1-27
INSTALLATION
TANKLESS WATER HEATER 199
DOMESTIC HOT WATER
DELIVERY
@ 67°F / 37.2°C temperature
rise
199,000 Btu/hr
199,000 Btu/hr
5.4 GPM
CAUTION
A
field supplied
thermostatic
mixing valve may be installed
on the domestic hot water
piping connections at the unit
or at the outlet of a domestic
hot water storage tank.
Aquastat
Combi Boiler
Combi Boiler
Tankless
Water Heater
Tankless
Water Heater
Figure 26: Tankless DHW Piping Options – concept drawing. This drawing is only a simple
schematic guide.
1.7.3 Tankless Domestic Hot Water with a Storage
Tank
The Tankless Water Heater
Tankless Water Heater has the ability to connect a domestic hot water
storage tank to the unit to provide larger volumes of domestic hot water during
peak demands.
The storage tank is piped to the unit’s domestic hot and cold water piping
connections (see B in Figure 26). You must install a bronze or stainless steel
pump to circulate water from the storage tank through the unit’s domestic hot
water coil.
The storage tank aquastat will enable the pump causing the unit to fire when the
temperature drops below the aquastat setpoint. The units DHW setpoint must
be set higher than the storage tank aquastat setpoint. Once the storage tank
temperature has reached its setpoint, the aquastat will disable the pump.