I'm having a persistent problem with the reset button (flame failure) tripping on a hot water boiler. It happens almost daily, usuallyduring the night. All the usual suspects have been replace - ignition transformer, electrodes, nozzel, filter, burner control (twice!). The flame sensor was upgraded from an old coil type to an optical sensor. The burner fan and fuel pressure are okay. Anyone have any other ideas?

 

This sounds like either a maladjustment of some sort or a bad start switch on the burner motor. When you reset the flame saftey does the flame ignite promptly. Any smoke or rumbling? Is the flame larger & more orange than normal?

 

You did not mention burner motor and if you still have any hair left, replacde that next. The manual reset overload switch makes most people think that a motor can not be bad if the overload isn't tripped. However, a motor that develops a dead spot can drive you up the wall. Replace the motor (use a PSC) and you may be all set. The only other suggestion is to make sure the cad cell you mounted is in a good position to view the flame (but not too close) and another word of warning...I have had 6 or more defective safety controls right out of the box this season. Beckett and Honeywell 7184s. They trip out even with flame present.

Ken

 

Do you have an ohm meter & know how to use it? What is the number on the primary control (the box containing the reset button)?

 

Haven't replaced the burner motor yet (maybe next). First pass on the burner control was a Honeywell 7184. When the problem remained, that was replaced with a Carlin 40200-02. I've got a multimeter. What needs to be checked?

 

I forgot to say - when resetting the system it start up with no problems, light immediately with no rumbling or other unusual noise.

 

If you have been doing all this yourself. You sure the nozzle is set right to the nose cone. The cone head ok not burnt off any?

ED

 

I'm doing some troubleshooting myself not the repairs (they've been done by a procession of boiler techs which I am not). Nozzle replacement has been done. What's the cone head?

 

On the tip or head of the air tube inside the furnace is the cone. So the nozzle and it like work together. If its ok then like if you change the nozzle spray angle you might have to change how far in or out you will set the nozzle to the cone head. Also you said new electrodes you mean also new ceramic insulators. i know some times the old insulators can short out on you if you only change the SST ignitor rods. just kicking things around here.

ED

 

The cone looks okay, straight and not burnt. The tech who installed the nozzle and electrodes (with new insulators) used a gauge - but I think that was to set the electrodes. Is there a standard distance for cone to nozzle? Special gauge?

 

There are special gauges for setting the "Z" dimension. That is the distance from the end cone to the nozzle face. What brand of burner is on the boiler? A model would help too. If you can't find the make & model of the burner, make & model of the ignition transformer will do.

To check the motor, you need an ohm meter which will measure down to single ohms. This is how you do it: TURN OFF THE ELECTRIC AT THE SWITCH.
Disconnect the motor from the primary control. Set the motor on the floor or a work bench with the shaft end up. Attach the ohm meter leads to the motor leads (preferably with alligator clips). Note the reading on the meter. Gently lift up on the motor shaft & watch the meter. If the reading drops, replace the motor. The start switch is bad. This procedure will work with any split phase motor. Not just burner motors.

 

My wife was here when the nozzle/electrodes were replaced, sounds like the gauge used to set the electrodes also set the cone. Burner is a Carlin 100CRD with and Emerson motor (1/7 hp 2.35 amp), ignition coil is a Allason 2275-630 (replaced last week). When lifting the motor shaft (has shy of 1/8 inch end play - don't know if that is normal on this motor), the ohm meter drops slightly (from 3.4 to 2.5), but comes back the the original reading. The drop is about the same as I get with a slight twist of the shaft - so I think that might be what I'm seeing.

 

Sounds like the motor is ok. I would love to have a look at this thing. Have you ever left it & let the service tech reset it? Often we can tell something which the homeowner can't pick up on. About the only thing I can come up with at this point is loss of fuel (solenoid failing to open?) or ignition failure. With ignition failure, there would be excess oil in the chamber but maybe not enough for the homeowner to detect. After re-reading your original post, I have to presume this is an old boiler. What kind of boiler & what nozzle?

 

I'll try leaving it tripped next time round, I'm hoping it's warm enough to avoid playing Russian Roulett with burst pipes (last week was single digits to -0 every night). Boiler is a 45 year old Weil McClain. I don't know nozzles, but it says Monarch 122 and 1.00 60°AR.

 

I'm stumped without being able to see it. I suggest you call the service company back & let them have another look. Please post back on this thread & let me/us know what they found.

 

like Grady when you dont see it you dont know. Like that 60o nozzle is the boiler or burner chamber long like. That 1 gal is about 140,000 btu so the boiler is not to big.Like does the burner run for long times or just very short runs.

You see you can have many ifs here.

ED

 

The burn chamber is about as long as wide (maybe 1 1/2 feet). Burn time depends, but minimum is about 3 minutes. Part of the house is cast iron baseboard - if it's cold, the burner can run continuously through several cycles of the circulator (20+). I'll post again next time it goes down and after I have checked. I'm at 24 hrs, the record is 48 since this started. In the mean time, if you have any sudden revalations ...

 

This part doesn't particularly concern me. Carlins typically use a 60º nozzle.

