New Install-Electrical problem?

[midevs2]

Just had a new 4ton 15 seer Carrier performance series Central air system installed on Wednesday. I just noticed that when the system goes on all the lights in the house quickly dim. I don't remember the old system doing that but that was a 3 1/2 ton unit. Each of the lines are dedicated for the AC although one of them had to get upgraded to 220 for the air handler. My thinking is, why would all the lights dim if the AC is on completly separate electrical lines? The other thing is that I purchase a variable speed air handler and starts off slow and builds, I would think that would pull an even lesser load off the electrical.
Any advice?

[Senior Tech]

Call the installation company back, there is a kit that they can install on the unit to cure the problem.

[cem-bsee]

were new wires installed?
why not?

[midevs2]

No new wires installed. Just installed new breakers in box to upgrade to 220. The wiring in the attic looks a mess. I am definately calling the installer back.
What is the name of the unit that can correct the light surge issue?

[captainrat]

dude , you better get an electrician, that could be serious

[toddgotfish]

most likely not the AH , but the condenser compressor start up. a 3.5 is usually 10-2 wire , where a 4 ton requires #8 AWG. something you can do as a Homeowner , is go to the unit outside and look at the nameplate, it will have a MAX size circuit breaker , then go to your electrical box and see if it matches . if not give the contractor a call, if it does , the wire size still may wrong. either way , a call to an electrician may be in order.

[woody-dhstp]

One reason the lights dim is that something, in this case the compressor, is drawing a heavy load at start up and the wire size feeding it is not big enough, causing a voltage drop to the rest of the house. As the compressor ramps up the load decreases thus the lights return to normal output. If the wire size is correct then a hard start kit should reduce or eliminate this situation.

Also distance from the panel to the compressor is important, if it is more than 100ft from the panel (actual wire length) the wire size should be increased to offset the resistance in the line.

[beenthere]

Is your outdoor unit a 2 stage unit.