Titus ZECV User Manual

Installation Manual

Installation, Operation & Maintenance of the ZECV

Analog Pressure Controller

General Description

When applying Zcom diusers in an changeover/
bypass application with a constant volume rooftop
unit, provisions must be made to control duct static
pressure. The duct static pressure is typically
controlled by a system bypass damper installed o
of the supply duct, and controlled from a static
pressure tap installed 2/3 down the main duct.

Figure 2 illustrates a re commended installation of
the bypass damper to maximize mixing of the
bypass air with the return air. This location of the
bypass minimizes the opportunity for developing
hot or cold spots in the rooftop.
Installation Instructions

ZECV-IOM-1.0 3-1-03

Figure 1. ZECV

These instructions are intended only as a basic
guide for the installer. They do not assure
compliance with local codes. Consult the
authorities having jurisdic tion be
terminal.

fore installing this

Receiving Inspection

After unpacking the pressure controller, check it for
shipping damage. If any shipping damage is found,
report it immediately to the delivering carrier.

Supporting the Terminal

The basic control is light enough so that it can be
supported by the duct work in which it is installed.
Where the accessory modules such as coils,
attenuators or multiple outlets are included, the
assembly should be supported directly. Use the
support method prescribed for rectangular duct in
the job specications.

Duct Connections

Slip the inlet duct over the inlet collar.
The diameter of the inlet duct in inches must be
equal to the listed size if the terminal: e.g., a duct
that actually measures 8 in ches must be tted to a
size 8 terminal. Attach the
by using standard SMACNA slip and drive
connection method. Fasten and seal all
connections by the method prescribed by the job
specications.

rectangular outlet duct

Figure 2.

Static

Pressure

Tap

Bypass

Air

Constant Volume Rooftop Unit

Supply

Air

ZECV

Return

Air

Zcom

ZECV-IOM-2.0 3-1-03

Field Wiring Instructions

Inspection

Factory mounted controls and accessories are mounted
inside the sheet metal enclosure located on the side of
the terminal. Remove the cover and inspect all
components for visual damage.

Power and Supply

Analog electronic controls require 24 VAC -15/+20
percent power supply. Allow 14 VA for the controller.
Factory supplied transformers are available with supply
voltages of 277V, 240V, 208V, or 120V. Field supplied
transformers can be mounted inside the control box.
Attach the 24 volt leads to terminals 9 and 10 on the
controller (See Figure 3).

Single Transformer Wiring

The same 24 VAC transformer may be used to power
the controller plus control relays, contractors and/or
valves on a terminal. For single transformer wiring see
figure 3.

Multiple Loop Wiring

If multiple controllers are looped together in a single
circuit using a common transformer, wire all #9
connections together, and all #10 connections together.
If the transformer secondary is connected to earth
ground, this lead must also be connected to terminal #9.
ALWAYS OBSERVE PHASING!

CAUTION: NEVER connect power to the controls until
all wiring has been installed. ALWAYS disconnect power
to the controls before servicing the unit controls or
accessories. DO NOT connect line voltage to the
controller or other unit components.

Balancing

The following guidelines are recommended when
balancing a constant volume rooftop unit and Zcom
diffuser system.

1. Adjust rooftop to supply cooling or heating during
the balance. The Zcom diffuser has three modes of
operation; cooling, heating and ventilation. If the
supply air temperature is between the heating and
cooling setpoints, the Zcom will operate in the
ventilation mode and go to the ventilation damper
position of 50% closed. Therefore, to properly
balance the system, the rooftop unit must be in either
cooling or heating.

2. Drive the Zcom diffusers fully open with the
Zapper, shown on the Zapper as “CL Open” or “HT
Open” (CL for cooling mode and HT for heating
mode), or power down all Zcom diffusers which will
return the Zcom’s to the fully open position.

3. Balance each diffuser for the required design air
flow.

The next steps apply to balancing the bypass damper to
maintain duct static pressure.

1. Command all Zcom diffusers to the minimum
position except one Zcom master, which is to remain
fully open. The Zapper is used to command the Zcom
to the minimum position by pushing the down arrow
selector button until “CL Close” or “HT Close” (CL for
cooling mode and HT for heating mode) is displayed
on the Zapper.

2. Set the bypass damper by adjusting the ZECV
constant volume module to the desired static
pressure as measured at the static pressure tap
installed 2/3 down the main duct. The TITUS ZECV
has a time delay of approximately five minutes before
reacting to any adjustment.

NOTES:

Consult local codes for specific types of wires and
enclosures required for low voltage wiring.
Troubleshooting information is found on page.

All wiring diagrams shown in this manual show single
transformer wiring.