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Weil McLain Ultra 80 Series 1 NG boiler Error 02: Ignites, then shuts off

SDesign
SDesign Member Posts: 33
Weil McLain Ultra 80 Series 1 NG boiler Error 02: Ignites, then shuts off

History:
This is a problem that I have seen almost every year since owning this boiler. Let me start off by saying that I know this boiler better than any tech I have hired over the years. I have the manual and have read it cover to cover multiple times. The boiler started this season fine, but then began producing the E02 as it had many times before. Typically I would wake up to a cold house and find the heater with the (E02) error. Reset worked a couple times to fix it, but now it will not stay lighted. In the past, installing the yearly maintenance kit would normally fix the problem, but not this year.

What happens:
Boiler fires, lights (visual inspection shows nice flame), and then the boiler shuts off after a couple seconds. I presume it is not sensing the flame teven though I can visually see a nice flame. It does this 5 times and then produces the E02 code. If I reset boiler, the same thing happens... Lights (nice looking flame), then shuts down after a couple seconds, repeats 5 times, then E02 is produced again. Will not stay lighted.

Here is what I have done this time:
  1. Cleaned the burner, and replaced the gasket.
  2. Cleaned heat exchanger and replaced cover gasket.
  3. Flushed condensate trap and confirmed sump is working properly.
  4. Replaced the Venturi gasket.
  5. Replaced the flu sensor and flu sensor boot + checked and re-seated sensor wiring. Also tried another new flu sensor just to be sure I did not get a dud.
  6. Replaced the ignitor and gasket. Also tried another new ignitor just to be sure.
  7. Checked ignitor wire condition and reseated all connections. Proof of flame shows that the ignitor works fine, but the system does not register the flame.
Additional troubleshooting:
  1. Checked and re-seated input and output on-boiler temperature sensors.
  2. Checked blower for proper functionality.
  3. Checked for obstructions in the flu.
  4. In the past when this happened, I once replace the Venturi and it did not fix the problem.

I am stumped and hoping someone here might have some ideas that I have not tried. Any thoughts?



«1

Comments

  • skiereric
    skiereric Member Posts: 55
    What are you seeing from the outputs prior to it cycling?

    Flame signal, blower signal?

    Do you have this problem when adjusting the force rate in the manual test mode to low, medium or high.

    your rate might low or you’re flame signal could be weak but you need to see what happens as the boiler cycle 



  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,

    Did you re-seat the connectors to the control module ?
    Did you check this ?





    In case this is a different manual than yours.
    https://www.weil-mclain.com/sites/default/files/field-file/Ultra Series 1 Boiler Manual.pdf
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • HVACNUT
    HVACNUT Member Posts: 4,764
    If any of the sensors or limits were out of range, it wouldn't even attempt to ignite. So I would lean towards the gas valve, gas pressure, or the blower not reaching the RPM needed to increase the firing rate. 
    The igniter is also the flame sensor so make sure there's a solid ground from the connector at the igniter bracket back to the ground at the U-Control.
    You could try partially covering the silencer opening with your hand once there's flame to see if it stays on. If it does stay on, then that's an air/fuel ratio issue and you'll need a manometer and combustion analyzer to solve that.
    Do you have an analyzer? After a maintenance, the boiler needs to be tested in High and Low fire to check/adjust CO2 and CO parameters. 
  • SDesign
    SDesign Member Posts: 33
    Thanks for the initial replies. I truly appreciate it.

    Yes, I re-seated connections at the control module, but I will reinspect those.

    I have not gone through the low/high fire setup in a while, but I will read up on it and go through that after I determine the low voltage issue at terminal 9 noted below.

    Regarding flame sensor low-voltage... sorry for my ignorance, but is this checked while firing and showing flame through inspection window? If so, then the voltage is low. I read less than 1 volt. Red lead of my volt meter set to volts DC (3 volt scale) touching low-voltage terminal 9 and black lead going to ground, I read less than 1 volt.

    So, since I have several new igniters that produce the same result, I will go re-check the ground wire from ignitor to control module for proper continuity and I will also check the main ignition wire again for damage.

