My furnace (Atwood 8531) will not ignite. The fan runs constantly but no tick tick tick of the ignition. The unusual part is that the interior lights continuously blink when it's trying to start up. The outlets are a solid 120V. I suspect a bad circuit board but the cycling lights have me wondering. I checked the incoming power to the furnace motor and it is cycling as well. The camper is a 1998 Mallard 29. Has anyone else seen this continuous blinking? Thanks for your time.
Interior Lights Blink when Furnace is trying to start
- Thread starter Superior
- Start date
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Gary RV_Wizard
Site Team
If the furnace fan runs but it does not attempt ignition then the fan is too slow to close the sail switch (fan speed sensor). The usual cause is low voltage to the furnace fan. Are the lights LED bulbs? They too often react to low voltage by blinking.
The furnace fan is a fairly large 12v power draw, typically about 5A. Maybe more if the fan is having trouble pushing air (clogged air inlet?) or the motor is failing. That amount of power is enough to drop battery voltage. Is your converter/charger producing 13+v for interior use and battery charging? Get a voltmeter and start taking measurements.
The furnace fan is a fairly large 12v power draw, typically about 5A. Maybe more if the fan is having trouble pushing air (clogged air inlet?) or the motor is failing. That amount of power is enough to drop battery voltage. Is your converter/charger producing 13+v for interior use and battery charging? Get a voltmeter and start taking measurements.
Kirk
Well-known member
Your outlets are powered by 120V power from the power pedestal that you are plugged into. The lights, furnace, and most appliances are power by 12V from either your battery or the converter. How long has it been since you last checked the electrolyte levels in the battery cells? How old is the RV battery? Like Gary, I suspect that you have low voltage on the 12V system. If you start replacing parts without any troubleshooting you can spend a lot of money without fixing the problem. I suggest that you use these links and download a copy of the Atwood User's Manual and then get the Atwood Service Manual and troubleshoot, if the problem really is the furnace. It is far more likely that your problem is a bad battery or a bad converter, or possibly both.
OldWEB
Well-known member
I agree with the DC voltage diagnosis, if the motor, lights and voltage all dip low (cycling), then the batteries are either non-existent of so dead it will not smooth out the converter output. Is the battery disconnect closed?
Also the motor is drawing too much current if it is seizing up... but bad voltage would also have to come into play.
I do not have a 12V batt. I only run the camper off shore-power which points to a converter ,so I am going to locate that and check the output as suggested by Gary. Thanks for your input.
Do you have to have a battery if I run off shore power all the time? I did it all last year and the furnace worked fine. Thank you for your response.
Kirk
Well-known member
I have never seen an RV that didn't have a battery installed unless it was removed by the owner.
RV's always come with a battery installed and if it has failed it is very possible that it is pulling the voltage from your converter down. Typical RV batteries also require fairly regular maintenance so if you have not removed the battery and have never done any maintenance on it, that is most likely what is causing your problem. If you find the battery, first disconnect power from the RV, then remove the cable from the negative (-) battery post and plug your power in to see what you get. It would be wise to get yourself a volt/ohm meter and learn how to use it. It would also probably help us to help you if you would tell us what the make and model of your RV is.;
Gary RV_Wizard
Site Team
Given that your RV is an older Mallard, I'm guessing it has an old-type single stage converter/charger. Those can operate without a battery but don't always regulate the 12v power well. Connecting even a small 12v battery provides a lot more stable power. Doesn't have to be a big battery or high tech, just functional. Even basic RVs typically come with a group 24 size 12v marine/RV battery which serves as a back-up amp source as well as a stabilizer.
Hello Kirk, I stated in my original note a 1998 Mallard 29ft. Thanks for your relpy.
Thank you very much Gary. I have a battery I can connect and try it.
John From Detroit
Well-known member
A trailer that moves MUST have a battery
Your lights blink becuse the converter has not the OOMPH to start the blower motor on the furnace.
You need a battery to provide the added OOMPH (Amps in this case)( or at the least a "Battery Simulator" (Magnetek sold these. it's also known as a Hardening cap over at the high car audio store)
Your lights blink becuse the converter has not the OOMPH to start the blower motor on the furnace.
You need a battery to provide the added OOMPH (Amps in this case)( or at the least a "Battery Simulator" (Magnetek sold these. it's also known as a Hardening cap over at the high car audio store)
Mark_K5LXP
Well-known member
With the old magneteks the full output of the supply was available on shore power, so this should work OK without a battery. On those units the battery wasn't in parallel with the output, it had a separate regulated, relay isolated supply for battery charging while on shore power so the battery won't contribute anything to the loads anyway. We don't know what converter is in there though but whether it's a magnetek or a more modern transformer or switcher unit, it should be able to run a furnace fan without a battery unless there are other loads that are adding to it. Some quality time with a voltmeter will reveal all.
Mark B.
Albuquerque, NM
Mark B.
Albuquerque, NM
Kirk
Well-known member
Sorry! I guess that I missed that. At that time the Mallard was built by the old Fleetwood Co. but when they went through bankruptcy the trailer brand names were all bought by Heartland(2/2010) and most of them have not been built since. I'm not sure what converter they were installing in 1998 but, like Mark suspect that it was Magnatek 7300 series. If it is, this owner's manual should apply.
OldWEB
Well-known member
You are batting 0-2 Kirk...
Mark B. mentioned the relay, a weird converter I never liked, but would be the 6300 series.
Mark B. mentioned the relay, a weird converter I never liked, but would be the 6300 series.
Thanks for the link and your time.
You are correct my convertor matches the 7300 series. Thank you Kirk.
Kirk
Well-known member
You need to read just a little bit further.
Gary RV_Wizard
Site Team
I'm not sure that applies to the 7300 series. Unlike the 63xx, the 73xx has only a single pair of battery leads that serves both charging and off-grid battery operation.
Kirk
Well-known member
Have you taken any voltage readings?
