Rheem RGRA SERIES, Руководство по установке

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46
AIR FLOW
The importance of proper air flow
over the heat exchanger cannot be
over emphasized. One of the most
common causes of heat exchanger
failure is overheating due to low air
flow. An air flow table is located inside
the blower door.
TEMPERATURE RISE CHECK
To determine if the air flow is correct,
make a temperature rise check.
1. Insert a thermometer in the
supply air duct as close to the
furnace as possible yet out of a
direct line from the heat
exchanger. See Figure 51.
2. Insert a thermometer in the
return air duct as close to the
furnace as possible.
3. Operate the furnace.
4. When the thermometer in the
supply air duct stops rising
(approximately five minutes),
subtract the return air
temperature from the supply air
temperature. The difference is
the temperature rise.
5. Compare the measured
temperature rise to the approved
temperature rise range listed on
the furnace name plate. See
Figure 52.
If the measured temperature rise is
above the approved range, the air
flow is too low. More air must be
moved by speeding up the blower,
by removing restrictions in the duct
system, or by adding more supply or
return air duct. If the measured
temperature rise is below the
approved range, the air flow is too
much. Use lower speed tap on the
multi-speed blower.
Ideally the measured temperature rise
should be in the middle of the range.
FIGURE 51
TEMPERATURE RISE MEASUREMENT
FIGURE 52
FURNACE NAME PLATE