Any dirt and debris need to be removed following the "Cleaning procedures" on page 31 .
If there is evidence of biofilms the system, including piping should be drained, flushed and cleaned of slimes and
other organic contamination. Refill system with water and apply biocide shock treatment. Check pH value and
functionality of ongoing biocide treatment.
HEAT TRANSFER SECTION
The inspection procedure is as follows:
1. Shut off fan(s) and pump(s).
2. Remove the eliminators and access doors.
3. Inspect the coil for
-
obstructions
-
damages
-
corrosion
-
fouling
4. After inspection, install eliminators and access doors and start pump(s) and fan(s).
Remove any obstructions from heat transfer section(s).
Any damages or corroded areas need to be repaired. Call your local BAC Balticare representative for assistance.
Minor fouling can usually be removed chemically or by temporary changes to the water treatment programme.
Contact your water treatment supplier for advice. Major fouling requires cleaning and flushing according to the
"Cleaning procedures" on page 31 .
Regular checking of the total aerobic bacteria count (TAB) and maintaining it within acceptable levels are the key
to prevent fouling.
FINNED DISCHARGE COIL (OPTIONAL)
The dry finned coil is susceptible to corrosion and entrapment of airborne particulates (coil fouling).
The dry finned coil requires periodic cleaning to maintain the highest operating efficiency possible under the
environmental conditions in which the unit operates. Regularly scheduled coil cleaning makes a significant
contribution to extending equipment lifetime and is an excellent source of energy conservation.
Periodic cleaning of the heat exchanger coil can be accomplished by a vacuum cleaner and/or pressurised air
stream. In polluted environments cleaning will require commercially available coil cleaning agents. Cleaning coils
by spraying them with water may remove large deposits but do little to remove pollutants. Removing dirt and salts
requires a detergent to break the bond between the soil and the surface of the heat exchanger. However, if water
spray is applied, the water pressure must never exceed 2 bar and the water jet must never be applied at an angle to
the surface of the fin, but only in parallel to it.
Selecting a coil cleaner is important since the cleaner must neutralise and remove deposits on the surface of the
coil. BAC does not recommend the use of alkaline and acidic coil cleaners. These coil cleaners can cause foaming
action (oxides or hydroxides of aluminium) resulting in the stripping away of minute layers of the base alloy and the
attached soil. Most of these foaming cleaners are harsh and known as reactive cleaning products. One way to
recognise this type of cleaner is that normally it will be labelled as corrosive. The base ingredient of a coil cleaner
should not be so harsh that it attacks the metal, coil coating or the personnel applying the cleaner.
An important concern when applying coil cleaners is rinse-ability. Most hydroxides tend to cling the surface unless
sufficient wetting agents have been added to the formula to reduce surface tension of the solution. If the solution
does not have enough wetting agents and is not rinsed thoroughly from the surface, the residual material can settle
at the fin/tube interface and continue to attack the fin.
BAC recommends the use of the more sophisticated cleaners, known as a "surfactant system". They reduce
surface tension, penetrate, emulsify, and dissolve the soils without the base alloy. Surfactant systems are safe for
the coil alloy, they are free rinsing, they lift and remove deposits better than alkaline cleaners, and they are
environmentally safe, as well as safe and easy to apply and rinse. Surfactant systems are almost always non-
corrosive.
W W W . B A L T I M O R E A I R C O I L . E U
27
5 Maintenance Procedure
5 Maintenance Procedure
