IBC DC 33-124

INSTALLATION AND OPERATION INSTRUCTIONS
1-28
DC SERIES COMBI BOILERS DC 23-84, DC 29-106, DC 33-124, DC 33-160
1.7.2 – Domestic Hot Water Piping
The domestic water piping connections are located at the bottom of the boiler,
see Figure 30, Page 1-29. The connections are 3/4" male NPT threads. The cold
water inlet is on the right side and the hot water outlet is on the left side.
A Temperature and Pressure Relief valve with a maximum pressure setting of
150PSI and rated for a minimum capacity of less than the rated input of the boiler
(NOT Supplied with the boiler) must be installed on the domestic hot water outlet
piping within 6" of the boiler. The temperature and pressure relief valve must be
installed between the boiler’s outlet and any isolation valve so as to ensure the
temperature and pressure relief valve cannot be isolated by closing a valve. A
valve kit designed for this purpose is recommended to reduce installation time
and reduce the space required.
The DC Series boiler is supplied with a 3-way thermostatic domestic hot water
tempering valve. This valve must be installed to eliminate extremely high outlet
water temperatures when the boiler is switching from high temperature heating
loads to supply domestic hot water. See Figure 30.
If the boiler installation is only using the space heating portion of the heat
exchanger and not using the Domestic Hot Water portion of the heat exchanger,
then the mixing valve and the Temperature and Pressure Relief valve need not
be installed.
Do not cap off the hot and cold piping connections if they are not being
used.
The DC Series boilers can be connected to the pressurized 1/2" or larger
domestic cold water supply piping and the domestic hot water piping in the home.
The minimum domestic water pressure required is 40PSI and recommended to
be 50PSI or higher. Generating domestic hot water with a water pressure lower
than 40PSI will reduce the amount of hot water generated and will increase the
risk of scaling in the heat exchanger.
The domestic water piping must be installed with isolation valves and ushing
taps installed on both the cold and hot domestic connections.
Thermal expansion of the water in the domestic hot water piping and boiler
can cause excessive pressures to build in the piping system. This can cause
the temperature and pressure relief valve to discharge on a regular basis. This
condition must be prevented with the installation of a properly sized and installed
domestic water expansion tank or other device designed for the purpose.
WARNING
This boiler model can burn
either Natural gas or Propane.
A boiler congured for
Propane can be converted to
Natural gas with gas valve
adjustments. Refer to section
3.3 for further instruction.
If a boiler is to be converted
from one fuel to another,
a conversion kit must
be ordered prior to the
conversion. The conversion
kit must be installed according
to the detailed instructions
supplied with the kit.
Failure to perform the
required fuel conversion
correctly can result in serious
injury or death.
NOTE
It is essential to check gas
supply pressure to each
boiler with a manometer or
other high-quality precision
measuring device. Pressure
should be monitored before
ring the boiler, when the
regulator is in a “lock-
up” condition and during
operation, throughout the
boiler’s full modulation range.
Pay special attention to
retrot situations where
existing regulators may have
an over-sized orice and/or
worn seats, causing pressure
“creep” and high lock up
pressures.