gas oven diagnostic help, please

I have a BlueStar gas range, six burners, oven+broiler, all gas. A few days ago the oven quit working: the pilot light comes on but there is no ignite r heat or gas flow at any position of the oven control knob, including broi l.

A bit of googling and we figured it was the igniter. I had the igniter fail in my boiler a while ago so I was familiar with this.

The old igniter has a cold resistance of over 300 ohms; when the oven knob is on, 120 V appears across it but no current flows (I have a clamp ammeter ). Got a replacement igniter, cold resistance is about 50 ohms.

But it still doesn't work. There's still 120 V across the igniter but still no current flows. The igniter doesn't heat and the gas valve doesn't open. Obviously at 50 ohms it should be passing 2.4 amps and generating 280+ Wat ts, at least until it warms up.

So there's some other very high resistance in the circuit--but I *do* see 1

20 V so it's not a broken wire.

Is the gas valve the next likely culprit?

The gas valve is a dual design that combines the oven and the broiler contr ols into one block. I cannot tell if these functions are inter-wired, excep t that the broiler doesn't work either, so perhaps they are. I never knew w hether running the broiler also lit the bottom burner.

Any advice appreciated,

Chip C Toronto

Reply to
Chip C
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ys ago the oven quit working: the pilot light comes on but there is no igni ter heat or gas flow at any position of the oven control knob, including br oil.

I'm confused. I thought appliances that had pilot lights did not have ignit ers.

il in my boiler a while ago so I was familiar with this.

b is on, 120 V appears across it but no current flows (I have a clamp ammet er). Got a replacement igniter, cold resistance is about 50 ohms.

ll no current flows.

That would seem to be impossible. If it has a resistance of 50 ohms and 120 v across it, current has to flow, per ohm's law.

The igniter doesn't heat and the gas valve doesn't open. Obviously at 50 o hms it should be passing 2.4 amps and generating 280+ Watts, at least until it warms up.

Agree, are you sure you're measuring what you think you're measuring.

120 V so it's not a broken wire.

It doesn't matter what other resistance there is, if you have 120v across t he igniter substantial current has to flow and it has to get hot.

I doubt it. The igniter should get hot with or without the valve.

trols into one block. I cannot tell if these functions are inter-wired, exc ept that the broiler doesn't work either, so perhaps they are. I never knew whether running the broiler also lit the bottom burner.

Reply to
trader_4

He is probably calling a gas solenoid valve the igniter. If so, ohms law for DC does not apply,but for AC. To find the current, you would need to know the inductance of the coil, or maybe must the name tag of the solenoid.

Reply to
Ralph Mowery

In fact I was calling the front panel indicator lamp the "pilot light", sorry for the confusion. The igniter and the gas valve I'm pretty sure I got right.

The fact that the indicator lamp is lit suggests that the thermostat is calling for heat, and obviously that there's power.

I think the gas valve is the next thing to look at; possibly it's failed in a way where it "passes" 120 V by induction but won't pass current.

I don't know what to make of the difference in cold resistance between the old igniter and the new one. I can believe that as they age their resistance changes but I don't know how it might factor into this situation.

Anyhow, thanks for the comments, the gas valve is on the back of the range so it's more of a hassle to get to.

Chip C Toronto

Reply to
Chip C

Again, if there is in fact 120V across the igniter and it's not getting hot, then it would seem to me there are only three possibilities:

1 - The igniter is bad

2 - Ohm's Law has been repealed

3 - You're not measuring what you think you're measuring
Reply to
trader_4
[snip]

It's possible. High source impedance, where 120V is present only with no load.

Reply to
Sam E

Sure if it's some widget with an impedance of 1 meg ohms and his amp meter can't measure current that low. But that's not what it is. It's a resistive igniter, and he stated that the cold impedance is 50 ohms. It can't have 120V across it, not be hot and be working.

Reply to
trader_4

Note that I said SOURCE impedance not load impedance, that is something wrong with the source of the 120V.

Current should be 2.4A and power 288W. Perhaps the source can't actually maintain 2.4A.

Reply to
Sam E

What makes you think something is wrong with the source impedance? He says he has 120v across the igniter. If that's true and the igniter is good, it would get hot and glow. It really is that simple.

If that was the case, then he would not be measuring 120v across the igniter.

Reply to
trader_4

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