OMEGA | WATER SOURCE HEAT PUMPS OMEGA-VSHP.F-IOM-1907
11 www.omega-heatpump.com
a jumper wire to enable this feature. See Figure
24:Thermostat Wiring Detail for wiring instructions.
Fan Control with ECM X13 Motors
Omega utilizes the X13 ECM motor for larger sized Heat
Pumps. The X13 ECM motor is a multi-voltage motor,
with 5 low voltage speed taps, utilizing 208VAC for pri-
mary power and 24VAC for speed selection.
SEQUENCE OF OPERATION
Call for Heating and Cooling
Demand call for Heating or Cooling are initiated at the
thermostat.
If a HEAT PUMP Thermostat type is used, with DIP #1
set to “ON”, control signal form thermostat to terminal
block sets the following:
“Y” Terminal Closed = call for compressor.
“O/B” Terminal Open = Reversing Valve De-Energized
(call for HEATING).
“O/B” Terminal Closed = Reversing Valve Energized
(call for COOLING)
If a 1HEAT/1COOL Thermostat type is used, then DIP
#1 should be set to OFF. Control signal form thermostat
to terminal block sets the following:
“Y” Terminal Closed = call for COOLING.
“O/B” Terminal Closed = call for HEATING.
Note: If both “Y” and “O” are closed, a call for HEATING
is assumed.
When a compressor request is made, the auto shut-off
control valve (COAX Flow valve) will open. The com-
pressor contactor will then be energized so long as none
of the following fault conditions are present:
• High-Pressure Alarm
• Low-Pressure Alarm
• Condensate Over Flow Alarm (Optional)
• Compressor Anti-Short Cycle 7 min. timer has not
expired
• Entering Water Temperature is greater than 115
o
F
• Leaving Water Temperature greater than 127
o
F
When call for compressor request is terminated, the
auto shut-off control valve (COAX Flow Valve) and the
blower fan will remain open for an additional 3 minutes.
Low-Pressure Bypass
During a call for compressor, the low-pressure switch is
bypassed for the first 2 minutes of compressor operation
to prevent nuisance low-pressure start-ups.
Timers and Interlocks
Microprocessor board utilizes a number of timers and
interlocks in the control sequence of the unit.
Anti-Short Cycle Timer
The compressor anti-short cycle timer of 7 minutes
starts every time a call for compressor is terminated to
prevent compressor over cycling.
Fan-On Timer
The Fan-On timer of 3 minutes starts anytime there is a
call for fan request.
Fan-Off Timer
The Fan-Off timer of 3 minutes starts anytime a call for
compressor is terminated to ensure fan runs for a period
of 3 minutes after the compressor turns off.
Valve Open Timer
The valve open timer of 1 minutes starts anytime a fan
and compressor request are made to develop flow in the
water coil.
Valve Closed Timer
The valve closed timer of 1 minutes starts anytime a call
for compressor is terminated to allow for flushing of the
water coil.
Random Wait Time on Unit Power Up
Microprocessor controller uses a random wait time dur-
ing unit start up between 1-30 seconds.
9. TROUBLESHOOTING
Refer to the Table 6: Troubleshooting Guide for identify-
ing common issues and possible resolutions. The micro-
processor control board has a number of LED lights for
simple identification of common alarms and faults. Refer
to Table 7.
TEST MODE
A Test mode feature can be enabled in order to perform
diagnostic testing of the unit. Test mode will bypass all
unit timer delays for 10 minutes.
To enable test mode jumper “DI1” pins on the micropro-
cessor board. The unit will operate in test mode. Re-
move jumper from DI1 if not already done so to get out
of test mode. Failure to remove DI1 jumper will disable
important safety controls such as High and Low Pres-
sure switches.
Failure to remove DI1 jumper will disable criti-
cal safety controls and may cause equipment
or property damage if left disabled.
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