Lennox 50P2050 H Series User manual

50P2050xH
EN ERGY RE COV ERY SYSTEM
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a qualified installer or service
agency.
IN STAL LA TION IN STRUC TIONS FOR EN ERGY RE COV ERY SYS TEMS (ERS)
USED WITH LC/LG 072 SE RIES UNITS
ETL Certified
per UL 1995
and CSA 22.2
KITS AND ACCESSORIES
P20A-50LDW
July 12, 2010
Supersedes 02-12-10
SHIP PING AND PACK ING LIST
Package 1 of 1 contains: See Illustration 1 and 2.
1-Energy Recovery System Assembly
1-Outdoor Fresh Air Hood with Filter
1-Outdoor Exhaust Air Hood with Barometric
Damper
1-Top Filler Panel
1-Bottom Filler Panel w/ Platform Support Rail
(Mounted)
2 - Side Filler (Installed on ERS)
1-Hardware Bag:
14' -Gasket ¾" x 1 ¼"
7'-Gasket 18" x ½"
1-Field Harness
4-Wire Ties
10-Self-Tapping Screws 10-16 x ½"
8-Gold Screws 10-16 x ½"
1-Installation Instruction
Illustration 2
FRESH AIR BLOWER
CON TROL BOARD
POWER EN TRY
EX HAUST FAN
WIR ING
MAKEUP
BOX
MIXED AIR
RETURN AIR
OUT DOOR AIR DAMPERS
FRESH
AIR
EXHAUST
AIR
MIXED AIR OUTDOOR AIR
FIL TER ACCESS
EN ERGY
RE COV ERY
WHEEL
RETURN/
EXHAUST AIR
Illustration 1
The ERS enthalpy wheel contains parallel layers of a
polymeric material that are impregnated with silica gel
(desiccant). The wheel is located in the entering (intake)
air and exhaust air streams of the ventilation equipment.
As the wheel rotates through each air stream, the wheel
surfaceadsorbssensibleandlatentenergy. Intheheating
mode, the wheel rotates to provide a constant transfer of
heat from the exhaust air stream to the colder intake air
stream. During the cooling season, the process is
reversed. When the temperatures are mild the wheel
pivots out of the air stream to allow economizer to operate
PRIN CI PLE OF OPERATION
normally for "free cooling" when outdoor temperature and
humidity is acceptable. During economizer operation, the
ERS exhaust blower continues to run, providing power
exhaustforthesystem. The intakeblower isde-energized
during economizer operation.
PAGE 1
Patent# 5,548,970
TELE SCOP ING LEG
20 516 55 38
37 ½
37 ¼
20 516
37 ¼
55 38
37 ½

PAGE 2
ROOF TOP UNIT PREPARATION
1. Maximum weight of unit is — 300 Lbs (crated).
2. Remove crating and retrieve hardware bag that is
inside of ERS.
3. All ERS door panels must be in place for rigging.
4. Use straps to lift unit.
1. Disconnect all power to rooftop unit.
2. Open filter access door. If installing pivoting wheel
verify and/or install an internal modulating
economizer.
3. Remove the rooftop unit horizontal return air access
panels.Also remove anyhoods and/or power exhaust
equipment.Discardhoods,powerexhaustequipment,
and horizontal return air panels. See Figure 1.
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or mai ntenance, turn the
electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
CAUTION
GENERAL
REQUIREMENTS
SHIP PING DAMAGE
RIG GING UNIT FOR LIFTING
Theseinstructions are intended as a general guide anddo
not supersede local codes in any way. Authorities having
jurisdiction should be consulted before installation.
When installed, the unit must be electrically wired and
grounded in accordance with local codes or, in the
absence of local codes, with the current National Electric
Code, ANSI/NFPA No. 70.
Check unit for shipping damage. Receiving party should
contact last carrier immediately if shipping damage is
found.
REMOVE PANEL
Figure 1
Figure 2
Figure 3
Figure 4
4. If a factory install ERS Harness (J298/P153) is
installed go to Step 5, otherwise use the provided
harness from the hardware bag within the ERS and
complete the following steps.
A. Locate the field harness from the hardware bag
shipped inside the ERS.
B. With door panels open on the economizer and
control side of RTU, route the wire harness bare
ends (3 wires Green, Pink and Black) from
economizer section along the RTU wire at the top
ofunitandthroughpanelabovethefilterrack.See
Figure 2.
C. Follow wires all the way through blower section.
See Figure 3.
D. Continuetofollowwiresalongthe top andthrough
dividerpanelintothecontrolcenter.See Figure 4.

