6 | © Danfoss | 2019.10
VI.KA.A5.3S
Brazed Plate Heat Exchanger
Startup sequence:
1. Close all valves connected to the heat
exchanger.
2. Fill up and ventilate the coldest side first.
3. Open the valves gradually and start the
circulation pump. Keep opening the valves
gradually until they are open to designed
values.
4. Repeat point 3 on the hot side.
5. Start the automatic control.
The surface of PHE might reach the temperature,
equal to the temperature of working media.
Warning!
Apply necessary precautions on all
contact surfaces to avoid hot burns.
OPERATION
For the highest efficiency of heat transfer the
media should flow in Counter current flow
(Fig. 4).
To prevent clogging of the heat exchanger by
different mechanical particles, please make sure
you have filters on each inlet of the PHE.
Connection size
Mesh size
(mm)
G ¾"
< 1
G ¾"
G 2"
< 1.5
G 2.5"
and up
< 2
Table 3:
Mesh size
Corrosion resistance
For checking corrosion resistance of the
heat exchanger under different chemical
composition of working media in a single-phase
application please use Danfoss water quality
recommendations available at the Danfoss.com.
Please follow:
Danfoss.com / Products / Heat exchangers / Brazed
heat exchangers / Documents / Declaration - BF :
Guideline of Water Quality for copper brazed Plate
Heat Exchangers
On above location you can find Product
approvals and Declaration of conformity.
Avoid any media, which could be corrosive to
materials of Brazed plate heat exchanger.
Warning!
Flow rate changes must be
implemented slowly on order to
defend the PHE against sudden and extreme
temperature and pressure variations.
Important note!
In case of hard water be advised that
limescale starts actively depositing if
the temperature of the water is above 60 °C.
Protection against thermal or pressure stress
should be ensured during the operation of the
heat exchanger:
1. Adjustment of flow rate should be done
slowly to prevent extreme changes of
pressure and temperature.
2. Temperature sensor should be located as
close as possible to outlet connections of the
heat exchanger
3. Control equipment (such as valves and
controllers) should be able to give stable
temperatures and pressures
4. To avoid water hammers don’t use quick
closing valves (example – on/off valves)
5. Programming of controls should ensure
minimum amplitude and frequency of the
pressure variation during start/operation/
stop of the system.
Liquid evaporation warning: in case
temperature on the hot side of heat exchanger
is higher than 100 °C, make sure on the cold
circuit is high enough to avoid evaporation of
liquid.
CLOSE DOWN
Important note!
Incorrect PHE operation
stop may lead
to water hammer damages.
Close down sequence:
1. Close the hot side by means of slow
adjustment of the control valve. Full flow on
the cold side should be kept.
2. When the control valve is totally shut down,
the pump must be switched off.
3. Slowly close down the cold side, stop the
pump.
4. Close all shutoff valves.
5. If the PHE will be close down for a long
time, it should be drained. Also, it should be
drained if there is a risk of freezing the heat
transfer media inside the PHE due to low
ambient temperature.
Damages of PHE, made by frozen media
inside are not covered by the warranty.
CLEANING OF HEAT EXCHANGER
Warning!
Always use protective equipment as
gloves and eye protection when use
cleaning agents.
Backwash water cleaning can be recommended
to remove light adhesive particles from the
heat exchanger. It should be performed with
high speed water flow, going in the direction,
opposite to the direction of flow in normal
operation.
In case heat exchanger cannot be cleaned by
backwash, CIP equipment should be used to
chemically clean the PHE. Choose a cleaning
compound based on the type of contamination
inside the PHE.
Please follow the user’s manual of CIP machine
and chemicals producer. Make sure selected
cleaning compounds are not damaging the
materials of the heat PHE (Stainless steel
heat plates; copper or stainless-steel brazing
materials). Make sure all safety measures are
used in accordance to user’s manual of CIP
producer.
Before putting PHE back to operation please
make sure it is flushed by fresh water,
so no chemicals go in the system circuits.
STORAGE
If the PHE must be stored, make sure it is
protected from environment. No mechanical or
thermal stresses should be applied on the PHE
during storage. Storage temperature should be
between -20 °C to +60 °C and humidity between
30 % to 90 %. Make sure foreign objects or
liquids don’t get inside the heat exchanger
during storage.
UTILIZATION
Warning!
This product should be dismantled
and its components sorted, if possible,
in various groups before recycling or disposal.
Always follow the local disposal regulations.
For any further information, please contact
your local Danfoss’s representative or your local
Danfoss company.
