Quick Start Manual
8
Installation, Operation & Maintenance  HTV/HTD/HTH SERIES  Heat Controller, Inc.
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* Some units include a painted drain connection. 
Using a threaded pipe or similar device to clear 
any excess paint accumulated inside this fitting 
may ease final drain line installation.
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Figure 6: Horizontal Condensate Connection
Horizontal Installation
Condensate Piping – Horizontal Units
Pitch the unit toward the drain as shown in Figure 2 to improve 
the condensate drainage. On small units (less than 2.5 tons/8.8 
kW), insure that unit pitch does not cause condensate leaks 
inside the cabinet.
Install condensate trap at each unit with the top of the trap 
positioned below the unit condensate drain connection as shown 
in Figure 6. Design the depth of the trap (water-seal) based 
upon the amount of ESP capability of the blower (where 2 inches 
[51mm] of ESP capability requires 2 inches [51mm] of trap depth). 
As a general rule, 1-1/2 inch [38mm] trap depth is the minimum.
Each unit must be installed with its own individual trap and 
connection to the condensate line (main) or riser. Provide a 
means to fl ush or blow out the condensate line. DO NOT install 
units with a common trap and/or vent.
Always vent the condensate line when dirt or air can collect in 
the line or a long horizontal drain line is required. Also vent when 
large units are working against higher external static pressure 
than other units connected to the same condensate main since 
this may cause poor drainage for all units on the line. WHEN A 
VENT IS INSTALLED IN THE DRAIN LINE, IT MUST BE LOCATED 
AFTER THE TRAP IN THE DIRECTION OF THE CONDENSATE 
FLOW.
 CAUTION! 
Duct System Installation
The duct system should be sized to handle the design airfl ow 
quietly. Refer to Figure 3 for horizontal duct system details or 
fi gure 8 for vertical duct system details. A fl exible connector is 
recommended for both discharge and return air duct connections 
on metal duct systems to eliminate the transfer of vibration to 
the duct system. To maximize sound attenuation of the unit 
blower, the supply and return plenums should include internal 
fi berglass duct liner or be constructed from ductboard for the 
fi rst few feet. Application of the unit to uninsulated ductwork 
in an unconditioned space is not recommended, as the unit’s 
performance will be adversely affected.
At least one 90° elbow should be included in the supply duct to 
reduce air noise. If air noise or excessive air fl ow is a problem, 
the blower speed can be changed. For airfl ow charts, consult 
specifi cations catalog for the series and model of the specifi c 
unit.
If the unit is connected to existing ductwork, a previous check 
should have been made to insure that the ductwork has the 
capacity to handle the airfl ow required for the unit. If ducting is 
too small, as in the replacement of a heating only system, larger 
ductwork should be installed. All existing ductwork should be 
checked for leaks and repaired as necessary.
DUCT SYSTEM INSTALLATION
C
ondensate Pipin
g
CAUTION! Ensure condensate line is pitched toward drain 
1/8 inch per ft [11mm per m] of run.










