16
Pre-installation continued-
NOTICE
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.