3
GENERAL SELECTION
HEAT LOSSES
Should be calculated according to
ASHRAE Guide or other reliable
source.
MODEL SELECTION
The model selected should be suitable
for the type of building or area to be
served. Model H units are generally
used with low ceilings (see Table 2 for
mounting height and spread). Model V
units are recommended with high ceil-
ings. They are particularly efficient in
plants, warehouses or similar applica-
tions where they recover warm air
which stratifies near ceilings (see Table
3 for mounting height and spread).
Model V unit heaters with louver cone
diffusers can also be used with higher
ceilings.
NUMBER OF UNITS
Select required number of units to han-
dle the heat losses, and also for proper
air motion, adequate coverage of the
occupied space, and operation within
permissible sound levels. For instance,
although one large unit may be suffi-
cient for a certain area, two smaller
units may be specified at a lower RPM
for quieter operation, and to provide
better heat distribution and circulation.
SPOT HEATING
It is usually more effective to discharge
air across, instead of into, an open
door. The throw shown in the perfor-
mance tables applies to draft-free build-
ings with relatively stable temperatures.
When heating only a small area within a
cold environment, experience shows
that the published throw may be
reduced by as much as 50%.
UNIT LOCATION
Unit Heaters should be spotted to aim
the discharge towards the source of
heat loss, but precautions should be
taken to avoid blasting people with the
warm air mass. Model H units should
be located to achieve maximum air
rotation in the same direction at the out-
side walls.
ECONOMY AND COMFORT
Where individual comfort is not an
important factor, the prime considera-
tion is to design the most economical
system which will satisfy overall heating
requirements. Larger units requiring
less piping are recommended. Where
the physical comfort of the occupants is
important, several smaller units will pro-
vide quieter operation, better heat dis-
tribution, and more even temperatures.
PIPING
For unit heater piping connections, see
AMCA Bulletin No. 15.
NOTE:
Although the cone diffuser can be
mounted on Model V as shown
throughout this literature, it is recom-
mended that the cone diffuser be
mounted approximately four inches
below the fan collar using fourbrackets
(not shown) to provide optimum heat
dispersion.
MODEL H
MODEL V
UNIT HEATERS
To Next Page
Loading...
Need help?
General
