Need help on an old R-22 Lennox unit (my house)

[Pilot1]

Hello, new to the forum, and thanks in advance for your help.
Just bought a house:

I have a REALLY old Lennox 4 ton R-22 outdoor unit (prob about 15+ years old) with a newer 4 ton indoor air handler unit (about 6 years old) AC ONLY, Not a Heat Pump...

The Lennox outdoor unit has failed (given up) I have a brand new 3 ton 12 seer R-22 Goodman outdoor unit Would this work on a 4 ton air handler? The house is only 1300 sq ft.

This would be a temp fix, untill I raise enough money to install a R410A System.

Please give me your input on if this would work as a temp cooling fix?

Again, Thanks for all of your help
Mike

[coolwhip]

Nope, the evap. coil will need to be changed as well as blower speed.

[Home&Marine]

Mikey, Your post Lennox with the Dead 4 ton unit is exactly what I quoted on about 2 weeks ago.

It "sounds" like your system was Over-sized... for a 1,300 sf home, unless you don't have any insulation or doors? The good thing is, if you are going for a Temporary Fix (which tends to be permanent) and we just entered into Fall. Before you spend any money you need to have a Manual J calculation done. Call a Contractor and get them to look at your house/system and see what's the best direction to go. A "good" Tech can make a 3 ton condenser work with your 4 ton air handler (but there's things that have to be changed).

Also, Mike

[Pilot1]

I am an HVAC tech (been out of the field for awhile (3 years) since I am an office engineer But I am very knowledgeable in HVAC (5 years in the field///ex military)I have all the equipment (vacc pumps, recov machines, guages, torches, etc.etc. in my shed) I think I am knowledgeable in the field done over 50 comp change outs (1 phase/ 3 phase R-22 and limited on the R-410A) Back in the day But I am obviously Universal certed, and have my old cert card.

So I know enough to get into trouble

short story, I am broke (3 kids in college) and my wife has been sick for over a year, so she is not working. So, Yes this will have to hold me over for about 2 years, until I can at least get 2 of the 3 out of school to free up some income..

any advise to make this work would be a huge help (knowing the right way would be to swap the inner coil to match the 3 ton) But what would be the key to make this work.

AGAIN<<< THANKS SOOOOO MUCH FOR YOUR TAKING THE TIME TO HELP ME OUT

Regards,

"Mikey"

[ga-hvac-tech]

OK, here is what will happen if you do what you plan to do...

You will have a mis-match that will not cool well, will be humid, and will use WAAY too much elec. There are other issues also... call a Pro out and they will explain them.

It will be a temp repair... It may (and may not) last long enough to get the $$$ together for a new system.

My advise is to not try to go the 'thrifty' route here... rather just take the plunge and get a new system. What usually happens with these 'mis-match repairs' is too much $$$ is spent on the mindset of 'saving a buck by doing _____'. This same $$$ could be applied to a new unit, which would perform a lot nicer.

Oh, and if you are married, will your wife see the 'thriftyness' of this... or will she fuss about the thing not working properly... Might want to think about this also...

[cjpwalker]

Will it work, will it cool? Maybe, even probably. Will it work properly and be any kind of efficient? You know the answer to that already. This is an open forum and DIY advice can't be given here. I understand you are experienced in the field, but it is what it is.

I will tell you this, several things need to be addressed and may have to be changed: metering, lineset size, airflow, charge... it will need to be dialed in to as good as it will get but know that it will probably never look perfect.

If it doesn't work at all and you are out $100 in parts, I say it was a worthwile experiment. If its going to be hundreds I would probably step back and craigs list that unit you have. You wouldn't ever do this for a customer, but you don't have the $ to "take the plunge" now or in the next couple of summers - reality is what it is. If it were me I would give it a try.

Just remember temporary is temporary and start filling that coffee can with dollars as soon as you can!

