Weil Mclain Ultra won't fire

JUGHNE

Regulators do wear out. If you have only a single stage reg and it is on the tank it has seen a lot of action.
Typically here in cold country we have a high pressure (10 psi) at the tank and a second one on the house to provide 13-15" WC.

If your tank regulator had ice build up on it then it is overworked, IMO.

I can not imagine anyone thinking of throwing money at a new boiler before installing new regulators....2 of them.....hi and low.

Jamie Hall

double check the whole line and regulator, end to end. And what @JUGHNE said. Actually, in my humble opinion, the regulator or regulators should have been replaced when the boiler was changed.

Oh -- and PS. According to the gas company, the regulator is never the problem. Right...

JUGHNE

Most LP providers will change them out on a regular basis around here.....go by date codes etc. Maybe more fear of lawyers than most.

Some gas valve/trains have a safety setup to prevent firing if gas pressure is too low. There could be enough pressure for one try and possibly something locks outs.

But to drop that much pressure on the inlet side of the gas valve makes it a no brainer that it is a supply problem. IMO

Ironman

hweeres said:

The tech told me that he cannot analyse the combustion until it actually fires - and it just won't light. WM only suggested to throttle it up/down a little and later concluded "replace the entire gas valve/venturi unit". - And finding someone who know these units better seems impossible in the area here.
after 8 days of cold I am ready to throw in the towel and just buy a new unit, but WM is no longer on my shortlist.

You said in your first post that the boiler ran fine for 8 hours and that the installer "adjusted the flow and got it dialed in". Did he do that with a combustion analyzer and manometer? If so, what are the numbers? If not, he may have gotten it so far out of adjustment that it won't ignite. A negative pressure gas train is not something that can be properly adjusted without instruments.

icy78

> @Ironman said:
> (Quote)
> You said in your first post that the boiler ran fine for 8 hours and that the installer "adjusted the flow and got it dialed in". Did he do that with a combustion analyzer and manometer? If so, what are the numbers? If not, he may have gotten it so far out of adjustment that it won't ignite. A negative pressure gas train is not something that can be properly adjusted without instruments.

That's a good point. I worked on one last year that was adjusted so far out, it would just occasionally poof!
When I had it close to where it normally sets, it burned, but poorly. Think I ended up installing a new burner and maintenance kit.
It supposedly had been cleaned, but I got a good cup of deposits off it.
Important to clean the venturi also.

hweeres

So here is the timeline
Ultra 105 broke (boiler cracked)
Bought a used ultra 80 series 3 NG
Had HVAC come out to install the ultra 80, convert to LP (full kit) and dial it in.
Worked fine - for 8 hours
Then no start lockout (ever since)
Came out again today and measured gas pressure, tried throttle up and down a bit, check spark (And igniter cable) , ventilation, cleaned boiler on e again from corrosion- checked air ducts ... nothing
Had weil McLain on the phone and after testing gas inlet pressure 13 dropping to 9.x when trying to light ... WM support suggested with little confidence to replace the Venturi/gas valve unit.

I now have about $2k in this ordeal and still no heat. Buying another kit for $350 to couple hundred in another technicians visit to go out on a limb is something I rather avoid.
My hope was that one of you knew what else I could try.

And thanks for all the responses I got so far !!!

Finally, yes the installer used proper Analyser to get it within the specs from the manual <60 ppm CO2. I was at work that day, so that is what my wife told me.
And that is when unit ran based on these settings for the 8 hours before it crapped out.

hweeres

So what I am hoping for is someone to tell me what the default throttle setting would be (you know similar to a carburetor) turn throttle all the way in and then 2 1/2 turn out - something along those lines. I know I am grasping at straws here.

Ironman

What is needed are the CO2 and O2 readings.

Ironman

Have you checked the condensate trap/drain for blockage?

rick in Alaska

Ironman said:

Have you checked the condensate trap/drain for blockage?

