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Old 05-22-2013, 10:00 AM   #1
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Please help me correctly size my A/C condenser


I have a Lennox air handler & C3-41-1FF evaporator coil in the attic of my tri-level 2158 sqft. home.
Lennox has told me the evaporator coil will accommodate an A/C condenser to a maximum of 3tons.

Some A/C Installers tell me I need 3.5 ton condenser because of the length of the line set, about 20~25ft.
One installer told me the evaporator orifice also determines the appropriate coil size, & the orifice on my evaporator unit is 3/8 x 3/4

Which size condenser should I have installed?

Thanks,
Uni

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Old 05-22-2013, 10:41 AM   #2
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Please help me correctly size my A/C condenser


Not exactly sure of your specific coil but the new one that is a 41 is 41,000 Btus or 3.5 tons BUT it has a 7/8" suction line so I assume yours is good for 3 tons because of the 3/4" line and it may have a thermostatic expansion valve built onto it rated for 3 tons. Lennox is correct if they looked it up. The older units were confusing as nowadays a 3 ton has a 36 model but the older ones used a 411 on the outdoor unit. I would go with what Lennox said. You size a AC with a heat load calculator.

http://www.hvaccomputer.com/gtarget1...Fe4-MgodPF4AoQ

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Last edited by yuri; 05-22-2013 at 10:44 AM.
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Old 05-22-2013, 12:41 PM   #3
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Please help me correctly size my A/C condenser


Isn't that a coil from the 70's? I would not use it.
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Old 05-22-2013, 12:48 PM   #4
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Please help me correctly size my A/C condenser


That's what I was thinkin too. Probably the condenser/compressor is shot. The new coils are C33 etc. Like Marty said probably not worth reusing as it may spring a leak soon and is a R22 coil whereas your new unit uses R410 and this coil will lower the efficiency etc. It will be a 8 SEER coil and will not work very well with the new higher SEER units which are 13 SEER and higher.
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Old 05-22-2013, 01:02 PM   #5
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Please help me correctly size my A/C condenser


Several Installers "looked" at the air handler & evaporator coil.
Even though it's old, they all have said it is very good shape.
That's 1 reason why I'm planning on having a dry charge (Goodman)
condenser installed.

When they do a suction test, hopefully there will be no leaks.

By the way, how long should the duration of the vacuum test be to ensure there's not a leak?

Thanks Again,
Uni
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Old 05-22-2013, 01:11 PM   #6
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Please help me correctly size my A/C condenser


You CANNOT look at the coil to see if it is good. I have installed Lennox for 34 yrs and Marty has done a lot of Lennox. If you want a cheap fix then go for it but you WILL be sorry. Copper gets work hardened/brittle from age and vibration and that coil will not last much longer. You will get some weird pressures and operating characteristics as it is a 8 SEER and hooking it to a 13 SEER Goodman is basically cobbling it together but hey it is a free world.
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Old 05-22-2013, 02:15 PM   #7
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Please help me correctly size my A/C condenser


Quote:
Originally Posted by yuri View Post
You CANNOT look at the coil to see if it is good. I have installed Lennox for 34 yrs and Marty has done a lot of Lennox. If you want a cheap fix then go for it but you WILL be sorry. Copper gets work hardened/brittle from age and vibration and that coil will not last much longer. You will get some weird pressures and operating characteristics as it is a 8 SEER and hooking it to a 13 SEER Goodman is basically cobbling it together but hey it is a free world.
I definitely need a cheap fix, but don't want to throw money away.
If the coil does not last, can it be repaired, or another flat coiled retrofitted?

Thanks,
Uni
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Old 05-22-2013, 03:20 PM   #8
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Please help me correctly size my A/C condenser


It is very difficult and impractical to try repair a coil that old as the copper is brittle. Like repairing a 20-25 yr old car radiator, will keep springing leaks. They also leak in places that cannot be repaired or easily. Don't know about another flat coil as coils for air handlers are specific to the air handler and yours is obsolete and the new air handler is a different size so the available coil is a different size. There is no cheap lasting fix and the new coils are 13 SEER and won't work properly either.
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Old 05-22-2013, 08:27 PM   #9
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Please help me correctly size my A/C condenser


Lets say the coil does go bad... Then you have to find a R22 coil because your new condenser is R22 and the refrigerant would probably have leaked out and R22 keeps sky rocketing in price. Replace the whole system, IMO. Goodman air handlers are not that expensive.
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Old 05-22-2013, 08:42 PM   #10
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you will just be throwing money away.....but its your money...ben sr
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Old 05-22-2013, 11:09 PM   #11
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Please help me correctly size my A/C condenser


Quote:
Originally Posted by hvactech126 View Post
Lets say the coil does go bad... Then you have to find a R22 coil because your new condenser is R22 and the refrigerant would probably have leaked out and R22 keeps sky rocketing in price. Replace the whole system, IMO. Goodman air handlers are not that expensive.
Thanks,

How much are Goodman 3 ton Air Handlers & Goodman 3 ton Condensers, 13 SEER, cash & carry?
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Old 05-22-2013, 11:14 PM   #12
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Please help me correctly size my A/C condenser


You will have to find that out locally or get one online.
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Old 05-22-2013, 11:35 PM   #13
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Please help me correctly size my A/C condenser


Quote:
Originally Posted by hvactech126 View Post
You will have to find that out locally or get one online.
Which are the best online sources?

Thanks.
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Old 05-23-2013, 01:11 AM   #14
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Please help me correctly size my A/C condenser


Quote:
Originally Posted by Unicornz0 View Post
Which are the best online sources?

Thanks.
Kinda scary buying big equipment online but if you want a good one, Alpine home air has the best reputation for online sales and they apparently have great customer service.
I've bought a couple thermostats and humidifiers from them, it was cheaper than buying locally.
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Old 05-23-2013, 07:57 AM   #15
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Please help me correctly size my A/C condenser


Quote:
Originally Posted by sammy37 View Post
Kinda scary buying big equipment online but if you want a good one, Alpine home air has the best reputation for online sales and they apparently have great customer service.
I've bought a couple thermostats and humidifiers from them, it was cheaper than buying locally.
Thanks!

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