for liquid systems:
Pump on = 7 to 11 degrees C (12 to 20 degrees F).
Pump off = 2 to 4 degrees C (3 to 8 degrees F).
**************************************************************************
By substituting variable resistors for collector and storage tank
temperature sensors, Contractor shall demonstrate the differential
temperature controller correctly energizes the system pump[s] when the
collector sensor indicates a temperature of [8] [_____] degrees C [15]
[_____] degrees F greater than the storage tank temperature, as indicated
on the controller display panel. The differential temperature controller
shall de-energize the system pump[s] when the displayed temperature of the
solar collectors is [3] [_____] degrees C [5] [_____] degrees F greater
than the displayed temperature of the storage tank.
3.2.4.7
Temperature Sensor Diagnostics
Contractor shall demonstrate that the controller will correctly identify
open and short circuits on both the solar collector temperature sensor
circuit and the storage tank sensor circuit.
3.2.4.8
Overall System Operations
Contractor shall demonstrate that the solar energy system will operate
properly while unattended for a period of at least 72 hours. The system
must demonstrate that the controller will start pump[s] after being warmed
by the sun, and that it will properly shut down during cloudy weather or in
the evening over a minimum of three complete cycles. Contractor is
permitted to manipulate the temperature of the storage tank by the
introduction of cold water at local groundwater temperature.
SECTION 13600A
Page 30
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