what keeps eating my ignition transformers
#1
12-31-09, 01:44 AM
what keeps eating my ignition transformers
10 y/o burnham oil boiler; beckett af burner; 4 zones. 3 years ago, no heat; hvac puts in new ignition transformer. 1 year ago, no heat; a different guy puts in a used transformer [it was easter]. used one worked ok. i replaced this asap with a new allanson unit, which is now 9 months old. for the last 5 weeks there is increasingly frequent double ignition, and short cycling [30 seconds or less]. that 30 second cycling was the harbinger of failure of the 2 earlier units. 1 hour ago i replaced my 9 month old allanson with the old used one. immediate cure. what is going on? what could be ruining the 2 new transformers in 3 years while the old one seems to work fine? the only change i made to this system was 4 years ago when i got rid of the remote water heater and used that zone to supply a new heating loop to the new family room addition. aquastat is honeywell R8182.
am i cursed?
am i cursed?
#2
12-31-09, 05:52 AM
I skimmed thru your post from last April.. ya, that does seem to be a whole lot of transformers to go through.. lol
I'd think if the power was *that* dirty (over/under or harmonics), you'd be having other things fail in the house. No problems with tv/audio/computer stuff ? Blower fans, a/c units ?
Can you set up a test to verify that you have 120v a/c going into the transformer (while no spark is happening) ? Maybe monkeying with the transformer each time is shaking the controller unit back into a 'good' situation ?
I'd think if the power was *that* dirty (over/under or harmonics), you'd be having other things fail in the house. No problems with tv/audio/computer stuff ? Blower fans, a/c units ?
Can you set up a test to verify that you have 120v a/c going into the transformer (while no spark is happening) ? Maybe monkeying with the transformer each time is shaking the controller unit back into a 'good' situation ?
#3
12-31-09, 07:46 AM
dave
i don't know how to try that because the "new transformer" did work, it just worked intermittently. it was on the way to total failure.
the allanson is rated at 23 ma [i assume that is input]. is it possible that using 4 tstats is causing an overload if by some chance all 4 are calling for heat at the same time?? does the current supplied by a tstat even go directly to the transformer?? i thought that the only signal to the t'former comes from the aquastat. the electrodes were adjusted as per the beckett install manual and i triple checked the accuracy: 5/32 gap, 5/16 above nozzle center, 1/16 ahead of nozzle. however, i did notice that the electrode tips were burned away after 3 months use; like about 1/8-1/4 inch was gone. does that sound excessive? could there be too much current going through the high output secondary burning away the tips? thanks for the feedback.
i don't know how to try that because the "new transformer" did work, it just worked intermittently. it was on the way to total failure.
the allanson is rated at 23 ma [i assume that is input]. is it possible that using 4 tstats is causing an overload if by some chance all 4 are calling for heat at the same time?? does the current supplied by a tstat even go directly to the transformer?? i thought that the only signal to the t'former comes from the aquastat. the electrodes were adjusted as per the beckett install manual and i triple checked the accuracy: 5/32 gap, 5/16 above nozzle center, 1/16 ahead of nozzle. however, i did notice that the electrode tips were burned away after 3 months use; like about 1/8-1/4 inch was gone. does that sound excessive? could there be too much current going through the high output secondary burning away the tips? thanks for the feedback.
#4
12-31-09, 02:53 PM
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Transformer
Once the flame ignites, it doesn't care if there is spark present or not. All new controls shut off the spark after the "trial for ignition" period is over. One manufacturer keeps their ignition on only for a fraction of a second.
In a nut shell, I don't think your problem is the transformer.
In a nut shell, I don't think your problem is the transformer.
#6
12-31-09, 05:06 PM
Originally Posted by reisjdmd
however, i did notice that the electrode tips were burned away after 3 months use; like about 1/8-1/4 inch was gone. does that sound excessive? could there be too much current going through the high output secondary burning away the tips? thanks for the feedback.
As Grady mentioned once the flame is lit the ignition can be shut down. With the burner not holding the flame there is something else wrong. Which may be part of the issue with the electrodes being burned back.
Such as flame impingement on the electrodes. Or the flame being too close to the burner retention cone. I think if you find the reason the electrodes get burned back, you will also cure the intermittent flame issue along with the transformers going out.
Al.