Figure 6
A7
WIRES
E. Routewirethroughthecontrolsectiondowntothe
IMC2controlboard. Strip the wireends3/8" ifthey
have not been pre-done. Place the Green wire
under screw terminal at J298-8 (Purple
connector). Do the same routine for Pink at
J298-10 and Black to J298-9. See Figure 5.
5. The economizer may use an A7 enthalpy sensor
located on the division panel between the economizer
outdoor air and return air dampers. If present, the
sensor must be moved to the intake air section of the
ERS. Disconnect sensor A7 wires from logic module,
removescrewssecuringthesensor,andretainsensor
assembly and screws. See Figure 6.
Figure 7
Figure 5
8 9 10
J298
PAGE 3
6. Disconnect plug P4 from connector J4.
7. InstalltheprovidedERS fieldharness betweenJ4and
P4 by plugging P27 into J4, plugging J27 into P4
harness.
8. PlugpurpleandbluewiresfromERSfieldharnessinto
logic module at SO+ (purple) and SO (blue).
9. Plug field harness P27 into economizer plug J4. See
Figure 7 for field wiring.
Figure 8
WIR ING HAR NESS (P153)
1. Apply¾"x1¼"gaskettotopandbottomdecksofERS
as shown in the figure. See Figure 9.
Figure 9
IN STALL EN ERGY RE COV ERY SYSTEM
10. Using wire ties neatly route the wires to clear any
moving parts.
11. Route the 6-pin connector P153 and wiring harness
under the economizer and out the return air. Coil
excesswireandrouteintoreturnairoftherooftopunit.
See Figure 8.

PAGE 4
2. Attach bottom filler panel with platform support rail to
bottom opening of rooftop unit aligning with screw
holesusedbyremoveddoorpanel. Secureinplaceas
shown in Figure 10
Figure 10
BOT TOM FILLER PANEL
PLAT FORM SUP PORT RAIL
Figure 11
TELE SCOP ING LEG
Figure 12
TOP FILLER PANEL
SIDE MOUNT ING FLANGE
3. Removeallscrewsholdingthetoppanelofrooftopunit
aroundthehorizontalexhaustairopening.Ensurethat
the top panel will move upward at least 2".
4. Lift ERS at least three feet (3'). Remove four screws
holding telescoping leg to guide and pull out leg.
Reinsertthelegfromthebottomwiththeflatfootunder
the unit and reinsert one of the screws to hold leg into
place. The leg will need to be adjusted later when unit
is in position.
5. PositionERSinfrontofhorizontalexhaustairopening.
Line up the ERS to the rooftop unit. Ensure that there
arenotanyscrewsontherooftopunitthatwillinterfere
withthe mountingflangesof theERS andif soremove
them.
Note: Equipment support kit or equivalent should be
used under feet of standoff legs to prevent roof
penetration. See Figure 11.
6. Lift ERS front end into the platform support rail
catching the base pan of ERS.
7. Removethescrewsplacedinthetelescopinglegsand
adjust the legs on the ERS until it is level. Replace all
four screws in each leg to secure the ERS in the
leveled position. See Figure 11.
Figure 13
10. Check and seal, if necessary, along the edges where
theERSmeetstherooftopunittoensurethereisnoair
leakage. Final assembly should resemble Figure 13.
11. Removetherightfront(rooftopunitside) access panel
and locate the field wiring harness that was previously
routed into the return air of the rooftop unit. Plug the
field wiring harness into the connector located at the
bottomofthe access door inside theERS. See Figure
14.
Figure 14
FIELD HARNESS
CONNECTION TO ERS
EQUIPMENT SUPPORT
9. Useprovided10-16x½"self-tappingscrewstosecure
the of the ERS to the rooftop unit. See Figure 12.
8. Insert top filler panel under the rooftop unit top panel
with1"flangepointingoutawayfrom unit andontopof
ERS top panel to provide a rain seal. See Figure 12.
12. Locate the A7 enthalpy control sensor (if removed
earlier from the rooftop unit.)
13. Installations using an A7 enthalpy sensor - Remove
the screws to the filter access panel of the fresh air
hoodontheERSandremovetheairfilter.Reinstallthe

