National Oilheat Research Alliance 43
If the manufacturer’s instructions call for two
or more risers and the system in installed with
less, the water level in the boiler will become
sloped. This often causes the boiler section(s)
at the opposite end from the riser to fail due to
low water content. Figure 2.
Correct near boiler piping for parallel flow
systems with two supply risers is shown in
Figure 3.
Turbulence causes water droplets to be present
in the steam flow. When a boiler is piped
as shown, most of the water droplets continue
to the equalizer while the steam rises up to the
system. The piping helps to separate the water
from the steam resulting in ‘dryer” steam in the
distribution system.
Many older boilers were piped with the
take-off located between the risers. With a new
boiler, this piping arrangement causes water to
pool under the take-off which leads to much
wetter steam causing water to be carried into
the system. This leads to water hammer, damage
to system components and the frequent
addition of make-up water due to low water
conditions in the boiler. Figure 4.
Figure 3
Figure 2
Figure 4