Makes me wonder when he said he could blow in to the venturi tubing and it would light, that it is some kind of blockage in the intake line. I am not very familiar with that boiler, so am not sure what that line is hooked to, but it sounds like the direction to go to for checking.
Condensate line sounds good though seeing as it ran for 8 hours then quit. Could easily fill up a trap in that amount of time and shut it down.
So, make sure the condensate is draining, and check the air intake. If you can, take the air intake line off the boiler and see if that makes it fire up.
Rick

icy78

If he cleaned it, that includes flushing the condensate trap. If he missed that, who knows what else was missed.
The heatex is supposed to be rinsed after the flat blade cleaning. A hacksaw blade works even better.

Look at the clear drain tube/trap.
Grey crud in it?
Procedure is in the manual.

DZoro

Can you post some pictures, stand back and get the whole system in. Then a close up of the venturi-gas valve with the drop tube off.
First and foremost, gas pressure. You can't do a thing until that is proper. Doesn't matter whether you have a new or old boiler. The pressure must remain stable <1" drop during fire and run.
Then you can proceed to other adjustments/repairs. But get the gas right first.
There is no default setting that I'm aware of on that unit. Small adjustments, make a huge change. That is why it is imperative one knows what you are doing with a analyzer. Without one your just going to mess it up badly.
It was asked, but was the heat exchanger opened up and fully cleaned out using the WM kit? If not that needs to be done.
Unusual for a used unit, makes one wonder,,,why?
D

hweeres

Hi guys,

Nice frosty morning and so many more good comments.

Condensate trap: yes, I cleaned it myself and later heard that the first tech that was here also blew it out all the way to the sump pit - on w cleaned we added the necessary water to prevent fumes to get out through it. So that is a 100% checked

Drop in gas pressure is still open - the WM support guy said it was within the tolerances, but I am going to talk to my LP gas supplier today.

Lastly - picture of the unit - coming up here shortly.

Thanks

DZoro

Has the Heat Exchanger been fully opened up and cleaned? Using the kit from WM?
D

hweeres

Here are the pics, and the gas company is coming out today to check the pressure and regulators

hweeres

Cleaning the burn chamber - yes done twice - with the proper WM tool in all 3 directions

Ironman

hweeres said:

Hi guys,



Nice frosty morning and so many more good comments.



Condensate trap: yes, I cleaned it myself and later heard that the first tech that was here also blew it out all the way to the sump pit - on w cleaned we added the necessary water to prevent fumes to get out through it. So that is a 100% checked



Drop in gas pressure is still open - the WM support guy said it was within the tolerances, but I am going to talk to my LP gas supplier today.



Lastly - picture of the unit - coming up here shortly.



Thanks

Check the condensate again. It could have filled with crud from the heat exchanger after running 8 hours.

If the drain becomes blocked, the collector will fill with condensate blocking flue gasses from venting.

DZoro

Did you flush it out with water? Confirm the bottom aluminum pan under the exhaust pipe did not rot out a hole in the back of it.
D

Ironman

I just saw this in the I/O manual. Was the burner replaced with the one for LP?

icy78

> @Ironman said:
> I just saw this in the I/O manual. Was the burner replaced with the one for LP?
>
> (Image)

I think that's only true for the series 1 boiler and his is a series 3, but it's a very good point.

hweeres

Hi guys,

Yes, we ordered the proper replacement kit and changed out the Burner and the orifice as described in that extra kits manual

Regarding the trap - it’s clean and I even hack saws off the long drain line to make sure it cannot back up into the unit.

Thanks

hweeres

And the gas company was here and checked gas pressure all the way in and it’s at 12 inch, dropping just 1/2 inch when it tries to fire. But that was outside the gas valve, the resting on the inlet of the valve was different yesterday.
I guess my gas valve must be bad then ?

Solid_Fuel_Man

Whar happens if you turn off the gas valve to the boiler, initiate a heat call and go outside and feel if there is air moving out the vent? Does it feel like someone exhaling in volume and velocity?

Gas pressure dropping indicates that the valve is at least opening, the drop to 9" is excessive, but the boiler should still fire at least.

