UFC 3-240-13FN
25 May 2005
Table 7-1. Cooling System Controller Functions
Function
Type
1. Conductivity
Blowdown control
2. Timer
1. Water meter initiated
2. Function of blowdown
3. Continuous percent time
Chemical inhibitor feed
4. Calendar
5. Based on real-time, continuous measurement
of the inhibitor concentration in the recirculating
system water.
1. Calendar
Biocide feed
2. ORP (oxidation-reduction potential for oxidizing
biocides)
pH control
pH electrode
1. Alarms
Remote monitoring
2. Telecommunications (wired, wireless, or
internet)
7-1.1.2
Boiler Water Controllers. Boiler water controllers control blowdown and
chemical inhibitor feed, as a minimum. Chemical feed can be accomplished through any
of several modes (e.g., continuous, water meter-initiated, blowdown, pH), depending on
the requirement. Remote monitoring can also be established. The most desirable boiler
water chemical feed control strategy incorporates real-time, continuous measurement of
the chemical concentration in the water. The controller should then make precise
chemical feed adjustments based on the real-time measurement, so that treatment
levels can be reliably maintained. Typical controllers used in boiler water systems are
listed in Table 7-2.
Table 7-2. Steam Boiler System Controller Functions
Function
Type
1. Conductivity
Blowdown control
2. Timer
3. Percent flow
1. Water meter initiated
2. Function of blowdown
Chemical inhibitor feed
3. Continuous percent time
4. Calendar
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