Honeywell AUTOMATIC CONTROL User Manual

ENGINEERING MANUAL OF AUTOMATIC CONTROL
CHILLER, BOILER, AND DISTRIBUTION SYSTEM CONTROL APPLICATIONS
361
Fig. 83. Constant Temperature Hot
Water Converter Control.
Fig. 85. One-Pipe System.
Figure 86 shows a two-pipe reverse-return system. The length
of supply and return piping to each terminal unit is the same,
making the system self-balancing. The reverse-return is used
in large or small installations.
Fig. 84. Hot Water Converter Control with
Constant Temperature and Reset Zones.
HOT WATER PIPING ARRANGEMENTS
General
Hot water piping systems use one- or two-pipes to deliver
the water to the terminal units. The one-pipe system shown in
Figure 85 uses flow diverting fittings to scoop water out of the
single loop into each radiator or baseboard radiation section.
Another fitting returns the water to the main where it is mixed
with the supply water. The next unit will be supplied with
slightly lower temperature water. One-pipe systems are typically
used in small buildings with only one or two zones.
SINGLE
INPUT
CONTROL
STEAM TO
HOT WATER
CONVERTER
HOT WATER
SENSOR
SUPPLY
RETURN
PUMP
STEAM
SUPPLY
C2831
CONDENSATE
RETURN
LOAD
LOAD
LOAD
LOAD
LOAD LOAD
FLOW DIVERTING
FITTINGS
BOILER
OR
CHILLER
EXPANSION TANK
C2833
Fig. 86. Two-Pipe Reverse-Return System.
Figure 87 shows a two-pipe direct-return system. The direct-
return system is used on small systems. The shorter return piping
reduces installation cost but each load loop must be symmetrical.
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
EXPANSION TANK
BOILER
OR
CHILLER
SUPPLY
RETURN
C2834
STEAM
SUPPLY
STEAM
VALVE
STEAM TO
HOT WATER
CONVERTER
OUTDOOR
AIR
SENSOR
CONTROL
3-WAY
MIXING
VALVE
HOT
WATER
SENSOR
TO OTHER
SYSTEMS
TO SYSTEM
REQUIRING
TEMPERATURE
RESET
RETURN
SUPPLY
RETURN
SUPPLY
CONTROL
C2832

Honeywell AUTOMATIC CONTROL Specifications

General

Brand	Honeywell
Model	AUTOMATIC CONTROL
Category	Controller
Language	English