A/C evaporator location

[upand_at_them]

The alt.hvac snobs wouldn't answer my question, so I'm posting here...

I was going to install my new humidifier this weekend, but I see that the A/C evaporator is in the way. And I have no room on the return plenum. I have an upflow system and the evaporator was installed at the very top of the supply plenum.

Here's a diagram:

``````````| ducts to all of the rooms | ``````````+-----------------------------------+ ``````````| | ``````````| | ``````````| | ``````````| A/C evaporator located here | ``````````| | ``````````| | ``````````| | ``````````+-----------------------------------+ ```````````\\ | ````````````\\ | `````````````\\ section of duct | ``````````````\\ | ```````````````\\ | ````````````````+-----------------------------+ ````````````````| / ````````````````| / ````````````````| section of duct / ````````````````| / ````````````````| / ````````````````+-----------------------+ ````````````````| | ````````````````| | ````````````````| | ````````````````| furnace | ````````````````| | ````````````````| | ````````````````| | ````````````````| |

I have some questions about this...

1) Should the evaporator have been installed lower in the supply plenum? (It sure would have made it easy for me to install my humidifier.)

2) I plan on having my A/C system replaced this spring, because it is very old and doesn't work well. Can I ask the installer to locate the evaporator lower in the supply plenum?

3) There is a little bit of asbestos tape on the duct where the evaporator lines enter. Will the A/C guys remove this? Will they ask for me to have it removed before they work?

4) Depending on the answer to #2...Can I have someone evacuate the A/C system so that I can remove the evaporator and install my humidifier? There's at least two feet of duct below this (and above the furnace) where the evaporator would fit.

Mike

[nicksanspam]

Good idea.

Bad idea. Caulk the house instead, to lower vs raise your fuel bill.

Nick

[Oscar_Lives]

You need a new furnace. Get it replaced now. Do it right once and for all. Get a pro to do it.

Start the payback period of a new system now. Don't put off what is needed.

[upand_at_them]

Why do you say that I need a new furnace? I was asking about the A/C system. My furnace works just fine.

[SQLit]

Installer made the decision for a reason. Maybe not a good one

Every evaporator I have ever seen is right on top of the furnance. Mostly because they parts fit together well that way. The picture seems to show a the furnance and evap of differing sizes.

Asbestos tape?, new one on me. Sure it is not just duct tape?

Mike it is impossible to answer you. There are a thousand things to look at and your only providing a few details. Call several licensed contractors and ask them. They can see the job.

Might be a good time to replace everything now or maybe wait till after the holiday.

Installing the humidier now may be more trouble than it is worth.

[Oscar_Lives]

Surely you aren't going to put a new air conditioner system on an old furnace?

New furnaces are ~92-94% efficient. Furnaces that are older than about 12 years old are only 65% efficient at best.

Yes, you need a new furnace. Don't half-ass it.

[m Ransley]

Nick in his ultimate wisdom thinks caulk is always the answer, to bad he doesn't live in own home were added humidification is necessary.

Just as funny-sad is when he used to recommend flooding your basement floor or removing steam radiator air vents for humidification.

[CJT]

Who said he was going to replace the A/C? He said he wanted to add a humidifier.

[m Ransley]

Mine is hooked up on a return with a new duct fed from the supply, same as yours, an upflow

[nicksanspam]

It's the best one. Houses that need winter humidification leak too much air.

Never done that. What are you smoking? :-)

Nick

[upand_at_them]

Yes, but I have zero room on the return plenum to mount the humidifier; it is too close to the wall. There is a nice big spot on the supply plenum, but like I said the A/C evaporator is in the way.

And, yes, I will also be having the A/C replaced this spring.

What I was considering doing was to remove the A/C evaporator (no, I wasn't going to disconnect it, just pull it out of the plenum) and install the humidifier. The HVAC tech would have to remove this anyway to put in a new one. But this assumes that the evaporator can be installed in the plenum below.

Mike

[Bubba]

Keep in mind, junior............when you install a water producing appliance (IE: humidifier) on the supply plenum it is just amazing how that water is attracted to that expensive circuit board below in your furnace like a magnet. That doesnt happen if its on the return plenum. Bubba

[m Ransley]

You must be senile ol Nick, everyone kicked your butt on your " Keeping the basement floor wet for humidity recommendation"

[CJT]

You're just _full_ of baloney, aren't you?!

[Dr. Hardcrab]

Do you still have the receipt for the humidifier?

If you do, take it back and go by a free-standing whole house unit. I don't mean the ones that hold one gallon that you have to fill daily. Get one of them suckers that look like a piece of furniture. Then place it somewhere near the retuen on your duct sytem. You'll be a lot happier with it......

[CJT]

... and you won't have to run a water line to it.

[m Ransley]

Hardcrab, Buy a freestanding unit you have to fill 5 gallons in every day or so and pay to run a second apliance when the furnace does it free, and have that extra fan noise and one more piece of junk to store in summer, Dumb Hardcrab real dumb expecialy considering control to an April air that monitors outside temps and keeps humidity optimal and a freestanding unit does little in out of the way rooms, dumb. A furnace humidifier is one of the main benefits of forced air vs HW radiators, yea Ive lived with HW radiators and cheap looking furniture that humidifies and makes noises and rattles .

[m Ransley]

Yea you dont run a water line just a bucket

[CJT]

He may overstate his case, but there's at least an element of truth in what he says -- leaking your warm, humidified air to the outside and replacing it with cold, dry air which you then heat (lowering its relative humidity) _will_ boost your need to humidify.

[cornytheclown]

Do high efficiency furnaces really pay off ??? From what I have seen in newer high effiency hvac equipment the cost savings thru higher efficiency are offset by the higher repair costs.....

You can look on the internet and see many many stories of furnaces that have to have the igniters replaced yearly or bi yearly....flame sensors need cleaning...... heat exchangers needing replacement after only a few years......newer equipment doesnt last like the old stuff did.....then you have your hvac companies who spend as much time on parts replacement or new equipment sales training for their technicians than on real trouble shooting and maintenance training.

I still see old williamson, carrier, lennox, janitrol, bard furnaces.....all brands that were installed 30-35 years ago still kicking along every winter...good tight heat exchangers...they might require service every few years...usually a thermocouple...if even that....seems withn the newer equipment its something every season....inducer motor bad, flame sensor dirty, bad board......

Today the only way you can expect your furnace or ac to operate right is to have a maintenance agreement with an hvac contractor...this offsets savings even more...and then you might be unfortunate enough to get saddled with a maintenance outfit that requires its employees to sell so many parts a month...which is quite common....

So....really....Is a new high effiecincy furnace or ac system really gonna save anyone money.....