Figure 5-9 - Water Control Valve - Gardner Denver EAQ99S Operating And Service Manual

Hex head zinc anodes are used in the return bonnet (opposite end to the water pipe connections) of heat
exchangers to provide internal water system corrosion protection. These anodes should be inspected
periodically and replaced when the zinc has been reduced to about 13mm in length.
Figure 5-9 – WATER CONTROL VALVE
WATER FLOW CONTROL VALVE FOR HEAT EXCHANGER (Optional Equipment) (Figure 5-9) - The
water flow control valve is adjustable to compensate for varying water inlet temperatures and pressures
and is to be mounted in the water outlet line after the oil cooler ( , page 44). Use the compressor
Figure 5-2
discharge air temperature gauge on the instrument panel in setting the flow control valve. The
compressor discharge temperature must be maintained a minimum of 5° C above the dew point
temperature at the maximum anticipated ambient; refer to Figure 5-1, page 43, for the dew point
temperature at the operating pressure and ambient temperature of the application.
To decrease water flow (increase compressor discharge air temperature) turn the adjusting screw from
left to right, increasing spring tension. To increase water flow (decrease compressor discharge air
temperature) turn the adjusting screw in the opposite direction. The groove at the lower edge of the
adjusting screw is an index line for use with the index scale 0 to 8 in obtaining a desired setting.
These valves must be handled with care and proper tools and techniques must be used when working on
the valve.
Care must be used when handling the capillary tube; a kink or break in the tubing or connections will
make the valve inoperative. Never attempt to change capillary length. Excess capillary tube should be
carefully coiled and placed so that damage will not occur in normal maintenance or traffic past the unit.
If the leak develops through the packing, tighten the packing gland nut firmly with a wrench to reseat the
packing around the valve stem, then back off the nut until loose, and finally retighten the nut finger tight.
Tightening the packing nut too tight may cause erratic operation. An occasional drop of oil on the valve
stem at the packing nut will prolong packing life.
If valve malfunctions, check for bent or binding, paint or corrosion on valve stem, foreign material in valve,
erosion, or thermal system (capillary) failure. If foreign material or scale is likely, the use of a strainer in
the inlet water line is recommended.
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