AAON BL-600 - Manual (Page 43)

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Temporary strainer must be removed
following system clean up.
After all debris has been removed from the
system, or a maximum of 24 running hours,
stop the pump and close the pump isolation
valves. Drain the Suction Guide by
removing the drain plug or opening the
blowdown valve, if installed
Remove the Suction Guide cover and
remove the strainer assembly from the valve
body.
A temporary fine-mesh start-up strainer is
tack-welded to the permanent stainless steel
strainer. This temporary strainer should now
be removed from the permanent strainer.
The fine-mesh strainer is designed to
remove small particulate from new piping
systems and could easily clog with debris if
left in place. This will be detrimental to the
operation of the pump.
Inspect the cover O-ring and replace if
necessary.
Replace the permanent strainer into the
fitting body, once the temporary strainer is
removed.
Replace the cover into the body. Ensuring
that the strainer is properly seated, tighten
the cover bolts diagonally, evenly and
firmly.
Glycol Auto Fill Unit
The glycol auto fill unit (GLA) is designed
to maintain the HVAC system pressure by
adding the appropriate mix of glycol and
water to the system. During the normal
operation of the HVAC system, fluid is lost
causing a drop in the system pressure.
Standard Unit
When the system pressure drops below the
set point on the pressure switch, the GLA
pump is started adding fluid from the GLA
tank into the HVAC system. When the
system pressure returns to normal operating
conditions, the pump stops. As the tank
empties, a level switch is actuated
preventing the pump from running dry.
Ultra Unit
When the system pressure drops below the
set point on the pressure switch, the GLA
pump is started adding fluid from the GLA
tank into the HVAC system. When the
system pressure returns to normal operating
conditions, the pump stops. As the tank
empties, a level switch is actuated lighting
the low level pilot light. If the system is not
filled, a second level switch stops the
pump(s) preventing the pump(s) from
running dry. Should the system be
overfilled, a high level alarm is actuated by
level switch. Dry contacts can be provided
for remote indication of the above
conditions.
A manual “push to mix” switch is provided
for agitation of the contents of the GLA unit.
The switch starts the pump and opens the
return line solenoid valve circulating the
fluid.
Duplex units are equipped with a manual
alternator to equalize wear on the pumps.
Essential Safety Requirements
Glycol is toxic and the glycol supplier’s
safety instructions must be adhered to. In
critical areas a retaining wall should be used
to contain any spillage or leakage.
Overflows should be arranged not to
contaminate drainage systems.
It
is recommended that initial
commissioning be carried out with water.