Service alert summary
Repeat duct static pressure trips due to duct static pressure readings below -0.1"wc
Known Diagnostics or Symptoms
If Duct Static Pressure Local (AI-10155) drops below -0.10", the unit will locks out the operation of the indoor fan until reset. This is the correct operation of the point and it hard coded into Symbio 700, alarming values and limits will not change this. Negative values can be caused by building pressurization issues when the unit is off or when fan powered VAV boxes operate in unoccupied heating mode and potentially pull a negative pressure on the supply ductwork.
Actions that can be taken now
UPDATE: Symbio 700 v7.02.0020 released on 4/22/2025
This firmware for the Symbio 700 disregard sensor out of range issues during off times. Symbio will still enforce these limits and alarms when the fan has been on for 10 seconds.
UPDATE: Symbio 700 v7.03.0017 released in Sept 2025
Further improvements were made to delay alarming for 40 seconds to resolve issues seen on Voyager III where the duct static may not show in a valid range in the 10 second time frame in v7.02 firmware.
For information on how to update Firmware see: Symbio™ 700 - Firmware Update for Unit Controller Module
Is there a related published service bulletin for this issue
At this time, we do not expect any bulletin will be published.
Are WMS (Warranty Management System) claims allowed for this issue?
Yes
Does this service alert indicate a final resolution?
Yes, update firmware to the latest version
Internal Admin use / Info only
Zendesk Problem Ticket #2690740
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