Catalogue

26 UH-PRC001-EN
Performance Data
Technical & Mounting
Data
Horizontal Unit Heaters
Te c h n i c a l D a t a
The performance data listed in
Ta bl e 13 , Tab le 14 , and Table 15
include sound ratings. The ratings
provide a guide in determining the
acceptable degree of loudness in
particular occupancy situations.
Certain general rules apply to specific
selection of unit heaters with regard
to degree of quietness (or loudness);
• The greater the fan diameter, the
higher the sound level.
• The higher the motor RPM, the
higher the sound level. Note that
on most units the lower the
speed mode results in lowering
the sound rating one increment.
• Selecting a larger number of
smaller units generally results in
lower overall noise levels than
fewer large units.
All horizontal steam and hot water
unit heater motors, whether fan
guard or shelf-mounted, are isolated
from the mechanical mount by
resilient isolators. This mounting
along with balanced fan blades and
excellent overall construction
integrity, assures you the utmost in
quiet operation.
The following table outlines sound
ratings for various applications. The
lower the number, the quieter the
unit and the lower the sound
requirement.
Mounting Heights and Throws
The following table is based on 60°
entering air and either 2 lb. steam or
200° water with a 20° T.D. The data is
based on the higher speed CFM
throughout and velocity. Care should
be exercised in locating adjacent unit
heaters and allowance should be
made for obstructions in the air
pattern and conflicting air currents
from other air moving devices.
*Depending on specific use in these facilities, size of operation, etc.
*Compared to water.
CATEGORY OF AREA SOUND RATING
apartment, assembly hall, classrooms, churches, courtrooms, executive
offices, hospitals, libraries, museums, theatres
I
dining rooms, general offices, recreation areas, small retail stores II
restaurants, banks, cafeterias, department stores, public buildings,
service stations
III
gymnasiums, health clubs, laundromats, supermarkets IV
garages, small machine shops, light manufacturing V
Factories, foundries, steel mills III-VII*
Table 21. Corrections When Using Glycol Solution in System
Propylene
Glycol
Heat transfer @ 180°F with no
increase inflow rate
20% solution .97*
50% solution .90*
G.P.M. Req'd. @ 180°F, 20°F ∆
t (no
correction to pump curve)
1.10%*
Pump Head Req'd. @ 180°F w/
increase in G.P.M.
1.23%*
Specify gravity (water = 1.0) 1.045-1.055*
Pounds/Gallons @ 60°F (water =
8.3453 Pound/Gallon)
8.77
pH @ 50% by volume 9.5
Freezing Point by volume
55% -
50% -28°F
40% 13°F
30% + 4°F
20% +17°F
Table 22. Approximate factors at varying altitudes
Altitude Factor
Sea level - 1000 ft. 1.00
1000 ft. - 3000 ft. .958
3000 ft. - 5000 ft. .929
5000 ft. - 7000 ft. .900
7000 ft. - 10000 ft. .871