Air Conditioner Freezing Up

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Turtle,
If the OP replaced an 825 RPM motor with a 1075 RPM motor, the condensor air flow would go up quite a bit. Check your fan laws. This would lower the head pressure which could also lower the suction pressure enough to start freezing the indoor coil. Especially if he has a clogged or restrictive air filter and marginal refrigerant charge. However the outdoor fan amps would also go up quite a bit and most likely burn the new motor out.
Cleaning the outdoor coil with a marginal refrigerant charge and a very dirty outdoor coil would have a similiar effect. I have seen it a number of times
Most likely the two problems are unrelated and just a coincidence that they happened around the same time.
Stretch
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Stretch wrote:

Snipe add on's
This is Turtle.
They don't have no fan laws that would speak about too much air across the coil as small as going from a 825 rpm motor to a 1075 rpm motor. It would move more air but it would play very little difference in the head or the suction pressure as to what you say trouble or freeze up the evaperator coil.
Also in my life i have changed bunches -- 825 Lennox cond. fan motors over to 1075 and just change the blade or increase the h.P. and leave the blade.
Stretch, Someone has been bullshitting you by saying changing the speed of the air going though the condenser will in some way make the evaperator coil freeze up if it is correctly charged. In the real world it don't happen. In the Salesmanship world it maybe true.
TURTLE
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TURTLE wrote:

So you've hacked up a bunch of peoples systems. That's nice. Did you at least consult the fan laws when you only increased HP and left the blade? You might be surprised at how much higher in HP you have to go to keep running amps down to the nameplate rating of the new motor.

That isn't what he said Turtle.
hvacrmedic

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RP wrote:

This is Turtle.
Earth to Richard , been there and done that. I use to have a chart for the units you wanted to convert. yes Pecker Wood , I went to Lennox and got the required cu. ft. per minute for all their stuff and keep a blade for each unit as to 2 and 5 ton condenser blades. There is 6 blades that would cover most any of the brands and just keep them on the truck. In the last 5 or 10 years the number of blade have changed so much that you have to get the right blade for the job. there was very few Trane around and lennox was the only 825 rpm motors needing to change out this away. Then when everybody stated the 850 rpm motors I stopped doing that. In my area a Lennox Wholesale cost of a 850 rpm motor [1960's & 70's ] was more than What i got for the whole job if it was a 1075 rpm motor. After the Lennox Union Strike we had to go to other companys to sell equipment and Lennox cut our dealer ship because they would not ship equipment for 8 months and expected use to shut down our business till the strick was over. We went back to Rheem / Ruud/ dunn & Bush / singer / others which got them to killing us for parts because we did not wait out the strick and stay loyle to Lennox.
In 1970 Lennox wanted $141.00 wholesale for 1/3 house power 850 rpm condenser fan motor We changed out 1076 condenser fan motor for $125.00 total cost.
TURTLE
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TURTLE wrote:

Ok, you've covered your ass on one of the two statements that you made. How about the other statement that you left the old blade and just upsized the motor when going from 825 to 1075RPM? Sure you can adjust the charge, but like I said, the system is now mismatched, not to mention the fact that the OEM blade wasn't necessarily designed to withstand that kind of added stress. I'll tell you now that I've converted a couple of 825s to 1075, but I didn't leave the original blade on them. You're correct about the pricing, not an issue these days, but it was at one time. Just keep in mind that those units that you left with excessive condenser airflow never worked right after you left. Hell yes they *worked*, but that isn't exactly sufficient. If you cost them $100 dollars extra on their light bill over the life of the unit then you didn't do them any favors by using the cheaper motor, and you didn't do yourself any favors either because you made less on that job than you were supposed to. It isn't your fault they had an 825RPM motor that was out of stock or 3 weeks out.
hvacrmedic
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RP wrote:

This is Turtle.
Your words sound good but to a 90 year old fellow and a 30+ year old system and he said just doctor it up and when i go I can let some else worry about it.
Now the Uping the horse power and leaving that big ass lennox 24 inch with 45 degree pitch blade on it was really a no no but only for they are going to change the system out soon like in a month or two.
Now the blade causing a extra $100.00 on the light bill a month. Hell here in louisiana in the 1970's we did not know what a $100.00 light bill was or did they go that high.
TURTLE
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TURTLE wrote:

