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I have a Nordyne M1SB 066 furnace. It is an oil-fired, forced-air system. The thermostat calls for heat, oil starts being pumped it, and the furnace tries to ignite the fire after 15 seconds. Oftentimes a flame doesn't start, which causes the furnace to go into lock out.

I thought for a while that the thermostat might have been short cycling the furnace. In other words, call for heat, after just a few seconds, the house warms up by 0.5 degrees, and the heat is turned off. So oil is pumped in before the flame starts. I put in a new thermostat that has a programmable minimum run time.

I thought my issue was solved. But alas, twice in the last two days the flame hasn't started. I've had a tech out here a few times, he's replaced the ignitors, and some other things. He thinks the furnace looks OK, and can't find out why it is doing this.

So I am turning to this forum for help. Any ideas?

Hi,

I do not work on oil furnaces and have limited experience with them. Will leave this here for those who are experienced with them.


That said, should be able to test each component in the circuit to see what is not working.


Nothing should be replaced without knowing it is bad.



Thanks,
Robert

Thanks for the reply Robert. I've been doing some more reading, and some manuals say this is a common problem with these types of oil-fired furnaces. One manual said something like "randomly, for no apparent reason, the flame may not ignite." So I guess that makes me feel better?

Anyway, I don't think it's the cad cell, that looks clean. For the next few weeks, I am going to run over to my furnace, and open the firewall to see if there actually is a flame before it shuts off. This time of year it is getting colder and colder in Alaska.

You're very welcome, wish I could help more. Keep us posted.



Thanks,
Robert

This unit has an R1784B1024 primary control. I have been reading online that my problem is not unique. A lot of people are having this lockout issue with this primary. Read for example here:

http://www.heatinghelp.com/forum-thread ... nt-Problem

Are there other primary control units that I could buy that would replace this? Or am I stuck with this specific model?

Call Mark at 605-229-2627 and see if he can cross reference or match it with another control that can be used.



Thanks,
Robert

Thanks for all of the responses. I replaced the transformer (ignitor), and the issues seems to have gone away. I finally caught a dirty start in action, and indeed there was no flame.

I also purchased the Genisys 7505b1500 and the digital display/programmer. I know that my primary control (r7184b) is good, but I like some of the features of this next generation primary. Such as programming the pre-purge length, and it gives a detailed history of the last 15 cycles, and any errors that occurred.

All they need is to add wi-fi to these primaries so we can view history and monitor activity from a website. I know commercial furnaces have these features, but I will be very interested to see Beckett add this to their residential appliances.

You're very welcome, glad you got it going.



Thanks,
Robert