7
3.4 The Reagents
The indicator reagent reacts with any oxidant, generally chlorine, to
create a pink color which the instrument measures and compares with
a sample of water without reagents.
The buffer reagent is required to control the sample pH to bring the
sample to neutral. The reagents are provided already hydrated and
require little operator preparation.
Each 125 mL indicator will require the addition and mixing of the DPD
powder contained in the small brown bottle. This activates the indicator
reagent. The indicator reagents should be changed out on a 90 day
basis even if they are not fully used.
The 500 ml buffer does not require any preparation and is good for
one year.
After one year all the reagents will have been consumed and replacement
reagent set will be required. This can be ordered through agent Catalog
No.09991. This set will include four sets of Indicator reagents plus one
500 mL bottle of Buffer.
3.3 Remote Standby
This feature will allow for remotely placing the instrument into a standby
mode. This can be done to lower reagent usage while not performing
ballasting or de-ballasting operations. The last operation of each
cycle is a flush and hold. Whenever the instrument is not being used
(standby), it is stored such that the optics is clean and dry.
Dry contacts are provided as feedback as to the operation
of the instrument (operating or standby). For more
information on this feature refer to sections 4.4.4
Remote
Standby Connections and 6.2 Routine Measurement with
Remote Standby.
3.5 The Reagent Cooler
A reagent cooler is provided for the 125 ml indicator reagent.
For proper operation power must be applied by the Air Sentinel controller
to the cooling chamber temperature controller. Clean dry compressed
air must also be provided at pressures between 5.5 and 7 bar (80 to
101.5 PSI).
The cooling chamber temperature controller governs the solenoid
which controls air flow to the vortex cooling unit. The air flow is turned
on or off as required to maintain the indicating reagent temperature at
20-25˚C. This extends the life of the reagent up to 90 days.
To provide this extended reagent life, power to the cooling power supply
and air pressure must be supplied full time.
4.0 Installation and Commissioning
Prior to use for the first time, one of the reagents
(the indicator) will have to be mixed. Refer to section
11.2
Replacing or Installing the Reagents.
4.1 Mounting and Site Selection
The instrument is designed for wall mounting. Choose a location that is
easily accessible for operation and service and ensure that the Purge
Control lamp is about eye level. Consideration must be made for the
plumbing and electrical conduit connections. The overall mounting
dimensions of the instrument are shown in Figure 4.
Figure 4: Overall Mounting Dimensions of the Instrument
Be sure that the instrument be mounted as close as possible to the
sampling point to ensure a quick response time (within 2-3 meters
(6-10 ft) of the sampling point).