 

If you had the motor out to check the end play, you could certainly replace it yourself. It is still the part I suspect the most. It was partially confirmed by the fact that there is no rumbling or delayed ignition on any of the start ups. That could be due to the fact that the motor never spun up on a call for heat. A dead spot is one of the hardest things to pinpoint because you can't replicate the problem when you want to. The cost of the motor is probably less than the cost of having the tech change it.

Ken

 

Flash:

A common cause of intermittent lockouts is the fuel system; Grady mentioned the solonoid valve; if your system has an oil delay valve, this is a common culprit; to check, the delay valve can be removed from the fuel pump & the copper supply tube can be connected from the nozzle port directly to the nozzle assembly.

Have you tightened all connections in the fuel line between the tank & the burner; & is the fuel tank BELOW the burner; & is there a check valve in the fuel line???? All these are potential trouble spots; check valves eventually wear out & allow fuel to siphon back to the main tank during burner off cycles.

The slightest pinhole leak due to a loose fitting anywhere in the fuel line is enough to cause a periodic lockout by allowing the fuel to drain down away from the fuel pump during off cycles.

 

I'm not sure about a delay valve, but under normal operation there is no perceptable delay between when the burner comes on and the flame ignites so I suspect not. Pump pressure was checked and that was okay. The boiler is feed by an above ground tank about 10feet away (above burner level), so there should always be positive pressure on the pump - the only fittings are at the tanks (shut off valve and filter) and burner. I'll check tightness, but they don't drip.

The most common time for it to trip out is early a.m., about the time the thermostats should be calling for heat to warm the house in the morning after being off all night.

After all the trouble shooting, the system hasn't gone down in 3 days (but it's been warm - should get cold Friday). I'm starting to think it was a loose electrical connection somewhere which I moved or tightened in the process. I did find a loose connection in the aqaustat at the thermostat terminals - but I don't see how that could be the problem.

 

I wouldn't get my hopes up about the electrical connection. The oil problem is doubtful also because when you reset the burner, it fires right up. A fuel problem would either delay ignition or cause you to have to bled the pump. A problematic solenoid valve is still possible and bypassing it could be a solution to try for a few weeks to see if the problem goes away.

Ken

 

Ah-Ha!! We may have our culprit. If after tightening this connection & the weather cools off again, let's see what happens. If the problem persists, try putting the thermostat(s) in Hold. Don't ask me why because it defies logic but sometimes programable thermostats seem to cause this same problem.

 

Problems again this morning - but with a new twist. I didn't get flame failure - but the burner flashed back hard enough to blow apart an elbow in the smoke pipe, and blow the draft damper off. When I discovered the problem it was running and the burner sounded normal.

It seems to me that this would rule out the motor - it must have been pumping fuel. Could this be water in the fuel? (Indoor tank, but I got a delivery yesterday.)

 

Todays problem indicates an ignition problem. You did say that the ignition transformer was replaced but there are other other critical settings with that burner. The retention head has to be all the way back against the nozzle adapter, the strut has to be centered between the electrodes. The electrodes have to be 3/16" ahead and 1/4" above the center of the nozzle, the retention setting has to match the firing rate (not the nozzle size), and the flame needs to be adjusted by measuring CO2. You said you had someone out to work on it. Why don't you let them follow up? They set almost everything I mentioned according to one of your earlier posts and should stand behind the setup. It still sounds like weak ignition. The new transformer should be checked just to be sure it is up to snuff. Carlins are fussy about setup but they are a good burner.

Ken

 

3/16 ahead? Sounds awfully far. I get to work on very few Carlins but I normally set my electrodes about 1/16 to 3/32 ahead. In fact, I use the Beckett settings. Am I messing up?

 

Actually I always use 1/4" for both settings. Because I get them mixed up which one should be 3/16". And sure enough, I gave it to you backwards. I never found a problem using 1/4" for both. Here is a link to the settings.
http://www.oiltechtalk.com/Just%20For%20Tek's/carlinOB.htm#Carlin%20"100%20&%20101%20CRD"

There are a few nice plastic gauges for setting electrodes on different burners. There is a nice one too for the Beckett AF & AFG to set the 'Z' dimension from the inside with the nozzle installed.

Ken

 

I got a new fuel pump (and smoke pipe) as a result of Saturday's blow back. Last night the primary control was replace (again). The nozzle, electrodes, and cone adjustment were checked using a plastic gauge. I didn't ask if the gauge was the right one for a Carlin burner (it was 1 a.m. - I'm not sure I would have liked the response I'd have gotten to the question anyway.)

I didn't check the part no. on the primary control (it's a Carlin - has an LED failure indicator on it). I was told it's a continous ingnition unit - rather than the intermittent ignition unit it's replacing. The heat was out again 2 hours later. This time I had to cycle it twice to get a restart (this is the first time it didn't light up immediately on reset).