PAGE 5
A7 enthalpy control sensor with retained screws
removed on the bottom panel of the fresh air intake
hood. See Figure 15.
Figure 15
14. IftheA7 enthalpy sensor wasretained,locatethe blue
and purple wire harness on the top deck. Remove the
intake air access panel and route blue and purple
harness to the A7 enthalpy sensor harness and
connectpurple toSO+ andblue toSO.Secure excess
wiring. See Figure 16 and Figure 17 for field wiring
diagram.
Figure 16
EN THALPY CON TROL WIRES
Figure 17
Figure 18
Figure 19
HIGH VOLT AGE ENTRANCE
Note: Unit v oltage entries m ust be sealed w eather
tight after wiring is complete.
18. ReplaceaccesspanelsontotheERSunitandsecure.
1. Open access panel to rooftop unit controls.
2. Theminimumdamperbladepositionmustbeadjusted
ontheeconomizercontrolboardtothecorrectamount
of outside air specified by the customer. Refer to
Lennox rooftop unit manual for setting.
Wheel Pivot Adjustment
The Electronic Configuration To Order (ECTO)
parameter must be set at ECTO 7.22 = 10 to indicate
ERS is installed.
In the A55 Integrated Modular Controller II (IMC2)
[Prodigy] of the RTU setting is required for the
economizer to go to minimum outside air.
ROOF TOP UNIT WIR ING
(See Field Wir ing Dia gram)
15. All electrical connections must conform to any local
codes and the current National Electric Codes (NEC)
and Canadian Electric Code (CEC). Refer closely to
wiring diagram in unit and/or in these instructions for
properconnections.Refertotheunitnameplateforthe
minimum circuit ampacity and maximum over current
protection size. Electrical data is listed on unit rating
plate and motor nameplates.
16. Connectlinevoltagepowerto ERS unitfromERSfield
providedor rooftop unit disconnectswitch (disconnect
must be properly sized). Then connect line voltage
from disconnect switch through ERS knockout on
middle post to control box per the wiring diagram. See
Figure 18 and 19.

PAGE 6
During default operation the ERS will start when the
RTU unit blower is on and dampers are at minimum
position.Thewheelwillpivotoutofthefreshairstream
at power exhaust signal or free-cooling demand.
The A55 (IMC2) uses the following parameters to
control wheel position. See Figure 20.
For Smoke Mode reference the Sm oke Mode
Operation table .
At startup, If
ECTO 7.22 = 10
(ERS Installed)
Blower on &
Lennox
economizer >=
min. position
ERS on
D01 = 1
D02 = 0
Power Exhaust on
OR
Free-Cooling
ERS on
D01 = 1
D02 = 1
ERS on
D01 = 0
D02 = 0
Yes
Yes
Yes
No
No
Notes:
1. D01( turns on B28, B26, B27 thru ERS controller) and
D02 (turns on B29 thru ERS controller) are relay outputs
from Lennox IMC2 control board.
2. B28 - ERS Wheel Motor, B26 - ERS Exhaust Air Blower,
B27 - ERS Fresh Air Blower, B29 - ERS Wheel pivot/damper
motor
Figure 20
Nor mal Op er a tion
Smoke Mode Set ting
(ECTO 5.01) Blower D02 Damper D01
0, unit off (default) OFF OFF Closed OFF
1, pos. pressure ON OFF 100% Open ON
2, neg. pressure ON ON Closed ON
3, purge ON ON 100% Open ON
4, neg. pressure OFF ON Closed ON
5, neg. pressure ON ON Closed ON
6, purge ON ON 100% Open ON
7, neg. pressure OFF ON Closed ON
Smoke Mode Op er a tion
OP TIONAL KITS (Fac tory In stalled)
Motorized Intake Air Damper
Damper mounts behind the outdoor air intake hood. It
opens when the ERS is energized and closes when
de-energized. Powered by B30 damper motor.
Pressure Sensor
Measurement device on the ERS to determine airflow
across the Enthalpy Wheel.
Low Ambient Control Kit (S26)
Prevents frost formation on energy wheel heat transfer
surfaces by terminating the intake blower operation when
discharge air temperature falls below a field selectable
temperature setting. Intake blower operation resumes
operation after temperature rises above the adjustable
temperature differential.
The frost threshold is the outdoor temperature at which
frost will begin to form on the ERS wheel. For energy
recovery systems, the frost threshold is typically below
10oF. Frost threshold is dependent on indoor temperature
and humidity. The table shows how the frost threshold
temperatures vary depending on indoor conditions.
FROST THRESHOLD TEMPERATURE
INDOOR RH AT 70oFFROST THRESHOLD
TEMPERATURE
20% 0oF
30% 5oF
40% 10oF
Because Energy Recovery Systems have a low frost
threshold, frost control options are not necessary in many
climates. Where outdoor temperatures may drop below
the frost threshold during the ERS operational hours,
exhaust only frost control option is available.
ECONO MIZER SET TINGS
Refer to economizer instructions for minimum air flow
requirement. The damper setting on the internal
economizer assembly are field adjustable to any position
above minimum air flow for fresh air requirements at the
customers specified conditions.
3. Close access panels on the rooftop unit and secure.
4. Restore power to unit.
5. Once ERS is working properly, caulk any open joints,
holes, or seams to make the units completely air and
water tight.
6. Leave this instruction manual with owner or in an
envelope to be kept near unit.
BLOWER SPEED AD JUST MENT
Blower speed selection is accomplished by changing the
speed tap wire (refer to wiring diagram) on both fresh air
and exhaust air blowers. All blowers are factory set at
"high" for maximum airflow. To determine air flow setting,
external static pressure readings will need to be read
across the ERS. Reference Table 1 on page 8. For
location to take pressure readings. See Figure 21.

