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Pre-installation continued-
Increasing the boiler DOE heating capacity above the
values listed in Table 3 will not increase the rating of
the water heater.
2. Circulator Sizing – Refer to Table 5 for the corresponding
pressure drop through the coil for the given model. Calculate
the pressure drop of all straight pipe and fittings on the supply
and return of the water heater at the selected flow rate. Add
the piping/fitting pressure drop to the pressure drop through
the water heater coil.
Select a circulator that will provide an appropriate flow rate at
the combined pressure drop.
SYSTEM ZONE CONTROL
The indirect-fired water heater must be installed as a zone
separate from the space heating system. The domestic hot
water zone's piping and circulator must be sized for a
minimum flow rate with all zones in use and a maximum flow
rate with only the water heater in use. For this reason, the
preferred method of zone control is with circulators.
1.
Circulators – With space heating zones using
circulators, the indirect-fired heater should be added
as an additional zone with a circulator.
2.
Zone Valves – Select a valve with a low-pressure
drop to assure adequate flow through the water heater.
3.
Hybrid – The space heating zone can be zoned using
zone valves and the indirect-fired heater zoned with a
circulator.
NOTICE
15
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