C NC NO M B 1 IN IN OUT 1 M 2 3 4 5 6 7 8 TC1 1 1 2 3 4 5 6 7 8 M IN IN OUT P M B 1 2 3 4 5 6 IN IN OUT IN IN OUT P M B P M B IN IN OUT M P B 9 10 11 M 9 10 IN IN M 11 LOGIC OF OPERATION The controls look at all the thermostat signals determining the greatest demand for heating and cooling via MHLS1, HS1 and LS3. If all thermostats are modulating their respective zone dampers the system "knows" that all zones are within 1F° of set point. Under this condition, the cold deck is controlled to minimum cooling and the hot deck is controlled to minimum heating. Any thermostat may lower the cold deck temperature limited by TC1 and TC3. The warmest thermostat "tells" the fan controls via the logic relays that at least one thermostat has closed off its hot deck completely and opened its cold deck completely. As the highest signal rises the cold deck will gradually become cooler. The dampers return their minimum position when the outside air is more difficult to cool than the return air via TC2. Any thermostat may raise the hot deck temperature, limited by TC4, after it has opened its hot deck completely and closed its cold deck completely and reduces its signal beyond that point. 8.86 RESTRICTOR DRAWING THREE RETURN FAN SUPPLY FAN SPH SPH RETURN AIR TO ZONE (TYPICAL) NC NO NC TT4 TT1 LL1 TT2 TT3 TO ZONE DAMPER T1 T1 CWR CWS HWR HWS DM1 DM2 DM3 3#-13# 3#-13# 3#-13# OUTDOOR AIR EXHAUST AIR MIXED AIR COLD DECK HOT DECK DM4 3#-13# NC C NO C NC NO 5#-12# V1 PUMP V3 RA TOP PUMP C NC NO OUT SECONDARY HEATING LOOP PERIMETER TT HS3 B M 1 2 3 TC5 DA OSA HWS -10˚F 200˚F 60˚F 80˚F LOCATED IN PUMP ROOM GROUND FLOOR. 4# - 11# V2 B M 1 2 3 B M 1 2 3 B M 1 2 3 B M 1 2 3 H M L M M EP1 HS2 BR2 8#IN---=--3#OUT TC4 DA TC2 RA TC3 DA BR3 13#IN = 3#OUT MHLS1 HS1 LS3 MIXED OSA COLD TEMP. TEMP. DECK OSA HD HOT DECK -10˚F 130˚F 60˚F 70˚F 70˚F 55F LS1 LS2 LMR1 BR1 1:2 3IN = 10.5 OUT 10.5# M B LMR2 10.5# BR4 5IN = 10.5 OUT 1:1 RATIO MPR1 B P M PE1 NO T1 BRANCH PRESSURE RELATIONSHIP 75˚F = 20# 74˚F = 16# 73˚F = 12# 72˚F = 8# 71˚F = 4# 70˚F = 0# HOT DECK MIXED AIR 55˚F
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