Airmax MaxAir 100e P2, Design, Installation And Maintenance Instructions

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Page 7
Thermal siphoning is flow of water through
the space heating circuit while the circulating
pump is not operating due to hot water rising
by natural convection. This phenomenon is of
little consequence during winter months, but
during the summer this will cause
overheating, interfere with air conditioning,
and waste energy.
The check valve is supplied an integral part
of the circulating pump.
circulating pump
Air handlers come with external, field
installed pumps, for flexibility and service.
The circulating pump is matched for
maximum performance for combo use
utilizing a storage type water heater. Contact
your Airmax representative for applications
other than storage tanks.
flow control valve
An adjustable flow control valve is
recommended to optimize system
performance and ensure that the output from
the water heater is stable. Any throttling type
valve may be used, but for convenience,
AirMax can include a valve, at additional cost,
with each air handler for field installation.
Combo heating systems function poorly if the
temperature drop through the air handler’s
coil is not maintained between 20-30°F (11-
17°C). The only way to adjust the water
temperature drop through the coil to match
the rated output conditions of the coil is to
adjust the flow of water.
The performance relationship between the air
handler and the water heater is ignored by
most manufacturers. The
MaxAir(e) ™ combo
fan coil system has been specifically
designed to optimize the output of the water
heater to which the air handler is attached.

If the temperature drop is less than 20°F
(11°C), the system has an excessive flow
rate. This will cause turbulent mixing
within the water heater storage tank,
reducing the domestic water capacity, and
creating large fluctuations in delivered
water temperature.

If the temperature drop across the heating
circuit is greater than 30-40°F (17-22°C)
there is inadequate flow. This will cause
poor heating performance of the air
handler and can cause stacking of the
water heater leading to unsafe water
delivery temperatures for domestic use.
EQUIPMENT SELECTION AND SIZING .
This section of the manual is to assist the
designer of the
MaxAir ™ Mini Ducted
Combo fan Coil System in the quantity and
placement of outlets, the size and location of
the supply duct, and the size and location of
the fan coil. To size a
MaxAir ™ system for a
residence, it is necessary to have an
accurate heat loss/gain done for the structure
in order to eliminate improper sizing.
After completing the room by room load
calculations, select the
MaxAir ™ model unit
that will properly meet the load requirements.
selecting the number of diffusers
From the recommended number of diffusers
indicated in Table 1, determine the number of
diffusers needed. It is recommended that you
design for the median number of diffusers .
This will yield favorable system noise levels
and minimize potential nuisance equipment
failures.
If a cooling coil is to be included
always design for at least the median
number of diffusers
.