Operation
Never operate this unit with guards or parts missing.
Once the unit has been commissioned, it will
operate automatically in the following modes:
Continuously Normal, Continuously Economy
or Timed Set Back (if fitted).
The unit can also be switched ON/OFF from a remote
timed or direct signal. On twin pump units rotate lead
pump at regular intervals to equalise wear and prevent
seizing.
Units with 40/50mm Pumps
Pumps used within the unit contain an internal thermal
contact. If this contact operates it will cause the
appropriate circuit breaker to operate, the appropriate
TRIPPED indicator to illuminate and lock out the pump
until manually reset.
Units with 32mm Pumps
Pumps used within this unit contain an internal thermal
contact. If this contact operates, it will cause the pump
to stop running, when the contact resets, the pump will
resume normal operation. No visual indication is given
for this condition.
NOTE: If the package has not been fitted internally with
a secondary circulation pump, one must be fitted in the
system pipework to maintain circulation whilst the
system is in use.
Maintenance
Ensure that the unit is electrically isolated
before any maintenance is carried out.
Plate Pack
If after a period of time, the plate pack is found to be
leaking, the plates can be tightened further. It is
essential that we are informed, and advice shall be
given regarding the ‘A’ minimum dimension. (See Fig. 1)
The guide bars at the top and bottom of the plate heat
exchanger and the threaded plate pack clamping bolts
should be kept clean and lightly greased. It is
occasionally necessary to strip down the plate heat
exchanger for inspection and cleaning.
Procedure as follows:
1.
Close the unit isolating valves and remove the
front and two side covers from the unit, this will
provide adequate access to the plate heat
exchanger.
2.
Ensure the plate pack is at ambient
temperature.
3.
Drain the heat exchanger as much as possible,
using the appropriate drain valves.
4.
Release the clamping bolts gradually and
uniformly, so that the frame plates are kept as
parallel as possible. Continue until the clamping
bolts can be removed.
5.
Separate the mobile pressure plate away from
the plate pack and avoid personal injury or
damage to the plate.
6.
Access to ind ividual plates is now possible.
Care should be taken when removing these
plates so as not to damage the gaskets. Make a
note of the plate order and orientation to ensure
correct re-assembly.
7.
Deposits on the heat transfer plates can be
removed with a scrubbing brush and rinsed with
clean water.
A steel wire or carbon steel wool
brush must never be used.
The plates can be cleaned with a soda solution, or with
a solution of water and a synthetic detergent. After
cleaning, the plates must be thoroughly rinsed with
clean water. Other chemical cleaners can be used, but
check first that they are not harmful to plate or gasket
material.
If lime deposits have occurred on the service medium
side, this can be removed as follows:
a)
Open up the heat exchanger (at room
temperature) and apply a fine coat of 10% Nitric
Acid solution to the plates. Let the acid solution
soak in for 1 minute, then rinse and wash the
plates clean. If necessary, repeat the treatment.
b)
When all deposits have been removed, brush
the plates with a dilute Sodium Hydroxide, or
Caustic Soda solution.
c)
Finally rinse the plates with clean water.
Sterilisation with active chlorinated agents involves the
risk of damage to stainless steel. If sterilisation with
Hypochlorite or other chlorinated agents is specified, the
concentration of active chlorine must not exceed 100pm
and the temperate must not exceed 20
?
C. Circulation
time should be restricted to 10 minutes only.
8.
If the gaskets require replacing this can be done
by unclipping the existing gaskets, cleaning the
plate grooves and fitting the new gaskets. Care
should be taken to ensure that the gaskets are
the correct way up, compare the position with
the old gasket.
9.
When-re-assembling the plate pack, ensure that
the gasket side of the plates face the fixed end
of the frame. The plates are placed in the frame
according to the plate arrangement details. The
plates are numbered from the fixed end of the
frame. The first plate, plate number one, is
referenced as a D-plate. All 4 port holes are
surround by gaskets, thereby preventing liquid
from entering the space between the plate and
the fixed end frame plate. The second plate
within the pack is reference as type B, the third
is referenced as type A, the fourth is referenced
as type B and so on. (All odd numbered plates
are generally type A, whilst all even numbered
plates are generally type B). The last plate in
the plate pack is a blank plate, i.e. no port
holes. The mobile pressure plate is then re-
fitted and the clamping bolts positioned.
