ReplyCan it be done,but it could endanger your life,not a good idea.
Regular Guest
I bought a new system from a supposed to be reputable dealer. He put in a 4 ton bryant heat pump and a 4 ton coil with a 58mtb 1400 cfm gas furnace. According to the carrier rebate program manager this is to small unit. He said I needed 2000 cfm. My queston is can a new fan be put in this housing?
Last edited by wormie1205; 11-11-2007 at 09:51 PM.
Banned
Can it be done,but it could endanger your life,not a good idea.
Professional Member*
6 ton heat pump on a 4 ton coil?
Regular Guest
Why is it dangerous to change the fan in the 3.5 t gas unit?
Regular Guest
It is a 4 ton coil, and a 4 ton heat pump. The gas furnace is a carrier 96 with a 1400 cfm fan. I mistyped.
Regular Guest
Why is the gas side of these furnaces so cool? Seems it is warmer on the heat pump side.
Regular Guest
Could I just replace the verible speed fan with a larger one?Originally Posted by dash
Professional Member*
Why don't you call the local distributor for some assistance IF the dealer won't work with you?
Perhaps you should have read the instructions before calling.
Regular Guest
most designs in my area at least are 400cfm per ton...so 4 ton=1600 cfm.
that 1400 cfm gas furnace is a bit low..but 2000cfm is too high..you won't get proper de-hu from the ac in such a case.
my company designs on 350cfm/ton for cool (for de-hu) and 400cfm/ton for heating and it has worked out nicely for our area.
just throwing in a different blower isn't the answer..it seems both of those guys are off..if you need 4 tons of heat/cool then you're looking at an airhandler/furnace that needs to push 1600cfm.
was a proper manual J calculation done on your home? was an infiltrometer test done?
seems you need to call the install company back and push a warranty on them
Regular Guest
Since the OP did not specifiy the rating for the furnace it can be assumed that the 1400 cfm matches the furnace rating and given the 350 cfm for cooling he should be ok with 1400 cfm for 4 ton/
I had the reverse happen to me, on my addition the builder's installer installed an oversized furnace with a 1200 cfm unit with a 2 ton AC. Luckily my regular HVAC contractor was able adjust the speed using the lowest available speed. Still not optimal, if I would have known what I know now I would have insisted on a variable speed unit on my addition.
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