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My AC started making grinding noises in the basement so i turned it off and checked and a doughnut piece of metal broke off the blower fan by the wheel where the belt attaches. I noticed now i can wiggle around the axel of the blower fan freely, so it seems obvious what is wrong. Does this mean the whole blower fan unit needs to be replaced? If so is this very difficult, im fairly handy and an engineer but never have tackled much HVAC work. Additionally, how difficult is it to find a replacement blower fan? I think the unit maybe relatively old, so do these unit come in a standard size.

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My AC started making grinding noises in the basement so i turned it off and checked and a doughnut piece of metal broke off the blower fan by the wheel where the belt attaches. I noticed now i can wiggle around the axel of the blower fan freely, so it seems obvious what is wrong. Does this mean the whole blower fan unit needs to be replaced? If so is this very difficult, im fairly handy and an engineer but never have tackled much HVAC work. Additionally, how difficult is it to find a replacement blower fan? I think the unit maybe relatively old, so do these unit come in a standard size.

Thanks
Sounds like maybe a pillow block bearing. Grainger would probably have it, otherwise try an HVAC wholesaler and see if they will sell one (or a pair) to you. If one fell apart the other one probably isn't in good shape either.
 

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Discussion Starter #4
update

ok, so the furnace is the original williamson oil furnace model 1167 12-5. I think its from 1975. I opened up one side of the furnace and realized i wouldnt be able to replace the blower unless i removed the other side of the furnance. I unscrewed all the screws but 2 of them are competely locked up so ill have to drill them out i guess.

I had a guy come out to give his analysis, and he said i probably wouldnt be able to find a replacement blower and i should replace the furnace and the orginal interior ac coil that has a small leak (the exterior ac unit is only 7 years old). He quoted me 4600 for a lennox oil OV23 furnace, coil replacement, themostat, 1 year service, 5 year parts warranty, with tax and installation. Also he also said id save a bunch on oil (50%) and ac with the new furnace and coil.
- First off is this price reasonable, it sounds high to me?
- Secondly, is oil the right way to go? I dont have access to gas but what about a heat-pump (i live in cincinnati)?
- How much more would a heat pump system cost? Could i get a tax credit also?
- Should i just fix my existing blower? Anyone know if there is a match for my make and model?

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Laymans terms

1 Therm of energy can be had from approx. 0.71 gal of fuel oil and 8.4 kwh of heat pump heat.

YOYIZIT, Why don't you answer in layman's terms ?? most people on DIY don't know what most of your answers mean.

Remember not engineers but laymen asking questions that should not need interpretation.

You are a very complicating person to the average DIY with all your charts and references and calculations.

These people are just trying to get basic answers to save a buck.

I have read many of your posts and couldn't take it anymore had to say something.

To the op just install a new high eff oil system with new high eff A/C forget the heat pump, you still need oil back up in Cincinnati anyway.
I am going to get many replies from the Heat Pump Fanatics.
 

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YOYIZIT, Why don't you answer in layman's terms ?? most people on DIY don't know what most of your answers mean.

That's why there is Google, or they can ask for clarification. I didn't know what a therm was, either, until last year. I called the gas company, but it turns out I could have looked it up.
By asking, they are showing some interest. If they don't ask, I don't pursue it. Otherwise, I end up writing huge replies explaining every little detail, and they are not read anyway.
It's hard to gauge the level of expertise of OPs.


Remember not engineers but laymen asking questions that should not need interpretation.
You are a very complicating person to the average DIY with all your charts and references and calculations.
These people are just trying to get basic answers to save a buck.

That's the problem; sometimes there are no simple answers. You have to know basic physics, elec. theory and some HVAC stuff.


I have read many of your posts and couldn't take it anymore had to say something.

It seems other people have the same problem with you, but for different reasons.


To the op just install a new high eff oil system with new high eff A/C forget the heat pump, you still need oil back up in Cincinnati anyway.
I am going to get many replies from the Heat Pump Fanatics.
While you have a point*, this is supposed to be a cooperative effort so there should be some burden on OPs to do basic research if necessary.
At any point along the way the OP can decide if (s)he wants to bail (and hire someone) or put in the effort to find out the answers him/herself.
Sometimes the right DIY answer is: Hire someone.

*And I thank you, Mr. Sultan, for not replying to me in a provocative way, or a way intended to demean.
 

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You might save up to 50% on your heating bill with a new oil furnace. If the contractor actually sizes it to the load(heatloss) of your house.

If he just installs the same size. Then you might get a 15% savings.

While a heat pump may save you more. Deending on your electric rate. It will probalby cost you more to have installed.

In order to get the tax credit. You have to get a pretty high efficiency unit. And sometimes. You don't even break on the installation cost. And it can take a while to recoup your money. Again, depending on your electric rates.

