American Standard GRWF130A94A0A Installation Manual page 13

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WARNING
!
SAFETY HAZARD.
PRESSURE RELIEF VALVE OUTLET MUST BE
ROUTED TO WITHIN 6" OF A FLOOR DRAIN OR
OTHER AREA SAFE FOR DISCHARGE OF HOT
WATER AND SAFE FROM FREEZING. THIS
PIPE MUST BE FULLY 3/4" IN SIZE THE ENTIRE
LENGTH AND IT MUST NOT CONTAIN ANY
RESTRICTIONS, TRAPS, VALVES, PLUGS, OR
CAPS.
FAILURE TO FOLLOW THIS WARNING COULD
RESULT IN SERIOUS INJURY, DEATH, OR PRO-
PERTY DAMAGE.
Figure 9 - Head Loss versus Flow Chart for Models *GRWF130
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0 5 10
Water Flow (GPM)
Characteristics of system water
In the presence of water harder than 14 grains per gallon,
we recommend the use of suitably conditioned water
in order to avoid possible scaling in the boiler, caused
by hard water, or corrosion produced by aggressive
water. It should be remembered that, because of its
low thermal conductivity, even scaling of just a few
mm thick causes signifi cant overheating of the boiler
walls leading to premature boiler failure.
Water treatment is indispensable in the case of very
large systems (containing large amounts of water) or
with frequent introduction of replenishing water in
the system. If partial or total emptying of the system
becomes necessary under these conditions, it is advisable
to refi ll it with treated water.
Proper boiler operating pressures
The system pressure when cold should be about 12psi.
For correct operation of the boiler, when hot, its pressure
should be between 18-24 psi.
15 20 25
18-CG02D1-4
13