    Are there any other things that would cause the low voltage at terminal 9 that I should check?

    Also, thanks for the manual link, it has more information than my printed one.
    109A_5 said:

    Hello @SDesign,

    Did you re-seat the connectors to the control module ?
    Did you check this ?





    In case this is a different manual than yours.
    https://www.weil-mclain.com/sites/default/files/field-file/Ultra Series 1 Boiler Manual.pdf

  • SDesign
    SDesign Member Posts: 33
    Define Flame signal output? If you are referring to the control module lights, my control module does not have the lights like the later series do.

    I do measure low voltage on the flame sensor terminal. See my other reply for more details on that.

    I am working through the firing test shortly.
    skiereric said:

    What are you seeing from the outputs prior to it cycling?

    Flame signal, blower signal?

    Do you have this problem when adjusting the force rate in the manual test mode to low, medium or high.

    your rate might low or you’re flame signal could be weak but you need to see what happens as the boiler cycle 



  • SDesign
    SDesign Member Posts: 33
    It does attempt ignition and can hold it until the gas valve closes due to no flame sensor (assumed). I get the same result with multiple sensors/ignitors. Having worked on this unit for more than 15 years, I know it pretty well and can tell you the blower is fine.

    Partially covering (chocking) the air intake silencer does not keep it running, so air fuel seems fine and was last year and this year for a couple weeks.

    Gas pressure or valve may be it, but I have no way to test. Likewise with the CO2/CO adjustment. The flame looks great in the visual inspector, although this is purely visual and not with combustion meter. Trying out another heating tech would be the only way to analyze it.

    Ground has been triple checked for proper continuity on the ignitor/sensor.

    I am working through high low burner testing shortly.

    HVACNUT said:

    If any of the sensors or limits were out of range, it wouldn't even attempt to ignite. So I would lean towards the gas valve, gas pressure, or the blower not reaching the RPM needed to increase the firing rate. 
    The igniter is also the flame sensor so make sure there's a solid ground from the connector at the igniter bracket back to the ground at the U-Control.
    You could try partially covering the silencer opening with your hand once there's flame to see if it stays on. If it does stay on, then that's an air/fuel ratio issue and you'll need a manometer and combustion analyzer to solve that.
    Do you have an analyzer? After a maintenance, the boiler needs to be tested in High and Low fire to check/adjust CO2 and CO parameters. 

  • SDesign
    SDesign Member Posts: 33
    Update: I cannot go through the high low firing test as the unit will not stay lite.

    Since the voltage is low on the flame sensor #9 terminal bar as noted above and this happens with multiple new ignitor/sensors, I presume it has to do with something at the main control board level being bad.

    Note the ignitor works great, so that cable appears to be functioning properly (also re-seated). BTW the ground has been triple check for continuity. I also checked and re-seated all control module cables, etc.

    Any additional thoughts? This has stumped at least three techs over the years. In the past, it will just start working (sometimes for the remainder of the season) after a combination of things and we never know what causes the problem. This is the first time it has not righted itself by doing the times noted in the initial post.

  • pedmec
    pedmec Member Posts: 655
    Have you ever had a combustion and gas pressure test on this. i say this because your flame signal is low could be due to low gas flow downstream of your gas valve.

    do you have elevated gas pressure coming from the street? if you do it will have a regulator at the meter and the spring could be failing resulting in fluctuations in gas pressure.
  • Jamie Hall
    Jamie Hall Member Posts: 19,954
    Check the ground. Again. Disconnect anything in the ground path, clean it, and reassemble it. Then go all the way back to main power switchboard and check both your ground and neutral connections all the way through to the boiler. If this is a long standing problem, as it seems, it may well be somewhere in that ground or neutral path. I honestly don't know how this thing is wired inside, but I can easily imagine that a problem in either the neutral or the ground circuits could result in the neutral having voltage to ground, and that, in turn, causing a problem like this.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • SDesign
    SDesign Member Posts: 33
    Yes, a combustion test was done at install, and then again a couple years ago. Test would not be possible until it will run without shutting off prematurely.

