Reznor XBWS11 User manual

INSTALLATION INSTRUCTIONS
ENERGY RECOVERY VENTILATOR
Applies to Model XBWS when used with Option AQ21
Vertical Supply and Return Air
INSTALLATION INSTRUCTIONS FOR ROOFTOP STAND ALONE
ENERGY RECOVERY UNIT IN SIDE BY SIDE DESIGN
FORM RZ-NA-I-XBWS-AQ21
MARCH 30, 2005
SUPERCEDES 09-13-04
DXX-2ZERV
PAGE 1
I-Shipping and Packing List
Package contains:
1 — Energy Recovery Ventilator Assembly
I I -Shipping Damage
Check unit for shipping damage. Receiving party should contact last carrier immediately if shipping damage is found.
III -General
These instructions are intended as a general guide and do not supersede local codes in any way. Authorities having
jurisdiction should be consulted before installation.
IV -Requirements
When installed, the unit must be electrically wired and grounded in accordance with local codes or, in absence of local
codes, with the current National Electric Code, ANSI/NFPA No. 70.
V-Application
These Energy Recovery Ventilators (ERV) are used in a down discharge manner equipped with field provided
balancing damper assembly through the roof. A roof curb must be provided to Rooftop Systems specifications. These
wheels conserve energy by mixing warmer air with cooler air in the following manner:
Recovery Wheel Mode
The Recovery Wheel mode is accomplished by two blowers providing continuous exhaust of stale indoor air and
replacement by equal amount of outdoor air. Energy recovery is achieved by slowly rotating the energy recovery wheel
within the cassette frame work. In winter, the ERV adsorbs heat and moisture from the exhaust air stream during one half
of a complete rotation and gives them back to the cold, drier intake air supply during the other half rotation. In summer, the
process is automatically reversed. Heat and moisture are absorbed from incoming fresh air supply and transferred to the
exhaust air stream. This process allows outdoor air ventilation rates to be increased by factors of three or more without
additional energy penalty or increase in size of heating or air conditioning systems.
VI -Rigging Unit For Lifting
1- Maximum weight of unit is — Varies per Series {300-1200 Lbs.} (Crated)
2- Remove crating.
3- All panels must be in place for rigging.
4- Remove barometric exhaust hood from door marked filter access. Install barometric exhaust hood over exhaust blower
outlet.
5- Duct work should be installed into roof curb before installing ERV on curb.
6- Roof curb gasket must be applied to all top surfaces of the curb.
Energy recovery COMPONENT certified
to the ARI Air-to-Air Energy Recovery
Ventilation Equipment Certification
Program in accordance with ARI
Standard 1060-2000 . Actual performance
in packaged equipment may vary.
ETL Certified per UL 1995
and CSA 22.2

6- Forklift channels must be removed from the base of ERV before setting unit on curb.
7 - Position unit on roof curb and provide service access to ERV control access door and wheel.
VII -Installation
3- Set ERV on curb. Verify ERV is positioned on curb properly.
4- Remove barometric exhaust hood from door marked filter access. Install barometric exhaust hood over exhaust blower
outlet.
5- Remove ERV control access panel to connect field wiring.
6- Route class II low voltage wire (3 conductor) from thermostat or energy management through small bushing in end
panel of ERV. See wiring diagram.
a- Thermostat (dependent) - connect in parallel at rooftop unit with "G", "C" and "W". Then connect matching color at
terminal 1, 2, and 3 respectively on ERV circuit board.
b- Energy Management - provide +24 VAC to "1" and common, 24 VAC to "2" terminals on ERV circuit board.
c- Thermostat (dedicated) - splice into +24 vac (blue wire) at (control circuit board) transformer connection run wire to
"R" terminal. Then run another wire from "G" terminal to ERV (control circuit board) terminal block #1.
7- All electrical connections must conform to any local codes and current National Electric Codes (NEC) and Canadian
Electric Codes (CEC). Refer closely to unit wiring diagram in unit and/or in these instructions for proper wiring
connections.
8- Refer to the unit nameplate for minimum circuit ampacity (MCA) and maximum overcurrent protection size (fuse).
9- Electrical data is listed on unit rating plate and motor name plates.
10- Connect line voltage power supply to ERV fuse block in control box of unit from disconnect switch. See wiring
diagram.
11- Ground unit with a suitable ground connection either through unit supply wiring or an earth ground.
NOTE-Unit voltage entries must be sealed weather tight after wiring is complete.
12- Remove motor access panels. Locate belts fastened to blower assembly. Install belt onto motor and blower pulley.
Adjust motor sheave to correct blower RPM for CFM and external static pressure requirements. See charts in this
instruction. Multiple pulley arrangements are available to meet the entire range.
Caution: Blower speed must be adjusted for the given external static pressure and airflow (CFM) requirements. If
blower speed is not adjusted for conditions, possible motor over loading can occur.
13- Replace access panel onto the ERV unit and secure.
PAGE 2
1- Attach duct work to duct flanges on roof curb.
2- Remove forklift channels from base of ERV.
CAUTION
Danger of sharp metallic edges. Can cause injury.
Take care when servicing unit to avoid accidental
contact with sharp edges.
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
WARNING

