1-27
INSTALLATION
DC SERIES COMBI BOILERS
DC 23-84, DC 29-106, DC 33-124, DC 33-160
1.7.1 Domestic Hot Water System
The DC series boilers 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 fires up to begin generating
domestic hot water. Due to the unique design of the boiler’s heat exchanger, the
boiler 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 passage-way
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 responds to a call for domestic hot water when a
faucet is opened. After the faucet is closed the boiler shuts down and waits for
a call for the faucet to open.
•
Comfort Mode:
After the faucet is closed the boiler 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 will maintain the programmed
domestic hot water temperature but based on a learned pattern, the boiler
will allow the water to cool. For example during the night, the boiler will see
no flow of domestic hot water therefore will allow the boiler to cool down each
night. If hot water is required at night, the boiler will respond to an open faucet
just as if it was in the Standard Mode.
While the DC Series boiler is less susceptible to lime scale build-up than other
units on the market, water quality must always be considered when installing
the boiler. Treating hard water and adjusting the pH to 6.5 and 7.5 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 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
7.5 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 is in
operation.
NOTE
See Domestic Hot Water
Warnings on page 1-26.
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 then 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 must:
•
Install the factory supplied
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.
Summary of Contents for DC 23-84
Page 76: ...SERVICE RECORD DATE LICENSED CONTRACTOR DESCRIPTION OF WORK DONE ...
Page 77: ...NOTES ...
Page 79: ......