    Yes, I believe my meter has a regulator. FWIW, my on demand Bradford White hot water heater has no issues keeping up though. Would this be a gas company request? Ask them to come check the regulator on the meter?
    pedmec said:

    Have you ever had a combustion and gas pressure test on this. i say this because your flame signal is low could be due to low gas flow downstream of your gas valve.

    do you have elevated gas pressure coming from the street? if you do it will have a regulator at the meter and the spring could be failing resulting in fluctuations in gas pressure.

  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,
    SDesign said:

    Regarding flame sensor low-voltage... sorry for my ignorance, but is this checked while firing and showing flame through inspection window? If so, then the voltage is low. I read less than 1 volt. Red lead of my volt meter set to volts DC (3 volt scale) touching low-voltage terminal 9 and black lead going to ground, I read less than 1 volt.

    The flame sensor Voltage is an easy to read Voltage (with a multi-meter) that is roughly proportional to the current flowing through the flame sensor rod, the igniter rod (in this case) when the flame is present.

    Since this Voltage is low there is a problem with this system.

    Poor flame.
    Poor placement or shape of the flame in relation to the flame sensor rod or the flame sensor rod is contaminated.
    Poor flame detection circuit.
    Defective control module.

    I would recheck the ground path from the heat exchanger all the way back to X1-6 on the control module (Green path). Also the continuity integrity of the High Voltage electrode wire. The High Voltage with ignition will jump poor connections, the low Voltage, low current of the flame detection may have troubles with poor connections.



    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    Thanks for the additional information.

    I rechecked the ground path from heat exchanger all the way back to X1-6 on the control module. I loosened the screw at X1-6 and retightened to be sure there was no corrosion on the wire. I also removed and reset all ground connection at the "Brass ground terminal Strip".

    High voltage electrode wire inspected and looks good. The ignitor is producing a really nice spark. It lights the burner nearly immediately and the shape of the flame looks good, until it cuts out. *-) The sensor rod on ignitor also looks to be fully covered in flame when viewed through the inspection window.

    I re-tested and produced the same result. Virtually no voltage on the low-voltage terminal 9 (flame sensor) with multimeter to ground. I also tested my meter with a 1.5 volt battery to be sure it is functioning properly, and it checks out.

    Looks like it starting to weight toward a defective control module. This is already the second control module. The original control module failed at around year 11. The current control module was purchased new in January of 2017.

    Additional information: This particular control module has been discontinued and is no longer available for purchase, so it is looking like a whole new boiler if the module is bad... Unless I can find an electronics tech to go over the board and diagnose. I still have the original one for parts.

    109A_5 said:

    Hello @SDesign,

    SDesign said:

    Regarding flame sensor low-voltage... sorry for my ignorance, but is this checked while firing and showing flame through inspection window? If so, then the voltage is low. I read less than 1 volt. Red lead of my volt meter set to volts DC (3 volt scale) touching low-voltage terminal 9 and black lead going to ground, I read less than 1 volt.

    The flame sensor Voltage is an easy to read Voltage (with a multi-meter) that is roughly proportional to the current flowing through the flame sensor rod, the igniter rod (in this case) when the flame is present.

    Since this Voltage is low there is a problem with this system.

    Poor flame.
    Poor placement or shape of the flame in relation to the flame sensor rod or the flame sensor rod is contaminated.
    Poor flame detection circuit.
    Defective control module.

    I would recheck the ground path from the heat exchanger all the way back to X1-6 on the control module (Green path). Also the continuity integrity of the High Voltage electrode wire. The High Voltage with ignition will jump poor connections, the low Voltage, low current of the flame detection may have troubles with poor connections.



  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,
    SDesign said:

    High voltage electrode wire inspected and looks good.

    You continuity checked this HV wire ?
    Looks like it starting to weight toward a defective control module.
    Maybe. I would also check the 220 Ohm 10 Watt resistor (with the boiler power off). Low Voltage Terminal Strip 5 and 9, See picture (Blue rounded rectangle), it may be considered part of the wiring harness, but it could be replaced inexpensively if defective. Not sure if this resistor is needed for proper boiler operation or it is just for the purpose of the terminal 9 Voltage.
    Additional information: This particular control module has been discontinued and is no longer available for purchase, so it is looking like a whole new boiler if the module is bad... Unless I can find an electronics tech to go over the board and diagnose. I still have the original one for parts.
    It would not surprise me if either control module has a poor solder connection causing its malfunction.

