United CoolAir VariCool EZ-Fit Series, Installation, Operation And Maintenance Manual

Installation, Operation and Maintenance Manual

VariCool EZ-Fit

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Subject to change without notice.

Operations Verification Check List

This checklist is designed to be a list of verifications after the 

initial install has been completed Assuming all electrical and 

tie in operations are complete and without issue

1� 

Base Verification – Ensure the base of the unit is 

supported in 1 of the 3 ways depicted in the Mounting 

Options section If not, support properly before any 

operation of the unit occurs

2� 

Air balance verification - Your unit was sold to specific 

parameters for CFM delivery at an ordered static 

pressure (ESP)  An air balance must be performed  To 

determine the total external static pressure, measure 

using a manometer or magnehelic gauge  Place the 

negative side of the device into the return ductwork, 

and the positive side into the supply ductwork  The 

supply must have a static pressure pitot tube to reduce 

velocity pressure and must not be near the blower, 

main plenum, or near 90°s, turning vanes, dampers or 

duct reducers, ie anywhere turbulence can occur  The 

reading indicated on the device is the total ESP  If the 

unit is using an open mechanical room as the plenum, 

the negative side may be placed in the room near the 

filters, but the door to the mechanical room must be 

closed  You can then verify (on the controller status 

screen) the RPM at which the unit is operating the VFD 

drive  Perform a duct traverse at the same time with an 

anemometer (or similar device), with similar operating 

parameters, to obtain the CFM

3� 

Water balance verification – Ensure that the unit has 

3 gpm per ton available to it at all times, if a pump is 

of variable speed it must be able to ramp up its speed 

based on that demand Variable Speed compressors 

require a minimum of 12 hours of continuous crank 

case heater energization before operation 

Failure to 

do so may result in liquid slugging on initial startup 

which may cause damage to the compressor and will 

void warranty To test the full water demand of the unit, 

you must use the controller on the unit and apply a 

manual control to the discharge pressure control valve 

Visually inspect the valve to ensure it reads or points 

to the OPEN position Also verify that the Water side 

economizer valve is in the CLOSED position This 

ensures that the valve is now requesting a full water 

load scenario for the unit in mechanical cooling At 

this time you may read the pressure drop across the 

system and compare it to the unit’s submittal data Note 

that each unit is built to custom specifications and you 

will need data about your specific unit The pressure 

drop data is an indicator of the heat exchangers 

pressure drop, it does not include the piping which will 

be marginal but will add additional resistance Note 

that units may be ordered with multiple DPC valves 

and other valves, in such case the design may require 

some additional consideration before a water balance/

verification can be performed The entering water 

temperature should not exceed 90°F and should not be 

reduced to less than 50°F for best operating results If 

equipped with a water side economizer the set point of 

water side economizer operation should be verified