You should get 2 or 3 more estimates. And ask them about switching to a heat pump. Or even a dual fuel heat pump.
 

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You may be able to get a new blower if it is/was made by Lau/Delhi and has a number on it like 8-13 which means a 8" by 13" wheel and can be cross referenced by a heating supplier. I would consider a new furnace as any oil furnace at that age probably has a poor combustion chamber/ is not efficient and going to be a money $$ pit in repairs. The new blower may get you buy in a pinch but a new furnace is better value for your $$ than doing repairs. Oil furnaces can also produce carbon monoxide and have cracked heat exchangers same as gas.
 

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HDD doesn't even need to be looked at.

Really has little to no bearing on the economics of a heat pump.
You need to know bin hours at temp, HDD won't tell you a thing.

HDD is just about the most abused number for figuring anything with heating.

Its ok for fuel delivery if you are going to adjust the K factor after every delivery. But thats about all its really worth using it for.

You can make HDD numbers look good by fudging the math to fit the results. But, they are fudged numbers. Makes them worthless.

People have been trying for more then 40 years.
 

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You need to know bin hours at temp
Each K factor adjustment was 5%? 10%? That's close enough for me for a first cut.

I thought 64 F for 24 hours = 24 bin hours = 1 HDD?
If it's
"The Bin Hours data is presented in 5 degree [wide] Fahrenheit bins." it's even more approximate, since you are rounding to the nearest five degrees F.
HDD data rounds to the nearest degree.
 

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So tell me. Why the same house can lose 23,075 BTUs on a 25HDD day, or can lose 16,400 BTUs on a 25 HDD day.
 

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So tell me. Why the same house can lose 23,075 BTUs on a 25HDD day, or can lose 16,400 BTUs on a 25 HDD day.
Insolation? Wind? Rain? Snow?

(23+16)/2 = 19.5, 19.5 -16 = 3.5, so it's 3.5/19.5 = ~18%, so it's a +/- 18% variation. Not bad for doing economics numbers.
And the best you can do with Manual J is +/-5%? I've seen this accuracy limit somewhere. . .?

The other thing is a statistical effect. You make the measurement above once and you +/- 18% accuracy. If you make it 100 times over several months you get to be within +/- ~2% of the true value.
 

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Insolation? Wind? Rain? Snow?

(23+16)/2 = 19.5, 19.5 -16 = 3.5, so it's a 3.5/19.5 = ~18%, so it's a +/- 18% variation. Not bad for doing economics numbers.
And the best you can do with Manual J is +/-5%? I've seen this accuracy limit somewhere. . .?

The other thing is a statistical effect. You make the measurement above once and you +/- 18% accuracy. If you make it 100 times over several months you get to be within +/- ~2% of the true value.
Yes, you can keep fudging it till you get it close.

Out of 4 guesses, you got 3 things. Your still missing atleast ONE big one.
 

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Yeah, a girl said that to me, once.

Absorption of the exterior surface? Ground temp. variation?

Fudging puts me in good company
http://en.wikipedia.org/wiki/Fudging
Doesn't put you in good company.

If you don't know all the things that can throw off the HDD calculation.
Then how can you come up with anything but a false result.

HDDs doesn't need to be known, to set up a dual fuel system.
Or to determine if a dual fuel system is appropriate for an area.

An area with 10,500HDDs may not be a good place for a dual fuel system. While another place with 12,000HDDS may be an ideal pace for a dual fuel system.

Its just an abused number.
 

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HDDs doesn't need to be known, to set up a dual fuel system.

No, only to determine if it's economical.

Or to determine if a dual fuel system is appropriate for an area.

An area with 10,500HDDs may not be a good place for a dual fuel system. While another place with 12,000HDDS may be an ideal pace for a dual fuel system.

Its just an abused number.

Here's what I've got to go on.

"A dual-fuel heat pump is an electric heat pump and a gas furnace all in one. In the Tennessee Valley, where temperatures are typically above freezing and we enjoy some of the lowest electric rates in the U.S., a heat pump is the most efficient way to heat your home. In those few instances when the temperature drops below freezing, a gas furnace provides heat more economically. By combining the two, you can have the benefits of both systems.
How it works
When the temperature is above 35 degrees or so, the dual-fuel heat pump uses electricity to heat your home as necessary. This type of heat circulates evenly throughout your home, and isn't too dry. When it gets really cold outside (around 35 degrees or lower), the heat pump automatically switches to supplemental gas heat for better efficiency."

And, HDD For Knoxville, Tenn.

6/1/08
13
7/1/08
7
8/1/08
7
9/1/08
26
10/1/08
264
11/1/08
586
12/1/08
712
1/1/09
880
2/1/09
627
3/1/09
447
4/1/09
272
5/1/09
77

With HDD totaling 3800 and change.
 
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