20
WATER PIPING AND CONTROLS
11. Use water that is low in mineral content and make
sure that there are no petroleum products in the
solution.
a. Less than 50 ppm of calcium
b. Less than 50 ppm of magnesium
c. Less than 100 ppm (5 grains/gallon) of total
hardness
d. Less than 25 ppm of chloride
e. Less than 25 ppm of sulfate
12. Check with the local water supplier for chemical
properties of the water.
13. The following test will determine if the water is of the
appropriate hardness. Collect a sample of 50% water
to 50% propylene glycol. Let the solution stand for 8-
12 hours shaking it occasionally. If white sediment
forms, the water is too hard and should not be used
to dilute the glycol.
14. Mix the solution at room temperature.
15. Do not use a chromate treatment.
16. Refer to Technical Topics #2a published by the
Hydronics Institute for further glycol system
considerations.
F. SPECIAL APPLICATIONS
1. If the PUREFIRE
®
boiler is used in conjunction with a
chilled medium system, pipe the chiller in a separate
secondary loop.
a. Assure that the boiler circulator is disabled during
chiller operation so that chilled water does not
enter the boiler.
b. Install a flow control valve (spring check valve) to
prevent gravity flow through the boiler.
c. See Figure 4.9 for recommended system piping for
chiller operation.
2. For boilers connected to heating coils in a forced air
system where they may be exposed to chilled air
circulation, install flow control valves or other
automatic means to prevent gravity circulation of the
boiler water during cooling cycles. See Figure 4.10 for
an illustration.
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