Marantec M50 will not close


Old 02-10-16, 10:15 PM
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Join Date: Feb 2016
Location: USA
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Marantec M50 will not close

I have a 3 year old Marantec M50 that will open but will not close when cold outside. I did determine that it is either the door photo sensors or in internal RPM sensor. This has just started to happen with the winter cold. Here is what is happening. Door opens fine and will close right away. I look at the LED's and Led #8(power) and led #2(OPEN door position) are the are the only ones solid red. after about 10 minutes in the cold with the door up LED #1 (photo eye sensor) starts to flash or blink, it looks like an LED when it is about to go out. After about 5 minutes it will go solid red. This is when the door will not close. The sensor lights (at the sensor itself) are solid green and red, indicating that there is no obstruction. (they flash when something obstructs the path) So they are working fine. Door will NOT go down. I manually let the door down and after 5 minutes of the door down, everything works again.
I look up at LED #1 and it is off. When I obstruct the path I can see the LED #1 go solid and the lights on the sensors flash. When I take away the obstruction the LED#1 goes dark again and the sensor lights quit flashing.
When the door is open in the cold winter air, Led #1 will go from dark to flashing to solid red (thus not allowing the door to close) but the lights on the sensor lights NEVER flash to indicate and obstruction.
What can I do to determine the problem??
can I look for a short or an open at the opener connections where the sensor lights connect??
This only started yesterday when it is cold 22 degrees
I thought that it may be condensation on the photo eye sensors, but the sensor never flash to indicate an obstruction
Old 02-11-16, 08:16 AM
Join Date: May 2015
Location: USA
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Will the door close if you press and hold the down button?

Try taking a hair dryer and gently warming the sensors...If that doesn't change anything, try gently warming the control board in the opener.
Old 02-14-16, 07:15 AM
Join Date: Sep 2006
Location: Indiana
Posts: 133
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You are not describing a M50.
You probably have a 4500, or a 4700. they have the 8 leds. The M50 has a display on the back.
The 4500, and 4700, had a board problem that would cause the problem you describe when it is real cold. The good news is if you are the original owner the parts are in warranty. Contact the people you bought it from or Marantec. They are very good about standing behind their warranty.

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