Unit Starting And Operating Conditions - Zehnder Rittling HP Series Installation, Operation And Maintenance Manual

Unit starting and
operating conditions
Notes:
Maximum and minimum values may not be
n n
used in combination.
If one condition is max. or min., the other
n n
two conditions may not exceed the standard
unit normal condition.
Extended range units may combine up to
n n
two maximum conditions with the others
being normal.
Operating limits
Environment: Units are
designed for indoor installation
only. Never install units in areas
subject to freezing or where
humidity levels could cause
cabinet condensation (such as
unconditioned spaces subject to
100% outside air).
Power supply: Voltage utilization
range complies with AHRI
Standard 110. Voltage Min/Max
are shown in the appropriate
Electrical Data tables elsewhere
in this manual. In general,
voltage variation of +/- 10% of
nameplate utilization voltage is
acceptable.
Determination of operating limits
is dependent primarily upon
three factors:
Return air temperature
n n
Water temperature
n n
Ambient temperature
n n
Table 10
Standard range units
Air limits
Cooling
Minimum 50 °F (10 °C)
Ambient
air
Maximum 100 °F (38 °C)
65/60 °F
Minimum
(18.3/15.6 °C)
Entering
80.6/67 °F
air Rated
(27/19 °C)
(DB/WB)
100/83 °F
Maximum
(38/28 °C)
Entering 55/45 °F
Minimum
(10/7 °C)
air: Start-
up only 110/83 °F
Maximum
(DB/WB)
(43/28 °C)
Table 11
Standard range units
Water limits
Cooling
Minimum 55 °F (13 °C)
Entering
Normal 85 °F (29 °C)
water
Maximum 110 °F (43 °C)
Minimum
GPM/ton Rated
Maximum
When any one of these
factors is at minimum or
maximum levels, the other two
factors should be at normal
levels to ensure proper unit
operation. Extreme variations
in temperature and humidity
and/or corrosive water or
air will adversely affect unit
performance, reliability, and
service life. Consult Tables 10
and 11 for operating limits.
Start-up conditions: Allowances
are made for a wider range of
entering air conditions during
start-up and are shown in
Table 10. Start-up conditions
are not normal or continuous
operating conditions but may
be used to bring the building
space up to occupancy
temperatures. Units are not
designed to operate under these
conditions on a regular basis.
Extended range units
Heating Cooling
50 °F (10 °C) 50 °F (4 °C)
85 °F (29 °C) 100 °F (38 °C)
60/50 °F
50 °F (10 °C)
(16/10 °C)
80.6/67 °F
68 °F (20 °C)
(27/19 °C)
95/75 °F
80 °F (27 °C)
(35/24 °C)
55/45 °F
40 °F (4 °C)
(10/7 °C)
110/83 °F
80 °F (27 °C)
(43/28 °C)
Extended range units
Heating Cooling
55 °F (13 °C) 30 °F (-1 °C)
70 °F (21 °C) 77 °F (25 °C)
90 °F (32 °C) 120 °F (43 °C)
1.5
3.3
4.0

Unit starting and operating conditions

Heating
50 °F (4 °C)
85 °F (29 °C)
45 °F (7 °C)
68 °F (20 °C)
80 °F (27 °C)
40 °F (4 °C)
85 °F (29 °C)
Heating
20 °F (-6 °C)
40 °F (4 °C)
90 °F (32 °C)
33