20
IM 725 (1-02)
Typical Hot Water Coil Piping
Figure 65 - Face and Bypass With End-of-Cycle Valve
(Piping Within Unit End Compartment)
Figure 66 - Face and Bypass With End-of-Cycle Valve
(Piping Outside Unit End Compartment)
Figure 67 - 3-Way Modulating Valve Control
(Piping Within Unit End Compartment)
Figure 68 - 3-Way Modulating Valve Control
(Piping Outside Unit End Compartment)
11
2
1
3
4
5
15
6
7
15
2
3
4
5
6
7
8
2
3
4
5
6
7
8
2
3
4
5
6
7
15
15
15
15
15
11
1
15
Coil Piping
Heating valve actuators should be mounted in an upright position
above the centerline of the valve body and should be piped normally
open to the coil. Modulating valve actuators for hot water applications
may be positioned above the valve body a maximum of 75
°
from the
vertical. For steam applications only, mount the modulating valve
actuator above the valve body at 45
°
from the vertical. Two-position,
end-of-cycle (EOC) valves used with face and bypass damper controlled
units may be positioned above the valve body a maximum of 85
°
from
the vertical. All control valves are shipped loose so no shipping
damage occurs to the piping or the coil connection stub from the
weight of the valve and to provide the installing contractor with
maximum flexibility in making the field piping connections. Refer to
AAF-HermanNelson factory instruction sheet shipped with the unit
for port orientation and a piping schematic. Control valves must be
installed on the units in which they are shipped. Indiscriminate mixing
of valves among units can result in valves not properly sized for the
desired flow rate. Control valves should be installed so that there is 2"
minimum clearance to remove the actuator from the valve body. As a
future service consideration, provide unions for removal of the unit
coil and/or the control valve.
Descriptions
Three-way control valve (AAF-HermanNelson)
Coil air vent (AAF-HermanNelson)
Coil drain (AAF-HermanNelson)
Shutoff valve (Others)
Balancing shutoff valve(s) (Others)
Supply
Return
Unions (Others)—Must disconect below floor line
2
1
3
6
4
5
7
8
15
14
13
12
11
10
9 Two-way, two-posiiton valve (AAF-HermanNelson)
Union: Half attached to coil, half attached to valve
Modulating control valve (AAF-HermanNelson)
All piping, fittings and unions by others (not AAF-HermanNelson) except as
noted
Check valve and pressure equalizing line (AAF-HermanNelson)
Float and thermostaic steam trap (Others)
Supply and return coil connection and stub-up unions by others