KitchenAid Superba oven not igniting normally.

[Epeescott]

Hi!  I have a KitchenAid Superba oven, model number KGST307HWH4 (serial # 1ML1138882) that ignites very poorly.  It actually catches several minutes after I turn it on.

 

There is a big smell of gas, and often a FOOMP! when it catches.  The igniter heats up almost immediately after I turn it on.

 

I know this is a safety issue, so I don't turn it on without igniting it manually (torch flame) before hitting start.

 

I really don't get it, if the igniter is glowing immediately and gas is flowing immediately, what's the problem?  I'm trying to fix this without making my landlord spend money.......

[johntech]

I would check the amp draw at the ignitor during start up. The ignitor needs to pull 3.5 amps to open the gas valve. As ignitor get weak it can take it longer to open the valve and ignite the gas. If you don't have an amp meter just replace ignitor and see if that fixes your problem. Ignitors fail so commonly on gas appliances that I bring one in with me on every gas oven call.

[vee8power]

Has the range been moved or jostled? It sounds to me like something may have shaken loose around the burner and ignitor area. There may be holes corroded in the burner or the ignitor has fallen out of its proper position.

[Samurai Appliance Repair Man]

40 minutes ago, johntech said:

 

I would check the amp draw at the ignitor during start up. The ignitor needs to pull 3.5 amps to open the gas valve.

 

[Epeescott]

11 hours ago, johntech said:

I would check the amp draw at the ignitor during start up. The ignitor needs to pull 3.5 amps to open the gas valve. As ignitor get weak it can take it longer to open the valve and ignite the gas. If you don't have an amp meter just replace ignitor and see if that fixes your problem. Ignitors fail so commonly on gas appliances that I bring one in with me on every gas oven call.

I can check this, but if I am hearing the gas hiss as soon as I press on, and I am smelling gas quite quickly while watching the ignitor glow, isn't the gas valve open?

[johntech]

then it sounds like your ignitor is pulling to many amps and needs to be replaced. 

[Samurai Appliance Repair Man]

4 hours ago, johntech said:

then it sounds like your ignitor is pulling to many amps

Igniters (or any load) don't "pull" amps. The current that flows through them is in direct proportion to the applied voltage and inversely proportional to its internal resistance. Ohm's Law: I = E/R

Also, igniters do not fail by their internal resistance DECREASING over time. Just the opposite: their internal resistance INCREASES over time due to internal fracturing of the carborundum crystalline structure. This is why igniter's are replaced: insufficient current flow through it to open the gas valve. For more info, see this Office Hours recording where we discussed hot surface ignition systems in detail: 

 

 

15 hours ago, Epeescott said:

but if I am hearing the gas hiss as soon as I press on, and I am smelling gas quite quickly while watching the ignitor glow, isn't the gas valve open?

At this point, I'm suspecting bad information. No offense, but customers are famous for giving inaccurate problem descriptions. I think this might be a case in point. Can you confirm this statement? Also, get the current draw reading on the igniter circuit.

If you don't know or aren't sure what you're doing, then STOP and call in someone who does! You don't know what you don't know and there are things here that can kill you or you could leave a bomb for yourself, like this:

 

 

 

[Epeescott]

No offense taken, I was an electrician but not an appliance Samurai.  I may have to wait a few days until I get off shift to finish this troubleshooting, and I will take a video of what I'm seeing.

[johntech]

Yeah my terminology was Wrong. Sorry. I did not know it was impossible for the resistance to decrease. I thought I have ran into a few that have and would open the gas valve prematurely. 

[Hiroshi]

it can be confusing as they are referred to as "exact amperage draw" components

[Samurai Appliance Repair Man]

1 hour ago, Hiroshi said:

it can be confusing as they are referred to as "exact amperage draw" components

Who refers to them as "exact amperage draw" components? Do you have a reference for this? And what exactly does this even mean?

 

Edited April 19, 2016 by Samurai Appliance Repair Man
Typos

[Hiroshi]

Yes Samurai, many fellow techs I know use this terminology, it only refers to the fact that ignitors open the valve at an exact amperage point. Thus, the rating they receive 3.5-3.7 for a flat Norton. And I did say it was confusing, I never said it was accurate!

"When current flows through the ignitor, heat is applied to the bimetal strip. The amount of heat
necessary to warp the bimetal enough to open the valve requires 3.0 amps of current flow"

That is straight from the Whirlpool gas appliance guide, and it would be easy to transfer current flow to amperage draw for most minds. No?

[Samurai Appliance Repair Man]

21 minutes ago, Hiroshi said:

ignitors open the valve at an exact amperage point

 

21 minutes ago, Hiroshi said:

the rating they receive 3.5-3.7 for a flat Norton

So which is it: a range or exact? Or is this kinda like it depends on what your definition of "is" is.

 

And what about the fact that the resistance of the igniter decreases as it heats up (and hence current flow through it increases). Where's the "exact" there? 

21 minutes ago, Hiroshi said:

That is straight from the Whirlpool gas appliance guide

Post the Publication number... if you have it.

21 minutes ago, Hiroshi said:

transfer current flow to amperage draw for most minds

Not getting your point here. Are you inferring that these are two different things?

21 minutes ago, Hiroshi said:

many fellow techs

Implying you're a tech. If you are claiming to be a tech and you're posting as a Grasshopper, this is a violation of our Guidelines.

Grasshopper accounts are DIYers here to get repair help by starting their own new topics, not muddy-up other people's topics with half-truths and misinformation. 

[Epeescott]

Uhhhh....Just for clarity's sake, when I said I was an electrician, I meant I was an electrician on submarines - i run a particle accelerator now for gainful employment.

 

 

[Samurai Appliance Repair Man]

1 minute ago, Epeescott said:

Just for clarity's sake, when I said I was an electrician, I meant I was an electrician on submarines - i run a particle accelerator now for gainful employment.

 

[Epeescott]

Ok, I put an ammeter on the igniter element and it looks like it is only drawing 1.1 amps.  I have attached a couple of photos of the setup and a video of the ignition.

Video:  

 

 

 

[Epeescott]

Can't seem to edit the inserted pictures.

 

https://photos.google.com/photo/AF1QipMVNjQCKjN-f_IrhHWeui69PO2uk-948EHNP-uc

 

https://photos.google.com/photo/AF1QipMzMaysHcuzi4egRewuhthBS-9dMGuPSUqFpEHx

[Epeescott]

As a side note, I did the same ammeter test for the broil element igniter, and it is only drawing 1.5 amps.  It lights in about 25 seconds, where the bake element lit at the 95 second point.

 

I guess I should replace both, then?

[Budget Appliance Repair]

No need to replace them both.  A good check for an oven hot surface ignitor is to time how long it takes to light the burner after you hear the control board relay click on.

If it lights the burner in under 45 seconds the ignitor is good.   Broil is usually always used much less then bake so you don't see broil ignitors going out as often as bake ignitiors.

When an ignitor starts taking longer then 1 minute to light the burner you can be pretty sure it is getting weak.

Sounds like you have an inaccurate amp meter or are doing something wrong when using it.