How to determine heat pump/air handler compatability?


  #1  
Old 09-26-05, 05:00 AM
sigtauenus
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How to determine heat pump/air handler compatability?

First off, let me take a moment to thank the owner of this site and the moderators, seems like a informative and well run place.

On to the problem...

I bought a 25 year old house in Virginia Beach, VA this spring and one of the selling points was a recently installed HVAC.

Well, the a/c wouldn't cool the house down below 80 all summer so we finally called a heat/ac company to come take a look at it for us and let us know what is going on.

Apparently only the inside air handler was changed, about 6 years ago. The outside unit is older, could be original but I doubt it.

Outside: Arco Aire model# HP5024A2C1 serial# FBY024Gc1

Inside: Janitrol model# A30-10 serial# 0002442385

The tech said the two components are mismatched and that is why the house won't cool. He also said the system is most likely overcharged but he wasn't sure...because they were mismatched.

Here are the comments he said "Superheat is operating at 0 deg indicating liquid presence in vapor line. possible overcharge or mismatched capacities.

78 deg O/D 76 to 64 deg, delta T 12-11 deg approx temps 65 deg w.b.temp."

I have been told that both units I have are cheap, builder grade products. That's fine, I'm a big fan of using regular preventative maintenance to make cheap products last a long time. And I don't have the money to buy a Trane.

Is there a way to determine what the correct charge is for this combination?

If not, I would like to keep the inside unit since it is newer and replace just the outside unit. How do I determine if a new heat pump will be compatable with my current air handler? I don't want to have to buy a complete new system unless I absolutely have to.

The a/c tech also said that the 2 ton heat pump I have is not enough for my size house (1600 sqft). He recommended we go to a 2.5 ton, but did not specify a particular model. I know there is some complex calculations to size it right, and I doubt he actually did them to make that determination.

I've been looking at the Goodman CPLJ30-1 Heat Pump 2.5 Ton, 12 SEER Heat Pump. Would this work? If not, can anybody make a recommendation?

Thanks in advance for any info you can offer.
Sam
 
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Old 09-26-05, 05:50 AM
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sigtauenus

I would say that it is fairly obvious you have an undersized and mismatched system-2 ton outside HP ArcoAir condensor and 2 1/2 ton Janitrol inside air handler. Dates of manufacture should be on dataplates and I would make an effort to get this info. Depending on your budget, you may want to scrap the Arco unit and look into a Janitrol/Goodman HP unit that would be compatible with existing air handler. You should verify compatibility with an established and reputable dealer.From a $$$ perspective, this would be your cheapest alternative. If this is main home, then I would scrap both inside and outside units and start over with a decent matching system-not a budget low end builder model. Do yourself a favor though and insist that a Manual J heat/cool load calculation is performed. Get ductwork inspected as well including size,condition, insulation,etc.

My opinion.
Good LucK!
 
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Old 09-26-05, 06:27 AM
sigtauenus
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Thanks for the info. I did not know the Janitrol was a 2.5 ton air handler, so that answers that issue.

I plan on installing this myself, but I don't feel right about having somebody come out to give me a free estimate, ie run the Manual J calculation and propose a system to install and then not hire them. I understand the calculations take into account doors, windows, insulation, etc in addition to square footage. Is there any way of running the calculation, ie online, software, etc that doesn't involve wasting the time of a professional?

If it turns out that 2.5 ton is the right capacity for my house, would it matter what brand of heat pump I put outside to match the Janitrol inside?
 
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Old 09-26-05, 06:48 AM
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sigtauenus

I am reasonably certain that your Janitrol air handler is 2 1/2 ton based on the A30 model number.

If it turns out that 2.5 ton is the right capacity for my house, would it matter what brand of heat pump I put outside to match the Janitrol inside?

Yes, it does matter. You would just be replacing one problem with another. You already have a mismatched system. While I don't like Goodman/Janitrol equipment(low end), I would first look into the compatibility of a Goodman outside HP unit to match inside air handler as your least expensive option. If it was my house though and I planned to be in home for the forseeable future, I would scrap both and get an HVAC pro to install even if it was budget type equipment.

Good LucK!
 
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Old 09-26-05, 08:55 AM
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You can get some pretty nice deals out there...for instance...
I know a guy who does heating and air work.
He is licenced runs a little add in the free paper to get work.
through him I purchaced a Comfort Maker 1.5ton matched unit for my basement. 12 seer,scroll compressor. He dropped off the unit and the reciept, unit and line set, and a few other things like duct boots and tape, it all came to $1290. and some change.
I did the duct work, and ran all the lines.
He came back the next day, he checked out my work and charged the unit.
It was running 2.5 hours after he arrived.
He wanted $75.00 for his time, but I thought it was worth more, so I payed him $150 cash.
He is happy...I am happy

With that said, the same install was quoted to me by 3 local residential HVAC outfits, with prices ranging from $3900-$5600 for the install.
 
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Old 09-26-05, 09:17 AM
sigtauenus
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Thanks for the replies.
 
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Old 09-26-05, 12:01 PM
sigtauenus
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One more issue I see possibly influencing this...

If the indoor unit is say, a 2.5 ton SEER 10, would it work with an outdoor 2.5 ton 12 SEER unit?
 
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Old 09-26-05, 12:32 PM
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it will work but i would recommend installing a TXV metering device at the AHU. i often see indoor coils 1/2 ton larger than the outdoor unit. i believe it increases the efficiency, having more surface area, but decreases dehumidification
 
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Old 09-26-05, 12:42 PM
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Wink

This day and time to look at or put in a heat pump you say on a 10 seer inside coil and a 12 outdoor unit Dont cut it Not the top of the line but we now have units with a SEER of 17.00 and a HSPF of 10.55 on the heat pump. The way fuel is going you will get a pay back here.

ED
 
 

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