I said "over the life of the unit". More like I was giving you the benefit of the doubt for them breaking even over 15 years, but in reality their extra expense on electricity would add up to more than 100 dollars over 15 years. A bunch more.
hvacrmedic
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Terry forgets that the rest of the country, isnt in the stone ages any longer.
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RP wrote:

This is Turtle.
Your words tell the very most truth but the average customer in this area would do this. I would explain that they could save about $1,000.00 over the life of the furnace if you just add this $6.00 part to it. The Customers having been bullshitted so much that the answer to this question would be " no put the regular part on it". the public has been told so many lies and bullshitted so many time that they don't believe anything a service man says now a days.
If you want a example of the public being bullshitted . go to your TV and turn it on and watch the commercials and see how much bullshit your handed out in advertisements. You are look " up on " as just one of these commercials and playing a game on them.
Also here in Louisiana they are just now getting a $200.00 electric bill and is having sticker shock over it.
TURTLE
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In other words, you raped him. No damn wonder the rest of the techs have a hard time with some people...someone like you was there and took the guys money and didnt do him ANY favors.

You damn liar. IF and I mean IF thats the case, you have a couple of options. Put him in a new system. If and thats IF hes serious, you will have your money in less time than most commercial accounts pay. The other option is to finance him out, and you have your money instantly, and hes gonna pay a few extra dollars in interest, unless you are a legitimate company that can offer 90 days same as cash, and then, hes still going to pay for that new ssytem hes gonna get in a month or two and not pay extra on it.

English wasnt taught there either was it?

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Terry, as a true, licenced, trained, and educated HVAC professional with a grasp of the English that I use daily, and a grasp of how a charge issue can be created and indeed, seems to be the case here, by a fan with too high of a speed that has created a false ambient for the current temps, and COULD have been corrected without replacing the fan....well, after 40 years (you state you started working in HVAC at 6...wow...all those child labor laws your father should have been fined for) you should know what was being stated.
Thank you again for proving to those of us that have a clue (lets see, you are still, after 40 years, a one man, Pinto wagon band right?) that you are indeed, nothing but a sweet talking salesman, that has no idea why the units he installs work, but damned if they dont.
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CBHVAC wrote:

This is Turtle
You just spoke the most Hog Shit that i've ever heard in my lift. Boy Howdee do we get some Rookies of the year on this group. Here below i will make a statement which you will be ask to reply to.
-------------------------------------------------------------
If you have a correctly charged hvac system and it running good with no problems. Then you come along and change the condenser fan motor to a faster speed/ more house power / more air across it . I say you can not freeze the evaperator coil up by increasing the speed of the condenser motor or the air across the condenser coil.
Then you say you can do it.
-------------------------------------------------------
Watch out Rookie of the year for this question will eat you up if you don't try to talk your way out of it. You should not be telling Hog wash like this and expect people to believe it.
TURTLE
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TURTLE wrote:

You're digging it deeper Turtle. "If the system is marginal already" as Stretch noted, meaning that it was under conditions such that it was *close* to freezing already, then it will go ahead and freeze if you increase condenser airflow. You aren't reading what Steve is writing. I wonder how many times you've had callbacks on units that you serviced. Just washing the condenser coil can sometimes be more than sufficient to cause freezing, in particular "when it was marginally close to freezing before you got there".
hvacrmedic
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RP wrote:

This is Turtle.
Your speaking of other thing low of freon, and 50 other thing that could be going wrong and then you make the statement as fact that if you increase the condenser fan speed it will cause the evaperator coil to freeze up. Then Stretch repeats your words again by saying just increasing the speed of the condenser air to the condenser , it will make the evaperator coil freeze up.
All the words your speaking about is other things causing the problem and then say make the increase of air to the condenser coil will cause the evaperator to freeze up. It's not going to happen in your life time.
TURTLE
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TURTLE wrote:

Seems the problem here is that you don't know what *marginal* means. Suggest you look it up before continuing. Here, I'll do it for you:
marginal (mrje-nel) adjective 1.    Of, relating to, located at, or constituting a margin, a border, or an edge: the marginal strip of beach; a marginal issue that had no bearing on the election results. 2.    Being adjacent geographically: states marginal to Canada. 3.    Written or printed in the margin of a book: marginal notes. 4.    Barely within a lower standard or limit of quality: marginal writing ability; eked out a marginal existence.
Excerpted from The American Heritage Dictionary of the English Language, Third Edition 1996 by Houghton Mifflin Company. Electronic version licensed from INSO Corporation; further reproduction and distribution in accordance with the Copyright Law of the United States. All rights reserved.
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Name the 50. Name them.
I want to learn from a master...name the 50 things that can cause it...there are not 50..dont go and bullshit the readers here.