[Pilot1]

Well, I appreciate all the help. And thanks for the honest opinions. Yes. It is what it is. Fortunatally the new Goodman unit was a left over that was sitting in the warehouse, and was basically given to me. So other than about $100.00 in parts (you are correct) It is worth a try. knowing that in teh next 1.5 years my 12k a month in tuition fees (for my kids) will go down to about4K a month when the 2 oldest graduate:P

Yes, I will dial it in (as best as poss) for the tonnage difference and in the mean time, put money in the coffers for a new system. I just need to suffer for another 1.5 years until the little ones get through school.

Thanks again for the $.02

If you all would like, I can post and let you know how it works out..

My best regards

Mike

[Special-K]

FRANKENUNIT!

There are ways to make it work fairly well. A good tech will know what to do to get the superheat in the proper range so the compressor won't be damaged.

The unit may not dehumidify well, but if had a 4-ton unit in a 1300 sq. foot house you're probably used to feeling muggy.

[Air Movers]

couldn't have said it any better!! 1300 sq with 4 tons is some clammy cooling, he should lower the fan speed on the AH

[Home&Marine]

Sure Mike, tell us how it works out. From what you've said experience wise, you know what to try. I'm still puzzled by the 1300 sf and 4 tons.

12k tuition monthly... Geeeee whiz, that hurts.

[DavyB]

Well, I appreciate all the help. And thanks for the honest opinions. Yes. It is what it is. Fortunatally the new Goodman unit was a left over that was sitting in the warehouse, and was basically given to me. So other than about $100.00 in parts (you are correct) It is worth a try. knowing that in teh next 1.5 years my 12k a month in tuition fees (for my kids) will go down to about4K a month when the 2 oldest graduate:P

Yes, I will dial it in (as best as poss) for the tonnage difference and in the mean time, put money in the coffers for a new system. I just need to suffer for another 1.5 years until the little ones get through school.

Thanks again for the $.02

If you all would like, I can post and let you know how it works out..

My best regards

Mike

Sweat it out for another year and when your kids are astronauts and city planners, they can pay you back and you will be able to afford a good quality 3 ton Tempstar!

[deux]

Believe it or not, yes. I do not sell stuff like this, but have butched a couple for property management guys with a collection of odds and ends. On a temp fix until a new system can be ready. IE ( keep the old split going until we can upgrade to a new RTU and duct in the fall )

You would be amazed what works. It is doable with the right McGiaver.

[supertek65]

12k a month???????????????????????


you must have a great job!!!!!!!!!!!!!!!

tell one of the kids to miss a semester and buy a complete new system!!!!!!!!!!!

[Swampfox]

Temporary fix, sure, be best to set the fan to a lower speed and change the orifice to the proper size for the outdoor unit, or install a TXV

lol at those that say it wont work

[Wheelbaron]

If the AH has a multi speed motor, change cooling to low speed, and add a TXV, should work if you can dial in that charge.

[Frosted]

I agree with WB and others; it will work for the temporary with the proper adjustments and might even find better RH in house with more runtime...to bad about the cash outlay. If you could swing finances you could get a new system that would save you $$ and get the $1500.00 tax cedit to boot! Its like getting $1500 off your purchase price. Alas, it goes Bye-bye 12/31/10...

[supertek65]

it may already have a txv?
it may also be the correct one?

[mgenius33]

Oversized airhandlers are common practice usually gaining SEER points in some cases. The mismatching is a little concern, but more so with a heat pump, in which you've stated you do not have. Most all recent residential Lennox airhandlers come equipped with TXVs. The only issue is that 3 tons of cooling in a 1300 sq home??? I guess we can't presume anything without seeing the actual load though. It's certainly better than the 4 tons that you're removing though. Good luck, just make sure you practice proper cleanup if the old unit was a "burnout" compressor.

[Diceman]

If the indoor coil has an expansion valve it will work ok.

Hook it up, whadda ya got to lose?

[dave sulz]

Goodman uses a bigger coil than the condenser. Try an expansion valve. I bet it will work long enough to get by.