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09-17-2012, 04:29 PM #1
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8 year old carrier replace/repair
I've got a 5 ton Carrier Heat Pump (38YDB outside unit, FV4B indoor unit), that has developed an evaporator coil leak. I believe my system is fairly efficient already (unable to find my combo in the ahri directory), so I'm wondering what my best plan of action is here. The quotes I've received to replace the evaporator coil have all been in the same ballpark, so I don't think I'm getting taken advantage of, but it seems expensive just to replace the evaporator coil. I was given a quote on the Infinity 21 with Greenspeed, and it seems like a really nice unit. I'm looking for advice on whether I should replace the 8 year old coil (an only get a 1 year warranty) and hope for the best, or to go ahead and replace the entire system(and get the 10 year warranty). It seems like my system is at an age where either decision could be correct, and I'm just looking for advice on which route I should take. I live in North Fl if that makes any difference, and the cost to buy the Infinity 21 system is about 4x's the cost of the coil only replacement.
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09-17-2012, 05:01 PM #2
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8 years for a system is young, replace the coil. I would still shop around if the cost of the coil is 1/4 the cost of the 21 seer. I would not opt. for the 21 unless improvements in the air distribution systyem and the house envelope is addressed, otherwise you will be wasting money and will never see the higher efficiency.
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09-17-2012, 06:11 PM #3
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09-17-2012, 06:31 PM #4
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09-17-2012, 06:44 PM #5
At 8 years, I would generally recommend to just replace the evap coil.
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09-17-2012, 06:54 PM #6
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Is your unit R410a (puron) ?
Also I would wager a guess that you have considerable ductwork issues causing your 5 ton to only be delivering around 3.5 to 4 tons to the house.
I say that only because the vast majority of duct systems are not designed proper and a 5 ton takes quite a bit of thought to deliver true 5 tons worth or air.
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09-17-2012, 07:02 PM #7
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My unit is 410(a), and the duct work was installed when the current unit was installed (8 years ago when we built the house). I'm not sure how I would determine if there is inadequate duct work.
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09-17-2012, 07:14 PM #8
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It is not something even some contractors really know how to determine.
We could start by seeing photos of how the indoor unit is installed.
Also filter sizes and location?
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09-17-2012, 07:29 PM #9
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I know they did have to use some large flex ducts in my attic due to the way the trusses were designed. I have 2 main "trunk" lines going across the attic (supply and return) that are 16" in diameter (I think....I saw 16 written on the outside of the flex). I know flex is less than ideal, but unfortunately I think it was all they could do. I remember having the discussion with the owner of the hvac company regarding it. The supply flex line runs into some duct board, and then all the flex lines for the far side of the house run off of that. From the other suggestions, it seems as though it would be in my best interest to just replace the coil at this time since the remaining components seem to be functioning properly. I have one more contractor coming out for a quote tomorrow, and then I will make the decision.
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09-17-2012, 07:49 PM #10
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Was that one 16 flex supply and one 16 flex return?
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09-17-2012, 08:01 PM #11
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SBKold,
Your statement is correct. Those 2 flex lines feed the far side of my house (2 bedrooms and 1.5 baths). Each line runs across the attic to a duct board plenum? From there, each of the supply lines for the bedrooms and bathrooms branch out. Same for the returns. I'm not 100% sure they are 16", they may be bigger...I just saw 16 written on the ducts in several places.
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09-17-2012, 08:29 PM #12
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Pictures would definatley help. If that is the case you are ok for about a true 2.5 to 3 at best tons worth of airflow.
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09-17-2012, 10:06 PM #13
Good call. Looks like 16 rigid says 39,400, so flex probably is 2.5. What size/type of filter?
If your system is grossly oversized to your duct, this might be the great opportunity your intuition is telling you it is. (Love to see pictures!) You'll want to make the best of it and get size right.
5 ton GREENSPEED will flip out on that duct. That's the fun part of communicating equipment, crappy installs get exposed.
How big is the house? Can you describe how the old system performed on the very hottest days. Run time, noise, etc...
Be nice to know homes leakage. Be nice to know how much of the outdoors and attic you are cooling. Ever had a blower door test?Which makes more sense to you?
CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%
DO THE NUMBERS! Step on a HOMESCALE.
What is comfort? Well, it AIN'T just TEMPERATURE!
Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.


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