Special Applications - PEERLESS Pinnacle PO-70 Installation, Operation & Maintenance Manual

WATER PIPING
8. Propylene glycol solution is expensive and is more
prone to leaks than water. Use welded or sweat joints
where possible to minimize leaks. Where threaded
joints must be used, inspect them regularly for leaks.
9. The propylene glycol solution must be checked at
least once per year as recommended by the propylene
glycol supplier. It includes a corrosion inhibitor that
can diminish over time causing the solution to
become corrosive.
10. Check local regulations to see if a system containing
propylene glycol solutions must include a back-flow
preventer or require that the glycol system be isolated
from the water supply.
Figure 4.8: Boiler in conjunction with a Chilled Water System
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E. SPECIAL APPLICATIONS
1. Boilers used in conjunction with a chiller.
a) If the boiler is used in conjunction with a chilled
water system, pipe the chiller in a separate parallel
loop.
b) Assure that the boiler circulator is disabled during
chiller operation so chilled water does not enter
the boiler.
c) Install a flow control valve (spring check) to
prevent gravity flow through the boiler.
d) See figure 4.8 for recommended system piping.
2. Boilers connected to heating coils in a forced air system:
a) If the heating coil is exposed to chilled air
circulation, install flow control valves or other
automatic means to prevent gravity circulation of
the water during cooling cycles.
b) See figure 4.9 for recommended system piping.