Page 199 - Boiler Operator’s Handbook

184 Boiler Operator’s Handbook

Since there’s only one filter on your home air condition- pop-riveted to the top and bottom of the duct as a guide.
er it can also serve to remove bacteria, viruses, and even My filter box, and filters, (Figure 5-42) are designed to
odors from the air depending on the grade of filter that filter every cubic centimeter of air that goes to that air
you purchase. Where those contaminants are a concern handling unit. When the salesmen come knocking on
with industrial and institutional equipment additional my door trying to sell me an air duct cleaning I just tell
filters are normally installed at the outlet of the air han- them what I have and ask if they will guarantee to show
dler to remove them. me dirt from my system or do the job for free. They all
Depending on the size of the facility the replace- slink away quietly. A proper, well sealed filter system
ment of those filters can become one of the duties of the will dramatically reduce cleaning and other mainte-
boiler plant operator. Arguments go both ways in this re- nance chores on the air handling equipment. It won’t
gard but I’m confident that it places the eyes, ears, and eliminate it but it can put the work off for years.
incomparable senses of the boiler operator next to the air I’ve seen some real disasters at some facilities be-
handling equipment on a regular basis to detect problems cause filter replacement was ignored, abused, mishan-
that can become very expensive. So, if you’re asked to re- dled, or overdone. I’m a firm believer that one can tell
place filters be certain to use those senses to monitor the how well a facility is maintained by simply looking at
operation of the equipment. The argument that it takes a few filter banks. Another typical indicator is the con-
you away from attending to the equipment in the boiler dition of replacement filters in storage. If they’re laying
room has its merits but properly spaced intervals of ab- on a shelf or in an open box without protection from
sence from the boiler room should have little, if any, effect the environment and collecting dust before they’re ever
on the quality of monitoring the boiler room and you’ll placed in the filter box they can actually introduce dust
find time to fit it all in. Large installations with many air and contaminants into the cooling and heating coils.
handlers are normally maintained by contractors. Check-
ing up on those contractors by reviewing the status of the Cooling Coils
equipment with a regular walk-through or check of the After the filters the air normally enters the cooling
SCADA system should also be a duty of the boiler plant coil although the coil may have face and bypass damp-
operator. ers on it (Figure 5-43) that are used to control equip-
One consideration of whoever is in charge of fil- ment outlet conditions. The air is not only cooled by
ters is the application of the right filter for the job. All the cooling coil but moisture is also removed from the
too often the filters are not specified carefully or the air. What happens at that cooling coil is dependent on
installing contractor puts in the cheapest filter box and a lot of factors including the inlet temperature and hu-
set of filters available. Don’t throw out a filter sales- midity of the mixed return and ventilation air, number
man that walks into the boiler plant and wants to talk. of people in the conditioned space, sunlight entering
There are modern filters that not only do a better job the conditioned space, outside air infiltrating the con-
and last longer than conventional ones but ones that ditioned space through doors and leaks at windows,
even cost less. When considering cost of replacement, and a lot of things that occupants can do. The face and
place a value on your time or your contractor’s time bypass dampers allow for varying supply air tempera-
as well. Cheap filters that have
to be replaced more frequent-
ly may cost less but when the
combined cost of replacement
labor and additional filters is
considered more expensive fil-
ters can cost less.
Don’t hesitate to consid-
er the replacement of the filter
frames. I’m certain the filter in-
stallation at 90 percent of hous-
es can’t compare to the one in
mine. The typical provision for
a filter is a hole cut in the side
of the duct and some channels
Figure 5-42. Ken’s home air filter box and filter