I dont understand this setup

This is a new set up to me.

The home is built in the late 50"s. There was an original Lennox and then a 11 Year old Goodman.
The return air & duct where tied into the older system.

Can someone explain to me why the original unit was kept and not removed when the Goodman was installed? There is only one thermostat.



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Lazy installer is my guess. Was the gas still on to the older unit?

Could there be an addition to the house?

There is no adddition. And the gas seemed to be only to the Goodman furnace. Just seems like a strange setup to me. The older lennox had 2 copper condensate lines.

Thanks for the responses.


Is one used as an A coil for the air conditioner? That’s my guess.

The refrigerant lines go to the newer Goodman & there is a coil in the Older Lennox. I didnt run the air it was a balmy 45 degrees this morning.

Ohio temps are up & down this time of year. 75 today & will snow maybe tommorrow.



I may be wrong but the copper lines look like water not refrigerant. is it possible this is some sort of home made boiler chiller set up or even the type ( cant think of the name) where under ground piping is used to cool or heat water?


thank you. Brain just quit temporarily

Definetly not Geothermal & the two lines discharged at an open drain in basement & appeared to be for condensate.

I would love to meet with an HVAC specialist on this system. I think Lazy installer is the best answer.

Didnt want to have to get ride of the old unit.

Thanks for the replies.


I can not tell you from a Pic how the units are designed to operate, but the units are installed in tandem. Could be two stage.

The Lennox coil is NOT a DX Coil, it is a water coil. There is a water pressure control valve on the copper lines which regulates water flow, relative to temperature of the water.

What you are telling about these lines piped as drains does not make sense to me.

There must be another source of hot/cold water somewhere, or it was there and has been abandoned.