Remak VCS Installation And Operating Instructions Manual page 65

Unit Activation
Outdoor and indoor temperature sensor failures will not shut
down the entire system, only the functions related to the
required input variable from the sensor. To operate properly,
the VCS system requires all sensors according the specifica-
tion to be operative.
Water Heater Antifreeze Protection Failures
The water heater protection system to prevent a breakdown
caused by water freezing during a heating water delivery
failure will report a failure if the heating water or air tempera-
tures drop below the pre-set limits. For details about water
heater antifreeze protection, refer to the chapter Description
of Control and Protection Features.
Possible Causes of Indicated Failures
Antifreeze Protection Alarm
n Low water temperature in the water heat exchanger
n Check water temperature in the water heat exchanger
n
Check the heating water source.
n Inspect or clean the SUMX mixing set filter.
n Inspect the heat exchanger's fins for fouling.
n Verify the circulation pump activation and operation.
n Verify functionality of the three-way valve
n
Check the NS 130 temperature sensor in the duct.
Electric Heater Failure
n Inspect the electric heater thermo-contacts.
n Check the electric heater switching.
n
Check the circuit breaker and EOS(X) electric
heater condition.
n Inspect or clean the filter insert.
n Inspect the dampers for opening.
n Verify smooth air flow
Electric Heater Specialities
The EOS series electric heater design provides safe, reliable
and long service life. As semiconductor relays (SSR) are used
to switch the electric heaters, it is necessary to pay close
attention to operating conditions, especially to over-voltage
in the wiring and permissible increases in the temperature
of the SSR relays.
SSR relays are advanced semiconductor components ensur-
ing electric heater output switching with minimum noise. Due
to the SSR relay design technology, the voltage at its poles
must not exceed 1200V. As standard, SSR relays are equipped
with over-voltage protection. If over-voltage exceeds the val-
ues specified by ČSN 330420 for wiring category III, there is a
risk of service life shortening or even SSR relay destruction. In
these cases, it is necessary to provide the control unit supply
line with multistage over-voltage protection. An increased risk
of over-voltage exists in the vicinity of 22kV/400V distribution
transformers, highly loaded power lines routed in parallel,
frequency inverters, etc.
Another danger comes from unacceptable overheating of
the SSR relay internal structure above the permissible limit,
leading to its destruction. Sufficient cooling of the SSR relay
is ensured by placing the SSR cooler in the air duct, where it
is cooled by the air flow.
Control units VCS
Overheating of the SSR relay internal structure can also
be caused by increased transition resistance at the poles
(terminals), i.e. between the feed conductor and terminal.
Therefore, it is necessary to ensure proper tightening of the
SSR terminal bolts.
Fan Failures
n Check connections of the thermo-contacts.
n Check the condition of the motor circuit breaker .
n Inspect the V-belt.
n
Check the fan for free rotation.
n Check connections of the P33N differential
pressure sensor.
n Check the motor current.
n Inspect the frequency inverter
Air-Flow Failure
n Check the condition of the V-belt .
n Check the fan for free rotation.
n Check performance of the differential pressure sensor.
n
Check the fan for proper operation and correct
direction of rotation.
n Inspect the frequency inverter.
Failure Signalling – Fire, Smoke
n Check the condition of the fire dampers.
n Check the condition of the connected external device.
Fouled Filters
n
Check the filter for fouling. Replace if necessary.
n Check the P33N pressure sensor settings.
Cooling Failure
n
Check the condition of the connected cooling unit.
n Inoperative cooling – without failure indication
n Verify the water cooler circulation pump activation and
operation (at active cooling signal above 20% = 2V)
Antifreeze Protection Sensor Failure
n Check the heating water temperature.
n Check the connections of the NS 130R sensor.
n Replace the sensor
Power indicator does not illuminate
n Inspect the supply voltage.
n Inspect the auxiliary circuit breaker.
n Inspect the power supply source fuses
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