OMEGA-VSHYe.F-IOM-2108
11
When call for cooling request is terminated, the auto
shut
-
off control valve (COAX Flow Valve) and the blower
fan will remain open for an additional 3 minutes.
Heating
When a call for HEATING is made, the auto shut
-
off
control valve (HC Flow valve) will divert water flow
through hydronic coil and fan will be energized.
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
Troubleshooting Guide
for identifying
common issues and possible resolutions. The micropro-
cessor control board has a number of LED lights for
identification of common alarms and faults. See
Micro-
processor 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.