what is the resistance range for a good Harman ignitor?

[lecomte38]

I think my ignitor is on the way out. How many ohms should a good one read?

 

[timbo]

There's a thread on here somewhere about this very subject; just got done reading it...I think I read that a working igniter is about 48-50 ohms. A dead one will be 0 (or infinity).

 

[Swaybar]

O Ohms is a short circuit... Infinity is an open circuit. (A piece of wire will read 0, a cut pice of wire will read infinity)

 

[timbo]

O Ohms is a short circuit... Infinity is an open circuit. (A piece of wire will read 0, a cut pice of wire will read infinity)

Duh...brain fart (and I'm an electrical engineer)...it's been a LONG day. Right...what swaybar said...a bad one will read infinity....YIKES!

 

[Swaybar]

Thanks Timbo, you had me questioning my degree!

 

[Swaybar]

I think my ignitor is on the way out. How many ohms should a good one read?

From what I have read 47-54 Ohms on a new one, but I also understand that the Ohm check is not reliable.. If the reading is 0 ohms or Infinity, I would take that as bad, but not sure what the actual reading should be.

 

[timbo]

Thanks Timbo, you had me questioning my degree!

I think I should be checking mine!

 

[hossthehermit]

O Ohms is a short circuit... Infinity is an open circuit. (A piece of wire will read 0, a cut pice of wire will read infinity)

Well, Swaybar, it all depends on how ya look at it. Actually, a cut piece of wire will read 0. If ya take that first piece of wire ya had, cut it in two, both pieces will read 0. All depends on where ya stick yer little probe thingys.

 

[Swaybar]

I think I read somewhere that these are 300 or 400 watt ignitors if they follow Ohms law (R = V2/W ) and are powered by 120 volts at the ignitor:

at 400 watts resistance would read 36 Ohms

at 300 watts resistance would read 48 Ohms

 

[Swaybar]

O Ohms is a short circuit... Infinity is an open circuit. (A piece of wire will read 0, a cut pice of wire will read infinity)

Well, Swaybar, it all depends on how ya look at it. Actually, a cut piece of wire will read 0. If ya take that first piece of wire ya had, cut it in two, both pieces will read 0. All depends on where ya stick yer little probe thingys.

YEP

 

[GVA]

47 ohms.
But the only way to REALLY see if the ignitor is failing is to use a megger.
They need to be tested under load....
Trust me 20 years in the extrusion biz......
(back to retirement )

 

[Lousyweather]

geez, GVA! We test them for resistance.....failed igniters have no continuity.....they read 0 on the meter.....depending on which series ignitor it is, the reading will be from roguhly 42-50 ohms, with the newest ignitors being about 47-49 ohms.....

 

[CanadaClinker]

if there is doubt as to whether the igniter is being fed proper voltage for the 'entire time' that the control board is supposed to be sending voltage to it, I would first put a AC voltmeter across the igniter connections to monitor the voltage for that time period (whatever time that is supposed to be from the service manual) ......this checks 2 things, the voltage 'and' the time voltage is supposed to be supplied by the control board circuit to get proper ignition (my stove is 4 minutes).

.......I would also put an AC clip-on ammeter around one of the wires to the igniter (at the same time as the voltmeter is attached) and watch for the approx. 2.5 A to 3.3A reading (at 300W or 400W) to see if it the igniter opens (becomes intermittent) once it 'heats up'. I the current falls off to zero during the heat up, (when voltage is still being applied by the control board), then toss the element...... if the voltage drops off sooner than it is supposed to (and the current at this time also) it's a control board or some other device responsible for supplying the voltage up stream........ could it also be just something (like a clinker) blocking the igniter from transferring its heat to the pellets?......my $.02

 

[GVA]

geez, GVA! We test them for resistance.....failed igniters have no continuity.....they read 0 on the meter.....depending on which series ignitor it is, the reading will be from roguhly 42-50 ohms, with the newest ignitors being about 47-49 ohms.....

Yeah I would test it that way too... but if they are "failing" not failed this would show it... And i can guarantee those slow starting stoves that everyone talks about could be identified before failure....
You can have an heater stick that reads in range and when voltage is applied will not put out the correct wattage.....
But my practice was allways when in doubt........toss it out...
canada clinkers way of checking is a little harder but alot cheaper. Either will work fine