    Additionally with the Discontinued 383-500-190-Ultra-Control-Module there appears to be an Upgrade Kit.

    Discontinued July 30, 2021
    https://www.supplyhouse.com/Weil-Mclain-383-500-190-Ultra-Control-Module-for-Ultra-Gas-Boilers-Ultra-80-to-230

    Ultra Control Upgrade Kit
    https://www.supplyhouse.com/Weil-Mclain-383-500-665-Ultra-Control-Upgrade-Kit



    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    edited October 28
    No, I only visually inspected the HV wire and figured since it was sparking well, that it was fine. Continuity test is negative! That is likely it problem. I am off to find the HV ignitor wire at Supply House: https://www.supplyhouse.com/Weil-Mclain-383-500-050-Ignition-Cable-Kit

    FWIW, I could not find the resistor you referenced, it must be under the rear cowl, which is hard to remove without disassembling the gas piping.

    Thanks for all your help, I will update after HV wire replacement.

    109A_5 said:

    Hello @SDesign,

    SDesign said:

    High voltage electrode wire inspected and looks good.

    You continuity checked this HV wire ?
    Looks like it starting to weight toward a defective control module.
    Maybe. I would also check the 220 Ohm 10 Watt resistor (with the boiler power off). Low Voltage Terminal Strip 5 and 9, See picture (Blue rounded rectangle), it may be considered part of the wiring harness, but it could be replaced inexpensively if defective. Not sure if this resistor is needed for proper boiler operation or it is just for the purpose of the terminal 9 Voltage.
    Additional information: This particular control module has been discontinued and is no longer available for purchase, so it is looking like a whole new boiler if the module is bad... Unless I can find an electronics tech to go over the board and diagnose. I still have the original one for parts.
    It would not surprise me if either control module has a poor solder connection causing its malfunction.

    Additionally with the Discontinued 383-500-190-Ultra-Control-Module there appears to be an Upgrade Kit.

    Discontinued July 30, 2021
    https://www.supplyhouse.com/Weil-Mclain-383-500-190-Ultra-Control-Module-for-Ultra-Gas-Boilers-Ultra-80-to-230

    Ultra Control Upgrade Kit
    https://www.supplyhouse.com/Weil-Mclain-383-500-665-Ultra-Control-Upgrade-Kit





  • HVACNUT
    HVACNUT Member Posts: 4,764
    @SDesign. Not sure about the Series 1, but the few U-Controls I've replaced also required the replacement of the display. Record all settings so they can be reentered. 
    SDesign
  • 109A_5
    109A_5 Member Posts: 449
    edited October 29
    Hello @SDesign,
    SDesign said:

    No, I only visually inspected the HV wire and figured since it was sparking well, that it was fine. Continuity test is negative! That is likely it problem. I am off to find the HV ignitor wire at Supply House: https://www.supplyhouse.com/Weil-Mclain-383-500-050-Ignition-Cable-Kit

    FWIW, I could not find the resistor you referenced, it must be under the rear cowl, which is hard to remove without disassembling the gas piping.

    Thanks for all your help, I will update after HV wire replacement.

    High Voltage will jump gaps rather easily (ignition spark), Low Voltage, super Low Current (flame detection) won't jump gaps, so the Control Module can't detect the presents of the flame if the HV wire is bad. With any luck replacing the HV wire will solve your problem. Inexpensive fix if that is the problem, good you continuity tested it. And flame detection may have been intermittent as the HV wire dilapidated. Also the movement during your annual cleaning may have had an influence too.

    If you still want to test the 220 Ohm 10 Watt resistor (with the boiler power off) you don't have to actually find the resistor. Just unplug connector X2 on the Control Module (so the Ohmmeter does not see the Control Module circuitry) and put the probes of the Ohmmeter on the Low Voltage Terminal Strip to positions 5 and 9. It should read in the range of 220 Ohms. The boiler may work fine even if the resistor is bad (it is probably not bad). It may only be needed for the Low Voltage Terminal Strip position 9 flame signal Voltage output function.

