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12
In all applications, the quality of the water circulated
through the heat exchanger must fall within the ranges listed in
the Water Quality Guidelines table. Consult a local water firm,
independent testing facility, or local water authority for specific
recommendations to maintain water quality within the pub-
lished limits.
GROUND-LOOP APPLICATIONS — Temperatures be-
tween 25 and 110 F and a cooling capacity of 2.25 to 3 gpm of
flow per ton is recommended. In addition to complying with
any applicable codes, consider the following for system piping:
• Limit piping materials to only polyethylene fusion in the
buried sections of the loop.
• Do not use galvanized or steel fittings at any time due to
corrosion.
• Avoid all plastic to metal threaded fittings due to the poten-
tial to leak. Use a flange fitted substitute.
• Do not overtighten connections.
• Route piping to avoid service access areas to unit.
• Use pressure-temperature (P/T) plugs to measure flow of
pressure drop.
INSTALLATION OF SUPPLY AND RETURN HOSE
KIT — Follow these piping guidelines.
1. Install a drain valve at the base of each supply and return
riser to facilitate system flushing.
2. Install shutoff/balancing valves and unions at each unit to
permit unit removal for servicing.
3. Place strainers at the inlet of each system circulating
pump.
4. Select the proper hose length to allow slack between con-
nection points. Hoses may vary in length by +2% to –4%
under pressure.
5. Refer to Table 3. Do not exceed the minimum bend radius
for the hose selected. Exceeding the minimum bend radi-
us may cause the hose to collapse, which reduces water
flow rate. Install an angle adapter to avoid sharp bends
in the hose when the radius falls below the required
minimum.
NOTE: Piping must comply with all applicable codes.
Table 3 — Metal Hose Minimum Bend Radii
Insulation is not required on loop water piping except where
the piping runs through unheated areas or outside the building
or when the loop water temperature is below the minimum ex-
pected dew point of the pipe ambient. Insulation is required if
loop water temperature drops below the dew point.
Pipe joint compound is not necessary when Teflon threaded
tape is pre-applied to hose assemblies or when flared-end
connections are used. If pipe joint compound is preferred, use
compound only in small amounts on the male pipe threads of
the fitting adapters. Prevent sealant from reaching the flared
surfaces of the joint.
NOTE: When anti-freeze is used in the loop, assure that it is
compatible with Teflon tape or pipe joint compound employed.
Maximum allowable torque for brass fittings is 30 ft-lb. If a
torque wrench is not available, tighten finger-tight plus one
quarter turn. Tighten steel fittings as necessary.
HOSE DIAMETER (in.) MINIMUM BEND RADII (in.)
1
/
2
2
1
/
2
3
/
4
4
15
1
/
2
IMPORTANT: Do not bend or kink supply lines or hoses.
Boiler
Drains
(field-installed)
Strainer (field-installed accessory)
(16 to 20 mesh recommended for
filter sediment)
Shut-Off
Valve (field-installed accessory)
Water
Control
Valve
(field-installed
accessory)
Flow
Regulator
(field-installed
accessory)
Pressure
Tank
Water Out
Water In
From Pump
A50-7733
Fig. 13 — Typical Ground-Water Piping Installation