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TVP Manual (full) March 2007 CE rev 03.doc
1.101 Resetting the system
To reset the STOP button after actuation it must be turned 90o clockwise, at which point it will
click outwards, all other buttons have a momentary actuation. The TVP will automatically
reset itself after a forced stop, a manual start or renewed remote start signal are required for
restart. If the unit is ready for operation the green start / standby button will illuminate. The
illumination of the action buttons is independent of the control mode they also provide status
indication.
If the system fails to operate the over pressure trip may have been triggered see diagram 12
in trouble shooting guide on resetting compressor over temperature and pressure protection.
1.102 Switching the system on
Depressing the illuminated start / standby button will start the system – in the case of a dual
coil unit only one of the start / standby buttons will illuminate this is normal. The system will
start and the display will read “Pre-cool”. On a TVP3500 a single compressor starts initially
when a CT value of less than –100
o
c is achieved the second compressor will start.
When the system is in the Pre-cool mode all other modes of operation are disabled, until
predefined conditions are met none of the control buttons will illuminate in this state. At the
end of the pre-cool phase the Start / Standby button will illuminate to indicate the system is
able to start cooling. At all times the scroll button remains illuminated
1.103 Standby
Standby is the normal “resting state” both cool and defrost may be selected when the standby
light is illuminated, however defrost will terminate instantly if the CO value is higher than the
defrost termination value. In standby the display shows DP and SP.
1.104 Cool
Pressing the blue cool button activates the cool solenoid valve, allowing refrigerant to flow
around the cryo-coil. The system display automatically switches from displaying DP and SP to
the temperature of the coil inlet and outlet (CI & CO). When the system is in cool the button
will remain illuminated.
1.105 Defrost
At any time defrost can be initiated by pressing the orange defrost button. Following the
initiation of defrost the cool solenoid valve is closed and the defrost valve is opened an audible
click will be heard. When the system is in “defrost mode” the button will remain illuminated.
During defrosting hot gas passes directly from the compressor into the cryo-coil causing very
rapid heating. The system monitors the returning gas temperature, and discharge pressure in
determining if the cryo-coil has been defrosted. For protection of the system it will terminate
defrost and automatically enter standby if greater than 4 minutes have elapsed following the
initiation of defrost. If defrost terminates prematurely check the discharge and water
temperatures first.
When defrost ends the system automatically enters standby this is indicated both on the
display and by the button illumination changing.