Trane CVHF AFD arc

[MikeVDS]

After punching the tubes one of our chillers had a high temp AFD alarm. The alarm was reset and did not return. The chiller was run as normal, with no alarms for about 10 minutes before an arc jumped from two of the phases to the box and shut down the chillers. No fuses were blown but two of the main breakers were tripped.

After a little inspection it was found that the system that circulated the water cooling the AFD / bus bar was plugged and likely the main cause of the overheating. It seems that punching the tubes just before was probably just a coincidence. We have since fixed the circulating system.

Our facility has engineers and HVAC technicians but no 100% qualified technicians to work on the chillers so we have outside contractors do major repairs with our assistance. I am a mechanical engineer and hvac tech and have been taking classes to become a competent chiller tech, so I'm just looking for more insight into what happened. Our electricians think that the panel heated up, ionized the air, which allowed the arc to the panel. It sounds like a reasonable explanation. Anyone else have ideas? We have not tried to run the chiller since, nor are we going to until we have our contractor come, repair if needed, and start it up.

[ON-CALL]

Let me guess the strainer for the condenser water to the heat exchanger was plugged.Don't be suprised if the drive has to be replaced and 50,50 shot with the motor,look in to retrofit for refrigerant cool drive and LET TRANE DO IT!!!!!!!!

[MikeVDS]

Let me guess the strainer for the condenser water to the heat exchanger was plugged.

Nope. The problem was on multiple levels, all done by the same technician who "was always right" but rarely was, and thankfully doesn't work there anymore. First he replaced the circulating pump with an undersized pump. The other thing was that when he replaced the water in the cooling system, he used tap water and did not add any treatment (watertool 4435C), so some form of algae was in the water we drained. Unfortunately no one caught his mistakes before they became a problem.

Why do you think we should have Trane do the repairs, rather than a competent contractor?

[ON-CALL]

whats the h.p of the motor

[ON-CALL]

Wait To You See How Much To Change The Drive They Don't Like Arc Flashs. Make Sure Tech Hooks Up To Tech View And Checks Config

[ON-CALL]

HEY MIKE what did you find out that drive.