1-29
INSTALLATION
DC SERIES BOILERS / WATER HEATERS
DC 15-95, DC 15-96, DC 20-125, DC 33-160
1.7.1 Domestic Hot Water System
The DC series boilers / water heaters have an independent piping circuit for
efficiently generating Domestic Hot Water. When a faucet is opened to draw hot
water, water flow is detected with a flow sensor and the DC Series boiler / water
heater fires up to begin generating domestic hot water. Due to the unique design
of the boiler’s heat exchanger, the boiler / water heater can fire with either no
water in the alternate space heating circuit or without flow of water if pressurized
with the heating system water.
The cast aluminum heat exchanger has two separate copper water passage-
way’s encased into the aluminum heat transfer block. Each copper passageway
is completely isolated from the other to eliminate cross contamination in the event
of a leak. This heat exchanger complies with the double wall heat exchanger
requirements in many regional jurisdictions.
The unique design of the cast aluminum heat exchanger acts as a heat buffer,
eliminating the cold sandwich effect when turning on and off the water repeatedly.
The domestic hot water operation can be set to operate in 3 different ways.
•
Standard Mode:
The boiler / water heater responds to a call for domestic hot
water when a faucet is opened. After the faucet is closed the boiler / water
heater shuts down and waits for a call for the faucet to open.
•
Comfort Mode:
After the faucet is closed the boiler / water heater will
maintain the programmed domestic hot water temperature so that the next
time the faucet is opened, hot water is delivered to the faucet immediately
without the “Cold Water Sandwich” effect.
•
Eco Comfort Mode:
As above, the boiler / water heater will maintain the
programmed domestic hot water temperature but based on a learned pattern,
the boiler / water heater will allow the water to cool. For example during the
night, the boiler / water heater will see no flow of domestic hot water therefore
will allow the boiler / water heater to cool down each night. If hot water is
required at night, the boiler / water heater will respond to an open faucet just
as if it was in the Standard Mode.
While the DC Series boiler / water heater is less susceptible to lime scale build-
up than other units on the market, water quality must always be considered when
installing the boiler / water heater. Treating hard water and adjusting the pH to 6.5
and 8.5 is strongly recommended. As a reference
Table 6
represents some of the
drinking water guidelines published by the US EPA. Consult a water treatment
advisor in your area to assess your local needs. Proper water treatment will aid in
the longevity of the boiler / water heater and ensure maximum efficiencies.
DESCRIPTION
MAX
MIN
Water Pressure
150 psi
40 psi
Programmable water temperature
149°F (65°C)
104°F (40°C)
Minimum Flow Rate to Activate DHW Sensor
N/A
0.5 GPM
Acceptable pH range
8.5 pH
6.5 pH
Chloride
250 mg/L
Iron
0.3mg/L
Total Dissolved Solids
500mg/L
Total Hardness
7 grains
Table 6: Water Quality
WARNING
A potentially hazardous situation,
which can cause serious injury
or death, can exist if the un-used
domestic water connections are
capped off. The unused domestic
water connections are meant to
be left open if not used to allow
for the air in the coil to expand
and contract as the boiler / water
heater is in operation.
WARNING
Bacteria growth can develop in
domestic hot water tanks and
indirect water heaters if the
minimum water temperature is
not set high enough to prevent
its growth.
WARNING
HOT WATER CAN SCALD!
Water Temperatures over 125°F
/ 52°C can cause severe burns
instantly or death from scalds.
Children, disabled, and elderly are
at highest risk of being scalded.
•
Never leave them unattended
in or near the shower, bathtub
or sink.
•
Never allow small children to
use a not water faucet or draw
their own bath.
To avoid any potential scald
hazard or if codes require specific
water temperatures at the hot
water faucet, the installer may:
•
Install a thermostatic mixing
valve at this appliance and
ensure it is working properly.
AND
•
Set the thermostatic mixing
valve to the lowest temperature
which satisfies your hot water
needs.
TO AVOID INJURY:
•
Feel and adjust water
temperature before bathing or
showering.
•
Water drained from the system
drain valve may be extremely
hot.
•
Make sure all connections are
tight.
•
Direct water flow away from
any person.
