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

SDesign

Hi @109A_5

No, the upgrade only uses one (two if you count the jumper from the high-voltage strip that feeds the block) and the new harness distributes that ground throughout via the new harness.
I hope that makes sense.

I will get more pictures soon.

109A_5 said:

Hello @SDesign,
Are all 4 Ground wires connected here now ?

SDesign

Hi @109A_5

I photographed the wiring more (images below). I even added an extra ground to the ignitor which connects back to the brass ground junction. So, now the junction has three plugs attached to it. As a jumping off point, Pages 12 & 13 (image below) show the wire connections to the new controller. Basically the new harness did not have the high and low voltage connections to the rear of the unit and the instructions walked through tracing and connecting them to the appropriate spots on the specified controller plug/location.

Pages 12 & 13.



Here are a lot more images of the wiring.
On the right side of the controller, the high voltage comes in and the low voltage is on the left. The right and left side close photos show the incoming wires that connect to the low/high voltage strip(s) at the rear of the unit.

Right side also shows hot, neutral and ground harness junction that shipped with the upgrade. Close of ignitor shows the new double grounding and new ground off the off the new harness (right).

That should get you oriented a bit.

SDesign

Some additional recent observations.

After the control module upgrade, I would say the burner lights slower than before. Not sure if has to do with the modulation capabilities of the new control module, or what. I am also not clear how long the ignitor needs to be in flame for it to register as lite. I am getting a second or two of flame before it locks out and tries again.

Does anyone know how often an Ultra 80 burner needs to be replaced?
The burner in this unit is 18 years old and I am wondering if it may not be producing a properly formed flame, even after three major cleanings. This would be supported by the version #3 ignitor (noted earlier) not lighting the burner. While a new a version #3 modified to a version #2 does, but not as well as before the control module upgrade.

neilc

anyone check gas pressures?

Jamie Hall

It may have been mentioned but just to be sure: there is another ground circuit which is essential with that type of flame sensor: a hard metal ground from the burner gas assembly through to the ignition control module ground plane. From there back to the electrical switchboard can be wire, but must be independent from the neutral. If you look at @109A_5 's sketch, he is mimicking that hard ground path with the red wire.

SDesign

No, but my on-demand Bradford White hot water heater has no issue with gas pressure. If I bring in a tech, I will have them check the pressure, but I have not way to do so without the proper equipment.

neilc said:

anyone check gas pressures?

SDesign

A bit of an update:

Looks like in maintenance mode, the display does not read the flame signal in real-time, but rather it flashes a value right after the lockout occurs... and if you blink, you might miss it.

Anyway, I was able to get a flame signal of 26 with a version #2 ignitor and flame signal of 17 with a version #3 (when it would light), but 26 was not enough signal to keep it lite.

Any thoughts?

realliveplumber

Check the gas pressure.

109A_5

Hello @SDesign,
I'm not sure what the numbers on that new display represents for an adequate Flame Signal, Does the new documentation tell you ? I suppose 25 could equate to 2.5 Micro-Amps, but I would think 25 would equal 25 Micro-Amps which should be plenty. It is sad from a software engineering point of view that the flame signal is not closer to real time. Analog to Digital conversions only takes Milliseconds, if that. And a stored history would be nice too. Keep in mind the sparking ignition mode probably has to cease to get the Flame Signal, since they share the same wire in your case.

As @realliveplumber suggests if there is a Gas flow restriction the flame may be Gas starved almost instantly after the flame ignites, do to a restriction locally to the boiler or just affecting the boiler only. It would be diagnostically interesting to measure the Gas pressure as close to the flame as possible.

SDesign

@109A_5

Regarding the proper number for a proved flame, I was not able to find the data for an Ultra 80, but in the document linked about the burner gasket. A WM155 is proved flame signal is 150 and a WM110 proved flame signal is 50:





Since I have no way to test the gas pressure, looks like I have to bring in a tech with the proper equipment. Unless you have another way for me to test. As I mentioned earlier, my on-demand Bradford White NG water heater does not have a gas pressure issue, but that may be of little help, as you said testing actual pressure as close to the Ultra 80 as possible is best.

This is again making me think the burner is not forming the flame properly, either via pressure as you mentioned, venturi, or the burner itself.

109A_5

Hello @SDesign,
If a value of 50 is actually a valid minimum for your present setup than 25 is too low. Either the Flame Detection circuit (as a whole) has excess resistance or the Flame is inadequate for some reason.