    Anyway if the HV wire solves your problem measure the Voltage at Low Voltage Terminal Strip position 9 and put that Voltage value with your notes for future reference. If that Voltage starts to drop the igniter probe probably needs cleaning.

    If you want some further reading on the ignition systems testing try reading this. A Google search found it, however I could not find a way to navigate to this document via this web site. Maybe it is suppose to be a secret.
    https://heatinghelp.com/assets/documents/Troubleshooting-Intermittent-Ignition-Systems-for-Gas-Furnaces-and-Boilers2.pdf
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    edited November 2
    No luck on the ignition wire. The new wire also shows no continuity... unless I am doing something wrong.
    My older analog multimeter has a "Cont." function in the old section that creates a tone when checking continuity. This function works fine when checking the ground, and other wire continuity on the boiler, but it does not produce a tone on the old or new ignition wire. I am checking red probe to one end and black probe to the other end of the ignition wire and I get NO tone. Is it possible that I got a bad new ignition wire?
  • 109A_5
    109A_5 Member Posts: 449
    edited November 3
    Hello @SDesign, I would use the Ohms function of the multimeter. (EDIT: With the meter in continuity test mode) The upper end resistance value (no continuity) varies from meter to meter. If you get a reasonable value from the new wire I would recheck the old one for defect verification.

    From a Series-3 manual.

    1. Check ignition wiring
    Check ignition cable electrical resistance. A good cable will have resistance between 900 and 1000 ohms. Replace if not acceptable

    Some may use a suppression type wire and the normal resistance is higher than others.

    So far I can't find an actual specification for the Series-1 ignition cable.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign, Here is a manual that may have more details for your Error 02 situation. See pages 28 & 29 maybe others.

    https://www.weil-mclain.com/sites/default/files/field-file/ultra-series-2-control-supplement_1.pdf

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    @019A_5
    Thanks again. I found this regarding the ignitor wire resistance measurement spec. I will do some checking later tonight:

    "Resistance of igniter wire should be 1000 ohms +/- 50 ohms. If resistance is more or
    less, replace igniter wire."
  • SDesign
    SDesign Member Posts: 33
    edited November 15
    Here are a couple in process shots of the controller upgrade. Old controller is out and the old wiring was fished up to the top and is now ready for tracing and splicing. New harness grommet rectangles cut and harnesses secured (silicon coming last.)

    FWIW, the "upgrade" instructions are pretty bad... 46 steps with only one confusing illustration. I was not able to find the PDF online to share with everyone. Just know that the upgrade is not for the faint of heart, I had a friend come over to help me wrap my hear around it. The process was a bit overwhelming at first.

    I will post more images later, since I was unable to find any images or video of the process.


  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign, I was hoping it would not come to this, the controller upgrade that is. Still much more inexpensive than a new boiler. Lots of wires if your are not used to doing that type of thing. Double check your work before you power it up.
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    SDesign
  • SDesign
    SDesign Member Posts: 33
    @109A_5
    New controller/brain + new wiring harness installation is complete. Good news is, the heater functions, so looks like I wired everything up properly... but the unit still does not sense the flame and thus locks out after multiple tries..

    Thoughts? I am now thinking that the burner may be the culprit. Not sure what else it could be. Nearly everything else is new.

    I will post picture of the final installation tomorrow.
  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,
    That sucks !!! Something is compromising the flame detection circuit or the flame has insufficient contact with the detector rod. Some part of the detection circuit has resistance that is too high or the ground side of the flame reference is not actually grounded properly. Basically two different detection circuits confirms this.