PAGE 3
14- Restore power to unit.
15- Cleanup once unit is operating properly, caulk any open joints, holes or seams to make the unit completely air and
water tight.
16- Leave this instruction manual with owner or in an envelope to be kept near unit.
VIII -Operation
How It Works
The unit contains an Energy Recovery Wheel (ERW) that is a new concept in rotary air-to-air heat exchangers. Designed
as a packaged unit for ease of installation and maintenance, only the connection of electrical power is required to make the
system operational.
When slowly rotating through counter flowing exhaust and fresh air streams the ERW adsorbs sensible heat and latent
heat from the warmer air stream and transfers this total energy to the cooler air stream during the second half of its rotating
cycle. Rotating at 50-60 revolutions per minute, the wheel provides constant flow of energy from warmer to cooler air
stream. The large energy transfer surface and laminar flow through the wheel causes this constant flow of recovered
energy to represent up to 85% of the difference in total energy contained within the two air streams.
Sensible and latent heat are the two components of total heat. Sensible heat is energy contained in dry air and latent heat
is the energy contained within the moisture of the air. The latent heat load from the outdoor fresh air on an air conditioning
system can often be two to three times that of the sensible heat load and in the winter it is a significant part of a
humidification heat load.
During both the summer and winter, the ERW transfers moisture entirely in the vapor phase. This eliminates wet surfaces
that retain dust and promote fungal growth as well as the need for a condensate pan and drain to carry water.
Because it is constantly rotating when in the air stream, the ERV is always being cleaned by air, first in one direction then
the other. Because it is always dry, dust or other particles impinging on the surface during one half cycle, are readily
removed during the next half cycle.
During the heating season, when outdoor air temperatures are below 15oF, it is recommended to use the (optional) low
ambient kit (field installed).
Low Ambient Kit is appropriate for climates with limited HVAC system operation when outdoor temperatures are below
10oF.
The frost threshold is the outdoor temperature at which frost will begin to form on the ERV wheel. For Energy Recovery
Ventilators, the frost threshold is typically below 10oF. Frost threshold is dependent on indoor temperature and humidify.
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 Ventilators 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 ERV operational hours, exhaust only frost
control option is available.
Low Ambient Kit (Optional)
Low Ambient Kit turns off the supply blower when outdoor temperatures fall below the frost threshold. The exhaust only
thermostat set points are field adjustable. Supply fan operation is automatically restored when the exhaust air temperature
rises above the thermostat set point. Provisions for introducing make-up air into the building when the supply blower is off
to avoid depressurization should be considered.
Recovery Wheel Mode
On a thermostat call for blower operation in heating, cooling or continuous blower, the ERW will rotate between fresh air
and exhaust air streams. Both the fresh air and exhaust air blowers will also be operating to overcome the air resistance of
the ERV.

