Robertshaw SlimZone PREMIER ZONE CONTROL SYSTEM - Manual (Page 7)

4 SlimZone Premier
3.3 ENVIRONMENTAL MODULE
ITEM QUANTITY CONSIDERATIONS
SZEM environmental module one (1) contains two (2) remote temperature
probes, and PVC tubing for static
pressure
use standard nonshielded 2
conductor 18-24 AWG copper wire
to connect to SZP
Motorized bypass damper one (1) - may require two (2) use standard nonshielded 3
in larger systems
conductor 18AWG copper wire
24VAC transformer one (1) 20VA (300mA)
Table 3.3: SlimZone Environmental Module Components
3.4 SIZING TRANSFORMERS
To avoid unsatisfactory operation DO NOT power the SZP control module with the HVAC
equipment transformer. A dedicated field supplied 24VAC, 75VA transformer is recommended
to power the control module, which in turn may have up to nineteen (19) zones connected to
it. Zone dampers require separate transformers.
Zone dampers may be powered by individual zone transformers or by a single transformer. A
single transformer used to power more than one damper must have a sufficient power rating
(VA) to energize all dampers. To determine the total power requirements, add each damper’s
VA rating. Typical dampers require a maximum of 12VA each. This total must not exceed the
VA rating of the transformer.
3.5 SIZING DAMPERS
It is important that dampers be sized according to system ductwork specification (CFM) and
balanced in compliance to SMACNA, ACCA and ASHRAE guidelines in order for the control
system to properly control comfort in each zone. Typical dampers are nonmodulating and are
available in two (2) wire (powered closed, spring return to open), or three (3) wire (powered
closed, powered open) configuration. The pressure drop across Enerstat dampers is negligible
and normally not a factor when sizing or calculating branch duct CFM. Typical dampers are
designed to work with low pressure systems (1.0" WC) or less.
3.6 TYPICAL SYSTEM DIAGRAM
Figure 3.1 illustrates a typical SlimZone Premier installation, including the optional
environmental module (SZEM) and its accessories.