    Just recently I read this, not sure if it would be applicable to your unit. In this thread
    https://forum.heatinghelp.com/discussion/189973/wm-97-flame-signal
    @skiereric posted this
    https://www.weil-mclain.com/download/file/fid/3021

    Apparently the old gasket dilapidation acts as an insulator, basically compromising the flame detection circuit.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    edited November 19
    @109A_5
    The link iss interesting as I had a burner gasket look like that in the past. The burner gasket gets replaced every year with the standard maintenance kit, but I never really focused on the burner base when cleaning the burner. I will pull the burner again and scotch bright the base as instructed in the document to see if I can get the flame sensor signal working. BTW, the maintenance kit does not have a graphite gasket, at least not that I am aware. Maybe there is an aftermarket one thatI can order.? I will look up part#: 570-318-101

    Here are a couple more bits of information...

    Ignitor:
    The ignitor design has changed over the years, I still have original one (2004) that came with the boiler as a reference (more of a thick point with smaller rod rather than gapped similar sized rods)... Anyway, a brand new current design ignitor with factory gap does not light the burner currently.

    I have a modified ignitor (increased gap that that does light the burner, but the factory gap on the new ignitor design is not enough spark to light the burner in its current state. The non-ignition with a stock ignitor makes me think it is the burner. FWIW, I have cleaned the burner twice with a wire brush (exterior) and toothbrush (inside).

    Burner:
    The way the intake air enters the Ultra 80 Series 1 is right on top of the blower motor, and under the right conditions, condensation can seep into the blower and then into the firing chamber/burner area. There was a service bulletin about the issue awhile back and the fix was a metal funnel like thing above the blower intake air vent that drained to the sump. Anyway, I mention this as the condensation may have caused the burner to corrode and it would typically corrode most at the bottom of the burner where the ignitor is. This also makes me think that the burner could be bad.

    That said, your link has me intrigued. I will focus on the burner base tomorrow to see if I can get the flame sensor to reading the flame and report back.


  • pedmec
    pedmec Member Posts: 655
    You need to have the silencer on the inducer motor intake installed. You will have difficulty with ignition if it is not on.
    SDesign
  • SDesign
    SDesign Member Posts: 33
    Yes, the silencer is installed properly.
    pedmec said:

    You need to have the silencer on the inducer motor intake installed. You will have difficulty with ignition if it is not on.

  • pedmec
    pedmec Member Posts: 655
    21 Air silencer kit - Air silencer and gasket Ultra-80, -105 383-501-026



  • SDesign
    SDesign Member Posts: 33
    edited November 19
    Yes, that is air silencer that is on my inducer/blower.
    The air intake I was referring to is the fresh air from outside which is located directly above the blower/boiler.
    pedmec said:

    21 Air silencer kit - Air silencer and gasket Ultra-80, -105 383-501-026

  • 109A_5
    109A_5 Member Posts: 449
    edited November 19
    Hello @SDesign,
    A few things have to be accomplished to make a system like that work and work reliably. The ignition spark has to be in a place where the Air (Oxygen) / Fuel ratio is suitable for combustion. Also if the spark gap distance is too great the spark may jump somewhere else or just not spark at all.

    Once there is a flame the flame detection rod has to have enough surface area enveloped in the flame to conduct enough current to satisfy the detection circuit. More Flame Rod length (in the flame) or a thicker Flame Rod diameter actually in the flame may accomplish this task. It may be a delicate balance with that burner assembly if they keep changing the design to optimize or stabilize the operation.

    The flame detection circuit basically has three states.
    1) A normal Current range detected, keeps the Gas flowing.
    2) Grounded, the High Voltage wire or Igniter Rod or an independent flame detection wire to a separate Flame detection Rod is compromised to ground or a compromised Flame Rod insulator to ground. Probably won't even attempt an ignition attempt. In this case the Current detection circuit probably detects too much Current and Current before the flame actually exists.
    3) Low or no Current, usually caused by excessive resistance or a break in the detection circuit. Any part of the detection circuit with excessive resistance including poor flame envelopment of the Flame Rod. The Control Logic ceases the Gas flow because it thinks the flame does not exist or is improper.

    Any part of the High Voltage section of the circuit that needs cleaning, I would clean with a nonmetallic method like a Scotch-Bright pad. With wire brushes metal from the brush can migrate to the item being cleaned and cause problems.

