Is $320 too much to replace the thermocouple on my classic 1950s-era oven?

May 16, 2007 1:27 PM

$320 to replace the thermocouple on my classic 1950s-era oven. Too much? Nothing happens when I turn on the gas. I believe the guy when he says it's a bad thermocouple, I just don't know if the price is crazy or not. It's $65 if I send them home without doing anything. Thanks!
posted by scarabic to home & garden (13 comments total)

Gas? Electric?

I'm guessing here, but I'd think you'd could get a new oven for a little bit more and probably re-coup the difference in engery savings pretty quickly.
posted by tiamat at 1:32 PM on May 16, 2007

Um..a thermocouple should be a couple of bucks at your local Home Despot-type-place.

I've replaced them on water heaters - very easy. The process may be completely different from overs, though.
posted by Cat Pie Hurts at 1:34 PM on May 16, 2007

tiamat, the "nothing happens when I turn on the gas" part is a clue.
Here are replacement thermocouples for $20. They also sell a bunch of other parts.
In fact, that whole site is worth a gander.
posted by Floydd at 1:41 PM on May 16, 2007

You're in Berkeley, right? There's a place on Cesar Chavez at Bryant called Rancho Grande. They have tons of rebuilt vintage appliances and ovens and I had a guy come over to my house from there to look at my old vintage stove. Another oven repair guy had wanted something like $300, but this guy charged me less than $50 and it worked fine after that. I can't remember exactly what the problem was but it sounds similar to yours. Maybe if you're in the city sometime you could stop by and ask them.
posted by otherwordlyglow at 1:41 PM on May 16, 2007 [1 favorite]

Also, head to Urban Ore or - even better - Ohmega down on San Pablo. They can hook you up with someone who specializes in old stoves and ovens, and the excellent advice from the kind folks at Ohmega is always free and very useful.
posted by luriete at 1:45 PM on May 16, 2007

I wouldn't pay $320 for the fix. But then I'd figure out how to do the job myself. I don't imagine the job is very difficult and should cost less than $320 even figuring in the $65 to send the guy home.

Information on oven ignition systems and repair.

I'm guessing here, but I'd think you'd could get a new oven for a little bit more and probably re-coup the difference in energy savings pretty quickly.

A new gas oven is likely somewhat more efficient since it probably has better insulation in the oven and doesn't have a continually lit pilot light. But the difference definitely won't be recouped quickly and if you look at it from an environmental perspective you've got energy associated with the manufacturing of the new oven and disposal of the old. And any new oven almost certainly won't last fifty years.
posted by 6550 at 1:48 PM on May 16, 2007

Also, you can find more information on ovens and repair by searching for gas oven thermocouple.
posted by 6550 at 1:49 PM on May 16, 2007

Send me a drawing and a schematic, we build them here in my manufacturing warehouse. If you want you can measure and take a picture. Our thermocouples are not expensive, usually around 50.00 and I gots major clout.
A thermocouple is 2 pcs of dissimaliar wires that when temperature is applied, they produce a milliamp(mA) current output that is proportional to the temperature applied. They come in various types according to temperature range. They rarely fail on their own as they are really just pieces of wire. Call me at the office if you wish 800-839-6381.
posted by winks007 at 2:08 PM on May 16, 2007 [1 favorite]

for more on thermocouples...
How a Thermocouple Works:
The TC is a very simple device that is simply the junction of two dissimilar metals. The junction of the two metals produces an electric voltage. The voltage produced is a very small direct current voltage and is actually in the millivolts (mvDC) range. Any two dissimilar metal wires will produce this voltage, however, certain types of thermocouples are selected as standard thermocouples because of the characteristics of the voltage output. The mvDC must be sufficient in magnitude to amplify so other instrumentation can utilize it for display and control of temperature. In addition to being a strong enough signal, it also should be somewhat linear over a range of temperature.


Standard Thermocouple Types:
Industry accepted standard thermocouples are: J, K, E, T, R and S. There are more types of thermocouples, however these are the most common with J and K being by far the most commonly used type.


Thermocouple Hot Junctions:
The hot junction is the tip of the thermocouple at which the heat measurement is sensed. Magnesium Oxide (MgO) Thermocouples are available in four basic hot junction styles as follows:

GROUNDED JUNCTION
Wires welded directly to the sheath material.
Rapid response time.
Protects T/C wires from corrosive environment.
Recommended for high pressure gases and liquids.
"U" UNGROUNDED JUNCTION
Sensing junction completely insulated from sheath material with MgO packing. (Slightly slower response time than grounded)
Recommended where readings may be affected by electrical or magnetic fields.
"E" EXPOSED JUNCTION
Instantaneous response time as T/C wires are welded outside sheath.
The Thermocouple is sealed with a special compound against moisture.
Not recommended for corrosive environments or high temperatures.
"I" UNGROUNDED ISOLATED
Ungrounded and also separated or isolated from each other. (Applies to dual thermocouples only)