The poor ignition performance of igniter #3 style may give the impression of poor burner performance, Air / Fuel mixture ratio is wrong, or the flow through boiler heat exchanger is not correct. External Vent / Exhaust piping too short or restricted.

SDesign

@109A_5

I will remove the exhaust vent pipe tomorrow and make sure there is no obstruction preventing proper outgoing exhaust. I know there is no interior heat exchanger obstruction as I have been completely over that area during the maintenance cleaning, including the sump and lower exhaust area.

It is hard for me to imagine the new brain with new flame circuit and all new wiring (including ground wires and new ignitor) would have excessive resistance.

I may also try adjusting the air/fuel mix ratio via the screw and but first marking where I start to see if I can get a longer maintained flame in either rotation direction to increase the flame signal number. If I can at least get the flame to stay lite, then perhaps a tech could come check the levels to be sure the numbers are in spec and could check the gas pressure at the same time. Not sure I am up for building a home brew Manometer to check pressure levels myself.

Without an ongoing flame, it is even possible for a tech to check air/fuel ratio?

Now that I have flame signal numbers I can log them to see what helps increase the flame signal number.

109A_5

Hello @SDesign,
Some systems need a minimum length of piping Vent / Exhaust piping to work correctly (flow resistance). When incorrect I suspect it either messes with the Venturi effect for the desired mixture ratio or maybe it causes the flame to be corrupted like it being pushed too far from the sweet zone where the Flame Detector Rod lives. The Air and Fuel mixture alone does not produce an Electrical Current path for Flame Detection.

SDesign said:

It is hard for me to imagine the new brain with new flame circuit and all new wiring (including ground wires and new igniter) would have excessive resistance.

I never trust unproven equipment. New or otherwise. Since the same basic problem seems to persist with the changing of the control unit and wiring, it does make it statistically less likely that they are both bad. But that is not a guarantee that the old one and the new one are both fine.

Without an ongoing flame, it is even possible for a tech to check air/fuel ratio?

Probably not, I believe a Combustion Analyze needs combustion to work. In a sophisticated laboratory it may be possible.

Now that I have flame signal numbers I can log them to see what helps increase the flame signal number.

That may help.

Tim_D

Check the ignition cable. It should have about 950 to 1050 ohms of resistance. If any different, replace the cable.

SDesign

Hi @Tim_D

Yes, the ignition cable was just replaced (one of the earlier times tried), but now I am wondering if the new cable is bad too.

Unfortunately, my old Radio Shack Micronta analog multi-meter is not up for proper ohm resistance testing. I plan to borrow a friends digital multi-meter tomorrow and I will then be able to test resistance properly.

Tim_D said:

Check the ignition cable. It should have about 950 to 1050 ohms of resistance. If any different, replace the cable.

109A_5

In general an old Radio Shack Micronta analog multi-meter or similar in good working order (good battery, battery compartment contacts not corroded, meter zeros correctly) will work reasonably well to measure the resistance of the ignition High Voltage wire.

For example say the ignition wire is 1000 Ohms.
Range RX1 the meter should display 1000 on the Ohms scale (may be hard to see).
Range RX10 the meter should display 100 on the Ohms scale.
Range RX100 the meter should display 10 on the Ohms scale.
Range RX1K (1K = 1000) the meter should display 1 on the Ohms scale.

The meter should be re-zeroed if the range is changed.

Flex the High Voltage wire during the resistance test, looking for intermittent resistance readings.

SDesign

@109A_5

Unfortunately, I could never get the Micronta to zero properly in the ohm setting. The knob did not allow me to zero it out.

But, I borrowed a friends Bosch multimeter and tested the new ignition cable:
It is bad! Yup, new cable is bad. Ugg!

I then checked the old cable and it was 975 ohms, so I installed that and got a flame sensor reading of up to 97... and then several lower readings. I checked it again with the multimeter and discovered I was able to flex/wiggle it and affect the reading, producing an open circuit a couple times. So, the old cable is bad too.

I am ordering a new cable and returning the previously ordered "new" one today.

Hopefully that is it. I will post back once I receive the 2nd new cable and have it checked and installed.

Thanks again for everyones comments/help on this, it is truly appreciated.

109A_5 said:

In general an old Radio Shack Micronta analog multi-meter or similar in good working order (good battery, battery compartment contacts not corroded, meter zeros correctly) will work reasonably well to measure the resistance of the ignition High Voltage wire.

For example say the ignition wire is 1000 Ohms.
Range RX1 the meter should display 1000 on the Ohms scale (may be hard to see).
Range RX10 the meter should display 100 on the Ohms scale.
Range RX100 the meter should display 10 on the Ohms scale.
Range RX1K (1K = 1000) the meter should display 1 on the Ohms scale.

