OMEGA | WATER SOURCE HEAT PUMPS                                                                 OMEGA-VSHP.F-IOM-1907 
 
 
9  www.omega-heatpump.com   
 
 
 
7. UNIT START-UP 
Ensure the building loop system has been cleaned, 
flushed, chemically treated and commissioned by the 
water treatment company. Verify that the main system 
strainers or mechanical filtration system has been in-
stalled and commissioned. The chassis should be at 
room temperature (68
o
F) prior to start up. 
Once the installation of the cabinet and chassis units is 
complete the riser shut-off valves can be opened.  The 
riser loop system should be filled and all trapped air 
should be bled from the system prior to unit start-up.  
Water flow failure will cause the unit to trip on the safety 
devices. Repeated water flow failures can cause equip-
ment damage. 
 
CHECKLIST  
Before energizing the unit ensure all steps are verified in 
the following checklist: 
___High voltage power supply is correct and in accord-
ance with unit nameplate ratings. 
___Unit is electrically grounded and circuit protection is 
the correct size. 
___Low voltage control wiring is correct as per unit wir-
ing diagram. 
___Riser loop system is clean, filled, and vented of any 
air. 
___Chassis unit high and low pressure caps are firmly 
secure and in place. 
___Chassis matches the cabinet model number. 
___Protective  cardboard  air  coil  cover  is  removed  and 
unit service cover panel and filter are in place. 
___There is a proper seal between chassis service cov-
er panel and unit cabinet. 
___Riser shut-off valves are in the OPEN position. 
___Riser loop system has been vented for any air intro-
duced during chassis installation. 
___Riser loop water is circulating through all units and at 
design conditions. 
___Unit  condensate  drain  hose  is  securely  attached  to 
drain pan and condensate riser. 
___Indoor unit blower spins freely. 
___All ductwork is complete. 
___Clean filters are installed. 
___All  cutting,  sanding,  drywalling,  patching  work  is 
complete. 
___Unit blower spins freely. 
___Thermostat is in the OFF position. 
 
INITIAL UNIT START-UP 
 
1.  Close disconnect switch. 
2.  Set thermostat to a high setting (above current room 
temperature), set system to COOL with fan on AU-
TO.  The compressor should not run. 
3.  Lower  the  thermostat  temperature  setting  until  the 
fan  and  compressor  energize.  Verify  the  following 
results: 
•  Leaving  water  temperature  (LWT)  in  the  heat  ex-
changer water coil is warmer than the entering wa-
ter temperature (EWT) by approximately 9
o
F—12
o
F. 
•  Blower is running smoothly. 
•  Compressor and blower amps are within nameplate 
data. 
•  Suction line is cool and no frosting is forming in the 
refrigeration circuit. 
4.  Set thermostat to the OFF position. Unit compressor 
and fan should stop running. 
5.  Allow  the  system  to  equalize  for  approximately  5 
minutes. 
6.  Set  thermostat  to  the  lowest  setting  and  switch  to 
the HEAT position. 
7.  Adjust  thermostat  temperature  higher  until  the  fan 
and  compressor  energize.  The  following  should 
occur: 
•  Warm air will flow from the supply register. 
•  Leaving  water  temperature  (LWT)  in  the  heat  ex-
changer water coil is cooler than the entering water 
temperature (EWT) by approximately 5
o
F—9
o
F. 
•  Blower and compressor operation is smooth and no 
frost  development  is  visible  in  the  refrigeration  cir-
cuit. 
8.  Set the thermostat to the desired temperature. 
9.  Check for any water leaks at the hose connections.