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Designed to Maintain Suction Superheat Anticipate Changing Conditions
MCS FAST SSH Designed to Maintain Suction Superheat and Anticipate Changing Conditions (Advanced Functions) Revised 1.0 -June 18, 2018
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Design Criteria Specialized Startup functions
Specialized Fast Zone Hold function Specialized EXV Delay functions Projected Fast Suction Superheat Degrees C
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System Requirements 1. Requires MCS-Config Version 18.00V or greater. 2. Requires MCS-Connect Version or greater. 3. Requires Magnum HVAC/RTU firmware Ver K hex or greater. 4. Requires Config Type 17.
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Specialized Valve Startup FUNCTIONS
BASIC DESCRIPTION EXV TME HOLD EXV TME QUICK EXV TME LONG EXV TME NORMAL SP 19 EXV STARTUP TIME = 90 SECONDS SP TARGET SP 10 ± 2 FAST ZONE (RED LINES) EXV HOLD CALCULATED 0 to 39 SECONDS (VER 17.25K) EXV QUICK CALCULATED 40 to 60 SECONDS (VER 17.25K) SP SECONDS EXV STARTUP (VER 17.25K)
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Specialized Valve Startup FUNCTIONS (cont)
BASIC STARTUP EXV TME HOLD EXV TME QUICK EX TME NORMAL EXV TME LONG HOLD EXV STARTUP SH < TARG + 5 TAKE CTL & NO CHG VLV% SH > TARG + 5 TAKE CTL & INCR VLV% BY 1.0 SH < TARG + 5 TAKE CTL & DECR VLV% BY 1.0
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Specialized Valve Startup FUNCTIONS (cont)
CONTROL TOO FAST, CONTROL CORRECT, CONTROL TOO SLOW EXV TME HOLD EXV TME QUICK EXV > HI TME & < LO TME EXV TME LONG HOLD EXV STARTUP SH > TARG & ROC > 0 TAKE CTL & INCR VLV% BY 1.0 PROTECTS VALVE FOR OPENING SET TOO SMALL TEST BEGINS AT END HOLD TIME SH > TARGET DEGREES AND GETTING LARGER
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Specialized Valve Startup FUNCTIONS (cont)
PROTECTS AGAINST LOW SUPERHEAT DURING STARTUP EXV TME HOLD EXV > WAIT TME & < LONG TME EXV TME LONG HOLD EXV STARTUP SH < LOW SH SP & ROC < 0 TAKE CTL & DECR VLV% BY 2.0 PROTECTS VALVE IF OPENING TOO LARGE TEST STARTS AT END OF HOLD TIME SH < LOW SUPERHEAT SP AND ROC < 0
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Specialized Valve Startup FUNCTIONS (cont)
PROTECTS AGAINST LOW SUCTION PSI DURING STARTUP EXV TME HOLD EXV > HOLD TME & < LONG TME EXV TME LONG HOLD EXV STARTUP SUCT PSI < LOW SUCT SP & SH > TARG – FAST ZN TAKE CTL & INCR VLV & BY 2.0 PROTECTS VALVE IF OPENING TOO SMALL TEST BEGINS AT END OF HOLD TIME SUCTION PSI < LOW SUCTION SP BUT SH IS ABOVE LOWER LIMIT FAST ZONE TAKE CTL AND INCR VALVE STARTING % BY 2.0
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Specialized Fast Zone Hold function
DEFINES STEADY STATE AND WHERE SP 10 USES MPLY IF REQUESTED FAST ZN + SH ADJUSTMENT MPLY SP 10 TIME FIELD SH = TARGET ± (FAST ZN / 2) ROC = 0 TARGET SH = TARGET ±(FAST ZN / 10) ROC = 0 OR ± .1 SH = TARGET ± (FAST ZN / 2) ROC = 0 SH ADJUSTMENT MPLY SP 10 TIME FIELD FAST ZN -
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Specialized Fast Zone Delay function
SP 19 DEFINES DELAY TIME WHEN EVALUATING EXV IN FAST SUPERHEAT FOR FAST SUCTION SUPERHEAT USUALLY 1 IF GREATER THAN 1 USED, IT IS ONLY USED WHEN WITHIN FAST ZONE IF OUTSIDE FAST ZONE SYSTEM DEFAULTS TO 1 FOR FAST DISCHARGE, EVAPORATOR LEVEL SENSOR OR DX RTU WILL NEED TO BE LARGER DUE TO SLOWER REACTION TIME WHEN WITHIN FAST ZONE SYSTEM USES VALUE SPECIFIED SP 19 WHEN OUTSIDE FAST ZONE, BUT LESS THAN 2 TIMES FAST ZONE EXV DELAY TIME IS DIVIDED BY 2 WHEN OUTSIDE FAST ZONE BY MORE THAN 2 TIMES EXV DELAY TIME IS DIVIDED BY 4
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Specialized Fast Zone Hold function
DEFINES EXV DELAY TIME WHEN VALUE 4 OR GREATER EXV DELAY = SP VALUE / 4 FAST ZONE 3 EXV DELAY = 15 FAST ZN + EXV DELAY = SP VALUE / 2 EXV DELAY = 30 FAST ZONE 2 FAST ZN + FAST ZONE 1 TARGET EXV DELAY = SP VALUE EXV DELAY = 60 FAST ZONE 1 FAST ZN - EXV DELAY = SP VALUE / 2 EXV DELAY = 30 FAST ZONE 2 FAST ZN - EXV DELAY = SP VALUE / 4 EXV DELAY = 15 FAST ZONE 3 ASSUMING CONTROL IS BASED ON LIQUID LEVEL SENSOR & SP 19 (EXV DELY = 60 SEC)
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Fast Suction SH F / PSI Setup
SP 9 FAST SH TRGT 11.0 DEGREES F SP 10 FAST SH ZONE DEGREES F SP 14 LIMIT ADJUST PERCENT & 1.5 PERCENT (ASSUMED DECIMAL 1.5) SP 18 LO SUPERHEAT DEGREES F
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Fast Suction SH C / BARS Setup
SP 9 FAST SH TRGT 6.0 DEGREES C SP 10 FAST SH ZONE 1.2 DEGREES C SP 14 LIMIT ADJUST 0.2 PERCENT & 1.5 PERCENT (ASSUMED DECIMAL 1.5) SP 18 LO SUPERHEAT 1.0 DEGREES C
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Fast LEVEL SH Setup SP 9 FAST LVL TRGT 35 PERCENT
SP 10 FAST SH ZONE 2.0 PERCENT SP 14 LIMIT ADJUST 0.2 PERCENT & 1.5 PERCENT (ASSUMED DECIMAL 1.5) SP 18 LO SUPERHEAT 1.0 DEGREES C
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(Support, Literature, App Notes)
MCS FAST SUPERHEAT For additional information please visit our website Application Note 116 (Support, Literature, App Notes) Or call MCS at 5580 Enterprise Pkwy. Fort Myers, FL 33905 Office: Fax:
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