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Figure 24: Supply Water Manifold Piping
Install pipe tee between circulator and boiler return
along with second tee in supply piping as shown in
Figure 25 or 26. Bypass should be same size as the
supply and return lines with valves located in bypass
and supply outlet as illustrated in Figure 25 or 26 in
order to regulate water fl ow to maintain higher boiler
water temperatures.
After the boiler is operational (reference Section VIII.
System Start-Up) set by-pass and boiler supply valves
to half throttle position to start. Operate boiler until
system water temperature reaches normal operating
range.
Adjust valves to provide 180° to 200°F supply water
temperature. Opening the boiler supply valve will raise
system temperature, while opening the by-pass valve
will lower system supply temperature.
J. A hot water boiler installed above radiation level
must be provided with a low water cutoff device as part
of installation.
K. If a low water cutoff is required, it must be mounted
in the system piping above the boiler. The minimum
safe water level of a hot water boiler is just above the
highest water containing cavity of the boiler; that is, a
hot water boiler must be full of water to operate safely.
L. Oil, grease, and other foreign materials which
accumulate in new hot water boilers and a new
or reworked system should be boiled out, and
then thoroughly fl ushed. A local qualifi ed water
treatment chemical specialist is a suggested source
for recommendations regarding appropriate chemical
compounds and concentrations which are compatible
with local environmental regulations.
M. After the boiler and system have been cleaned and
fl ushed, and before refi lling the entire system add
appropriate water treatment chemicals, if necessary, to
bring the pH between 7 and 11.
N. If it is required to perform a long term pressure
test of the hydronic system, the boiler should fi rst be
isolated to avoid a pressure loss due to the escape of air
trapped in the boiler.
To perform a long term pressure test including the
boiler, ALL trapped air must fi rst be removed from the
boiler.
A loss of pressure during such a test, with no visible
water leakage, is an indication that the boiler contained
trapped air.