CAUTION: Properly maintain and adjust the Proportional Control Valve so it will proportion makeup to blowdown –to stop overheating of make-up. Overheated make-up results in (a) severe shell-side scaling of the Heat Exchanger and Proportional Control Valve
A proper preventative maintenance program includes yearly overhauling and cleaning of the Exchanger and Proportional Control Valve. Failure to do so can result in scaling equipment beyond salvaging. Replacement of the diaphragm every two years or sooner a
Disassembly And Reassembly Close blowdown and makeup water valves before disassembly
Proportional Control Valve
Except for replacement of the diaphragm, the above procedure is not routine maintenance.
Heat Exchanger. Shellside scaling is typically the cause of any required maintenance. Descaling may be chemical and in-place – by circulating inhibited acid through the shellside.
Operator should contact water treating chemical for appropriate descaling procedures, agents and apparatus.
Disassemble the exchanger
If the shellside is severely scaled:
Reassemble in opposite fashion.
Overhaul And Repair/General Cleaning
Proportional Control Valves
Make visual examination for suspected leaks in an assembled exchanger as follows:
Repair minor leaks by one or more of the following actions:
Note: Flow control valves are intentionally installed backwards. This arrangement provides greater valve life and does not affect performance.
Source: Cleaver Brooks