Sizing The System - Lennox iHarmony 10C16 Installation And Setup Manual

How to convert electric heat watts to
BTUs/Hr
Verify Zoning Target Air Temp for HP Heating is 90°F (10° overshoot
»
range is 90°- 100°F).
Verify Zoning Supply Air Temp Limit for Cooling is set to 40°F.
»
Adjust Zoning Supply Air Temp Limit for Gas/Electric Heating
»
to160°F. Set high heating limit to minimum of 15° above operating target
DAT and round up to the nearest 5° limit option setting. Recommend
160° limit temp to avoid short cycling and DAT cool down mode
Verify HP Heating Lockout Time is set to 60 min.
»
• Go to the Verify Airflow Per Zone Screen.
From the Equipment list, select reset and on the right side of the screen,
»
select re-configure system.
Verify the dealer info is completed on the first screen.
»
Continue to navigate through the various screens until you arrive at the
»
iHarmony zoning screen. Verify the names for each zone are correct.
Then select continue.
» Select the following for each zone and set the correct CFM for the zone.
- Blower Circulation Airflow per zone: For up to four zones, each
zone assigned airflow at least the minimum CFM value per ton-
nage, for example 250 CFM for 3-ton, 380 for 4-ton or 450 CFM for
5-ton. Adjustment are in 5 CFM increments.
- Heating Circulation Airflow per zone:
◊ Enter Recommended CFM Per Zone from "Zoning CFM Tables"
on page 17.
◊ On staged units, values are mid-range temp rise specific and
should only be changed if the maximum of <79% Indoor Blower
Power (IDBP) cannot be achieved.
◊ Final adjustment will be made after IDBP testing.
◊ If lower CFM is needed to maintain proper IDBP the value must
remain within the recommended range listed in the blower ta-
bles.
◊ On modulating units any value between the recommended and
max airflow will operate at the same temp rise and can be se-
lected based on the amount of BTU's each zone requires as per
load calculations.
◊ The percentage of Max BTU is relative to the percentage of Max
CFM.
◊ If a lower CFM is needed to maintain proper IDBP the value
must not go below the Absolute Min CFM per Zone listed in the
blower tables.
15KW = 15,000 Watts
15,000 Watts X 3.413 = 51,195 BTUs/Hr
- Cooling Circulation Airflow per zone:
◊ Enter the recommended CFM per zone for the cooling load per
zone maintaining CFMs above the minimum CFM values per
zone .
◊ Final adjustment will be made after IDBP and target air tempera-
ture approach are determined
• Once adjustments have been completed, select continue. This will take you
to the test mode.

Sizing the System

Select manual test then apply.
• Record and verify all blower settings were saved.
• Select continue at the bottom of the screen and select manual tests and
then select apply.
• From the select tests to run screen, select the option deselect all.
• Select maximum rate for the heating unit being tested.
» Verify heating rate 100%.
Verify CFM demand matches the high heating airflow setting.
»
Verify IDBP <79%. The indoor blower power is helpful in determining if
»
the zone ductwork has a high static pressure that the blower may not be
able to overcome and cause the blower to run in cut back mode.
- If IDBP is <79 % do not adjust high heating airflow.
- This value is designed for mid-range temp rise operation vital to
maximum heat exchanger life and performance.
» If IDBP is <79 % scroll down to the second discharge air temperature
(S30) reading below the zoning section on the same screen.
» Calibrate the DATS
- Move DATS probe in or out as required until discharge air sensor
value (located in diagnostics) is close to the actual discharge air
temperature target, the DAR is based on BTU/CFM/1.08+Return Air
Temperature. This is a mapping value generated by the DATS not
based on actual stratified plenum temperature.
- If the DATS value exceeds the overshoot range the furnace will not
maintain 100% capacity operation
Return to previous screen
»
Select maximum or 2nd stage cooling and start.
»
- Verify cooling rate 100%.
- Verify CFM demand is the value selected. Set the assigned airflow
equal-to, or greater-than the maximum airflow (airflow assigned for
peak cooling load)
10