Zebra Instruments, # VZPRO ECM Motor Protector Surge Protection for 120-240V GE & GENTEQ 5-PIN ECM Motors

I bought this as a preventative measure and had it installed by my husband in minutes. It was recommend by our HVAC repair company. Quick and pretty easy to install. No issues and happy to have the extra prevention on the furnace

So a variety of factors conspired to knock out my ECM air conditioner blower motor during the miserable wretched pit-of-hell Texas summer a few months ago. I had some vents closed (as I found out later, this increases static pressure which is bad for the motor), and also the power went out during a storm while the motor was running. What can happen in that situation is that as the voltage drops in a power outage, the motor starts drawing in more current to make up for the smaller voltage. The additional current can then fry the electronics in the motor control unit. The motors themselves are almost indestructible, but the electronics that control them, on the other hand.... not so much. And of course you (normally) can't just buy the control unit, but have to buy a whole new $700-$1000+ ECM motor (and if you're not installing it yourself, add the service fees). Unless you get lucky and the 'thermistor' (sort of a built-in surge protector inside the control unit) on the power board burned out before the rest of the electronics got harmed. This a couple-dollar part and easy to solder in a new one on the upper, exposed power board. In my case, unfortunately, the thermistors were intact but a fusible trace was burned out on the power board. The only times I read about this failure it was associated with one of the microchips on the control board failing into a short. And the control board is potted in a thick black goo so you can't even see if something burned out on it or not (and I wouldn't have been able to replace those types of components myself anyway). At that point I decided to go ahead and just replace the motor. New was $700, but I got a used one off ebay for $230. Installed it and had AC again. However, I obviously would like to keep this from happening again. And as I found out while trying to diagnose + fix this problem, the ECM motors are exposed to line voltage all the time the breaker is on-- unlike the outside compressor unit that has a relay that turns the power supply on and off. This means the ECM motor electronics are exposed to whatever surges or problems that occur in your electricity supply whether the motor is on or off. And then you have the power-failure-while-motor-is-running issue. All this being said, the motor had worked flawlessly for 14 years. So it might have been bad luck or whatever. But I heard about this device and figured if it does what it's supposed to $30 is very cheap insurance (compared to $1000 for a new motor!). It seems to just be some thermistors like the ones inside the control unit, but since you install it in-line before the motor, this device will take the hit first, sacrificing itself to protect your motor electronics. Also, when there's thunder outside I turn off the breaker to the AC unit.

The picture on the web site is inaccurate, the item I installed on the ECM works fine and hopefully will do its job if/when needed

east to install. red light indicates protection is working. gives added level of surge protection.

Won't know if they actually protect it until I get hit by a monstrous surge or lightning. But at >$1000 just for the circuit board, IF I REPLACE IT, I decided it was worth the insurance.

Living in Florida, I have had a lot of problems with lightning destroying electronics, including one of my air handler ECM motors which are very expensive to replace. As a result of my misfortunes, I installed two whole-house surge protectors, two ZPROs, and point-of-use surge protectors on all electronics, including the refrigerator and washing machine. In mid-January when there was no atmospheric electrical activity, both VZPROs failed within a few hours of each other, with no visual signs of damage. In addition, the output relays of two new thermostats fried as well, so I had to replace all four components. No other electronics failed and the two whole-house surge protector indicator lights are still green. I wrote to Zebra Instruments and received no response.

I won't know if this works for years to come. If it prevents another motor controller from going bad, it will be worth the expense. However, this item is horribly overpriced. All it is is a couple of connectors, some wire, and everyday components. Probably about $7 to mass produce--but that's not what you're paying for. The idea is to protect the motor and controller in your AC. Will update someday.

Plug and play.HVAC Tech recomended I get one. Installed it myself at 1/3 his cost. Had furnace inspected since then working great. Insurance against possible expensive repair.