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-   -   Found cracks on my inducer housing (http://www.diychatroom.com/f17/found-cracks-my-inducer-housing-90172/)

rlukas79 12-21-2010 01:59 PM

Found cracks on my inducer housing
 
So i was having short cycling issues. I noticed that it wasnt just some sloppy work the factory workers did when they put the inducer on the unit, it actually has 3 cracks that are covered with high temp sealant.

WOuld a cracked housing cause the pressure swtich to shut the furnace off?

yuri 12-21-2010 02:41 PM

Yes, it loses draft thru the cracks. Probably a Rheem or Ruud. The replacement is cast aluminum.

rlukas79 12-21-2010 03:13 PM

Quote:

Originally Posted by yuri (Post 554895)
Yes, it loses draft thru the cracks. Probably a Rheem or Ruud. The replacement is cast aluminum.


rheem built in 94. A local spot has the replacement for 200. The service guy said it would cost 700.00 to replace. I was born at night, but not last night. 4 screws and a gasket. If i can tear down engine blocks and rebuild them, sure as **** can replace this on my own.

I noticed that this inducer had high temp sealent all around it. Do people not use gaskets for these and just use high temp sealent?

yuri 12-21-2010 03:20 PM

It comes with a new gasket in the box. We charge over $500 to replace it. Dealer cost has nothing to do with it. GM sells spark plugs for under $20 but installs them for 5X as much.

hvaclover 12-21-2010 04:23 PM

hey ruklas79 where do you live? I want to open shop there if they are getting $700 for an inducer.

rlukas79 12-21-2010 07:11 PM

Quote:

Originally Posted by hvaclover (Post 554973)
hey ruklas79 where do you live? I want to open shop there if they are getting $700 for an inducer.

Central NJ

hvaclover 12-22-2010 01:46 AM

Quote:

Originally Posted by rlukas79 (Post 555102)
Central NJ

uuhh..maybe not. protection rates are too high there.

rlukas79 12-22-2010 08:02 AM

replaced the inducer fan, it was easy. 4 screws. Someone did a hack job on this though. Old owners must have had someone out here to service the furnace. Half the abestos gasket was missing, the used high temp sealent every where and the inducer had 3 massive cracks, Of course they used the sealent to patch the cracks up but the sealent seperated. The new part had the metal housing and a new gasket. I noticed these two things immediately:

1. The new inducer is quiet. Leading me to believe the old one was on it's last legs.
2. The temperature of the unit itself was down. I had my fan speed set on high due the short cycling. I was getting temps of around 125 with the fan on high and taking the reading at 2 feet into the supply plenum. Now the temperature is down about 5 degrees. I switched the fan speed back to it's normal setting and I'll observe the temperature.

Could a bad inducer also cause the internal temperature to get too hot? Thus a installing a new one, getting it in the right temperature?

rlukas79 12-22-2010 09:09 AM

So I put the fan on medium, where it was before it started short cycling etc.

I get these temperatures. After 45 mins of running.

my supply plenum is 136
my return is 78

(thermostat is calling for 72 degrees)

heat rise is 58 degrees
furnace spec is 75k BTUs 80% (rheem criterion)
temp rise is 40-70

Should I be lower than those numbers? Keep in mind it's a 16 year old furnace. I can always use the higher fan speed.

HVAC_NW 12-22-2010 01:27 PM

Quote:

Originally Posted by rlukas79 (Post 554929)
rheem built in 94. A local spot has the replacement for 200. The service guy said it would cost 700.00 to replace. I was born at night, but not last night. 4 screws and a gasket. If i can tear down engine blocks and rebuild them, sure as **** can replace this on my own.

I noticed that this inducer had high temp sealent all around it. Do people not use gaskets for these and just use high temp sealent?

It's the trade culture. They make sure parts are inaccessible to DIYers in order to protect job security for service techs. The outfits that do offer them to the public often charge substantially higher prices than supply houses. Rheem parts are supposed to be pretty easy to get.

When you say "short cycling" do you mean the unit is cutting out before the thermostat tells the unit to turn off?

rlukas79 12-22-2010 02:19 PM

Quote:

Originally Posted by HVAC_NW (Post 555512)
It's the trade culture. They make sure parts are inaccessible to DIYers in order to protect job security for service techs. The outfits that do offer them to the public often charge substantially higher prices than supply houses. Rheem parts are supposed to be pretty easy to get.

When you say "short cycling" do you mean the unit is cutting out before the thermostat tells the unit to turn off?

yes. when it would happen, there would be no flashing LEDs on the board. However, the inducer housing was substantially cracked

hvaclover 12-22-2010 02:39 PM

Sounds like a separate issue all it's own now that you have changed the inducer.

rlukas79 12-22-2010 02:57 PM

Quote:

Originally Posted by hvaclover (Post 555548)
Sounds like a separate issue all it's own now that you have changed the inducer.

There are no other issues that were found. It hasn't short cycled in over a week now. The pressure switch had to be the cause of the problem due to lossing pressure from the inducer.

No soot or rust around the heat exchanger area, solid blue jets.

Structurally the system is fine, meaning the supply and return system and duct size. So air flow isn't the problem

The temperature rise is within spec. The fan speed has been set to medium high from medium low. So my temp rise went from 57-58 to 52-53. The HVAC tech said to shoot for the middle. HE said I could have left it ont he medium low setting and it would have been fine but the medium high setting would help keep it int he middle of the heat rise. HE told me that most of the rheem furnaces he services today that are over 10 years old are all on the high side of the temp rise (40-70).

hvaclover 12-22-2010 04:17 PM

didn't read the whole post . My bad.

HVAC_NW 12-22-2010 07:43 PM

Did you check the gas manifold pressure? Utility brings me gas at 6.5" WC and manifold was supposed to be 3.5" but mine was pushing 5" WC brand new. Who knows how it happened. It's a Honeywell valve on a Rheem.


Turn off every other appliances, or subtract their gas consumption on paper. At 75,000 BTU input, it should take 4 minutes to go through five cu.ft of gas. (assume 1,000 BTU/cu.ft). If its less than 4 minutes/5 cu.ft, you need to get the manifold pressure checked. It's over-firing if it's going through five cubes in considerably less than four minutes. If that's the case, the regulator on gas valve should be adjusted, then checked over the next few weeks(by clocking the meter) If it won't hold the setting, the gas valve needs to be replaced.

Oh and obviously, new filter and cleaning the blower fan doesn't hurt.


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