Viking T-21 Manuals & Support

The Viking T-21 is a 1 HP, 24 VDC swing gate operator for residential and commercial gates up to 12 ft and 2,000 lb, or 20 ft and 1,200 lb. It runs on the VFlex control board with soft start and soft stop.

It has a thermostat-controlled heater, a quick release handle, a 1/4 in steel chassis and two 7 Ah backup batteries for up to 400 cycles during an outage.

Identify your model

The model is on the label inside the cover. Units built from 2013 on use the VFlex control board with an LCD display. Check the logo color on the board: black logo boards are 2013 to 2016, green logo boards are 2016 to 2018 and orange logo boards are 2018 and later.

First generation units (2009 to 2012) use an older control board and some different parts. Use the first generation manual below for those units.

Key specs

Max gate	2,000 lb / 1,200 lb / 12 ft / 20 ft
UL 325 usage class	Class I, II, III and IV
Motor	1 HP, 24 VDC
Duty cycle	100%
Operating voltage	24 VDC
Main power	115 VAC or 240 VAC single phase, 3.0 A / 1.5 A
Alternative power	24 VAC/VDC (60 VA) or solar
Accessory power	24 VDC, 750 mA
Motor current, typical	5.0 A
Battery backup	Two 12 V, 7 Ah batteries included
Operating temperature	-20 to 160 °F
Open time	13 to 16 seconds per 90°

Manuals and documents

Troubleshooting

Press the Diagnose button to scroll the LCD. Error messages show first, and the Diagnose LED flashes once for each error.

ERR SENS UL or ERR SENS RO

A monitored sensor on the UL or Re-Open input is missing, faulted or not learned.
Check the 10K sensor wiring at the UL and Re-Open terminals.
Relearn: press Diagnose until UL LEARN shows, hold Stop and tap Diagnose once. The display shows how many sensors it found.

Gate stops: STOP BY OBSTRUCT or STOP BY OVERLOAD

Release the operator and check that the gate moves freely by hand.
Check the ODS (obstruction) sensitivity setting.
ERR FUSE means the motor fuse is blown. Replace it with the same rating.

Power errors

ERR AC LOW, HIGH or NO AC: check the 115 VAC or 240 VAC supply and the power supply panel.
ERR EMI NO FUSE: the 4 A main fuse on the power supply panel is blown.
ERR BAT LOW or the Battery Low LED: check the batteries and the 4 A charging fuse. Charge voltage should read 26 to 28 VDC.

Limits and alarm

A flashing Open Limit or Close Limit LED means that limit was erased. Set the limits again.
A solid Siren LED means a second obstruction in a row. Clear it and press the Alarm Reset button.

Common questions

A swing gate needs at least one monitored 10K sensor on the UL or Re-Open input. If there is an entrapment zone in the open direction, a sensor must be on UL. Wire them, then run the UL LEARN process from the Diagnose button.

Use the quick release handle on the operator to free the arm. Lock the handle again before you run the operator.

It uses two 12 V, 7 Ah batteries (Viking DUBA12 or Yuasa NP7-12). A full charge reads about 26 VDC across both batteries. Check terminals for corrosion when you service the operator.

The alarm sounds after a second obstruction in a row. Remove the obstruction and press the Alarm Reset button on the operator.

Check the logo color on the VFlex board. Black logo boards are 2013 to 2016, green logo boards are 2016 to 2018 and orange logo boards are 2018 and later. Order the board that matches your logo color or the current orange logo board.

Identify your model

Key specs

Manuals and documents

Installation Manual

Parts List

Spec Sheet