HVAC Equipment Causing Surges

[mikev86]

Hello all,

We recently had a new 480V panel installed to serve some sensitive automotive equipment and a new 10-ton packaged HVAC unit.

Prior to HVAC unit being installed, SPD counter was at 3. Since HVAC unit was installed we have been getting an average of 4 hits/day.

There are no VFDs present and the HVAC unit is not cycling on and off frequently. We have checked for damaged wires and loose connections, even had Trane come out to investigate their unit and found nothing. That being said, when we turned off the disconnect, the surges stopped.

We are looking at moving the HVAC unit to another panel to not have it on the same source as the sensitive equipment, but have concerns the surges will still happen and the other existing 480V panels do not have any surge protective devices.

Looking for recommendations on what else to check and troubleshoot.

Thank you!
Mike

 

[ron]

When the surge counter activates is not regulated. It is often a marketing scheme for the SPD vendor to make it seem as though the SPD is working hard and to encourage early replacement.
Put a Power Quality Meter to see if there are real surges being seen and to what magnitude.

 

[Deltaforce]

It better engage PQ analysis specialist do the job

 

[retirede]

Is your “sensitive equipment” exhibiting signs of distress from the purported surges? If not, do you really have an issue?

 

[Deltaforce]

Is your “sensitive equipment” exhibiting signs of distress from the purported surges? If not, do you really have an issue?

But they may with individual surge protection usual

 

[retirede]

But they may with individual surge protection usual

Huh?

 

[Jraef]

Do you now anything about the HVAC equipment? For example, if they are using a Wye-Delta starter on a compressor, that will cause significant spikes on the line when it transitions.

 

[mikev86]

Do you now anything about the HVAC equipment? For example, if they are using a Wye-Delta starter on a compressor, that will cause significant spikes on the line when it transitions.

We didn't open up the HVAC equipment, but did just confirm the surge counter goes up when the compressor kicks on. Voltages all checked out:
278v- A phase to neutral
280v- B phase to neutral
282v- C phase to neutral

278v- A phase to ground
280v- B phase to ground
282v- C phase to ground

484v- A phase to B phase
485v- A phase to C phase
487v- B phase to C phase

Turned down the thermostat so the AC kicked on. SPD light didn't turn red and alarm didn't go off, but counter went up.

 

[Jraef]

I’m betting it has a Wye-Delta starter on it and the surge counter is detecting the transition spike. I’ve seen it before.

 

[ron]

Turned down the thermostat so the AC kicked on. SPD light didn't turn red and alarm didn't go off, but counter went up.

On many SPDs, the light / alarm doesn't change state unless a MOV fails.

 

[mikev86]

On many SPDs, the light / alarm doesn't change state unless a MOV fails.

Thank you, good to know! I was also asked about when we would know we have to replace the SPD. My understanding is when those indicator lights turn red because of a failure. I haven't personally seen a SPD go bad under normal conditions.