PAGE 4
IX -System Check
1- Disconnect main power.
2- Turn to "Cont" for blower operation on thermostat controlled models.
3- Restore power to unit. Observe ERV wheel rotation and both fresh air and exhaust air blowers while operating.
NOTE: If Low ambient kit is used the jumper between TB37-5 & TB37-6 should be removed. Also if system check
out is being conducted at low ambient temperatures, technician should be aware that this kit can cause
system not to operate.
4- Verify that the ERV (3) three phase blower motors are phased sequentially ensuring correct rotation and operation.
a - Disconnect power.
b - Reverse any two field power leads to the ERV.
c - Reapply power.
5- Verify that both blower motors are operating under their full load AMP rating (FLA). The FLA can be found on each
motor and the unit nameplate
A - Return Damper Settings
Manually adjust position of field installed dampers to balance air flow.
B - Air Flow / Blower Speed Adjustment
Blower speed selection is accomplished by changing the sheave setting on both fresh air and exhaust air blowers. To set
ERV for the required air flow (CFM), the external static pressure applied to the ERV (duct static) must be known. See the
CFM vs External Static Pressure chart for the appropriate unit to determine the correct blower RPM for the specified CFM
and External Static Pressure.
After blower speed adjustments have been made. Ensure that when the belt is replaced it is tensioned correctly. The
motor mounting plate can be adjusted to tension the belt. If using a belt tension checker, adjust the span to the appropriate
setting and check the belt defection force. The belt deflection force should be between 5-8 lbs or the lowest tension at
which the belt will not slip under peak load conditions.
5- Disconnect main power to unit before making adjustment to economizer and/or ERV unit.
6- Replace ERV control access cover.
7- Set thermostat to normal operating position.
8- Restore power to unit.
X-Maintenance
1- All motors use prelubricated sealed bearings; no further lubrication is necessary.
2- Make visual inspection of motors, belts and wheel rotating bearings during routine maintenance.
B
C
A
D
E
D
HUB
SEGMENT
FIGURE 5
SPOKE
SEGMENT RETAINER CATCH
WHEEL RIM
SEGMENT RETAINER
3- Eight pie-shaped segments are seated on stops between
the segment retainer which pivots on the wheel rim and is
secured to the hub and rim of the wheel. Annual inspection
of the self cleaning wheel is recommended. With power
disconnected, remove ERV access panels (rear) and
unplug [J150 & P150] (Refer to wiring diagram in this
instruction manual). Remove segment and wash with
water and/or mild detergent.
4- To install wheel segments follow steps A through E . See
Figure 1. Reverse procedure for segment removal.
A- Unlock two segment retainers (one on each side of the
selected segment opening.
B- With the embedded stiffener facing the motor side,
insert the nose of the segment between the hub plates.
C- Holding segment by the two outer corners, press the
segment towards the center of the wheel and inwards
against the spoke flanges. If hand pressure does not
fully seat the segment, insert the flat tip of a screw driver

PAGE 5
between the wheel rim and outer corners of the segment and apply downward force while guiding the segment into
place.
D- Close and latch each segment retainer under segment retaining catch.
E- Slowly rotate the wheel 180o. Install the second segment opposite the first for counterbalance. Rotate the two
installed segments 90oto balance the wheel while the third segment is installed. Rotate the wheel 180oagain to
install the fourth segment opposite the third. Repeat this sequence with the remaining four segments.
XI -Pulley Kit Installation
The units are shipped from the factory at the low static setting. Pulley kits are available for the medium and high static
settings. To install a pulley kit.
1- Check content of pulley kit, if pulley kit contains:
A- An adjustable sheave and a fixed pitch pulley then remove belt and both motor and blower pulley
B- An adjustable sheave then remove the motor pulley.
C. A fixed pitch pulley then remove the blower pulley.
2- Replace pulley(s) with the pulley(s) from pulley kit. Make sure each pulley is installed with a key. Tighten the set screw
on the pulley(s) to 100 in.lb.
3- Install the belt that came with the pulley kit. Tension belt as explained in the blower speed adjustment section.
4- Check the speed of the blower. Adjust the motor sheave to increase or decrease the speed of the blower. See blower
adjustment section.