RUNNING TIME (RUN TIME)
(See fig. k)
Run time is the length of time the snow melting system
operates once the slab has reached melting temperature.
• During the time slab approaches melting temperature, run
time does not decrease
• Once the slab has reached melting temperature, run time
begins counting down
• When run time reaches 0:00 (displayed by the STATUS item in
the View Menu) the control has finished the melting process
NOTE:
If a slab sensor is not used, the run time
begins counting down as soon as the melting
mode is enabled.
COLD WEATHER CUT OUT (CWCO)
(See fig. l)
Maintaining a slab temperature at either a melting or idling
temperature when outdoor conditions has dropped below
system design parameters can be both expensive and
impossible. Cold Weather Cut Out (CWCO) is a feature that
allows the control to automatically shut the system down at a
particular outdoor temperature setting to save energy.
• When the control is not in melting mode and the outdoor
temperature drops below the CWCO setting, the control
goes into CWCO mode which prevents any melting events to
take place until the outdoor temperature rises above the
CWCO setting.
• When the control is already in melting mode, the CWCO only
occurs when the outdoor temperature is less than CWCO
setting and slab surface is less than 29°F. This allows the
control to finish the current melting cycle and helps prevent
refreezing of left over moisture on the slab surface.
BOILER OPERATION
Refer to Section F (page 80) for a description of the boiler
operation.
BOILER PROTECTION
The SYSTEMpro 311 ensures the boiler water temperature
remains above Boil MIN setting
• If boiler water temperature begins to drop due to slab return
temperature, the mixing device is throttled back to allow the
boiler to recover
• Throttling back minimizes time boiler operates below its
condensing temperature and prolongs life expectancy of boiler
MIXING SYSTEM PUMP (P1) OPERATION
The mixing system pump (Mixing Pmp P1) contact closes and
remains closed as long as control is either in the melting or
idling mode. The mixing system pump contact shuts off if
control is in WWSD or CWCO, or if there is no call for melting
or idling.
75
CONTROL FUNCTION
OVER
VIEW
CONTROL FUNCTION OVERVIEW - Section E - Snow Melting
Adjust
hr
k
Adjust
o
F
l
Access Level
LTD
USER
INST
ADV
Access Level
LTD
USER
INST
ADV
Summary of Contents for SYSTEMpro 311
Page 1: ...SYSTEMpro 311 Installation Manual...
Page 90: ...88 APPENDIX II APPENDIX II SYSTEMpro 311 Menu Tree...
Page 91: ...89 APPENDIX II APPENDIX II SYSTEMpro 311 Menu Tree...
Page 92: ...90 APPENDIX III APPENDIX III Application Drawings...
Page 93: ...91 APPENDIX III APPENDIX III Application Drawings...
Page 94: ...92 APPENDIX III APPENDIX III Application Drawings...
Page 95: ...93 APPENDIX III APPENDIX III Application Drawings...
Page 96: ...94 APPENDIX III APPENDIX III Application Drawings...
Page 97: ...95 APPENDIX III APPENDIX III Application Drawings...
Page 98: ...96 APPENDIX III APPENDIX III Application Drawings...
Page 99: ...97 APPENDIX III APPENDIX III Application Drawings...
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