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Is there such a thing as different fan blade pitches for condensers?
Air is being pushed out the sides of the top instead of directly out of the top of the unit. In other words, you can put you hand directly over the top of the unit and not feel anything. All the air is coming out around the sides at the top.
Is it a 1994 Resco 3 Ton unit.
I am not the original owner of this unit and my thoughts are that someone along the line maybe put on the wrong blade.
It is possible the unit had a fan shroud in it and someone took it out and did not put it back after motor change seen this before lots of times, matter fact just Friday on a call saw this on a old Trane XL900, there will be screw holes in the top usually were the shroud was mounted in.
Yes ,there are different pitches on blades. The wrong pitch can and will cause pre-mature motor failure (not enough air over the motor) Too much pitch-- over-amping of the motor. That's just what can happen to the motor. The lack of air getting pulled through the condensor(not enough pitch) will cause other problems.
Is there a guide or reference to determine what should be on there?
A dirty condensor coil will also cause this. I would start there first.
I've seen that before on the Carrier cubes, even with the original fan blade in place. Not sure if you can stop it by playing with the blade on the shaft. The venturi ring is a part of the top so that's not it. Most of the air is coming though the coil but instead of blowing up, it blows out the sides and can recirculate. At 11 years, you're doing good - you don't have much life left in that heap!
We manufacturer some of the same units in both 50 and 60 hertz. Some of our 50 hz condenser fan motors must have a different pitch blade in order to move the right amount of air without overheating the condenser fan motors.
...after checking for shroud and clean coils change that sucker out
I bet someone installed the wrong rotation motor and it's running backwards he said it's pushing the air out the side.
I agree with ^ and also check and make sure that your fan blade is above or "into" the shroud at least 1 ".Quote:
Originally posted by karsthuntr
A dirty condensor coil will also cause this. I would start there first.
Good thinking, but he did specifically say "the sides of the top"Quote:
Originally posted by mrbillpro
I bet someone installed the wrong rotation motor and it's running backwards he said it's pushing the air out the side.
to me, that means he expects it to go straight up, which will never really happen. My old ducane is the exact same way- and it works fine.
My big green trane doesn't blow air out the top at all- it comes out the sides "near" the top.
Don't try to "fix it". It's not broke.
My ASSumption is that aw has just bought this house and is checking over everything with a fine-tooth-comb. It's good, but this is NOT a problem.
Don't worry about it if you are comfortable.
[Edited by old yeller on 06-21-2005 at 10:55 AM]
aw,
Is it cooling?
My experience has been that the blade and shroud relative position may be incorrect. Moving the blade up and down on the motor shaft changes this relationship.
Trial and error may be your only recourse. Then again, the airflow may be correct.
Good luck...
The unit is "cooling" so to speak..I think I have other issues such as heat gain/air loss in the house. Thermostat will not stay below 77 in the afternoon. Split between supply and return in 14-15 at the furthest supply duct. I have metal ductwork in the attic so taking a reading near the coil is difficult.
The unit will run for 11 out of 24 hours. This is an older house built int 1973...with little attic insulation.
There is no shroud so to speak and no indication there ever was one.
Thanks for the help everyone
Sounds like a decent temp drop. Call your local power company and ask if they have a program where you can get reimbursed for adding insulation to your home. I was quoted about 1k for added various amounts of blown-in in various places, and the rebate calculation paid for about 75% of it. Worth every cent if it's done right.Quote:
Originally posted by aw
The unit is "cooling" so to speak..I think I have other issues such as heat gain/air loss in the house. Thermostat will not stay below 77 in the afternoon. Split between supply and return in 14-15 at the furthest supply duct. I have metal ductwork in the attic so taking a reading near the coil is difficult.
The unit will run for 11 out of 24 hours. This is an older house built int 1973...with little attic insulation.
There is no shroud so to speak and no indication there ever was one.
Thanks for the help everyone
Sounds like you are new to this house. Have you given the unit a good look-see to find supply AND return holes? Either one can cause lots more problems than just wasted air in the attic.
Can you just take a picture of the unit so we can take that issue off the table?
Here are some pics of my steaming pile...er uh condensing unit. No air is blowing out of the inside of the red circle. It blows out where the blue arrows are...towards the side at the top.
http://web.wtez.net/aw55455/hvac/cond1.jpg
http://web.wtez.net/aw55455/hvac/cond2.jpg
[Edited by aw on 06-21-2005 at 11:56 PM]
AW,
The photos are great. There is a shroud. It is the ring in which the blade rotates. The curved lip controls the air leaving the blade.
We still haven't estabished if you have a problem with condenser air flow, so this is an FYI.
I would bet real $ that your condensor coil is very dirty.
It looks clean on the outside, but the fins change directions a couple of times. Dirt builds up where the fins change directions, and will eventually block the airflow through the coil.
When the condensor coil gets dirty enough, the fan will start pulling air down through the center of the top. When it starts doing that, it will throw air off the ends of the fan blade.
You can check it out by laying a piece of paper down near the middle of the top grill, you will find that it will actually get sucked down against the grill.
The condensor coil needs to be thoroughly cleaned and the refrigerant charge checked.
That may have never had a fan shroud. Trane used the same pressing for the tops of multiple units, but just put little plastic plugs in the holes if it was for a unit that didn't use a shroud. The plastic plugs generally desentigrate after a few years in the sun.Quote:
Originally posted by mrbillpro
matter fact just Friday on a call saw this on a old Trane XL900, there will be screw holes in the top usually were the shroud was mounted in.
My old ducane does the same thing and it is clean as a whistle with mch more coil surface area (it's a big sqare shape= larger coil surface). It does the same thing by throwing air to the sides instead of up.
Is the air that you feel coming out warm?
I still don't think you have a problem here, but getting your system looked at by a pro in a new house is ALWAYS a good idea.