I'm still thinking the adjustment is way too far out.

I assume its trying to light conservatively then locking out? I'm only familiar with the ECO and the 97+.

JUGHNE

Previously when the pressure dropped drastically was the LP regulator iced up as you had mentioned?

Tom_133

Had a similar situation, and it turned out to be the igniter cable, if you still have your old one it may be worth swapping

DZoro

Has anyone put eyes on the venturi? If the previous install was improper, you may have a deteriorated venturi. Which will cause ignition failure. @Tom_133 agree I forgot what the ohms should be on the cable but have seem them fail.
D

Ironman

Tom_133 said:

Had a similar situation, and it turned out to be the igniter cable, if you still have your old one it may be worth swapping

I Just had one that was occasionally arcing to ground and giving the same symptom.

icy78

Any update?

AcesN8s

It is currently Dec 28, 2019. How current are everyone's comments? I'm having a similar issue. I have it narrowed down on the troubleshoot menu to "Spark with no flame". Most of the troubleshoot items in that section need a manometer to determine how much natural gas is flowing in the system. How easy is one obtained? How likely is it that the problem lies in the gas valve unit? Is it just me, or do these systems seem very finicky?

Solid_Fuel_Man

They are not finicky, just need maintenance like most other things.

You really should get a qualified person to check gas pressures and give the appliance a good cleaning and proper digital combustion adjustment after.

If the tech cant do any one of those things they are not qualified.

DZoro

Generally good maintenance done takes care of most all issues. As long as proper installation procedures were followed in the original install.
Manometers and combustion analyzers can set you back at least a thousand dollars, probably more. Adjustments to your system can NOT be made without them.
Highly unlikely the gas valve is the problem.

D

AcesN8s

Wow! Thank you for the fast responses! I have a few calls in to places that work specifically on these units, and just waiting to hear back from the on call techs. The guy who actually installed my unit 11 years ago is not an on call guy, but might be able to come out Monday.

icy78

For larger company's, often the installer, is not the guy you want setting up the equipment. Better to have a tech who spends his/her time doing service work.
Definatly true at our company.

AcesN8s

I'm in Montana. Most companies are small, and all the employees become well versed in all the things...

Just had a tech stop by and the control module isn't telling the valve to open. He just left and is checking to see if he has one in his shop.

kenjwoods

Hello All, homeowner with a 155+. Had a propane tech out last week because unit would go from prepurge to ignition to post purge and the cycle would just keep repeating. I watched him while in phone with WM support and saw the cove the horn trick to get the system tuned for both low and high fire combustion levels. A week later system is doing the same thing. Odd thing was that it looked like it was lighting just fine through viewport. Went to the diagnostic screen and watched the flame sensor because it had an issue in the spring where a gasket needed to be replaced. During the ignition it would get barely above the threshold of 150 for the 155+ model before it would shutdown to repeat the cycle again. I changed the setting to a 110 model which has a different flame threshold and it fired up without any issues. I’m thinking the flame sensor was too low to allow the system to know it was fired but high enough to not trip the alarm like it did in the spring.  I plan on replacing the flame sensor to hopefully improve the signal levels. 

Solid_Fuel_Man

At the very least, pull the flame rod and clean it up with some emry cloth/fine sand paper. Be sure there is a good electrical connection and that the ground is connected to the flame rod plate it the 155 has that. I know the 70 and 110 do. 

skiereric

Here is the manufacturers troubleshooting guide. You can try increasing the min. Force Rate to see if that helps
force rate

tim smith

When was the heat exchanger cleaned last. They must be cleaned regularly to get proper combustion. Need a maintenance kit for it also. This comes with heat exchanger plate gasket, burner gasket, igniter etc. 1st thing to do if has not been done in last 2 years. Really suppose to be cleaned annually but sometimes can stretch it. Ignition lead is suppose to read 1000 ohms +or- 50 ohms. Need a qualified tech to dismantle, clean and assemble or you can have a real safety hazard on your hands.
Good Luck