25
7425MUM651
Model: QBS
- Use and Maintenance Manual
Rev. 02
Cause
Alarm or symptom
Solution
Execution
4. Intervention of the high pressure pressure switch
Condenser obstructed or
insufficient air flow-capacity
iA
Remove dirt from the
condenser and any obstacles
to the flow of air. Wait for the
pressure to drop below the
reset value, then rearm the
high-pressure pressure switch
by pressing the button on top
of it (see figure in paragraph
6.2).
User
The unit has operated outside its
operating limits (such as air or
water too hot)
iA
If possible, restore conditions
that are compatible with the
operating limits.
Reset the high pressure switch
(paragraph 6.2).
User
Fan not working
iA
See point 4
Excessive refrigerant charge
High subcooling
(greater than
10K//18°F)
Drain excess refrigerant
Specialized
personnel
Presence of air or incondensable
gas in the refrigerant circuit
Presence of bubbles
on the flow peep hole,
also with subcooling
values greater than
5K//9°F
Drain the circuit, create
vacuum and recharge
Specialized
personnel
Refrigerant filter clogged or
thermostatic valve stuck
Pipe downstream from
the component
covered with frost
Check and replace
Specialized
personnel
5. Fan doesn't start
Very low outside air temperatures
and consequent intervention of the
condensation control
Fan icon off.
Condensation
pressure normal
The machine can working
anyway
6. The unit is working without ever stopping
Excessive thermal load
Reduce the thermal load.
Reduce the temperature of
the incoming water and/or
the flow-capacity of the exit
tap of the unit a little.
User
No refrigerant
See point 6
7. Compressor intake pipe covered with frost
No refrigerant
High overheating, low
undercooling and high
output temperature of
the compressor.
Traces of oil on the
refrigerant circuit.
Check the chiller circuit with
a leak detector.
Repair any ruptures and
recharge the circuit.
Specialized
personnel
8. The unit stops and starts repeatedly; water temperature changes suddenly
Insufficient water flow rate
Check water flow rate.
Open the system tap fully.
If possible reduce system
feed leaks.
If possible add a pump in
series with suitable head.
Specialized
personnel
