Nailor 35SW - Reheat Sequence

IOM-EZVAVINST
Date: 10-2016 Supersedes: 7-2016
Nailor reserves the right to change any information concerning product or specification without notice or obligation.
Page 39 of 48
Installation and Operation Manual
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EZvav Digital Controls
ReheatSequence
The EZvav controllers can control three types of reheat installaons.
• Modulang reheat
• Staged reheat
• Floang reheat
All reheat is controlled by either the Heang loop or the Discharge Air Temp Liming (DAT) PID loop. Loops are described in the
topic PID control loops on page 36.
• If Discharge Air Temp Liming is enabled, reheat is controlled by the DAT PID loop.
• If DAT control is not enabled, reheat is controlled by the Heang loop.
In the following descripons, the loop controlling reheat is referred to as the Reheat loop.
Modulangreheat
If the controller is congured for modulang reheat, it controls an analog reheat unit with 0-10 volts DC at the analog reheat
output. On a call for reheat, the reheat output is modulated over the span of the Reheat loop. If the Reheat loop is less than 10%,
the reheat output remains at zero. The reheat is set to zero if the Cooling loop is acve.
See the topic Modulang reheat on page 31 for an applicaon drawing.
Figure8-4 Modulangreheatoperaon
Stagedreheat
If the controller is congured for staged reheat, it can control up to three stages of reheat through binary triac outputs. The reheat
outputs are commanded On when the Reheat loop rises above the On threshold and O when the loop drops below the O
threshold. Thresholds are described in the following chart, Staged reheat thresholds on page 39.
See the topic Staged reheat on page 30 for an applicaon drawing.
Table8–1 Stagedreheatthresholds
HeangStage
OutputState
Onthreshold Othreshold
Stage 1 35% 15%
Stage 2 65% 45%
Stage 3 95% 75%
Room temp increase
HTG SP-2F
HTG SPAN
loop %
0
100
10
HTG %
Reheat