Not when you dont have a clue, or learn....or get called back after you rape a customer.

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Go on Terry, try to dig out of this one, but its obvious that in this case, you are clueless, and I suspect in this case, its more for your desire to attempt a discredit, instead of simply saying you dont understand what is being discussed.
How about you go on, since you are on a roll, and start with your male sexual statements next...other than bullshitting someone that simply likes sweet talk from you about a problem you cant fully diagnose over the net, you sweet talk em and fail to mention the little things that you would if you were there.

I never said, CORRECTLY CHARGED. I doubt seriously you know what correctly charged is.
I DO hope that when you change out a fan motor, you check superheat/subcool after, since you dont know how long the motors been on a downward spiral, or how its perfomance was PRIOR to the failure, and if another tech was there trying to correct the problem.

Because it can.
Hey Terry...why dont you go back, read the OPs statement, and you tell US oh great one...what would really cause it not to freeze PRIOR to the fan replacement.

The only Rookie here is you, obviously. You exist to flame anyone that does not agree with you.
Flame on, and while you are at it, learn a new language: English.

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CBHVAC wrote:

This is Turtle.
I have to dig no where here. Your have to answer the question about the increase of the air to the condenser only will cause the evaperator to freeze up. That is Plain and simple BULLSHIT. If you can't answer correctly , please don't try to answer question here with BULLSHIT.
Nowe call you on some bullshit is not called flame or discrediting at all but i want you to explan this Bullshit to me. If you say some bullshit , be prepaired to explain it.
TURTLE
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TURTLE wrote:

Damn Turtle. Let's try this: The evaporator coil is plugged and the U-bends on the coil are already frosting over, but there is just enough air over the evaporator coil's fins to keep the frost knocked off of them. Then you go out and put a higher RPM motor on the condenser, increasing the condenser airflow. Now the suction pressure is going to drop 3 or 4 pounds from what it was. The coil then begins to frost over because it was right at freezing before you changed the motor. The evaporator was *marginally* close to freezing already, just 32.1 degrees when you got there, or .1 deg above freezing. So it only has to drop .1deg in order to freeze. But 3 or 4 pounds lower suction means that the coil temp has dropped about 3 or 4 deg, so it's now way below freezing.
So you want to add refrigerant to fix it, wrong already, but let's go ahead and add some refrigerant. Now the subcool is way too high, the unit is running less efficiently than before, and because the liquid is cooler (that's what higher subcool means) as it goes into the evaporator the suction pressure will never come back up as high as it was before you changed the motor out. It's now maybe 1 or 2 pounds lower than it was before, and the coil is 1 or 2 degree colder, or still below freezing. Ice still forms even when you add refrigerant, unless of course you overcharge the system, in which case the compressor is going to go out prematurely, because it'll slug liquid when it gets hotter outside.
A system is tuned so that all of its parts work together efficiently and correctly. If you change the balance that was engineered in then you have hacked up the system and aren't saving the customer a single red penny. In fact you probably cost them more in the long run than if you had done it right the first time. If you know what you're doing then you can actually improve upon the original engineering but you don't seem to know enough about the system to even keep it at its original efficiency.
hvacrmedic
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RP wrote:

this is Turtle.
you have listed causes of the problem but what I'm speaking about is ONE STATEMENT THAT CB MADE FOR WHICH WAS NOT TRUE AT ALL. i will slow it down here for you to see it. George up above seen it too but it has slipped by you.
If you have a perfectly tuned & matching hvac system and then you can speed up the condenser fan motor to a point to freeze up the evaperator coil. It will never happen without something else causing the freezing up of the coil.
Now start poking hole in these words and don't start adding anyother statements with it. Just read the statement and speak about it with nothing else or cause added to it.
TURTLE
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