    Maybe not directly your problem, maybe the Pre or Post Purge time should be increased to help minimize moist air and condensation in the combustion chamber.

    Basic Flame Detection circuit. The flame acts as a high resistance Closed Switch. With no flame the circuit is Open








    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    SDesign
  • SDesign
    SDesign Member Posts: 33
    Hi @109A_5
    Thanks for the explanation on the ignition circuit. I still cannot wrap my head around how the flame creates measurable voltage on steel with just fire, but I do understand the circuit better now.

    An interesting thing on the post you linked to earlier. My burner used to have an all fiberglass gasket and recently, they switched to a one-side fiberglass and the other side foil wrapped. I presume due to a similar issue with the flame detect circuit on the Ultra 80 Series 1. When servicing the unit awhile back, the previous all fiberglass design gasket appeared stuck and came off in two pieces... and I am betting that "... gasket glue seeped out of the gasket and electrically insulated the burner flame signal, so a weak flame signal would not allow the burner to run." This prospect has me excited and I will work on cleaning the burner base with Scotch Brite and Alcohol tomorrow. Stay tuned.

    BTW, with the new controller, I can also watch the flame sensor number in real time, so that should give me some good before and after numbers.
  • 109A_5
    109A_5 Member Posts: 449
    edited November 19
    Hello @SDesign,
    Re-look at the flame detection diagram. The flame is not the electrical power or Voltage source. Just a very high resistance Switch. Apparently electrons will travel through the flame in one direction. In the case that an Alternating Current (AC) is applied to the circuit the flame also acts as a Rectifier only letting current flow in one direction.
    The Current is extremely low (but measurably higher than no Current, an open switch) it is in the low micro Amp area (0.000010 Amps, or less). Maybe 10,000 times less than what an old 120 VAC, 100 Watt incandescent lamp would draw.

    Since the Voltage used for the flame detection circuit is very low compared to the ignition spark Voltage any circuit defects are not tolerated well.

    Also if the flame is excessively agitated the detection circuit may not like it.

    Some gaskets, more often found in the Microwave & Radio Frequency industry have wires embedded into the gasket material to enhance Radio Frequency shielding where assemblies and access plates are screwed together using gaskets.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    SDesign
  • SDesign
    SDesign Member Posts: 33
    Hi @109A_5

    I removed the burner again and did a third burner cleaning with scotch bright and alcohol, paying special attention to the area closest to the ignitor and the rim where it meets the gasket. Initially it looked promising as the burner had some glue on the burner rim similar what was mentioned in the PDF you linked to. Photos of the burner and controller to follow.

    FWIW, I never saw a flame signal other than zero on the controller, even when I could clearly see flame through view port. Not sure I snapped the photo at the proper time, but I even tried to increase the force rate to med and it clearly lite, but still no flame signal.










  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,

    At this point it sounds like to me the old control system had poor Ground bonding from the Ground side of the burner / igniter assembly to the controller / ignition Voltage source assembly. With the wholesale change-out of the controller / ignition assembly that ground path has been lost or made worse.

    Can you take a good quality picture of the present wiring diagram ? I can not find a PDF of the upgrade manual online.

    Or the flame is not in contact with the detection Rod although from the sight glass point of view it looks like it is, I think this is unlikely.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    Hi @109A_5

    The entire wiring harness was replaced, including a new ground to the ignitor and board. The only place the ground wire is the same wire as before is the jumper from the high voltage ground to the ground junction (left rear under rear cover) spot. I will specifically check that ground for continuity and and report back.

    Here is a photo of the rear ground junction area before wiring was finalized. Sorry it is out of focus, but you can see where and what I am referring to. There is jumper from the rear high-voltage ground terminal to this ground junction area and then a ground wire runs from the ground junction to the controller.


    After the upgrade, I think the current wiring is the same as as Ultra 80 Series 4.

    I will photograph the upgrade manual and post it shortly. Here are the upgrade instructions (text part), I will post the referenced Ultra 80 and upgraded controller wiring diagram soon.


  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,
    OK I was hoping the new documentation had a wiring diagram for the new equipment. Is there a mechanical metal path or a ground bonding wire to the combustion chamber housing or the igniter mounting ?

