Air handler

[Rachel]

We are in the process of buying a new home and one of the repairs we requested, after the home inspection, was the entire replacement of the one of the HVAC system (there are 3). They called today to say that the new system was installed but that the old air handler was left in the attic because removing it "may compromise the attic frame." I have never heard of this and can't imagine that it's a good idea to leave an old air handler in the attic. Any thoughts or advice?

[Ed Pawlowski]

Nor being able to see it, can't say but it sounds unusual. Don't see how it can harm anything unless it hits you on the head in an earthquake.

[Marilyn Manson]

The only thing I can think of is that someone had to modify the framing to install the previous air handler and maybe there are braces or headers or something that would need to be removed to get it out. The current HVAC guys are just that: HVAC guys and don't want to start taking the framing apart.

Did you ask them what they meant by "compromise the attic frame"? That's the first thing I'd do. If they can't explain why they said what they said, I'd have additional concerns.

If what they said is true - or if you don't like their answer - then maybe you should get a framing guy to take a look and let you know exactly what's going on.

[gfretwell]

Ask them again in the winter. They might not be interested in taking that thing apart in a 140 degree attic. OTOH is it actually hurting anything being there?

[micky]

That all sounds right.

OTOH, aiui, the air handler is just a box, a motor, and a fan blade, and until the motor burns out or slows down, an old one is as good as a new one. No?

(Unless a new one would be variable speed and the old one is fixed speed, but any house with 3 systems, I'll bet has 3 fancy air handlers.)

If the old one is as good as a new one, and the framing was involved like you speculate, I woudln't want them to change the handler. Don't go looking for trouble.

Even if one needs repair, isn't that just replacing the motor and keeping everything else the same?

I've never even oiled mine (though it was replaced once 20 years ago by mistake by someone who thought the noise was from the motor when it was actually from the squirrel cage.) Are you supposed to oil them? Do they slow down, and then go back to regular speed when oiled? Or are they self-lubricating?

[micky]

That's for sure. The last time I worked in the attic I was supposed to get up there at 5:30 AM, but I overslept and it was 8. It kept getting hotter and hotter up there. Once in a while there was a breeze and that was great. Finished about 10.

[gfretwell]

You usually get the condenser and air handler as a matched set. These high SEER numbers only come if you buy the system. Also ICC code has pretty much made attic A/Hs dead as disco anyway. They have to be in environmental space so you either box around it and make it part of the house or you put it in a closet. That is one thing that makes multi drop mini splits start looking good. You just need to run a line set and a 14/4 tray cable. No duct work, real good SEER, easy to zone, redundancy and no big air handler you need to hide..

[Marilyn Manson]

Look up "matched set".

If I'm selling you a new system, that I am warranting, I don't want it tied into some old POS AH. If you want my warranty, you get my equipment. I have the power, you have the choice.

[Tekkie©]

On Tue, 13 Jul 2021 21:15:02 +0000, Rachel posted for all of us to digest...

attic frame." I have never heard of this and can't imagine that it's a good idea to leave an old air handler in the attic. Any thoughts or advice?

Ask they installers why they have to do this. The framing can be modified or removed temporarily as long as there is no storms, winds or snow loading involved.

They probably can't get the old evaporator out because it was installed incorrectly from the get go. As stated in other posts the evaporator and condenser sizes must be matched to achieve the ratings. You stated you wanted an "entire replacement" that is what you should get.

The installers want to cheap out.

[Dean Hoffman]

You mentioned an inspector. What does he have to say?

[micky]

By box I meant the sheet metal box they always use. Not a wood box.

Check out the thread about many models of guns and many fewer models of ammunition.

The new AC was chosen for the same house and was similar in size to the original AC. Why shouldn't it use a very similar AH. What things could be wrong with the old one versus the new one? Physical dimensions? Cu.ft/second? What else? What IS wrong with the old one? Maybe nothing.

Calling it old or a pos doesn't make it that.

And it was the AC contractor which decided to continue using the old AH, not the customer.

You have no evidence the regular warranty wasn't given. Rachel said nothing about that, and she would have if it had happened.

[Ed Pawlowski]

Could have been designed for a different refrigerant and different valves. R410A is common nos, R22 years ago. Coil oxidizing, air flow impeded.

If I was the installer giving a warranty on my work I'd want it done right, all new.

[Clare Snyder]

The air handler is NOT the A coil.The A coil could easily be replaced in the "air handler" - which is, as noted previously, a fan in a box. It can have an AC A coil and or a heat rediator connected to a hydronic system - or even an electric auxiliary heat coil for a heat pump. ALL of those components COULD be replaced in the air handler without replacing it - as can the blower assembly. Getting the large steel box out of a truss framed attic CAN be a major job -even involving removal of roof sheathing/deck in some instances - and possibly even cutting a truss if the air handler is wider than the distance between trusses (which it often is)

[Ed Pawlowski]

True, unless the A coil is in the air handler

[Ed Pawlowski]

I should on expand this. Clare is making assumptions based on nothing. First of all, we don't know if there is an A coil. Not every AC unit uses that style. There are dozens of variation in styles and serpentine setup and size. Could be a flat multi row coil. Older units used copper tubing, many new use aluminum.

The units are sized for a given capacity and the dimensions change from brand to brand as they use different fin spacing, tube centers and sizes.

Clare says the individual components can be replace. But should they? If replacing a 20 year old unit you can now have the same CFM with lower RPM and larger blower wheels. Will it fit the same case? Probably not. The new unit probably has more insulation.

With different refrigeration coil designs in both the condensing and evaporator units have changed.Every manufacturer has parameters for their design and trying to fit new components in an old box is just dumb and could void warranty for both product and performance.

Clare knows cars. I spent 7 years as a supervisor in a company making heating and AC units.

[trader_4]

That's what I would figure too. The poster said they put in a whole new system, which would include a new air handler. Sounds like they put it nearby the old one and left the old one there. You'd think that would be a PIA because the ducts wouldn't line up, would be short, but I suppose if it's flex duct, etc, it's doable. And better than taking the old one out and having the framing fall apart..... The mistake here was that if it was a whole new system, the dopey seller should have just said they installed it, it;s done, left it at that.

[trader_4]

Agree. Plus new high efficiency systems have high efficiency or variable speed blowers too. You can't make a 16 SEER system using parts from a 10 SEER. You'd have to be nuts IMO, to use an old air handler with a new system. Half the cost is the labor of installation, why leave an old AH, you get a new warranty, etc. But I don't think that's what happened here. From the description they said a new system was put in and they left the old air handler there because of structural issue concern. That to me sounds like there is a new air handler. Probably put a whole new unit right next to the old one.

[Snag]

And not one of you has suggested the sawzall option ! The question in my mind at this point is this : Is the old one too big to come out , or is the new one too big to get in ?

[Ed Pawlowski]

I'd rather leave it than the mess of cutting it out. I'm assuming it is out of sight so why make the mess? Minimal scrap value for the labor involved.

[gfretwell]

You all keep missing the fact that if they have an energy code they can't put an A/H in an attic anymore. Not without boxing it in and making that area "conditioned space". (essentially swapping air with the house). If they pulled a permit, they might not have had a choice.

My bet is she lost a closet. I also am guessing the installers had no interest in taking the old one apart to get it out of the attic. We don't know where this is but down here attics are not useable for much because of the low pitch of the roof (2.5:12 is far from uncommon). It also gets so hot up there you wouldn't want to store much there.