OMEGA | WATER SOURCE HEAT PUMPS
OMEGA-VSHPe.F-IOM-1912
11
www.omega-heatpump.com
mined by the position of the unit mounted 3
-
speed fan
selector switch located on the electrical box cover:
L = LOW fan speed
M = MEDIUM fan speed
HI = HIGH fan speed
Fan Control with EC Motors (ECM)
Low voltage PULSE WIDTH MODULATED (PWM) sig-
nal is utilized to control motor speed between 0 and
100% of full speed. The controller has been pro-
grammed to use 3 preprogrammed speeds for Low, Me-
dium and High. See electrical schematic in Figure 23.
Inside electrical box a label indicates the factory pre
-
programmed speed settings.
Whisper Mode
Whisper mode is factory enabled and runs main blower
fan at pre
-
determined low fan speed for continuous air
circulation. A jumper is factory installed between
‘
R
’
and
‘
G1
’
terminals on TB1 of control board to enable Whis-
per mode.
8.2 SEQUENCE OF OPERATION
Call for Heating and Cooling
Demand call for Heating or Cooling are initiated at the
thermostat.
When a compressor request is made, the optional auto
shut
-
off control valve (COAX Flow valve) will open. The
compressor 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.
8.3 TROUBLESHOOTING
Refer to the
Table 8: Troubleshooting Guide
for identi-
fying common issues and possible resolutions. The mi-
croprocessor control board has a number of LED lights
for identification of common alarms and faults. See
Table 9: Microprocessor LED Code Guide
for fault ID
information.
If unit trips on Low or High pressure fault into a hard
-
lock
state,
do not disconnect power to unit in an attempt
to restart to unit.
The unit will allow 3 faults before it
hard
-
locks.
Failure to diagnose pressure fault and re
-
starting unit can cause serious equipment and prop-
erty damage.
Test Mode
A Test mode feature can be enabled for 10 minutes in
order to perform diagnostic testing at reduced time de-
lays. To enable, jumper or short the two
“
DI1
”
pins on
the microprocessor board. When done test mode re-
move jumper from
“
DI1
”
if used.
Unit status and diagnostics temperature readings can be
easily accessed using a web browser based tool as de-
scribed in the
Web Browser Access
section.