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Okay then. I guess I got more learnin' to do on HSI setups. I don't see them very often at all.

Even my Trane furnace has a HSI - located over on #1 in-shot burner, while a flame sensor rod is way over on #3 in-shot burner. I understand why they did that (3 burners w/cascading ignition) and I had suspected that the HSI had nothing to do with sensing flame. But now I'm wondering...

On this Lincoln oven, there's also a flame sensor rod. The module's schematic (or Honeywell's literature on it) doesn't explain that. However, I looked at the schematic in Lincoln's service manual and it kinda appears to indicate that the rod is grounded. If it is, then why is it insulated and tied by wire all the way back to the module?

I don't know. I'm a little slow on figuring out this one...and I'm usually fairly adept in figuring out the finer details that nobody else bothers with or cares to explore the whys & what-fors. I just fundamentally know ya gotta have a flame contacting an AC-energized component and a ground simultaneously to get flame rectification.

Nonetheless, to MY benefit - if we ever have an issue like this on one of our two Lincolns or on our Woodstone hearth oven and one of our guys gets all twisted over it, I can be the smart guy by asking "Was the plug changed recently?"

Tranes Voyager Rooftop Unit uses the hsi as flame proof. When the 120v drops at the hsi , its looks for the flame heating the hsi... somehow

Saw my first Voyager last week, and i was like Wth is this ??? because the gas pipe goes from main valve INTO the friggin draft inducer!

>Who the hell sat around bored enough to think.... hmm .. i wonder if current travels thru fire ?

Hmmm, looks like this guy is the first to patent the effect, for the British Gas Company...

HAMMOND PAUL S [GB]
Bibliographic data: US4427363 (A) ― 1984-01-24

Abstract of US4427363 (A)

A fail safe controller for a fuel burner has a rectifying probe positioned in the region occupied by the flame when it is burning normally. An alternating current power supply coupled to the probe is periodically interrupted by an inhibit circuit when the flame is burning. The intermittent rectified output from the probe controls the fuel supply by way of a diode pump circuit which ensures fail safe operation as it gives a null output for a steady state input.

>Ahhh...I think the HSI just lights the fire and has nothing to do with proving flame.


No, they use the HSI as the flame sensor also.

Pretty clever as if it did light the flame, it's *in* the flame, so why not use it as proof-of-flame.

Originally Posted by Snapperhead

Yea i scratched my head for a long time trying to figure out how the flame rod even functions. Tech supp said its a unique setup. 120 volts goes to it, and when fire touches it , electricity flows thru the fire to towards Hsi glow, and as it goes thru the flame it changes into DC current, and that current goes thru the cabinet ground and brings 3 volts dc to the honeywell box.

Who the hell sat around bored enough to think.... hmm .. i wonder if current travels thru fire ?

Ahhh...I think the HSI just lights the fire and has nothing to do with proving flame.

The voltage at the flame rod isn't what you're concerned with either. As long as the module is working correctly and everything is wired right, the voltage is there - be it 120v, 80v or whatever that ignition module manufacturer designed in it as the driving force to setting up a flame proof circuit. Honeywell is different from a RobertShaw, which are both different from a Fenwal...or whoever. Plus, they each make variations within their own product lines that are different from their OWN other controls.

It's the flame current that's important. It's an AC applied to the flame rod that gets rectified to a minimum amount of D.C. current flow that the module looks for. That's why you test it with an ammeter set to read microamps.

In circuits such as that, you usually read in series with the flame rod where the circuit leads to it from the SOURCE (the SENSE wire...I think they call it). In this case though, they direct you to read the current flow through GROUND since, how it's physically set up, it's not practical to attempt reading through JUST the flame sensor wire. Therefore, the alternative is to read flame current through the ground wire.

Ground is RARELY part of an actual circuit. In OUR application for HVAC and cooking equipment, the most prevalent exceptions are when it serves as COMMON in a low voltage 24 vac control circuit, or...as ground in a D.C. flame rectification circuit.

That's all I'll type on my phone. This wears me out. I want my computer back so I can write a book again.

[emoji13]



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Yea i scratched my head for a long time trying to figure out how the flame rod even functions. Tech supp said its a unique setup. 120 volts goes to it, and when fire touches it , electricity flows thru the fire to towards Hsi glow, and as it goes thru the flame it changes into DC current, and that current goes thru the cabinet ground and brings 3 volts dc to the honeywell box.

Who the hell sat around bored enough to think.... hmm .. i wonder if current travels thru fire ?

Originally Posted by ECtofix

My guess is that the side with LINE input must also supply the required AC signal to the flame sensing rod in order for flame rectification to occur. If the HSI's inputs are backwards, IT would still work. However, the NEUTRAL (instead of LINE) goes to the flame rod - therefore, no AC signal to IT...and no flame rectified DC signal back through ground to the module.

Yup, that's what it is.

There's TWO attachments below. Obviously the photo is the module's terminals as they're labelled. L1 is where the flame sensor rod ties in with the HSI Page 15 of the S89C.pdf reveals the problem in its troubleshooting flowchart:

GOOD JOB by you!

THAT was a lesson learned the hard way. Been there 'n done THAT for sure. You (we) NEVER forget those experiences.

