Overview Of Condensing Tankless Gas Water Heater - Noritz NCC199-SV Owner's Manual

Overview of Condensing Tankless Gas Water Heater

This water heater is a high efficiency, fully condensing appliance. Unlike a traditional tankless water
heater, a condensing type captures heat from the exhaust gas and uses it to preheat the incoming
cold water as it passes through the secondary heat exchanger as illustrated below.
Conventional
type
The condensing tankless gas
water heater discharges
condensate.
When heat from the exhaust gas is collected
within the secondary heat exchanger,
condensation occurs from moisture in the
exhaust gas and the resulting water is
discharged from the drain pipe (approx. 2
gallons/hour (GPH) maximum). It is not a
water leak. Do not plug or block the drain line
as it must always be allowed to freely flow.
The condensing tankless gas
water heater tends to show
white steam.
After the exhaust gas passes through the
secondary heat exchanger, it becomes low in
temperature and moisture rich which tends to
produce steam at the vent discharge terminal.
This is a normal occurrence.
8
Exhaust
About 400°F
Combustion gas
About 400°F
Primary heat exchanger
Condensing
Tankless Gas
Exhaust
Water Heater
About 120°F
Secondary heat exchanger
Combustion gas
About 400°F
Primary heat exchanger
Drain pipe
(Installation example)
Condensate
comes out
from here.
Water is heated
using the exhaust
gas which is about
400°F.
During combustion, white
steam may often be seen.
This is normal.