4
UNIT STARTING AND OPERATING CONDITIONS
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 – A voltage variation of +/– 10% of
nameplate utilization voltage is acceptable.
Starting Conditions
Consult Table 7 for starting conditions. vary depending
upon model number and are based upon the following
notes:
Notes:
1. Conditions in Table 7 are not normal or continuous
operating conditions. Minimum/maximum limits are
start-up conditions to bring the building space up to
occupancy temperatures. Units are not designed to
operate under these conditions on a regular basis.
. Voltage utilization range complies with ARI
Standard 110.
Determination of operating limits is dependent primarily
upon three factors: 1) return air temperature. ) water
temperature, and ) ambient temperature. When any
one of these factors is at minimum or maximum levels,
the other two factors should be at normal levels to insure
proper unit operation.
Extreme variations in temperature and humidity
and/or corrosive water or air will adversely affect unit
performance, reliability, and service life.
Cooling
Heating
Air Limits
Min. ambient air, DB
45ºF [7ºC]
39ºF [4ºC]
Rated ambient air, DB
80.6ºF [27ºC]
68ºF [20ºC]
Max. ambient air, DB
110ºF [43ºC]
85ºF [29ºC]
Min. entering air, DB/WB
70/61ºF [21/16ºC]
50ºF [10ºC]
Rated entering air, DB/WB
80.6/66.2ºF [27/19ºC]
68ºF [20ºC]
Max. entering air, DB/WB
95/76ºF [35/24ºC]
80ºF [27ºC]
Water Limits
Min. entering water
50ºF [10ºC]
50ºF [10ºC]
Normal entering water
60-90ºF [15-32ºC]
60-70ºF [15-21ºC]
Max. entering water
110ºF [43ºC]
90ºF [32ºC]
HCH/HCV
Operating Limits
Normal Water Flow
[3.2 to 3.9 l/m per kW]
2.5 to 3.0 gpm / ton
Table 7: Operating Limits
Piping System Cleaning and Flushing
Cleaning and flushing the WLHP piping system is the
single most important step to insure proper start-up and
continued efficient operation of the system.
Follow the instructions below to properly clean and flush
the system:
1. Insure that electrical power to the unit is disconnected.
. Install the system with the supply hose connected
directly to the return riser valve. Use a single length of
flexible hose.
. Open all air vents. Fill the system with water. DO
NOT allow system to overflow. Bleed all air from the
system. Pressurize and check the system for leaks
and repair as appropriate.
4. Verify that all strainers are in place (Heat Controller
recommends a strainer with a #0 stainless steel wire
mesh). Start the pumps, and systematically check each
vent to ensure that all air is bled from the system.
5. Verify that make-up water is available. Adjust make-up
water as required to replace the air which was bled
from the system. Check and adjust the water/air level
in the expansion tank.
6. Set the boiler to raise the loop temperature to
approximately 86°F [0°C]. Open a drain at the
lowest point in the system. Adjust the make-up water
replacement rate to equal the rate of bleed.
7. Refill the system and add trisodium phosphate in
a proportion of approximately one pound per 150
gallons [1/ kg per 750 l] of water (or other equivalent
approved cleaning agent). Reset the boiler to raise
the loop temperature to 100°F [8°C]. Circulate the
solution for a minimum of 8 to 4 hours. At the end of
this period, shut off the circulating pump and drain the
solution. Repeat system cleaning if desired.
8. When the cleaning process is complete, remove the
short-circuited hoses. Reconnect the hoses to the
proper supply, and return the connections to each of
the units. Refill the system and bleed off all air.
. Test the system pH with litmus paper. The system
water should be in the range of pH 6.0 - 8.5 (see table
). Add chemicals, as appropriate to maintain neutral
pH levels.
10. When the system is successfully cleaned, flushed,
refilled and bled, check the main system panels,
safety cutouts and alarms. Set the controls to properly
maintain loop temperatures.
PIPING SYSTEM CLEANING AND FLUSHING