Originally Posted by Snapperhead

.... when I look down at the receptacle and notice the cord has the handy dandy universal plug end. Hmm , I remember reading someplace this machine is picky about polarity , wonder if someones been in there. Take it apart , yup black and white are reversed. Are you @#$@#$%#*&#@! kidding me !!!!

Plug it up , fires up and runs

My eyeballs breezed right over that little statement about POLARITY as well. I SAW it, but blindly factored it out since I R-A-R-E-L-Y question the 120v polarity at the CORD CAP. (Again...I'll remember your experience here in the future)

So, my thoughts on this center around that ignition module's unusual set up of 120v to the HSI and having the flame sensor rod tied into one leg of it - and must be the part that's polarity-specific. My guess is that the side with LINE input must also supply the required AC signal to the flame sensing rod in order for flame rectification to occur. If the HSI's inputs are backwards, IT would still work. However, the NEUTRAL (instead of LINE) goes to the flame rod - therefore, no AC signal to IT...and no flame rectified DC signal back through ground to the module.

So I replaced the honeywell box , and OEM flame sensor / glow ignitor assembly , still losing flame , im like , WTH

Called tech support and we checked all kinds of stuff , 30 min later he was like , must be a bad honeywell out the box

Doubt it

So I continued doing above stuff , cleaned orafices , checked gas pressure 3.5 , took main board off and checked for cracked solder joints, checked all solenoids , checked both transformers under a load and they hung in there at 26 v , ohm wires looking for a bad connection or something , made my own grounds to cabinet and fire tube , checked all safeties

Still didnt work.

5 hours later im giving up , litterally leaned over the oven , my brains all worn out , shaking my head at it , im just gonna to tell them to call another company .... when I look down at the receptacle and notice the cord has the handy dandy universal plug end. Hmm , I remember reading someplace this machine is picky about polarity , wonder if someones been in there. Take it apart , yup black and white are reversed. Are you @#$@#$%#*&#@! kidding me !!!!

Plug it up , fires up and runs

Messican place and nobody knows much English , I will never know the story behind that ....

I tell the manager , yup , the Honeywell ignition box was shorted , and caused me all kinds of problems , got it runnin sir

I ordered the honeywell box , and the glow / sensor assembly

I hope it fixes it .... its a fairly new acct

I also ordered the little fan thats on the side , supposed to cool control boards , its been locked up for a long time

One more thing before I rush out the door to work...

Sounds like you went aftermarket on those parts and replaced the wiring. Since you did that, make sure the flame sensor is tied back to the correct terminal on the module. There's a little diagram on the module to refer to. If not, go to PartsTOWN website with the part number and pull up their PartsSPIN - which would allow you to zoom in on a new module and its label.

Originally Posted by Snapperhead

I changed the flame ignitor , wires to it , and changed sensor with a straight sensor bent into a 90 deg. Nobody stocks the 90 one

I then tried to test the current and cannot figure out why its reading on my meter

I unhooked the ground term and put my meter inbetween .... correct ?

Im thinkin its that honeywell ignition board

Yes, connect your micro-amp meter in series with the module's GND (burner) terminal and the ground wire. you should read at least 0.8μA within six seconds after the dual-safety valve was energized.

Another suggestion: Turn the temp control setting all the way down to disable the temperature regulation valve. That way, you'd get a view of just the bypass flame during ignition trial.

FYI: A replacement HSI, ordered as an OEM part from Lincoln...comes with a new flame sensor rod wired in.
http://is.shotfarm.com/viewer/index....32610_32718097

Also, both parts (HSI and the module) can be ordered from Amazon.com.

I changed the flame ignitor , wires to it , and changed sensor with a straight sensor bent into a 90 deg. Nobody stocks the 90 one

I then tried to test the current and cannot figure out why its reading on my meter

I unhooked the ground term and put my meter inbetween .... correct ?

Im thinkin its that honeywell ignition board

Here's the manual. Page 9 addresses that problem with some tests to perform:

http://download.partstown.com/is-bin...1116EA_spm.pdf

Some notables:

• You gotta read flame current in series with the ground wire.
  
  
• Obviously the gas valving isn't your usual combination valve, but a set of three solenoid valves. The first two valves is the dual-safety valve set and the only thing the ignition module controls. That valve set is powered up when the unit is turned on and should stay on as long as the module's flame proof circuit is satisfied . That dual-safety valve feeds gas to a bypass orifice (serves as a pilot) and to the temperature regulation valve (main burner).
  
  
• Upon powering up the unit, if the temperature control is set to call for heat and the temperature regulation valve is thereby energized...and the ignition module is still trialing to prove flame, I think (somebody correct me if I'm wrong) the main burner WILL fire up during that trial. Obviously it will go out (as you described) if the module's flame proof circuit isn't satisfied.

I recommend:

• Checking that flame current.
• Checking to make sure the bypass orifice is clear.
• Check integrity of flame rod circuit connections. The ground is too easy to overlook, so don't skip it.
• Check your gas pressure (especially during main burner function) to ensure it's adequate and stays pretty much the same throughout all varying demands of unit operation. Adjust it to match the spec. plate.

Lincoln Food Warmer , Conveyor

Model 1116-000-A

Natural Gas

Turn on , it lights flame , then flame goes out 3 seconds later

Cleaned flame sensor rod , replaced Flame ignitor ( glow type )