8
2.0 PIPING
2.1 Chilled Water Unit Piping
The required field installed water pipe sizes may or may not be the same as the connection
sizes at the unit. This will depend on the length of pipe and the calculated pressure drop of peripheral
components.
Shutoff valves should be installed within a few feet of the inlet and outlet connections of the
unit to allow the unit to be isolated for service. A fill valve with a hose bib connection should also be
used on the supply line or return line at the unit to allow the unit to be drained.
Water temperature and worst-case room temperature and humidity conditions should be
used to determine whether external piping should be insulated. Typical water temperature is 45° F
which is usually cold enough to cause pipes to sweat.
Field pipe connections are topically made at the bottom of the unit. Punching holes in the
back panel and making a 90° turn out the back of the unit is also acceptable. In some cases
provisions have been made to route the pipes out the right or left side or out the top of the unit.
Openings should not be made in the hinged decorative doors as this could prevent the door from
swinging open.
Standard chilled water units have a 3-way chilled water valve. An option for a 2-way valve is
also available. In either case the water connections to the unit should be made so there is a
counterflow between the water and air. Field water pipe connections are labelled but the counterflow
should also be verified before making field connections.
One of the most common problems in a Chilled Water system is the presence of air in the
chilled water water loop. Air vents must be installed in various locations in the piping system to
purge the air.
2.1.1 Connection sizes, Chilled Water units
Water In and Out Water In and Out
Evaporator Model Connections, OD Evaporator Model Connections, OD
DACx 07 1 1/8” DACx 22 2 1/8”
DACx 09 1 1/8” DACx 26 2 1/8”
DACx 11 1 5/8” DACx 30 2 1/8”
DACx 13 1 5/8” DACx 40 2 5/8”
DACx 15 1 5/8” DACx 45 2 5/8”
DACx 18 2 1/8” DACx 50 2 5/8”
2.2 Chilled Water Valve Ratings
All chilled water valves used on Data Aire Series models 7 to 50 tons use chilled water valves
that are rated at 400 psi operating pressure. The chart on the next page gives the valve size and Cv
rating on 3-way valves for all unit models. The same information plus maximum close off pressure
for optional 2-way valves is also indicated
To Next Page
Loading...
Need help?
General
