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Lennox Heat pump

3K views 6 replies 3 participants last post by  mark2007 
#1 ·
Hi everyone,
First time poster , but been a lurker for while!
I have acquired two lennox heat pumps both are (HP-13 ) one is a 4 ton unit and one is a 2 ton. I would like to have the 4 ton installed in conjunction with my current propane furnace ( a keeprite 9MPV075 ) . Problem is the installer said that my house/furnace will not handle a 4 ton due to lack of CFM and is more suited to a 3.5 ton unit. I got a good deal on these units and was wondering if there is a any way to derate the 4 ton unit or incrase the CFM output on my current furnace. I have a newer home 2000 square very well insulated.

Thanks
Rich
 
#6 ·
It might be. It might not be.

But before paying someone money to install a unit that won't do what you want.
Use the load calc program that I posted a link for.

Unless you like throwing away money to be disappointed.
 
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#2 ·
Newer 2000 sq ft home. well insulated.

Shouldn't even need 3 tons. Unless your in an area that has normal summer temps of 100°F.

What is the FULL model number of the furnace. It might only have a 3 ton blower.


There is no way to derate a 4 ton to a lower size. And have it work and last. Specially with heat pumps.
 
#3 ·
Thx Beenthere
The model number is C9MPV075F12D i have the manual but dont fully understand what im looking for .If im reading it correct it can handle a 3.5 ton cooling unit. My house is a 4 level split with a halve the house having 16 foot ceilings so there is a fair bit of space to condition.

Rich
 
#4 ·
Thats a 3 ton drive on that furnace.

If it was just the furnace and indoor coil. With no duct work on the supply or return. It could move enough for 3.5 tons. But you got duct work. So nope. Ain't gonna work right.

Space is not as relevant as you might think. Unless you have a lot of air infiltration. Meaning your house isn't constructed real well. In which case. Improving your homes envelope is the first thing to do.

Might want to do your own load calc, and see what size you really need.
But as accurate as possible. And don't fudge any numbers.
HVAC Calc . Its worth its 49 dollar fee.
And much cheaper then new duct work. Or replacing compressors.
 
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