 

I'm sorry to say it may be time for a different technician. What boiler/furnace is this burner installed on? There is a sequence of nozzle selection, burner setup and combustion adjustment. Just as an example, if the retention setting is too far forward, it will require less air shutter opening but will light up with a puff every time. The nozzle assembly needs to have its zero marking checked to be sure the setting for the firing rate corresponds with the Carlin specs. After that, the range of settings for the chosen firing rate needs to be matched to the combustion chamber shape. Short chamber needs the smaller setting and longer chamber needs the larger setting. Some manufacturers like Dynatherm actually had their own recommended settings that were different than Carlins regular specs but thats what it took to make the Carlin burner work in their boiler. You can't imagine how one small setting being off or overlooked can make that burner work poorly. Or maybe you can, yours seems to be pretty touchy.

Ken

 

Good question. It an old Weil McClain, (1960) - the name plate says size P-OB18, series 4. I can't find a model and it doesn't look like any of the boilers (current or discontinued) on the Weil-McClain web site. It got a rear vent, two removable inspection plates above the burn-chamber, the burner is inside the sheet metal cabinet, as is the circulator pump (need more?)

Maybe I'm going to have to learn to set up the burner myself. I'm starting to beleive your right about the burner setup being the issue - since it was "adjusted" last night, the problem has gone from once every day or two to flame failure 4-times in the last 18 hours (and I was gone all day, so it really isn't staying up for more than a couple of hours).

On the good side, the company servicing it is going to install an ONWATCH monitor. Sounds like it monitors everything for troubleshooting...

 

The ONWATCH is a nice piece of equipment, wish I could afford one. It will tell the tech what happened & when but it will not tell him why. I certainly hope you are not paying for all of these parts & the labor. Has anyone yet done a complete combustion analysis? If they have & you have the data, please post it. I would give this tech one more shot after the ONWATCH. Beyond that, I would insist on having the service manager or Sr.Tech come out & go over your burner.

 

I'll ask about a combustion analysis - no one has done one. I've paid for limited service - most is under warranty. I'll keep you posted.

 

My Gawd, these guys are guessing, at best. Get on the horn with the owner or at least the service manager in the morning & light a fire under their behinds.

 

You said new transformer there ?????? Have they checked it out to make sure its good????? Just a guess here.

ED

 

The Carlin CRD 100 was a great burner but not many people know how to set the electrodes or adjust the slide on the side for the nozzle assembly. Electrodes are always to far forward and slide adj is always to far back. For a 1.00 gallon nozzle the slide adjustment needs to be set almost half way forward. The third line. If he is using a gauge to set the electrodes he is more than likely unfamilar with the burner. Tell him to set the electrodes just a hair more forward than he would on a Beckett burner and make sure the slide adjustment on the left side of the burner (nozzle assembly) is set to the third or fourth line. Then notice how much he will be able to close the airgate down and maintain a clean fire.

 

Yesterday the burner wouldn't spin on reset until I shut the power off then on (actually did this twice over night, but one other time it started right up). In the morning it caughed back really hard (shook the house), then just wouldn't light (the motor would spin, but no flame).

I got the Sr. Tech this time. Unfortunately, I've missed too much work already, and wasn't able to stick around and quiz him on what/why he was changing things. Net result - the burner was completely readjusted (the light off and burn are much quieter - I'm hoping that's a good thing). Replaced the transformer with a Carlin. Replaced the General Controls aquastat with a Honeywell 8124A. Installed an ONWATCH. It's been 18 hours without trouble, and it's going to be a cold weekend (hopefully I can switch back to oil heat from wood).

Is it possible that a bad relay or contacts in the aquastat was causing low voltage to the primary and motor?

 

It is possible the aquastat was suppyling low voltage to the burner. It's a long shot but maybe. I question the replacement of the ignition transformer (again). I still think these guys are guessing, but in their defense, if they can't get it to act up while they are there it's tough for them to pin down the problem. That's what is great about the OnWatch. It will monitor & record several different parameters. Then the tech can analyze the data & hopefully pinpoint the source of your problem. Please keep us updated as to progress. BTW, did the Sr. Tech perform a combustion analysis?

 

The Sr Tech did do a combustion analysis, but I haven't been able to speak directly to him, so I don't have the numbers. After all the feedback here and troubleshooting I've done, I've come to the conclusion that the burner needed to be tuned, and was incorrect adjusted when I called in help. (Maybe I'm being harsh here, but Im going back to "if you want it done right, do it yourself".)

That said, as far as I can tell, this is not the OEM burner (Carlin 100CRD) for a Weil McClain boiler. The Carlin OEM guide lists generic electrode postion setting, but the nozzle setting seems to be boiler specific (and critical from what I've seen). Al - you suggested the slide between 3 and 4. Is this trial and error? How can I tell if I've got it right? (I'm very well equipped on tools/measuring instruments, but don't have access to a combustion analyzer.)

 

I'd hate to be the Sr. tech at that company. Might as well be the only tech. I gave you the address to the carlin settings and all you have to do is compare them to yours. The OEM settings were never far off of the recommended setup unless the boiler was pressure fired like the Dynatherm. Just use the standard settings. It will probably be better than your guys have been able to do anyway.

The address is:
http://www.oiltechtalk.com/Just%20For%20Tek's/carlinOB.htm#Carlin%20"100%20&%20101%20CRD

and it's all there.

Ken

 

Thanks Ken. Things are still working, but I'll be checking all settings myself.