controller lockout - controller or other component problem?

Tony Melo

I've been having a problem with one of my properties’ heating systems. The controller has been replaced a few times now because it keeps "locking out". My plumber/boiler tech' is stumped and can't quite figure out what is going on. We started with a Wilkerson controller and initially thought that the controllers where bad because the controllers kept going into lockout. We know have a Honeywell R8184G 4009 and this controller is also going into lock out mode. Does anybody know what might be causing this lock out problem?

I’ve been doing some reading on this controller “application, installation, troubleshooting…” and I’m starting to understand some of the components and the functions they provide.

What are the ramifications of replacing the cad cell with a jumper with the right ohms range? I would suspect that the controller would sense that the system is operating as it should be.

Could a clogged tank filter cause the nozzle to clog and trip the cad cell? The system was cleaned in September of this year and was tested to have about 83% efficiency. Co2, draft all seemed to look good. Or, at least did when it was cleaned. My boiler tech’ also did something called punching down the fingers for better heat transfer.

When looking into the boiler during initial fire-up what should the flame look like? Looks like a Yellowish / Orange flame of good size 2-3” diameter with ragged edges.

Any help or advice would be very very helpful

Thanks
Tony Melo
Melo Properties, LLC

psd_3

Lockout issue ...

First advice ... get a real professional to help you ASAP.

What you're describing probably has nothing to do with the controller and perhaps not the CAD cell either. It sounds like basic issues with ignition and/or combustion leading to lockout ... particularly since multiple controllers are acting the same way.

Defeating the CAD cell is down right dangerous, so don't even consider going there. This is a safety device. It will prevent the system from flooding itself with oil, or running in an abnormal condition that could be life threatening.

Steady-state combustion parameters may look great, but if it won't ignite/fire properly you will lockout. This could be related to a host of different issues ... weak/bad spark, bad/wrong nozzle, setup issues, etc ... and needs to be diagnosed by a qualified professional.

Tony Melo

reply to sid

Sid:

Thanks for the info'. I looked at it again last night and what I thought was a jumper was really the wiring for the cad cell. So I was wrong there is a cad cell in place even though I don't know where it is.

I sat there for about an hour last night and it took that full hour to go from 120° to 130° operating temperature. The pressure increased a couple PSI. The system is a fairly big system, I’m assuming, for the building about 5400 sq. ft. The system has two circulators one for the first and second floor and a third for the third floor.

What I’m seeing is that the system goes into lock out but the circulators keep running.

The guy I'm using is a master boiler technician and I do trust that he knows what he's doing. He's also a plumber but he specializes in heating systems (more of a service guy than anything else). I spoke to him yesterday and he said that he went in and cleaned everything again. He’s in the process of bringing in a 3rd generation oil guy that may be able to trouble shoot what’s going on.

I agree with you it’s defiantly not the controller(s). The cad cell and nozzle I’m not sure.

The system worked fine last night (5:30 to 6:30) while I was there and when I showed up this morning (6:00am). So that’s one night without problems. We’ll see.

I NOTICED THAT THIS BOILER HAD THREE LABELS ON IT. IS THIS NORMAL? WE HAVE THREE LABELS WITH THREE SEPARATE MODEL NUMBERS. BASED ON THIS THE NOZZLE SIZE/TYPE SHOULD BE SOMEWHERE IN THE ARE OF 1.50 60° TO 2.00 60°.

Thanks

Tony Melo

psd_3

Lockout

Tony,

Have you actually observed it going into lockout? If so, what is happening when it does so? Is the burner in the processing of firing/igniting when it happens, or has it been burning for a good while and then just goes into lockout? Knowing this is important to differentiate an ignition problem from something else?

Do you notice rumble starts when the burner ignities? Do you notice a strong exhaust oder after it starts? These could indicate delayed ignition and would point the tech to check for things like a weak transformer, bad or improperly spaced electrodes, bad nozzle, issues with your draft control, a vacuum/air leak in the fuel supply, etc.

