Ac Unit Blowing Control Board - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 05-20-2013, 04:38 PM   #1
Member
 
Join Date: Aug 2012
Posts: 133
Rewards Points: 75
Default

Ac unit blowing control board


I started a thread over in hvac and they directed me over here .
control board shorted out ac
I have a luxaire ac residential single phase ac unit model f6fp0366t3xh . The control board in the attic where the blower is has blown out twice once last yr and then again Thursday morning we had a lightning storm . I'm not sure if low voltage like when lights dim or high voltage from lightning strike is blowing the boards out. I've looked at surge protectors and surge arresters neither looks full proof. The boards are still under warranty but i have to pay to get it installed or do it myself. Any ideas would be appreciated .

Advertisement

Kpack is offline   Reply With Quote
Old 05-20-2013, 09:18 PM   #2
Member
 
Join Date: Oct 2010
Location: Cairns Australia
Posts: 2,701
Rewards Points: 2,362
Default

Ac unit blowing control board


What part exacitly of the board is blowing ?
Most likely it is the over voltage protection device,
(varistor) they sit across the incoming mains supply,
under normal voltage conditions they do nothing.
But should the incoming mains voltage rise above
a certain value, then it becomes active and effectively
puts a short circuit across the incoming mains supply,
This should blow the fuse/breaker, thus removing the
dangerously high incoming mains voltage.
It's crude but effective mostly.
Putting a large spike divertor in your panel might help !

Advertisement

dmxtothemax is offline   Reply With Quote
The Following User Says Thank You to dmxtothemax For This Useful Post:
Kpack (05-20-2013)
Old 05-21-2013, 03:46 PM   #3
Member
 
Join Date: Aug 2012
Posts: 133
Rewards Points: 75
Default

Ac unit blowing control board


Ok I went to the local electrical supply dealers is the name they gave me these numbers.
Delta la302
Delta ca302r
http://www.deltala.com/prod01.htm
http://www.deltala.com/prod02.htm
This is looking like a hard topic . Do y'all think I'm throwing money away or would I get some protection. Thanks
Kpack is offline   Reply With Quote
Old 05-21-2013, 06:47 PM   #4
Member
 
Join Date: Mar 2007
Location: Eighty Four, Pa.15330
Posts: 1,398
Rewards Points: 794
Default

Ac unit blowing control board


Have a surge suppressor installed at your main panel. Have the grounding and bonding verified. Low voltage can fail if a lightening strike occurs nearby your house.
bobelectric is online now   Reply With Quote
The Following User Says Thank You to bobelectric For This Useful Post:
Kpack (05-21-2013)
Old 05-22-2013, 08:01 PM   #5
Member
 
Join Date: Aug 2009
Posts: 77
Rewards Points: 75
Default

Ac unit blowing control board


Quote:
Originally Posted by Kpack View Post
This is looking like a hard topic . Do y'all think I'm throwing money away or would I get some protection.
The topic is based in concepts even taught in primary school science. Start with what Franklin demonstrated.

A surge (ie lightning) seeks earth ground. The better path to earth was a more conductive wooden church steeple. But a steeple is not that conductive. So a 20,000 amp transient created a high voltage in wood. A high voltage times 20,000 amps is high energy. Church steeple damaged.

Franklin installed lightning rods. The rod does not do protection. But the rod connects lightning on a better path to earth that was more conductive. 20,000 amp transient created a near zero voltage connection via wire and earth ground electrode. Near zero voltage times 20,000 amps is near zero energy. Nothing damaged.

A surge on AC electric wires seeks earth ground. A better path to earth was household appliances. But appliances are not that conductive. So an AC electric surge current created a high voltage in appliances. A high voltage times that surge current is high energy destructively inside appliances. Appliance damaged.

For over 100 years, the informed installed a 'whole house' protector. The protector does not do protection. That protector connects a surge (ie lightning) on a better path to earth that was more conductive. 20,000 amp transient (from AC wires far down the street) creates a near zero voltage connection to earth. Near zero voltage times 20,000 amps is near zero energy. No appliances damaged.

Protection of the structure is an earthed lightning rod. Protection of appliances inside that building is earthed utility wires (ie via a 'whole house' protector).

In your case, lightning may be finding earth ground destructively via the controller. Once permitted inside, a surge will find some or many connections to earth destructively via appliances. Protection is always about earthing that transient BEFORE it can enter the building. As was demonstrated originally by Franklin in 1752. And was standard protection even 100 years ago in any facility that could not have damage.

Those Deltala devices are one example. They don't do protection. Each has a ground wire to connect to what does protection - the earth ground electrode. However, the 'whole house' protector typically is 50,000 amps or larger. Because lightning can be 20,000 amps. Effective protectors remain functional even after a direct lightning strike.

And finally, the most important component is the earthing electrode (not a protector). A wire from protector to earth must be low impedance (ie 'less than 3 meters'), must have no sharp bends, must be separated from other non-grounding wires, no splices, not inside metallic conduit, etc. And it also must meet human safety code requirements.

That earthing electrode (and connection to it) are the art of protection. A protector is simple science based in what Franklin did well over 250 years ago. Defined by concepts originally taught in primary school science.

