air handler User's Manual

8
ENVISION SERIES AIR HANDLER INSTALLATION MANUAL
General Installation Information
Refrigeration
The Envision NAH series air handlers are supplied with an
expansion device. Once the line set has been brazed into
the air handler the txv bulb must be attached to the suc-
tion line outside of the cabinet and insulated with foam
tape. Be careful not to crush the txv bulb by over-tighten-
ing the clamp. The txv supplied has an internal check valve
so no external check valve is necessary. The air handler txv
should be adjusted initially per TXV Superheat Adjustments
table. Check sub-cooling and superheat, refrigerant charge
and txv may require further adjustment.
TXV Superheat Adjustment Procedure (see figure 4)
Txv’s may require adjustment for a specific application.
Remove the seal cap from the bottom of the valve.
Turn the adjustment screw counterclockwise to increase
superheat and clockwise to decrease superheat.
One complete 360° turn changes the superheat
approximately 3-4°F. You may need to allow as much as
1.
2.
30 minutes after the adjustment is made for the system
to stabilize.
Once the proper superheat setting has been achieved
replace and tighten the seal cap.
Warning – There are 8 total (360°) turns on the superheat
adjustment stem from wide open to fully closed. When
adjusting the superheat stem counterclockwise (superheat
increase) and the stop is reached, any further counterclock-
wise turning adjustment will damage the valve.
NOTE: The air handler is factory supplied with a holding
charge of dry nitrogen.
Charging the System
Refer to IM1592 for charging the system, checking sub-cool-
ing/superheat and unit operating parameters. Refer to the
Refrigerant Line Sizing table for initial refrigerant charge
amounts used with the Envision Split.
3.
Refrigerant Line Sizing
C\Wb /W` <H4OQb]`g
AWhS 6O\RZS`
AcQbW]\ :W_cWR AcQbW]\ :W_cWR AcQbW]\ :W_cWR
1VO`US]h
<AH </6 #&=2 !&=2 #&=2 !&=2 !"=2 !&=2 #$
&&
<AH! </6! #&=2 !&=2 !"=2 !&=2 !"=2 !&=2 #$
&&
<AH!$ </6!$ #&=2 !&=2 !"=2 !&=2 !"=2  =2 #$
'$
<AH" </6" !"=2 !&=2 !"=2 !&=2 %&=2  =2 %"
'
<AH"& </6"& !"=2 !&=2 %&=2 !&=2 %&=2  =2 '
 #
<AH$ </6$ %&=2  =2 %&=2  =2 &=2  =2 '
!
<AH% </6$ %&=2  =2 %&=2  =2 &=2  =2 &
#
<2H $ </6 $ #&=2 !&=2 !"=2 !&=2 !"=2  =2 #
&"
<2H!& </6!$ #&=2 !&=2 !"=2 !&=2 !"=2  =2 #$
'$
<2H"' </6"& !"=2 !&=2 %&=2 !&=2 %&=2  =2 '
 #
<2H$" </6$ %&=2  =2 %&=2  =2 &=2  =2 '
!
<2H% </6$ %&=2  =2 %&=2  =2 &=2  =2 "
#
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TXV Superheat Adjustments
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