Hey everyone,

I figured someone in the crowd would have some experience with this.

I've got a 9 year old A.O. Smith water heater and about a week ago it stopped working.

We called the tech out and he walked in, checked it out, disconnected the exhaust pipe and then turned the unit on. Dust flew around as it turned on and its been working fine ever since.

He said that the blower motor was going on it. He wanted $600 to replace it or $1190 to install a new tank. As I understand it the blower motor throws a pressure switch to let the system know its safe to run the gas burner. Makes sense. He said the blower was getting weak and was starting to be unable to throw the pressure switch.

I hopped on the internet and found the same replacement part for $200. I figured I could put it on my self. However the tanks been fine, at least until last night, it went out again. I popped off the exhaust pipe and now its fine again..

So I was thinking what causes an electric motor to weaken? The bearings start to go right? So I then thought about just replacing the motor itself instead of the entire assembly...

Motor:
Fasco Industries
No. 702110770
Type: U21B
RPM: 3275
115, 2.3A
AO Smith Part Number: 183505-000
Sealed Ball Bearing



What do you guys think? Suggestions? Thoughts?

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

Looks like a simple fix. if the tank is fine I'd just put on a new motor and let it be.

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Thats what I felt too. I just cant seem to find motor only. Its whole assembly best I can find.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

If popping the exhaust pipe fixes the problem, have you checked the exhaust pipe for blockages?

If the pipe is partially blocked/clogged the motor has to work harder. The bearings will wear and the motor will overheat. The motor may be a symptom, the pipe may be a contributing cause.

Check the air-vane...that's a part that's gets a little cranky over time. You mentioned "dust."

If you can SAFELY tear into it, disassemble the box and clean up the crap (dust) and while it's apart, get a part number off the switch. The switch MIGHT be about $25 or so, but be sure it switches on/off like the original. And...the blower is a good find.

Should be a simple, 2-hour DIYer project...just be sure to take a lot of pre-disassembly pictures and put yourself together a little step-by-step of taking it apart and putting it back together.

And as Yak mentioned, be sure EVERYTHING DOWNSTREAM FROM THE BLOWER/VANE ASSEMBLY IS CLEAR AS THE DAY IT WAS INSTALLED. Birds LOVE openings that provide cover from the elements. Exhast chutes and baffles make nice nesting areas and all they (birds) will build is a nest to fit the area and still allow a little heated air to get by...hell...they need some warmth too, don't they? Make it rough on 'em and get them to go build in the neighbors' flues and chutes.

And if gas is involved...leave the doobies upstairs...

__________________

M. G. Burg
'10 - Dakota SXT - Daily Ride / ≈ 172.5K
.'76 - 450SLC - 107.024.12 / < .89.20 K
..'77 - 280E - 123.033.12 / > 128.20 K
...'67 - El Camino - 283ci / > 207.00 K
....'75 - Yamaha - 650XS / < 21.00 K
.....'87 - G20 Sportvan / > 206.00 K
......'85 - 4WINNS 160 I.O. / 140hp
.......'74 - Honda CT70 / Real 125
.
“I didn’t really say everything I said.”
. . . . . . . . . . . . . . . . . . ~ Yogi Berra ~

We do not have a blower motor in the natural gas water heater in CA. What is it for? It is used to throw the pressure switch? Normally it is the ignitor/burner is faulty or a physical leak in our heater.

I would try checking whether there is a carbon brush inside the motor. A lot of the time is the brush is worn. It happens to my central vacuum, change them out and everything is fine.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

I gather that the average lifespan of a tank is 8 to 12 years. I know I've replaced them at 10 years a few times.

Might be less work and as economical in the long run to just replace the whole thing.

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1986 300SDL, 362K
1984 300D, 138K

It's a forced air exhaust. May be code depending on the location of the heater and/or the length of run of the flue.

The switch/sensor should detect that the motor is running prior to opening the gas valve. No fan = no exhaust gases = no CO build up.

I've had power vent space heaters that use that style motor, and a Whitfield pellet stove that I ran for 15 years- never replaced any motors. I would see if you can lubricate it.

Cant see the rest of the 3 in. PVC...Installation code states that onle 3 bends can be used. How many bends are on your PVC?

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CHILCUTT~
The secret to a long life. Is knowing when it is time to leave.

I'd check the air vane setup too or whatever mechanism is used to detect air movement.

Our furnace, can't remember the brand, has been great (knock on wood) except for the sensor from the exhaust fan.
They use a rubber hose from the exhaust to the sensor.
Dry rot gets it regularly, the sensor failed once too, last time I bought the rubber hose I bought about 2 feet (like 2 bucks a foot geesh), only need 6 or 8 inches, every year I trim off a few inches at the end and reconnect. works fine.

To check this, does the fan run but the ignitor does not kick in ?
Check the sensor or whatever your unit uses.

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KLK, MCSE

1990 500SL

I was always taught to respect my elders.
I don't have to respect too many people anymore.

As I understand it you have a forced draught {or draft} system. Inadequate pressure due to dust and dirt buildup would be sufficient to fail to trigger the pressure switch which activates the burner. If the motor runs well by itself simply disassemble everything associated with the draught tube, hell, even the pressure vane/switch may be weak or stuck due to buildup of debris.

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... but where was it going?

Electric motors are one of the most simple and rugged machines made. Unless the bearings are seized, or the windings have overheated and shorted, it probably isn't 'going' anywhere!

Sounds like they're trying to sell you an new motor instead of a good impeller blade cleaning.

Check carefully, and question everything!

Its probably just a draft switch. Big difference. Unless its humming on start up, the motor is fine.

Try cleaning everything first to see what happens.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2