ECN Forum Forums General Topics of the Trade General Discussion Area 3 phase star heater confusion

Here are the manufacturers install instructions http://dms.hvacpartners.com/docs/1009/Public/01/AR1000001A.pdf

lS1, etc are over temperature switches.

I am surprised at the apparently poor design

Says you.... Lol!

If the LS switches are "limit switches" or over loads, I stick with my last post. Based on the amp loads, L1 grounded out between relay and HEAT 1, LS 3 is tripped or defective. LS 1 and 2 are still closed possibly welded together. As for the relay, may be defective with L1 is open and L2 of the relay is welded. That would explain the goofy readings and why the breaker did not trip

the ground fault, L1 cant be grounded, but the heater element must be grouded.

im saying that because if L1 was grounded out, the dead short would trip the breaker.


so, the relay is closed, heater 3, either the limit is stuck open or the heater is o/c. Heat 2 is fine, and heat 1, the element is grounded out, and not connected to L1.


We will find out tomorrow.


on a separate note, do the elements on these things go o/c often?

I think I might have a spare, so it might just get swapped out, but either way, ill find exactly whats happening tomorrow.

I have the unit on my desk now, one element is o/c, one is good and the other is in about five pieces. the ground fault is gone, probably during the move

the limit switches are all good