Thermocouple Specifications
Type J: Iron / Constantan:

Useful range of temperature is -300°F to 1200°F.
Maximum temperature 1600°F.
Possible problems: Oxidizes rapidly due to the iron wire. The use of the stainless steel
metal sheathed MgO style of construction has overcome some of this problem and is
much preferred over the beaded bare wire style of thermocouple.
Type K: Chromel / Alumel
Useful range of temperature is -300°F to 1800°F.
Maximum temperature 2300°F.
Type E: Chromel / Constantan
Useful range of temperature is -300°F to 1800°F.
Maximum temperature 1000°F
Type T: Copper / Constantan
Useful range of temperature is -300°F to 700°F.
Maximum temperature 700°F.
Type R and S: Platinum / Platinum-Rhodium
Useful range of temperature is 40°F to 3000°F. Maximum temperature 2300°F.
Both the R and S thermocouples are used for very high temperatures. These couples
are relatively expensive compared to other thermocouples since they are made of platinum.
These thermocouples must not touch the sheath if a metal sheath is used for construction.
Normally a ceramic protective tube and ceramic beads are used for construction for both high temperature reasons and to prevent contamination of the noble metal.
METAL SHEATH MATERIAL LIMITS
Continuous Maximum Temperature
Ratings F, in oxidizing atmospheresMATERIAL TEMPERATURE

304 Stainless Steel 1650° F
310 Stainless Steel 2100° F
316 Stainless Steel 1700° F
Inconel 600 2100° F


Call Bobby @ 800-839-6381
posted by winks007 at 2:42 PM on May 16, 2007 [1 favorite]

Thanks folks. It's not really the price of the part that matters. I'm not comfortable working on anything in my house that's on a gas line. I will muddle through plumbing with the main off but for safety reasons I draw the line at electric and gas. Call me a pussy about to get fleeced, but I'd rather be that than a dead dipshit who didn't know when to call in a pro.

I was looking for perspective on the price. Sounds like I paid too much, or at least could have possibly paid less to have it done. This thing is a real dinosaur (it has a built in trash incinerator - that's how old it is!) and I don't think I was willing to haul it to a shop (good suggestion for the future, though. Thanks, otherwordlyglow).

I think they fleeced me based on the size and age of the machine. If it were some newish $350 piece of shit I would have balked right away. I guess I considered myself lucky to even find someone willing to work on such an ancient device. But that was dumb. The technology inside is still in use everywhere and in many ways easier to work on than more recent builds. The guy made me a big speech about how I can probably get $5K for the thing if I have a mind to sell it. That seals it.

Oh well. I paid a bit too much. But after months without an oven I'll be eating banana bread in the morrrrrrning!! :)
posted by scarabic at 6:34 PM on May 16, 2007

Send me a drawing and a schematic, we build them here in my manufacturing warehouse.

Holy crap, man. I've always been pretty amazed at the diversity of the MetaFilter community, but this has got to take the cake.
posted by Civil_Disobedient at 4:41 AM on May 17, 2007

...but this has got to take the cake.

Agreed! winks007, do you mind if I file your number away for next time my 1964 Roper oven needs an ungettable part?

Scarabic - I understand being uncomfortable working on gas/electric. I just bought a house, and it has taken me a while to get used to doing this as well. As long as you remember to kill the breaker and shut off the gas line leading to the oven, you should be A-OK.
posted by sluggo at 4:56 AM on May 17, 2007

Agreed! winks007, do you mind if I file your number away for next time my 1964 Roper oven needs an ungettable part?

sluggo, I can't help with applaince parts, in my off-time, I am somewhat of a tinkerer. That is - I take things apart and attempt to put them back together in a decent working condition.

In my 8-5 (read "SQUARE") working life, I sell temperature, pressure and flow products through a representative firm for about 20 companies in the above referenced disciplines @ www.teco-inc.com, It just so happens that in the shop downstairs, they repair/refurbish magnetic flowmeters and they also build thermocouples, thermowells and RTD. Feel free to keep my number anyway.

If any of your guys work in process measurement or the paper refining, petrochemical refining, and need some help with, flow, consistency, pressure or temperature, drop me a line. Email is in my profile.

Good luck SCARABIC, it sounds like you have one of the coolest ovens ever.

Also...find the temerature range or "type" of your thermocouple and I 'll send you a free sample of the thermocouple wire and you can apply heat and measure the mA dc voltage directly from the wires. A ton of fun!!! ok, ok, so I'm a geek, I still got the girl!
posted by winks007 at 6:41 AM on May 17, 2007