Trane LO - Manual (Page 31)

UNT-IOM-6 31
The automatic flow valve is an
optional end valve on the return of
the factory piping package.
See Figure 20. The valve regu-
lates water flow through the coil
to a specific (gpm) flow rate, as
ordered by the customer.
The automatic flow valve controls
to the specified flow rate, pro-
vided that the pressure drop
across the valve is within a
certain range. To verify that the
valve is operating properly, remove the protective caps from the P/T
ports and measure the pressure drop across the valve with a differen-
tial pressure meter. Carefully remove the P/T port connection caps,
since they will be at the same temperature as the pipeline. The
reading should be within the given ranges in Table 2. If the pressure
drop is not within the ranges listed, the valve will not control water
flow. If the valve orifice becomes clogged with debris, remove water
from piping and then remove the cap of the valve body and push on
the piston to dislodge any foreign matter. If this is not successful,
remove the cartridge and clean.
Balancing The Auto-
matic Circuit Setter
Valve
Figure 20. Automatic circuit
setter valve.
Replace the cartridge in the field without breaking the piping line to
furnish a higher or lower gpm. To do this, remove the water from the
system. Remove the cap assembly containing the plug from the valve
body. Grasp the cartridge by the piston to remove. Install a different
spring if the pressure drop range of the valve is being changed also.
Table 2. Automatic Circuit Setter Flow Rate Range.
Valve gpm
Pressure Drop Range (psig)
0.5 to 8.0 2 to 32
9 to 12 5 to 50