Last edited by westom; 05-22-2013 at 08:05 PM.
westom is offline   Reply With Quote
The Following User Says Thank You to westom For This Useful Post:
Kpack (05-22-2013)
Old 05-23-2013, 12:06 AM   #6
Member
 
Join Date: Oct 2010
Location: Cairns Australia
Posts: 2,701
Rewards Points: 2,362
Default

Ac unit blowing control board


Lightning doesn't have to strike the power lines directly,
If it strikes even nearby the imense electro magnetic field
generated can induce voltages in any nearby wiring.
Even if it is NOT plugged in.
This is why some equipment conectted to surge arrestors
can still be damaged,
But surge arrestors DO reduce the damage.

Last edited by dmxtothemax; 05-23-2013 at 01:41 AM.
dmxtothemax is offline   Reply With Quote
Old 05-23-2013, 12:28 AM   #7
Member
 
Join Date: Aug 2009
Posts: 77
Rewards Points: 75
Default

Ac unit blowing control board


Quote:
Originally Posted by dmxtothemax View Post
If it strikes even nearby the imense electro magnetic field generated can induce voltages in any nearby wiring. Even if it is NOT plugged in.
If lightning strikes nearby, then every automobile radio, computer, cell phone, calculator, and wrist watch is damaged? Of course not.

Lightning struck a lightning rod. That maybe 20,000 amps flowed to earth on a wire only four feet away from an IBM PC. The PC (and everything else in the office) did not even blink. Where is destructive EMF when 20,000 amps was only four feet away?

Well, lightning struck nearby a long wire antenna. An antenna maximizes the EMF effect. So the antenna lead saw maybe thousands of volts. Then an NE-2 neon glow lamp (what is also in lighted wall switches) wsa put on that antenna lead. Less than 1 milliamp through that tiny lamp caused thousands of volts to drop to ten.

EMF can create high voltages when no current flows. A tiniest current causes an EMF generated voltage to become near zero. EMF is tiny power. Protection already inside every appliance makes EMF irrelevant. Even a neon glow lamp is sufficient protection.

To be damaged, an AC controller must have a current incoming via some conductor. And another outgoing path to earth via some other conductor. The conductor need not be a wire. Only with both paths does a transient dissipate potentially destructive energy inside electronics.

Protectors too close to an appliance and too far from earth ground can sometimes even make damage easier. An effective protector connects low impedance (ie 'less than 10 feet') to single point earth ground. As described previously, protection is always about the current path. Voltage exists when something foolishly tries to stop or absorb a surge current.

Protection is always about how that current flows to earth. An appliance need not be plugged in to be in that path. For the same reason a wooden church steeple also conducts that current.

Last edited by westom; 05-23-2013 at 12:38 AM.
westom is offline   Reply With Quote
Old 05-23-2013, 01:40 AM   #8
Member
 
Join Date: Oct 2010
Location: Cairns Australia
Posts: 2,701
Rewards Points: 2,362
Default

Ac unit blowing control board


[QUOTE=westom;1185418]If lightning strikes nearby, then every automobile radio, computer, cell phone, calculator, and wrist watch is damaged? Of course not.

I never said everything would be damaged !
What I said was the electromagnetic field from lightning strikes
can induce voltages in nearby wiring !
Weather it is damaged or not depends on many variables.
I think it is fair to say that most things nearby would feel this EMF
and most things handle it pretty well.
But I have seen many electronic devices fried even thou they were
unplugged.
And the reason why is as I stated.
dmxtothemax is offline   Reply With Quote
Old 05-23-2013, 08:31 AM   #9
Member
 
Join Date: Aug 2012
Posts: 133
Rewards Points: 75
Default

Ac unit blowing control board


Tuesday night we had another storm so I cut the ac unit off . While we were watching tv electricity went off for about ten seconds then it came back on. If the ac would have been on and running at that time maybe that's how its getting damaged .
Kpack is offline   Reply With Quote
Old 05-23-2013, 11:26 AM   #10
Member
 
Join Date: Aug 2009
Posts: 77
Rewards Points: 75
Default

Ac unit blowing control board


Quote:
Originally Posted by Kpack View Post
While we were watching tv electricity went off for about ten seconds then it came back on. If the ac would have been on and running at that time maybe that's how its getting damaged .
Electronics must never be damaged by power loss. That was even defined by international design standards almost 50 years ago. Long before the PCs even existed. Designing for no damage is quite simple and standard.

Air conditioners dislike quick power cycles. Its controller has many functions including delaying an air conditioner restart for a period defined by the manufacturer.

Low voltage also does not harm any electronics. But low voltage can be harmful to motorized appliances. So utility equipment provides sufficient voltage. Or cuts off power when voltage cannot be maintained. To protect less robust motors. AC controller would also implement similar protection of the motor.

A blackout would not cause damage. However a surge can precede and cause that blackout.

Advertisement


Last edited by westom; 05-23-2013 at 11:30 AM.
westom is offline   Reply With Quote
The Following User Says Thank You to westom For This Useful Post:
Kpack (05-23-2013)
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New Roof but Fascia Trim Board Rotting ein0801 Roofing/Siding 6 07-15-2012 01:21 AM
Trane XL-80 Control Board got wet.... brandnewrock8 HVAC 10 07-11-2012 04:47 PM
New control board or fix it? Bobeht HVAC 26 01-18-2012 04:03 PM
How do you ground York furnance control board garryshaf HVAC 11 01-24-2010 01:06 PM
Water Heater Control unit makes noise then shut off... RyanD HVAC 2 12-23-2009 11:46 PM




Top of Page | View New Posts