Beckett Nx

Tom_133

Hey all,

So you know when you go do a charity job and it comes back to haunt you....

Anyway, I got a Beckett Nx burner on a Biasi SG boiler 5 section. I have been doing the servicing on this unit for 4-5 years. A month ago I put a new filter, new pump strainer, and new nozzle. This time we also swapped the electrodes, it was time.

It will run for about 2 weeks and then start locking out. I go back hit reset fires up nice, let it run for a bit to burn off any old fuel in there. Test it, and air settings are nice, right where it was the previous years.

I checked pump pressure good, checked draft good, Fuel is also good. So the 2nd visit I swapped nozzle in case.

This boiler feeds a very large auditorium, and its all radiant in the slab, so when I hit reset it may run for 8 hours. Then be off for another 5 hours.

I have it on a wifi thermostat and last night it emailed me saying, not getting to temp, the guy hit reset, fired right up and is cooking.

I dont want to just throw stuff at it, any ideas? I was going to do the transformer its about 12 years old, may be good?

HVACNUT

Do you know if there's flame loss during the run and goes into recycle (depending on primary) or no flame on trial for ignition?
Is there a vacuum gauge on the suction line? Do you have combustion numbers?

MaxMercy

Tom_133 said:

Hey all,

So you know when you go do a charity job and it comes back to haunt you....

Ain't that always the way? I'm not surprised to see it affects HVAC as it does electronics.

Anyway, my amateur input here is that I always open the CAD cell circuit and check resistance when the burner is running. If it's much over 1200 ohms I start looking for reasons.

EdTheHeaterMan

When I had a customer with nuisance lockout with no obvious cause ( as you have) I would install the Carlin 70200 primary control with all the diagnostic features. This will logue all the on and off cycles what the flame sensor (ohm) readings are and the amp draw on the motor, ignition, and valve (if equipped). Then from there I can see why the burner went off on safety.

Once, the control found a low amp on the ignition circuit in one of the last 1250 cycles. When I found that message, I replaced the Ignition Transformer with an electronic ignition. The problem was solved and I re-installed the original Primary control once the problem was resolved. Without the notice of low amp draw on one of the last 1250 cycles in the diagnostic messages, I would have never found the problem.

Many times I did the same thing and the customer requested that i leave the New Fangled control on there because they liked the additional features.

If you fail to prove flame on startup, or fail during mid cycle, you will look in different places for the problem.

This has worked for me many times and I highly recommend it.

Hope this helps.

Other possible causes: Burner coupling that connects the pump to the motor is loose and slips once it gets warm or hot(but works fine when cool), Partially clogged fuel line (look for a kink), dirt build up on the burner fan (Clean with a thick pipe cleaner or narrow brush) intermittent primary control failure, Cad cell holder wire or connection is loose. Dirt or carbon buildup on the retention head turbulator, Cadmium cell eye is failing (replace eye)

EDIT: If there is a Genisys Control already on there, you can connect a "Contractor Tool" to that control and get many of the (not all) features of the Carlin 70200.

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STEVEusaPA

Nx runs at higher ohms. I don't think the control locks out until something like 5200 ohms.
The main thing is to make sure the cad cell has the best view it's capable of. And check them while running. I think Beckett made a correction to the NX, maybe something with a hole in the combustion head. I think they'll send you the upgraded one for free if you call them. But you should know the running ohms.
Did you zero out the head?
True zero smoke?
Unless something is wrong, NX electrodes should last the life of the burner.
Where's the height of the oil in the tank compared to the height of the fuel pump? Might be a slight vacuum leak? Hate to say it but if that's the case, maybe a Tiger Poop.

But the one thing you mentioned..." hit reset fires up nice, let it run for a bit to burn off any old fuel in there..." Was there unburnt fuel? If so that would point me toward checking the ignitor.

EdTheHeaterMan

STEVEusaPA said:

Nx runs at higher ohms... I ...Hate to say it but if that's the case, maybe a Tiger Poop.

But the one thing you mentioned..." hit reset fires up nice, let it run for a bit to burn off any old fuel in there..." Was there unburnt fuel? If so that would point me toward checking the ignitor.

Really Steve... You recommending a Tiger Loop? What is this world coming to? I'm afraid to look out the window now!

EBEBRATT-Ed

@Tom_133

Question, was it locking out before the first service when you changed the oil filter etc? Check gaskets on filter especially the one under the bolt.

Is this indoor tank gravity feed or two pipe underground tank?

Could be anything and all the above comments are excellent.

But, when I get a burner that runs fine and sits a long time between starts and fires up when you reset it I always suspect dropping it's prime on the oil. Of course with an indoor tank this probably doesn't apply.

Tom_133

Ok, Lets try to answer some questions.

I dont believe it was locking out before tune up. Though I am not 100% since we were not in dead cold winter when we did it.

Tank is 10' away above ground, 1 pipe, and tank is 3/4 full.

We did zero the head, and set it up to the exact numbers as last year, 12.5 co2 and like 35ppm of CO.
It fires incredibly well.

No vacuum gauge, but can pop one on to check.

I havent been back over, but will need to over the weekend probably and look for something obvious, and check the cad and the other possibilities

STEVEusaPA

EdTheHeaterMan said:

Really Steve... You recommending a Tiger Loop? What is this world coming to? I'm afraid to look out the window now!

Only if there's a small unfindable, annoying vacuum leak, or a lift job with high vacuum

Tom_133

Found the problem, and the problem was... us. I do this with one other guy who wants to help. Unfortunately I never looked well enough at his electrodes position. They were too low. If Beckett wants 1/4" above center line, they were only 1/16" above it. As soon as I adjusted, it fired like it should, in fact you then could hear the electrodes firing. Thanks for the comments.

EBEBRATT-Ed

@Tom_133

I have seen if the electrode are too close to the oil it will sometimes build a carbon bridge from the oil mist across the electrodes shorting them out. You think you have a bad trans or electrode and can't here a spark

You pull the drawer assembly out and jiggling it around breaks the carbon and you get it out and see nothing.