Install Instructions

30
4 Hydronic piping
Installation & Service Manual
PUMP INSTALLATION AND MAIN TE NANCE: The
boiler circulating pump must be purchased lo cal ly. For
installation and maintenance information on the circulator
pump, refer to the pump man u fac tur ers in struc tion package
included with the pump.
The installer must ensure that the boiler has ad e quate flow
without excessive temperature rise. The tem per a ture rise on
a multiple zone system should be made when only the zone
with the longest length and/or high est head loss is open.
Low system flow can result in overheating of the boiler water
which can cause short burner on cycles, system noise and in
extreme cases, a knocking flash to steam. Sys tem noise may
also indicate an oversized boiler.
⚠ CAUTION
At no time should the system pressure be
less than 12 PSIG (83 kPa) (Non-metallic
system piping must have an oxygen
barrier to be considered a closed loop).
A boiler operated with an inlet temperature
of less than 140°F (60°C) must have a low
temperature bypass to prevent problems
with condensation. A 1 1/2" LTV Valve Kit
may be used. Follow the piping diagram in
FIG. 4-5 to complete installation.
Primary/Secondary Boiler Piping
Heating boilers with inputs of 315,000 - 500,000 Btu/hr or
larg er installed on multiple zone systems are rec om mend ed
to be installed with a primary/sec ond ary piping sys tem as
shown in FIG. 4-4. A primary/secondary piping system uses a
dedicated pump to supply flow to the boiler only. This pump
is sized based on de sired boiler flow rate, heat exchanger
head loss and head loss in the sec ond ary system piping only.
The secondary pump, in stalled in the boiler piping, ensures
a constant wa ter flow rate to the boiler for proper operation.
Boiler installation with a primary/secondary piping sys tem
can prevent noise problems caused by low sys tem water
flows. A primary/secondary piping system is recommended
on any boiler where low water flow conditions may present
an operational problem.
A primary/secondary piping system is ideal for sys tems filled
with a propylene glycol and water mix ture. A glycol and
water mixture is more dense than water only and may result
in a lower boiler flow rate. A lower boiler flow may cause
noise on operation or short cycling of the burners. A larger
secondary pump may be used on a primary/sec ond ary system
to pro vide an increased boiler flow rate. A glycol and water
system may require from 10 to 20% more flow to compensate
for the in creased density of the glycol and its effect on the
heat transfer process in the boiler. The exact in crease in flow
that may be required is based on the type and percentage of
glycol added to the boiler system. Consult the manufacturer
of the glycol for additional recommendations when using a
gly col and water fill for your boiler system.
NOTICE