RT-SVD03G-EN 11 7
ReliaTel Supply Air Tempering Control
Supply air tempering maintains the supply air temperature above a lower limit during minimum
ventilation periods when in heat mode on a CV unit and during inactive cool mode on a VAV unit.
Supply air tempering is available when using a BAYSENS019*/AYSTAT666* Programmable Zone
Sensor, BAYSENS006-11/AYSTAT661-664 Mechanical Zone Sensor, or Trane ICS system.
The unit requires an RTOM (options module) and BAYTUBE discharge air sensing kit. Supply air
tempering will not work with a conventional thermostat.
Enable Supply Air Tempering
Mechanical Zone Sensor BAYSENS006-11/AYSTAT661-664: remove the jumper from RTOM
J3-1 and J3-2.
Programmable Zone Sensor BAYSENS019*/AYSTAT666*: change Option 4 in the options
menu to 1=enabled. Or, remove the jumper from RTOM J3-1 and J3-2.
COMM 3/4 (TCI): Enable through appropriate menu. Supply air tempering can also be enabled
by removing the jumper from RTOM J3-1 and J3-2.
LonTalk (LCI): Enable through nciPersonality2. This function may not be available with some 3rd
party systems. Supply air tempering can also be enabled by removing the jumper from RTOM J3-
1 and J3-2.
Voyager 27.5-50 ton VAV with Staged Heat: Supply air tempering is not available. The
RTOM J3-1 and J3-2 jumper is ignored.
Sequence of Operation
Constant Volume Units with Staged Heat
When Supply Air Tempering is enabled, the fan mode is on, active mode is Heat or Emergency Heat,
and with the unit not actively heating. Stage 1 of heat is turned ON when the supply air temperature
is 10°F below the Active Heating Setpoint.
Stage 1 of heat is turned OFF when the supply air temperature is 10°F above the Active Heating
Setpoint or the Mode is no longer Heat or Emergency Heat. Should the zone temperature exceed
the Active Heating Setpoint by 1-2F, Supply Air Tempering will cease until another normal heating
cycle resumes.
For heat pump units, the auxiliary heat is used for tempering.
Note: Tempering on CV units with Modulating Heat is inherent to the modulating heat control
design.
Variable Air Volume Units
For VAV units configured with a modulating heat type if the unit is operating in Occupied Supply
Air Cooling mode, but the unit is not actively cooling, the unit will energize and modulate the Mod.
Heat output to prevent the Supply Air from falling below the SA Cool Setpoint deadband low end
(SACSP – 3.5°F) once the unit has de-energized all mechanical cooling (if energized). Upon
satisfying the SA Tempering requirements a five-minute ‘SA Tempering Delay’ timer will start
whenever the modulating heat is commanded to 0%. This timer will be reset to 5 minutes whenever
there is an active call for heat to meet SA Tempering demands.
Tempering will be discontinued whenever:
1. The five-minute ‘SA Tempering Delay’ timer has timed-out
and
2. There is an active cooling request from the VAV Occupied Mechanical Cooling function.
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