When the door goes back up on its own
The door starts down, touches nothing you can see, and rises again. Dominator says its openers detect when a door strikes something, then stop and reverse, so the opener may be doing its job and reacting to a real change.
That change can be a stone on the floor, a sensor knocked out of line, a track that has moved, or a door that has become harder to shift. On a gusty day it can be wind: Dominator's manual says very strong gusts can trigger the sensing part way through travel, which fits a city with 52 days a year of gusts over 61 km/h.
Two tests to try before you send the job
The block on the floor
B&D NZ says to run its safety test monthly. Put a piece of timber about 40mm high on the floor under the door and close it. The door should hit the timber and re-open.
The broom at the sensors
If you have safety beams, Dominator suggests waving something like a broom in front of them as the door closes. It should stop and reverse straight away.
If either test fails
B&D NZ's words are: "If the door is closing and is unable to re-open when obstructed, discontinue use." Stop using the door, keep people clear of it, and send the job.
A door out of balance
An opener is only meant to stand in for your own muscle, as Dominator puts it. When a door is out of balance the motor strains, and the fault can look like an opener problem. B&D NZ gives 20kg as the limit for moving a sectional door by hand and 15kg for a roller door.
Beams are part of the same picture. B&D NZ says they must be installed if the closing force at the bottom edge of the door exceeds 400N, or about 40kg, and Dominator's manual puts the beam 100mm above the ground.
Repairs around Christchurch
January breezes
NIWA has wind at Christchurch Airport peaking in January at 17.3 km/h, so an opener that only misbehaves in summer may be reacting to wind on the door.
Lyttelton and the coast
Exposure Zone D reaches 500 m from the sea and from harbours, as MBIE quotes NZS 3604, so check fixings and cables more often in Lyttelton and beach suburbs.
Rolleston and the plains
Add your postcode to the job and it reaches door businesses working in your area, inside the city boundary or out on the plains.
Yours to do, and what to leave
You can
- Clear the floor under the door and anything near the sensors
- Run the monthly timber test
- Check that the sensors have not been knocked out of line by a bike or bin
- Note when the fault happens: time of day, weather, door opening or closing
Leave to a door specialist
- Any spring, cable, drum or bracket
- Force and travel settings on the opener
- A door that fails the timber test
- Bent tracks or a door sitting crooked
What we would do
Write down when it happens before you send the job. A door that only reverses on windy afternoons points somewhere different from one that does it every time, and two lines in the message can save the door specialist a wasted first visit.