If the burner goes into lock after running for a while, it could be a poor flame detected by the CAD cell, a sooted up opening in the turbulator/blast tube to the CAD cell, a bad CAD cell, fuel supply issues, an excessive draft pulling the flame off the retention head, a venting issue, a cracked boiler leaking water/stream into the firing chamber, etc.

It's not surprising that the circulators run while in lockout because they may be controlled independently. Perhaps there is a low temperature limit at which they would shut off, or perhaps there is freeze protection and they will keep running despite the water temperature.

Some boilers have options for muliple firing rates, so that's why there might be a range of recommended nozzles listed.

Tony Melo

million dollar question

Sid:

That was what I was hoping for, was to actually see or hear what happens when it goes into lockout. I'm going to keep a close eye on it over the next couple of days. So far I've only been there when the burner has all ready ignited and working. You bring up a bunch of good checks points. I have no choice but to just watch it and if it fails again to try to record how when and where. The guy I've been using is big into close loop controls and eventually (depending on price) install a controller with remote capabilty or at least data logging. I've never thought about this stuff but it can get complex and the problems tough to find. We'll see what happens the next couple of day. Thanks for your help.

Tony Melo

Mitch_4

Hey Tony

The 8184G only goes into lock out for cad cell / flame circuit. This is not to say that it is a flame problem. Likely is not the control as you have changed it.

You did not say what the cad cell is reading (ohms) during the run cycle.

If it ran before, then the "punching down the fingers" (whatever that is) may have affected the combustion in certain conditions. Especially if it creates a restriction inthe heat exchanger. When you test and observe, I find it especially important to simulate the actual running conditions too. Did you close all the doors / windows that would normally be if you were not there?

Read the cad cell when it operates 400-900 is a good read, although below 1500 should not trip the safety on an 8184G.

The punching thing concerns me if it creates a restriction.. think of the heat exchanger as a bathtub including the drain fitting, the tap is the burner and the drain is your chimney. When you turn on the burner (tap) the flue products (water) go through the heat exchanger, and out the flue (tub and drain), now if there is a restriction (fingers in the drain opening), the water will not run out as quickly, eventually leading to a build up. In a heat exchanger, these flue products will affect the flame characteristics changing the luminescence of the flame, and possibly causing the cad cell to activate the reset.

Post all the combustion numbers and the cad cell reading so we can help.

Tony Melo

thanks for the reply.

I had the electronic igniter replace (because it died) on christmas morning. I haven't had a problem since.

I don't really know what the cad cell was reading although that was replace this year too.

"Punching down the fingers" just might be a term that folks in my area call cleaning the cast iron sections inside the boiler. The guy that worked on said he cleaned it out to the point that it was practically new.

He did effiency test and draft test and said that the should be running perfectly.

I don't know how (or even if) the transformer (ignitor) was the problem but it looks like I'm out of the woods for know. thanks


quick question: I was talking to a friend about oil heating systems and this friend insisted that the blower on these systems are used only to "evacuate" any fumes in the boiler. I told the him that its was for combustion & atomizing the oil into a fine mist for burning. WHO'S RIGHT?

THANKS
TM

psd_3

Blower question

Tony,

First, let's clarify which blower you are referring to.

I assume you mean the blower that is part of the oil burner assembly? If so, then this blower is used to support combustion by providing the appropriate amount of air (Oxygen) to the combustion process. Secondarily it provides mixing of the fuel and air in the combustion chamber by enabling specific aerodynamics with the head assembly (i.e., the end cone or turbulator). This same blower is often used during a pre-purge cycle to help establish a draft, or during a post-purge cycle to help vent the combustion chamber of residual waste gases.

Atomization is really derived from the nozzle but is also dependent on the pump pressure.

Other blowers that you sometimes see on oil/gas systems are draft inducers or power venters. These are used to control proper draft which is also critical for combustion. Draft is necessary to get the combustion by-products out of the chamber in order to allow fresh air in.

So I'll let you be the judge of "who's right" ... but there are many aspects to consider in the original question.