Oil Furnace Controller Tripping Intermittently
I have a Thermo-Pride forced-air oil furnace.
On Oct. 22, the primary controller was replaced because it was obviously broken. Everything seemed fine after that.
The yearly service was done on Dec 10.
Now we have an intermittent problem:
We set the thermostat to 50 degrees when we are not home and at night, and usually 62 otherwise. Three times recently, separated by 5 or 6 days, the controller has tripped the first thing in the morning when the thermostat is turned up. After it is reset, the furnace runs fine again.
This morning, I checked the controller reset button before I turned the thermostat up and it was not tripped. After I turned up the thermostat, I returned to the basement. I was standing next to the furnace when the controller tripped. This was several minutes after the furnace started and long after the 45sec lockout time. There was no indication to me that the furnace was not running normally when it tripped. If the flame had actually gone out, I’m pretty sure that I would have noticed, because I know what it sounds like when the pump is running but the flame is out. A minute or so later when I was able to reset the controller, the furnace again resumed running normally and seems fine now.
It is almost like the furnace has become reluctant to wake up in the morning. I put a min-max thermometer next to it and the temperature falls to 48-50 at night and when we are away during the day, but this was never a problem before the controller was replaced, nor is it a problem most of the time now.
Obviously, I have to get to the bottom of this or we can never leave home for an extended time.
Is the Honeywell R8184g Primary Controller sometimes defective when new? Is it possible that the cad cell is failing intermittently? What is the usual reason that an oil furnace controller will trip suddenly even if the there is a flame burning?
have you called the company who serviced it? they should come back to fix it. most likely an easy fix. if you wait much longer they might charge.
I had a similar thing happen with my sister-in-laws 31 year old Therm Pride in her vacant house next to my home here on the farm.
I checked he output of the furnace & it was half what it should be; however, the blower airflow is less than half what it needs to be; bad situations.
I figured with the low firing rate there would be way too much combustion air entering the combustion chamber; also the secondary air band was not closed as it should be on anything under 2-GPH nozzle rate. That would be a 280,000-Btuh Input furnace.
After I closed the secondary intake air & adjusted the primary down some, it has never failed to start for weeks thereafter.
You definitely need to call, & qualify some Techs so you know they know how to work effectively with a high level of knowledge & skill on oil burners.
Too much DIY info
Post the model & all the Ratings of the furnace, along with burner make (Beckett) or other; fuel pump Suntec Model#, or other make pump?
Cad cell may not be clean... or beginning to fail?
What else was done during the last servicing?
View this recent post with similar problems:
Last edited by beenthere; 12-30-2012 at 04:43 PM.
Reason: Too much DIY info
make sure the oil filter is tight
We really need change now
>> I had a similar thing happen with my sister-in-laws 31 year old Therm Pride in her vacant house next to my home here on the farm.
That sounds similar to me, too.
>> You definitely need to call, & qualify some Techs so you know they know how to work effectively with a high level of knowledge & skill on oil burners.
Yes, but I'd really like to understand what's going on with my equipment if I can. I never seem to find the best people, probably because I don't have a lot of money.
>> Too much DIY info
Currently, the secondary is closed and the primary is at 5 out of 10. It was smoke tested when it was set, but that was not recently. Temp and smoke testing can be redone soon.
But if the air setting is incorrect, what would be causing the lockouts? Although I didn't see what happened the first two times, the third one appeared to me to occur while the flame was burning.
>> Post the model & all the Ratings of the furnace, along with burner make (Beckett) or other; fuel pump Suntec Model#, or other make pump?
Thermo-Pride OL11-105 installed 1993
Rating: 126,000 BTU/HR, 0.90 GPH
Beckett burner 0.4-30 GPH (sticker says 'Model "A", "AF" (may be suffixed) MP 1192,' whatever all that means)
Suntec A2VA-7116 pump replaced June 2011
Installed nozzle: 0.85 GPH
>> Cad cell may not be clean... or beginning to fail?
It definitely isn't dirty, nor is it totally defective. But if it is not working every time, that would explain the lockout even with the flame burning. Do cells fail gradually like that sometimes? Maybe it should be replaced to see if it helps?
>> What else was done during the last servicing?
Heat exchanger vacuumed, oil filter replaced, nozzle replaced, electrodes checked, air filter replaced, forced-air fan motor oiled.
Thanks very much.
Last edited by beenthere; 12-30-2012 at 04:45 PM.
Reason: Too much DIY info quoted
Is that because air may be getting into the line? I checked and there were a few drops of oil under the filter, but nothing major. I snugged up the bolt, but it only went about 10 degrees. Could it be that sensitive? (No sarcasm here, I'm asking because I don't know.)
Originally Posted by catmanacman
Its less then a month since they came out and cleaned it. Stop messing with it and call them back. Repair/correct will probably be free or very inexpensive if you call them tomorrow morning. Wait much longer, and it will cost you.
Main reason I found primary controls went bad was because of issues with the burner motor. Whenever I replaced a primary I strongly suggested to the customer to replace the burner motor also. Yes it's running, but it doesn't mean that the motor is fine.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
the burner motor should be tested at the cleaning. not that everyone does it. i have never noticed the primary and motor as a common linked problem. good advice, i will pay more attention.
Originally Posted by firecontrol