Lifebreath CAF-02-MB Benutzerhandbuch

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temperature is approx. 130˚F (54˚C) which is
60˚F (15.5˚C) above the return air temperature.
These units typically have a temperature rise of
35˚F (2˚C) to 40˚F (4˚C) and therefore would
deliver air at the diffuser at approximately 105˚F
(40.5˚C) to 110˚F (43˚C).
Design vs. Field Conditions
The factors discussed above become ver y
impor tant to consumer comfor t. Even small 
differences between design parameters and
actual field conditions can impact greatly on 
output capacity. Therefore, it is important to do a
thorough and complete commissioning of the
integrated combo system to ensure the design
parameters are met.
Water System Pressures
Within the water system of an Integrated Combo
system, there are three ter ms that the
designer/installer must understand. These are head
pressure, water flow rate, and pressure drop.
Head Pressure
Head pressure is the pressure created by the 
circulation pump to push water through the 
piping system. It is this pressure which is used to
overcome the resistance to water flow 
(friction) caused by the water pipe and fittings. It
is similar in concept to the exter nal static 
pressure in an air duct system. Head pressure is
measured in feet of water (millimeters 
of water).
Note: Although the water in the combo system is
pressurized by the domestic water system the
pump is required to create water flow in the heating
loop. The domestic water system applies the same 
pressure to the supply and return sides of 
heating loop.
Note: The vertical height of the heating loop does
not impact on the head pressure as the pressure
required to push the water up the 
vertical height is offset by the weight of the water
in the vertical drop on the other side of the 
heating loop.
Flow Rate
Flow rate is the amount of water flowing in 
the system. It is directly related to the head pres-
sure and the resistance to flow. Flow rate 
is measured in gallons per minute (liters 
per minute).
Pressure Drop (PD)
Pressure drop (PD) is the reduction in total 
pressure caused by components added to a 
piping system such as coils, valves, and fittings.
The measurement of pressure drop is the 
difference in pressure on the inlet side of 
the component and the outlet side. Pressure
drop is measured in feet of water (millimeters 
of water).
When connecting the water lines for heating loop
(air handler) to the domestic water system, the
pipes should be connected with a “tee” to the
side of a vertical domestic water pipe or the 
bottom of a horizontal domestic water pipe. This
is to help prevent air from entering the heating
loop. The connections should be as near as
practical to the water heater.
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