The meter should be re-zeroed if the range is changed.

Flex the High Voltage wire during the resistance test, looking for intermittent resistance readings.

109A_5

Hello @SDesign,
Excellent, it sounds like you are making meaningful progress. This is why I never trust unproven equipment or parts. New or otherwise.

BTW often if the Ohmmeter function won't zero the battery is low or the battery compartment contacts are corroded. If you bought it new and it was that way maybe the multi-meter has issues.

SDesign

@109A_5

I work in computer tech, and way back I had co-worker/friend that used to say "Check The Cable" as his mantra. More often than not, it was the bloody cable. I think of him every time a cable is bad on anything. *-)

A bummer on the bad cable though as it caused the control upgrade to happen. Anyway, the boiler will be in fantastic shape and the new controller will likely have efficiencies (more burner modulation steps) built-in that may help it run better than before. Plus, it looks to have better monitoring and troubleshooting tools.

Fingers crossed the new cable is the final fix.

Regarding the Micronta, I was gifted it from an electrician friend, and I know it worked properly at the time. I just replaced the batteries, and the 9 volt was fine, but the AA set was corroded. I will go back and make sure the contacts are clean, perhaps cleaning the contacts better will fix my zeroing issue. Thanks for the mention of that. I will go check it out.

SDesign

New cable arrived and tested out at 1005 ohms before install. After install, there was still not enough flame signal to prevent lockout. I double checked the cable after it was installed and in place. It still checked out at 1005 ohms.

I double checked the entire system grounding again and everything checked out.

Then, I got to thinking. The only three parts that have not been replaced in this latest episode is the burner, which visually looks great and has been cleaned three times, the blower which seems to be running properly according to the new control module diagnostic monitoring, and the venturi/gas valve.

The Venturi/Gas Valve was replaced several years ago during another episode, so I decided to test the system with the original, first Venturi. I had put a note in the box with the first Venturi that said "likely still good".

That was it! Installing the original Venturi/Gas Valve did the trick. I installed it and the system fired and held flame on the first attempt. The system is now running properly.

Thanks to everyone for your help. It is nice to finally have my floors beginning to warm up again. *-)

109A_5

Hello @SDesign, Excellent !!!
Curious, does the flame look different now when it fires up ?

" got a flame sensor reading of up to 97... " I wonder why you got an intermittent flame signal that was OK, was the flame changing with the old Venturi ?

What is the normal flame signal now ?

You probably should have a Combustion Analysis done to verity the CO is not too high.

SDesign

@109A_5

Yes, the flame looks different now when it ignites. I would describe it as less bulbous and more precise in shape. I even put the bad one back on again, just to confirm it was truly bad as the Venturi/blower gasket looked suspect during the swap. It is bad. My records show the bad one was purchased in 2017 (5 years ago) for $274, the part is now $416.

Regarding the intermittent flame signal. On the second check of the bad valve, I observed that the flame would kinda of pulse a bit, perhaps causing the varying flame signal. With the good valve/venturi it gets right down to business.

When running, the normal flame signal is 180.

Agreed, I am even considering buying another gas valve/venturi to put on it, or as a backup.
Either way, I need to get a combustion analysis done to make sure the numbers are correct.

Thanks again for all your help!

109A_5 said:

Curious, does the flame look different now when it fires up ?

What is the normal flame signal now ?

You probably should have a Combustion Analysis done to verity the CO is not too high.

pedmec

Funny thing is you kept looking at the fault as an electrical issue. I tried to get you to look at it from the combustion end as the silencer affects your affects your air/fuel mixture. i never saw the silencer connected in any of the pic's. Glad you were able to solve this problem

SDesign

@pedmec

For the record, the silencer has always been in place. After install the silencer is hidden behind the exhaust flu on on the Ultra 80.

pedmec said:

Funny thing is you kept looking at the fault as an electrical issue. I tried to get you to look at it from the combustion end as the silencer affects your affects your air/fuel mixture. i never saw the silencer connected in any of the pic's. Glad you were able to solve this problem

culater

My Ultra 80 LP was doing the same thing. I've owned this since 2002 and have serviced it myself since new. One day out of the blue it would fire but the flame would just go out. I proceeded to do a full service and cleaning but it still refused to stay lit. I ended up backing out on the high start mixture screw 1/4 a turn at a time until the unit fired. It is now running perfectly with a nice colored flame in the sight glass.