Camus Hydronics DFH/W500, Installation, Operation And Service Manual

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18
4.1 FREEZE PROTECTION
•
Appliance installations are not recommended outdoors in
areas where danger of freezing exists unless precautions
are taken. Maintaining a mixture of 50% water and 50%
propylene glycol is the preferred method of freeze
protection in hydronic systems. This mixture will protect
the appliance to approximately -35ºF (-37ºC). To maintain
the same temperature rise across the appliance increase
the GPM flow by 15% and the head loss by 20%.
The following example demonstrates the procedure to follow
for calculating the revised head for the heat exchanger when
using a water / glycol mixture.
•
Given that Camus® is showing a heat exchanger flow
and head loss of 100 gpm @ 10 feet
•
Increasing the flow by 15% now results in a head loss of
13 feet at 115 gpm (from B&G system syzer). At this
increased flow Camus® now recommends to increase
the head loss by 20%.
•
The requirement for the heat exchanger with water /
glycol mixture will now be 115 gpm @ 15.6 feet. (ie.
1.2 x 13ft. = 15.6 ft.)
•
A similar procedure must be followed to calculate the
additional head loss in pipe and fittings in order to
arrive at the proper pump selection.
•
For Outdoor installations in colder climates a snow screen
should be installed to prevent snow and ice accumulation
on and around the appliance. Regular inspections should
be made to ensure that air intake and vent are free of
snow and ice. Always consider the use of a shelter such
as a garden shed in lieu of direct exposure of the
appliance to the elements. The additional protection
afforded by the shelter will help to minimize nuisance
problems with electrical connections and will allow easier
servicing of the appliance under severe weather
conditions.
4.2 WARNING REGARDING CHILLED WATER &
HEATING COIL SYSTEMS
When an appliance is connected to an air conditioning system
where the same water is used for heating and cooling, the
chiller must be piped in parallel with the appliance. Appropriate
flow control valves; manual or motorized must be provided to
prevent the chilled water from entering the appliance.
The appliance piping system of a hot water boiler connected to
heating coils located in air handling units where they may be
exposed to refrigerated air circulation must be equipped with
flow control valves or other automatic means to prevent gravity
circulation of the boiler water during the cooling cycle.
Figure 16: Chilled Water System
4.3 INLET AND OUTLET CONNECTIONS
•
All water connections meet American National
Standard Pipe Threads (NPT).
•
For ease of service, install unions on inlet and outlet
of the appliance. The connection to the appliance
marked “Inlet” on the header should be used for
return from the system. The connection on the header
marked “Outlet” is to be connected to the supply side
of the system.
4.4 MINIMUM PIPE SIZE REQUIREMENTS
Minimum water pipe connections are as follow for
DynaFlame® for single unit installations. The equivalent
number of straight feet of pipe for each valve and fitting in
the connecting piping must be considered to properly
arrive at the total equivalent feet of straight pipe in the field
installed piping to the appliance. See the piping
requirements in Part 12 - Installation section of this
manual. Consult factory if longer piping distances are
required for a specific application.
4.5 PRIMARY HEAT EXCHANGER
This appliance uses copper or stainless finned tubing to
maximize the heat transfer process. The copper heat
exchanger is comprised of vertical tubes rolled directly into
two circular bronze headers. The stainless heat exchanger
is an all welded construction. It is comprised of two rows of
vertical tubes welded into two circular stainless steel
headers. Both heat exchangers are designed to withstand
160 PSIG working pressure. A series of “V” shaped baffles
are installed between the individual tubes to control the
movement of the flue products over the finned tubes to
maximize efficiencies.
A factory recommended circulating pump ensures proper
water flow during burner operation and creates enough
water turbulence inside the finned tubes and header that
prevents the formation of sediments. Temperature rise
and erosion prevention in the primary heat exchanger are
controlled by the selection of a properly sized circulating
pump. To ensure proper operation and ensure longevity of
this heat exchanger minimum inlet water temperatures of
115ºF (46ºC) MUST BE maintained for non-condensing
models and 130 ºF (55ºC) for near-condensing and
condensing models.
When return water temperatures are below the
recommended temperature, the flue products passing over
the copper finned tubes will be cooled below their dew
point resulting in the formation of corrosive condensation
on the copper which shorten its life. Under these
conditions condensation will collect in the base of the inner
combustion chamber. Follow the piping recommendations
given for low water temperature systems if water
temperatures are expected to be below the recommended
value. During initial operation of the appliance in a cold
system some condensation will be generated but it will be
quickly evaporated once the system return temperature
reaches 115ºF (46ºC).