Instruction manual
CLIMATEMASTER WATER-SOURCE HEAT PUMPS
W (ERV) Series
Rev.: 15 May, 2015
4
ClimateMaster Water-Source Heat Pumps
times that of the sensible heat load and in the winter it is 
a signifi cant part of a humidifi cation 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, fi rst 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 (fi eld 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.
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 fi eld 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.
FROST THRESHOLD TEMPERATURE
INDOOR RH AT 70ºF
FROST THRESHOLD
TEMPERATURE
20% 0ºF
30% 5ºF
40% 10ºF
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.
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 will 
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 fi eld 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 fi eld installed dampers to 
balance air fl ow.
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 fl ow (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 specifi ed 
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 defl ection force should be between 5-8 lbs or the 
lowest tension at which the belt will not slip under peak 