#7
12-31-09, 11:11 PM
so i guess somthing is wrong if the electrodes are being burned away, and it sounds like that is because the flame is too close to the electrode tips. and that is not the fault of the transformer but it will secondarily destroy a transformer. is that about it? is there any way that a defective aquastat could be involved in the flame too close to the tips? other than make sure the electrodes are installed as per the beckett manual and other than replacing the nozzle with the same one the boiler came with, what else can i do? is there any trick to replacing the nozzle? i have a new one sitting down there. is it worth installing that one? the current one is only 4 months old.
#8
01-01-10, 05:03 AM
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Electrode Tips
If you are concerned about the pencil points on the electrodes, don't be. With a control which keeps the ignition on the entire time the burner is running, such as the R8182, the pencil points are going to burn off very quickly, usually in less than a year. Just take a file, clean up the ends, & re-adjust the electrodes to spec.
A way to prolong electode life is to change the aquastat to an R7224 & install R7184 primary control for the burner. The obvious downside to this approach is upfront cost. In a few rare cases, I've found by going back to an iron core transformer, instead of electronic ones, has helped but in those cases, the electronic transformers were actually failing completely.
A way to prolong electode life is to change the aquastat to an R7224 & install R7184 primary control for the burner. The obvious downside to this approach is upfront cost. In a few rare cases, I've found by going back to an iron core transformer, instead of electronic ones, has helped but in those cases, the electronic transformers were actually failing completely.
#9
01-01-10, 09:32 AM
grady
one last question, hopefully. when i did my seasonal cleaning/prep in august, i noticed that the points were burned back so far that there was about a 1/2" gap, and of course the gap was too high relative to the nozzle center. could that situation have led to premature failure of my new allanson iron core transformer? the pro last easter that put in the used transformer never checked the points; he just put in a used transformer and the unit worked. i replaced the used unit in a few days and the unit worked. it was only in the sunmmer i found the burned points. i replaced them but kept the same new allanson transformer which is the one that has recently failed. i suppose it was firing those badly separated points april and may and part of june. does this make sense?
one last question, hopefully. when i did my seasonal cleaning/prep in august, i noticed that the points were burned back so far that there was about a 1/2" gap, and of course the gap was too high relative to the nozzle center. could that situation have led to premature failure of my new allanson iron core transformer? the pro last easter that put in the used transformer never checked the points; he just put in a used transformer and the unit worked. i replaced the used unit in a few days and the unit worked. it was only in the sunmmer i found the burned points. i replaced them but kept the same new allanson transformer which is the one that has recently failed. i suppose it was firing those badly separated points april and may and part of june. does this make sense?
#10
01-01-10, 09:53 AM
Even though the electronic xfmrs SAY they are rated for 100% duty cycle, I imagine that's tough service for them.
You can just change the primary control to a 7184 and achieve interrupted ignition... you don't need to change the aquastat also... you will need to run an 'extra' wire to the burner to make this change because the 7184 requires a constant source of 120VAC.
You can just change the primary control to a 7184 and achieve interrupted ignition... you don't need to change the aquastat also... you will need to run an 'extra' wire to the burner to make this change because the 7184 requires a constant source of 120VAC.
#11
01-01-10, 10:06 AM
#12
01-01-10, 11:54 AM
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7184
Trooper,
One would have to change the aquastat as well because the 8182 is a Protectorelay, having it's own cad cell circuit.
Thanks for the Allanson link. I read that years ago but it was a good refresher. Gonna print a copy for the green (maybe half ripe
) horn.
One would have to change the aquastat as well because the 8182 is a Protectorelay, having it's own cad cell circuit.
Thanks for the Allanson link. I read that years ago but it was a good refresher. Gonna print a copy for the green (maybe half ripe
) horn.
#13
01-01-10, 01:06 PM
the 8182 is a Protectorelay
That Allanson brochure is a little long in the tooth... doesn't cover the new stuff (electronics) but good basic info.
#14
01-01-10, 02:04 PM
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I'd install a time-delay relay in the primary of the ignition transformer before replacing a working aquastat AND primary control. A TD relay would be less than $100 new and a whole lot less if you find one in surplus. As long as you don't change the existing cad cell primary there shouldn't be any problem with violating the UL listing.
#15
01-02-10, 06:01 AM
a clear, understandable article and very helpful replies. i suspect the culprit was the very wide wide gap, and so i will start with a new transformer and check the gaps evey 6 weeks or so during the heating season. thanks again to everyone, and a happy new year. this is an excellent forum!