DELTA PRES SURE
FRESH AIR
DELTA PRES SURE
EX HAUST AIR
Figure 21
OPERATION
Recovery Wheel Mode
On a thermostat call for blower operation in heating,
cooling or continuous blower, the ERS media will rotate
between fresh air and exhaust air streams. Both the fresh
air blower and exhaust air blower will be operating.
Economizer/Power Exhaust Mode
On the activation of the economizer mode (closure of EH
and EH1 of logic module), the ERS unit will shutdown for
approximately60secondstoallowtheERS mediatopivot
out of the air stream. After this delay timer has been
satisfied,theexhaustairblowerwilloperate.TheERS unit
will act as a power exhaust unit.
This mode will continue until economizer has been
deactivated.Theexhaustairblowerwill shut downandthe
delay timer will be activated. During this time period the
ERS mediawillpivotback intotheairstream.Whentiming
is complete the unit will operate in the Recovery Wheel
Mode.
Then if economizer continues to close the ERS will
shutdown when the "N" terminal is deactivated, thus
allowing rooftop unit to run in night set back mode.
1. Disconnect ERS main power.
Note: If Low ambient kit S26 is used the jumper
between TB37-5 and TB37-6 should be removed.
Alsoifsystemcheck outisbeingconductedatlow
ambient temperatures, jumper low ambient
switch.
2. Open rooftop unit blower access panel and locate
TB1. Jumper terminals 6 (24v) and 3 (G) to energize
rooftop unit blower. Refer to manufacturers
instructions when an electronic thermostat or other
energy management system is used.
3. Remove ERS control access panel and install jumper
at low voltage terminal strip between TB37-1 and
TB37-2.
4. Restore power to ERS unit. The recovery wheel will
pivot out of the air stream, fresh air blower dampers
will open, and after a delay, the exhaust blower will
operate.
5. Remove jumper from ERS control board TB37-1 and
TB37-2. The recovery wheel will pivot into the air
stream, the fresh air blower dampers will close, and
after a delay, the fresh air blower and exhaust air
blower will operate.
SYSTEM CHECK
PAGE 7
MAINTENANCE
Motor Maintenance
All motors use prelubricated sealed bearings; no further
lubrication is necessary.
Mechanical Inspection
Make visual inspection of dampers, linkage assemblies
and ERS rotating bearings during routine maintenance.
Filters should be checked periodically and cleaned when
necessary. Filter is located in fresh air hoods. DO NOT
replace permanent filters with throwaway type filters.
Energy Wheel Maintenance
Four pie-shaped energy recovery wheel segments are
seated on stops between the stainless steel spring
retainers, secured to the hub and rim of wheel. Annual
inspection of the self cleaning wheel is recommended.
With power disconnected, remove ERS access panels
(rear)andunplug(J150&P150).Refertowiringdiagramin
this instruction manual. Each segment is secured in place
by a stainless steel spring retainer located on wheel rim.
Removeoneendof thestainlesssteelspringretainerfrom
the slot in the wheel rim and remove. Do the same on the
next retainer. Remove segment and wash with water
and/or mild detergent. Replace segment by reversing the
above procedure. See Fig ure 22. Discoloration and
staining of ERS segment does not affect its performance.
Only excessive buildup of foreign material need be
removed. If the segment appears excessively dirty, it
should be cleaned to ensure maximum operating
efficiency. Thoroughly spray plastic surface with
household cleaner such as Fantasticor equivalent
middledetergent and gently rinse with warm water usinga
soft brush to remove heavier accumulation. Shake excess
water from segment and replace in reverse of removal
instructions.
6. Disconnect main power to unit before making
adjustment to economizer and/or ERS unit.
7. Remove all jumpers and replace ERS control access
cover.
8. Set thermostat to normal operating position.
9. Restore power to unit.
HUB
SEGMENT
FIGURE 22
SPOKE
SEGMENT RETAINER CATCH
WHEEL RIM
SEGMENT RETAINER

PAGE 8
ENERGY RECOVERY SYSTEMS
SCFM vs. PRESSURE DROP
900 950 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700
1500 1550 1600 1650 1700
1400 1450 1500 1550 1600 1650 1700
1200 1250 1300 1350 1400 1450 1500
1100 1150 1200 1250 1300
0
0.2 0.4 0.6 0.8
1
1.2 1.4
900 950 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700
SCFM
Equation of line:SCFM=(PD-0.0492647)/0.0005721)
TABLE #1
PRESSURE DROP (in. of W.C.)
ERS 1200 RPM 1100 RPM 1000 RPM 900 RPM
seireS *Hx0502P05

PAGE 9

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