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 igniter heat or gas flow at any position of the oven control knob, including broil.

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+ Watts, at least until it warms up.

So there's some other very high resistance in the circuit--but I *do* see 120 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 controls into one block. I cannot tell if these functions are inter-wired, except that the broiler doesn't work either, so perhaps they are. I never knew whether running the broiler also lit the bottom burner.

Any advice appreciated,

Chip C
Toronto

gas oven diagnostic help, please
 

On Thursday, March 15, 2018 at 6:18:31 PM UTC-4, Chip C wrote:
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 igniter heat or gas flow at any position of the oven control knob, including broil.


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




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.


That would seem to be impossible. If it has a resistance of 50 ohms and 120v 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 ohms 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.



So there's some other very high resistance in the circuit--but I *do* see 120 V so it's not a broken wire.

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




Is the gas valve the next likely culprit?

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


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

Any advice appreciated,

Chip C
Toronto

gas oven diagnostic help, please
 

On 3/15/2018 at 3:18:24 PM, Chip C wrote:


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 igniter heat or gas flow at any position of the oven
control knob, including broil.

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+ Watts, at least until it warms up.

So there's some other very high resistance in the circuit--but I do
see 120 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
controls into one block. I cannot tell if these functions are
inter-wired, except that the broiler doesn't work either, so perhaps
they are. I never knew whether running the broiler also lit the
bottom burner.

Any advice appreciated,


Check the gas safety valve, see this video.

https://www.youtube.com/watch?v=-RZtxSvOe-U



--
"In matters of conscience, the law of the majority has no place."

"Truth Sounds Like Hate To Those Who Hate The Truth"

gas oven diagnostic help, please
 

In article ,
says...
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 igniter heat or gas flow at any position of the oven control knob, including broil.


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




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.


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



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.

gas oven diagnostic help, please
 

On Thursday, 15 March 2018 19:38:12 UTC-4, Ralph Mowery wrote:
In article ,
says...
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 igniter heat or gas flow at any position of the oven control knob, including broil.


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




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.


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



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.

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

gas oven diagnostic help, please
 

On Friday, March 16, 2018 at 9:36:25 AM UTC-4, Chip C wrote:
On Thursday, 15 March 2018 19:38:12 UTC-4, Ralph Mowery wrote:
In article ,
says...
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 igniter heat or gas flow at any position of the oven control knob, including broil.


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




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.


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



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.

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

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

gas oven diagnostic help, please
 

On 03/15/2018 05:33 PM, trader_4 wrote:

[snip]

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

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

gas oven diagnostic help, please
 

On Friday, March 16, 2018 at 2:10:06 PM UTC-4, Sam E wrote:
On 03/15/2018 05:33 PM, trader_4 wrote:

[snip]

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

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

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.

gas oven diagnostic help, please
 

On 03/16/2018 02:51 PM, trader_4 wrote:
On Friday, March 16, 2018 at 2:10:06 PM UTC-4, Sam E wrote:
On 03/15/2018 05:33 PM, trader_4 wrote:

[snip]

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

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

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.

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.

gas oven diagnostic help, please
 

On Saturday, March 17, 2018 at 12:18:08 PM UTC-4, Sam E wrote:
On 03/16/2018 02:51 PM, trader_4 wrote:
On Friday, March 16, 2018 at 2:10:06 PM UTC-4, Sam E wrote:
On 03/15/2018 05:33 PM, trader_4 wrote:

[snip]

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

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

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.

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

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.



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

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