Makes you think

Jeff Lawrence_25

At my daughters school. The principal called and told me there was no cooling in the cafeteria and could I look at it. Sure!

I was more than a few miles away, so I called my 17 year old daughter and asked to do a visual check. The outside fan was running and so was the inside blower. Suction line was barely cool.

Hmmm.

Got there and saw the exact same thing. Compressor was warm and the one next to it was slightly warmer, but neither was running. Got the Fluke out and read voltages. L1-L2 240v L1-L3 240v L2-L3 nothing (3 phase). The condensers are the only 3 phase equipment at the school.

Looked up at the transformers on the pole nearby and saw a fuse was blown.

When the power company came out to replace the fuse on the transformer, there was a loud POP. oops, bad transformer. The kids got out the rest of the day so the power company could replace the transformer.

Interesting stuff, this HVAC work.

mtfallsmikey

You should have seen

what happened in one of my buildings when "B" phase blew...was undersized, 20a. pole fuse for 2 16k s.f. buildings...lost VFD's, elevator controllers, etc...was not a pretty sight!

mtfallsmikey

You should have seen

what happened in one of my buildings when "B" phase blew...was undersized, 20a. pole fuse for 2 160k s.f. buildings...lost VFD's, elevator controllers, etc...was not a pretty sight!

Jeff Lawrence_25

Round 2

They replaced the transformer all right.

They wired it wrong.

L2 to ground was about 440 volts
L1 to L2 was 327.

The school wondered why I turned the breakers off on the condensers.

arrggghhhhhh

Oh, I've seen high rise buildings single phase. True, it's not a pretty sight.