The 40″ wide O’Keefe & Merritt vintage gas stoves have a full sized broiler on the right side and a full sized oven on the left side. It’s an auto-light oven, meaning no match is needed to light it. There is a 24/7/365 small flame (standing pilot) instead, at the ready to ignite the main oven burner. That’s a fairly standard feature in gas stoves starting in the 1940s. What became common in that time were oven thermostats made by Robertshaw. They put their name on every oven thermostat dial.
Complimenting the Robertshaw brand labeled dial is a temperature chart enameled on the oven door’s inside panel. Even in the 1950s, precise temperature control was still a big enough advancement in stoves, makers felt it worthwhile to remind their consumers whenever they use the oven.
My stove’s status on delivery : grade C
Because this was my first gas stove and my first vintage stove, I only knew enough to judge it by appearance. It looked fine. But did the stove work fine? It was okay? Sort of. It took me weeks to realize the stove wasn’t in the best operational shape.
Issues:
- about a dozen gas leaks, large and small
- a few seized components and connectors
- badly degraded (corroded, rusting) parts
- gas valves in serious need of cleaning and relubing
- cracked cooktop burner D-stems
- areas that hadn’t been cleaned or maintained since the stove was made, some 60+ years ago
- electrical harness with cracking insulation
- grease saturated insulation in oven door
- non-functional clock and timer
- dust, dirt, burnt food in various pockets
- thermocouple in need of replacement
- The biggest problem was the oven thermostat. A thermostat is supposed to regulate the temperature. Well, it didn’t regulate the temperature. Once on, the flames would not diminish to maintain a temperature range. The oven temp would continue to climb and climb until I shut the oven off. Bottom line: the oven was very unsafe.
The stove cost me a couple hundred, which seemed inexpensive. Research indicated a replacement thermostat would cost a few hundred, on average. Prices ranged from $70 – $600 for thermostat that would meet the specifications for my stove.
Oven operational overview
| Normal operation for oven requires each of these components to work | image | status | |
| stove shutoff valve (A) |  | open | |
| oven pilot valve (B) |  | open | |
| oven pilot burner & orifice (C) |  | flame on, orifice clear | |
| thermocouple (D), connected to safety valve |  | generating 30 millivolts when heated | |
| oven thermostat valve (E) |  | open and regulating temperature | |
| gas solenoid valve, connected to clock (F) |  | open when clock set to manual | |
| oven safety valve (G), connected to thermocouple |  | open when receiving 30 millivolts from thermocouple | |
| oven orifice/shutter (H) |  | open, correct air/gas mixture for optimal burn |
A view of the real thing!
I’d never seen the workings of a gas stove. Looked a bit overwhelming to me during the first few weeks. But I was determined to get familiar. Happily, I began to realize it was not that hard to grasp the basics.
Just like the popular phrase “follow the money’, here it’s follow the gas flow. The gas flows in thru the flexible yellow gas hose to the black pipe (manifold).
Regarding the oven, the gas stops at the oven control until that’s opened. If everything else is working, the gas flows thru the gas line all the way to the big burner underneath the oven chamber where the little pilot burner ignites the main burner. Pretty simple.
See it all at once
What if my oven isn’t working
Now that I have a solid idea about what it takes for the oven to operate, if it stops working, I won’t feel so helpless. I could probably fix it, with a little luck.
If the cooktop burners and the broiler work, then I would know to focus on the just the oven portion. I know the chances are pretty good that, if the oven pilot is working, gas flow isn’t the problem. My first thought would be the thermocouple is dying. A weakened voltage would cause the safety valve to close, preventing gas from getting to the oven burner. I’ve learned to keep a spare thermocouple, since they aren’t expensive and not terribly hard to replace, at least in comparison to the other things that would be causing a problem.
I’d glance at the clock to make sure it’s set to “M”. Since Lucy’s clock and timer aren’t reliable, I don’t play with the controls, so I’m usually not worried about the clock interfering with the oven’s function.
Worse case scenario would be the safety valve or the oven thermostat failing. Repair or replacement of either of those can get pricey; $100 – $200 at the low end, $400 – $600 at the nosebleed high end.
The other components that could impact the oven are more obscure, so I’d worry about them last.
More detailed troubleshooting help, check out this page: Oven Won’t Light