    I just built the circuit in the picture below. I had no problem getting a 12 Micro-Amp Current with a 14 Ga. Copper wire stuck in a flame of a Mapp Gas torch. The Current was best with a nice flame (up to 15 Micro-Amps ), not too aggressive not too low. The 3400 Ohm Resistor was just to protect the fuse in the Multi-Meter in case I touched the copper wire to the metal tip of the torch and it was handy. The flame eventually melted the Copper wire.

    No flame no current, and when the DC power supply leads were reversed almost no current in the reverse direction as expected, due to Rectification.

    Interestingly and expected I could get more current from hand to hand. Over about 100 Micro-Amps.



    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    The ground I mentioned earlier has proper continuity. Additionally, I checked the ground wires at the board in 3+ spots to be sure all of them had continuity and were not loose. I also checked the ignitor ground and proper continuity has been confirmed.

    The ground junction has a jumper to the incoming high-voltage circuit ground at the rear high-voltage wiring harness. The other ground wire coming from the junction goes to the new control board (P1 #3).



    Here are the remaining pages of the upgrade manual. Page 10 has the current module and wiring diagram. Let me know if you need anything else.






    Lastly, here are the three versions of the ignitor showing the changes Weil McLain made to it over the years. The Version #2 design (not this exact ignitor) seems to work best for me as the Version #3 design does not light the burner properly at the moment.



  • 109A_5
    109A_5 Member Posts: 449
    edited November 20
    Hello @SDesign,

    Igniter version;
    #1 looks worn out,
    #2 insulator a bit contaminated,
    #3 I would think would work the best, but if the spark is not in the right place or direction with the combustion gas mixture it may work poorly.

    I only count 2 Green wires on your Brass Ground terminal strip, where are the other 2 wires for a total of 4 as in the wiring diagrams New and Old. Also I would expect a Ground wire going to X1-6 not P1-3 / X1-3.

    ****
    Edit: I thought P1 went to X1, I now see they are different.
    ****

    Are they connected together in a different place now ?

    The only bonding between the Neutral (White wire) and the Ground (Green wires and the boiler cabinet or internal assemblies) should be at the Electrical Service panel not at equipment like your boiler.
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 449
    Hello @SDesign,
    Are all 4 Ground wires connected here now ?


    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • SDesign
    SDesign Member Posts: 33
    Hi @109A_5

    I probably confused things with the ignitor image. The photo is just for reference to show the different designs over the yrears, although version #3 is brand new, the other two are not in service and you noted, they are worn out. I have several brand new ignitors and a brand new one has been modified to look like version #2, which is what I am using, since that design seems to light the burner properly. A brand new version #3 does not light the burner.

    There is actually only one ground that is used from the previous block, the only reason I am using the grounding block is that the original Ultra 80 Series 1 factory ground was connected to the grounding block via a wire from the high voltage terminal strip at the back of the unit.

    So, two connectors on the ground block, one goes to the ground of the high voltage strip, the other goes to the new controller. The other ground wires from the original Series 1 wiring are not used in this upgrade. Only one ground was called out as used in the upgrade.

    Yes, the other ground wires the controller unit uses are connect to this main ground via the new harness. I will try to get some decent pictures of more wiring this morning.

    I hope this explains that a little better. Thanks for your patience. *-)
    I will follow up on your other message separately.
    109A_5 said:

    Hello @SDesign,

    Igniter version;
    #1 looks worn out,
    #2 insulator a bit contaminated,
    #3 I would think would work the best, but if the spark is not in the right place or direction with the combustion gas mixture it may work poorly.

    I only count 2 Green wires on your Brass Ground terminal strip, where are the other 2 wires for a total of 4 as in the wiring diagrams New and Old. Also I would expect a Ground wire going to X1-6 not P1-3 / X1-3.

    ****
    Edit: I thought P1 went to X1, I now see they are different.
    ****

    Are they connected together in a different place now ?

    The only bonding between the Neutral (White wire) and the Ground (Green wires and the boiler cabinet or internal assemblies) should be at the Electrical Service panel not at equipment like your boiler.