Lennox "Will Start Soon" problem

[greginca]

Hi,

I have 3 systems in my home. They were installed a few days ago. 1 5T and 2 4T.

XC25-60 + SL280-100NV
XC25-48 + SL280-80NV
XC25-48 + SL280-80NV

One of the units just won't heat. When the heater wants to kick in, it just shows "Will Start Soon", and starts the blower (and won't stop it). No error reported anywhere.

While perusing this forum, I noticed mention of a grounding wire between the outside unit and the furnace.

The tech that installed the unit did not run a wire from the outside unit to the furnace, which seems to be designed to bond the grounds. He didn't do it because he was replacing an existing system and was one wire short, so he connected the ground wire from the board to the chassis.

He explained to me that when he went through the Lennox training, they mentioned this as an acceptable method to set up the system, and me having a EE background, I couldn't find anything wrong either since the grounds are bonded anyways through the electrical panels and the whole home wiring, so they should be at the same electric potential, whether going one way or the other.

However, his boss insists that I should be running more wires to connect the furnace and outside unit directly. The cost isn't an issue to me, but what's involved is a fairly destructive operation resulting in a hole coming out of my attic and conduit along the wall. I would prefer not to do that because holes are always problems (insulation, water-proofing), and the specific area where he would have to do it has a special architectural feature that would make it pretty difficult to "get right" and would most likely end up in a pretty ugly result.

Could someone please explain to me why bonding via a direct link vs bonding via the home existing wiring would make a difference?

Would this be a possible reason why I have this problem with this one system (out of 3)?

I found a thread that mentions this on this forum, but my low post count doesn't allow me to link it here. The title is "How to Troubleshoot Lennox 'Will Start Soon' error message".

Thank you for your help in advance.

[kdean1]

Please explain why the contractor hasn’t fulfilled his contract to provide working systems.

[Gunslinger]

Probably why his home has 13 tons in it.

[beenthere]

So they didn't run new shielded wire. That could be the cause of your unit not working.

Should only be grounded at the indoor unit.

[Deathpunch0311]

13 TONS! You must have a GIGANTIC house!