Coil Piping and Connections
UNT-SVX07E-EN
59
Perform the following procedure to set maximum water
flow through the coil:
1.
Establish water flow through the coil. Perform an open
override of the valve if the control valve is closed to the
coil, either manually or by Tracer.
If the piping package has two-position, normally
closed valves: Drive open the valve using a 24 V signal.
If the piping package has two-position, normally open
valves: Manually drive open the valve by removing
power to the valve.
If the piping package has modulating valves: To
manually drive the valve open, depress the button
stem on top of the valve and push the lever located on
the side of the valve to the full open position.
2. For presetting, use the appropriate valve curve shown
in
Figure 35, p. 59
to determine which setting is
necessary to achieve the appropriate pressure drop.
The “M” line is the appropriate line.
3. Carefully remove the Schrader pressure port
connection caps on the manual circuit setter, since they
will be at the same temperature as the pipeline.
4. Bleed all air from the hoses and meter before reading
the pressure drop. Refer to the gauge operating
instructions.
5. Adjust the circuit setter valve by turning the valve stem
until the appropriate pressure drop is achieved.
6. After achieving the proper setting, slightly loosen the
two socket head cap screws and rotate the memory
stop around until it touches the back side of the
indicator. Then tighten the screws to securely set the
open memory position. The memory stop indicates the
last set open position.
7.
If using a three-way valve: close the control valve to the
coil, with the differential pressure meter still
connected. This will divert flow to the bypass side of a
three-way valve.
Adjust the balancing fitting to obtain the same pressure
drop across the circuit setter valve as in step two when the
control valve was open to the coil.
Note:
Instructions for using this chart appear on the
preceding page. For the manual circuit setter
provided with fan-coil or Force-Flo units, use the
‘M’.
1.
Make piping connections to the steam coil as shown in
Figure 37
. Cap the unused connection.
2. The coil is already pitched within the unit to provide
proper pitch to drain condensate out of the coil. Verify
that the unit has been properly leveled.
3. Install a 1/2-inch, 15-degree swing check vacuum
breaker in the unused condensate return tapping as
close as possible to the coil.
Figure 34.
Automatic circuit setter valve
Figure 35.
Manual circuit setter valve, differential
pressure vs. flow
NOTICE:
Coil Damage!
In all steam coil installations, the condensate return
connections must be at the low point of the coil to
ensure condensate flows freely from the coil at all
times. Failure to do so could cause physical coil
damage from water hammer, unequal thermal stresses,
freeze-up and/or corrosion.
