Heating - Page 2

• 2" cleanable filters
• Supplementary heaters for Gas, Oil steam, Hot water, Electricity
• Variable-speed heat wheel drive for capacity control
• Supplementary direct expansion or chilled water cooling coils.
• Recirculation damper
• Units less supply or exhaust air blower
• Indoor model without intake louver, birdscreen or back-draft dampers.
• Purge sector for .02% maximum carryover of exhaust air.
• Roof curb
• Motorized supply and exhaust air dampers
• Two speed motors
• Clogged intake of filter switches and indicating lights.
• Frost elimination control
• Main disconnect switch
• TEFC motors.

Equipment Selection

1. Choose model S or E for desired heat recovery type and resistance to corrosion.
2. Select size based on supply and exhaust SCFM from Table 1
3. For chosen size, also obtain from Table 1 the necessary motor HP for the exhaust and supply fans to develop the required external static pressures(ESP). Note that ESP of supply fan must allow for pressure drop of any supplementary heating or cooling equipment in addition to that of the supply duct system.
4. For unequal airflows, select size based on the larger airflow. Obtain necessary motor HP for small airflow from Table 1 based on ESP required at that SCFM.

Model Designation :

Sample Selection :

Select VHR unit for sensible and latent heat recovery in air conditioned building. supply and exhaust airflow evh equal 3000 SCFM. Supply ESP =1 1/4 WC exhaust ESP =3/4" WC

1. Model VHRE is chosen

2. From Table 1 size 3 is required VHRE 3

3. Also from Table 1, supply motor = 2 HP, exhaust motor = 1 1/2 HP

4. Not applicable.

TABLE 1 - SELECTION TABLE