Surge/Spike Protectors


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Old 04-29-19, 05:38 PM
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Surge/Spike Protectors

Several years ago, I installed a Supco SCM-150 surge protector on the disconnect box to my heat pump compressor as instructed by the supplied literature. Since then, these have been recalled because they are catching on fire.

I did register mine when I installed it and a couple of weeks ago, I got a letter from the manufacturer stating they have been recalled and that they were willing to send me another design/replacement. (LBK10)

Several confusing instructions that came in the manual.
1. Do not install this at the disconnect box. (opposite of the original item)
2. Install it less than 3 "wire feet length" from the device to be protected
3. For compressors, it must be installed within the cabinet.

My limited knowledge of SP's and how they work is that they "clamp" surges/spikes thur the green/white/copper ground stake. The manufacturer believes that instances where they failed are due to improper connections to the ground wire.

The replacement SP has a large contactor in the middle of the circuit board and the literature for it states that it removes power to the device when there is a surge/spike to protect it.. IMHO any surge/spike has already passed thru the contactor before it could react?

Appreciate any insight/opinions on this. Tx Mike
 
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Old 04-29-19, 05:58 PM
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Looks like the relay (contactor) is only to cut the 24vac to the compressor's contractor and to trigger a remote alarm.
 
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Old 04-29-19, 09:24 PM
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Yes..... I've seen that.... a problem with a ground connection. Baloney. Those suppressors use MOV's that were either too small or fail gloriously. This problem has been kicking around for a few years.

The new style.... removing the 24v power.... is probably the next best step.
Really.... these A/C units should already be protected from surges.

LBK10 surge protector
 
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Old 04-30-19, 05:39 AM
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There are new regs about to hit that will require thermally protected MOV's. I'm starting to use these in my new designs. They cost a bit more, but have a built-in thermal fuse that opens when the MOV overheats.
 
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Old 04-30-19, 07:16 PM
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Great feedback. Three instructions from them:

The LBK10 features an All Weatherproof Type 4X Enclosure, allowing it to be mounted outside of the condensing unit.

For air conditioner installations, the LBK10 is intended to be connected at the condenser.

Always keep the protector at least 3 linear feet (wire length) from the device that is to be protected. This allows proper response time for the protector to do its job before the transient power surge reaches the protected equipment.

Might have to have a few "brewski's" to get this straight. Tx Mike
 
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Old 04-30-19, 08:08 PM
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Three linear feet before the protected equipment wouldn't be at the condenser........ it would be at the disconnect.
 
 

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