Bleed Control - Braemar RPA Series Installation, Operation & Service Manual

Variable Pitch Pulley and Belt Tension (cont.)
Motor / Pulley arrangement for models RPA700 TO RPA1500
1.6mm/100mm SPAN @ 2.0kg
BELT DEFLECTION FORCE
If turning pulley counter clockwise to reduce

blower speed, be sure that the V section is not
opened far enough to allow the belt to ride on
the threaded part of pulley, as this will cause
damage to the belt.
 Too great a belt tension will increase
motor load, and shorten belt and bearing life.
Too loose a belt will cause belt slippage and
excessive belt and pulley wear.
 Check the Full Load Amps
After any adjustments to belt tension, the maximum full load current must be checked
to ensure it is within the rating specified on the serial plate. If the amps are not within
rating, make adjustments to the motor pulley as described in this section. Only units
with a variable pitch pulley can be adjusted, other units will need to have the
installation checked.
Check that the full load current on high and low speed is within the motor rating.

Bleed Control.

To reduce the accumulation of salts and minerals in the recirculated water it is essential to bleed a
certain amount of water to waste. Increased flow of make up water reduces the salt content.
The bleed rate will vary with the water supply quality, but should initially be set to the minimum
recommended bleed rates as set out in the chart below. The bleed line from the flow and bleed
controller in the pump delivery line, inside the unit , must be suspended through the overflow
stand pipe, or into the side of the optional drain valve. Connect suitable pipe work to bottom
thread of the drain bush so that water drains directly to waste.
Table 1 Recommended Minimum Bleed Rates (LPH)
RPA400
RPA450
RPA500
 Location of Bleed Control.
The bleed control tap is located externally on a corner pillar.
Adjustment to the bleed rate is made by turning the black/red tap control to the desired setting.
Check the bleed rate by running into a graduated container for a set time, say 10 minutes.
Build up of salt deposits in the pads or the tank indicates that the bleed rate is inadequate.
Increase the rate where necessary.
RPA INDUSTRIAL AIR CONDITIONERS
11 RPA600 16
12 RPA700 18
13 RPA900 24
PULLEY
BELT TENSION SCREWS
RPA1000 26
RPA1200 31
RPA1300 34
PULLEY
RPA1400 36
RPA1500 39