Beckett Genisys 7565 - Recurring LIM indicator lockout

njsmith · January 18

I recently replaced the pump, coupler and primary on my Miller that has a Beckett AF. CAD cell was also replaced as it was original (1983). Previous control was an older WhiteRogers that was working fine. I've kept it as a backup. I wanted the Genisys 7565 for the diagnostics and a C wire that the WR doesn't provide. I'm planning to upgrade the thermostat in the near future.

I have been experiencing a lockout after several days of normal operation with the LIM indicator lit. Unfortunately the myTechnician app does not indicate any faults with a normal end to every cycle. All of the parameters look in line with what I'm expecting (min 111V, motor current 2A, CAD around 700 -900ohm). Flame looks / sounds normal and appears to have a good draft. The only thing I see is that the last cycle run time (before the lockout) is usually between 45 minutes and 60 minutes in duration (thanks to the diagnostics). This is usually bring the temperature from 62F to 69F from overnight. Normal cycles only run about 12 to 15 minutes through the day. I'm starting to wonder if there is a timer or internal temperature sensor in the 7565 that is tripping this lockout. There doesn't appear to be much useful information on the LIM indictor or much on the fault tree of the 7565 in general that I could find.

I just had it fault again (bringing the temp from 45F to 54F) and when I touch the surface of the primary it is very warm. An attempt to reset the lockout fails. Power cycling the primary results in the LIM LED re-illuminating and remaining in lockout. Diagnostics indicate the cycle was exactly 60 minutes. There was another cycle immediately after that one that is recorded as <1 minute but I didn't even here ignition.

The nature of the Miller is that there is a fair amount of heat buildup in the area of the burner head since it behind a door.

Does anyone have any experience with this primary?

Maybe this control just isn't a good fit for this application?

Ready to put the WR back in service…

EdTheHeaterMan · January 18

LIM means the limit control is closed. That is normal. It has nothing to do with the lockout. What was the fault code that occurred at the end of the 60 minute cycle just before the lockout? It should be in the fault history.

njsmith · January 21

There are no fault codes, no faults are indicated but the module will not respond as in lockout. Cause of last cycle end is always thermostat open. The control goes into the observed lockout mode with the LIM on. I've had this happen 2 more times since the OP. Each time the control was hot after more than an hour of running. It is odd that I've seen the 60:00 entry twice now There seems to be a over-temp lockout on the control that isn't reported or cleared with the fault button. I've reprogrammed the thermostat so it isn't moving by more than a couple degrees in a 4 hour windows. I have not had it happen since. Seems the control has thermal protection built in that isn't part of the normal fault reporting process. I don't think this control is going to work in a Miller without better cooling to the burner compartment.

Any recommendations on a control that will take the abuse of a Miller burner compartment?

EdTheHeaterMan · January 21

Since this Beckett control is new and I retired over 5 years ago, I'm not familiar and have never held one in my hands. I have had experience with the burner compartment on a miller getting very hot. I installed a Fir-o-matic valve inside the burner compartment and had it melt the lead threads out (as it was designed) from normal operation with the door closed. After replacing the hand wheel it failed again within a few days so now I leave the door ajar on my Miller, but it is in my garage, not in my home so the noise of leaving the door open is not a problem.

Back to your overheating problem. I have used the Carlin 70200 PRO control with great success. But if the only reason you want a new control is to be able to use a smart thermostat that needs a C wire connection, you can get that from your White Rogers control. I can tell you how, if that is the direction you want to go.

EdTheHeaterMan · January 21

I had another idea, If you truly think that the control is going into lockout as a result of overheating, (and you may be correct) you can try this as a temporary test. Make up eight 24" long wires with a male spade on one end and a female spade on the other end and run them outside the burner compartment. Then connect the control outside the burner compartment and see if that makes a difference. If you find that the control being outside the burner compartment solves the problem, then you can make a more permanent mounting for the control. Then you can see the diagnostic without opening the burner compartment door and causing the power to go off when you open the burner compartment door. (unless you have already disconnected the door switch)

HVACNUT · January 21

Why is the primary getting so hot?

Why is there 60 minute run times?

EdTheHeaterMan · January 21

@SuperTech and @HVACNUT.

to answer your query, the miller mobil home furnace has a very small burner compartment that needs to be closed off from the room where the front door of the furnace is located. That's because the return intake for the ductwork is the front door.

They are generally installed in the hallway of a mobil home because that is the central location of the home and the best position for the return opening. the furnace heat flows down under the floor where the duct work is located.

Since you can not have the combustion air intake from the same pressure zone as the blower intake, the front door must be kept closed by design and code.

Bottom of this door (the solid part) is covering the burner compartment to maintain that separation of the combustion air from the blower return air opening. The combustion air on this model comes from below the floor by way of a 2" air intake duct that is place below the bottom covering of the mobil home. Some mobil home furnaces are designed with a concentric vent thru the roof to bring in combustion air in from above the mobil home. So, in either case, the combustion air is originating from outside the mobil home.

That very small compartment where the burner is located usually has a small observation port to view the flame and take over fire draft reading. The burner compartment door gasket on many of those doors is nonexistent allowing the negative pressure zone caused by the blower operating to pull some air from the burner compartment. If the gasket on the observation port is compromised, or the observation port door is not closed tightly then the over fire draft may not be enough to keep a small amount of heat from the flame from entering the burner compartment. Granted this is not the best design for a piece of heating equipment, but it is what is approved for use in manufactured housing. A standard ducted furnace you might fInd in a basement would not be approved for this location.

That is how the burner compartment can get So Hot.

SuperTech · January 21

@EdTheHeaterMan I work on plenty of Miller/Nordyne Mobil home oil furnaces and I have never had any problems with the burner/primary control overheating. I would think the problem might be due to poor airflow or malfunctioning fan and limit switches. The newer furnaces without a real fan and limit control have all sorts of problems with the bi-metal limit switches failing.

EdTheHeaterMan · January 21

https://forum.heatinghelp.com/discussion/comment/1836704#Comment_1836704

I am just letting you know how a miller furnace's burner compartment can over heat. I have one that gets hot enough to melt the Fir-o-matic handwheel if I leave the door closed. Just offering you the information based on my experience. Here are some interesting specifications

Firomatic part number 12810 handwheel is rated for 165°F
Firomatic part number 12815 handwheel is rated for 200°F
Beckett Genisys operating temperature range is -40° to 150°

So I believe that @njsmith's concern about the temperature in the burner compartment may be REAL! The fact that it takes an hour every time for the temperature to get above the 150° specification is somewhat interesting. As long as the burner run time stays less than 60 minutes the control operates just fine seems like some software glitch that was not considered an issue for the Beckett folks to make note of it in their literature.

My recommendation to put the control outside the burner compartment will verify that the temperature in the burner compartment is or is not an issue.

Now someday when you work on a Miller or Coleman or Intertherm and you find that you have a problem that has no other explanation, you will have this information in your toolbox.

Your Welcome!

SuperTech · January 21

Thats unbelievable to me that the firomatic wheel melted. I can't imagine one of the ones I work on getting anywhere near that hot!

I'll take your word on it Ed, I know you have a lot more experience with this stuff than I do.

I bet the difference is that none of the ones I work on are operating for an hour without satisfying the call for heating.

Steamhead · January 21

Has anyone checked to see if that Miller is over-fired?

EBEBRATT-Ed · January 21

Never liked the Millers but that is what they use. I replaced a Miller once with a new Miller and the HO kept complaining about an oil smell after the new one was installed. After numerous trips and not finding anything, we took the new furnace out in the driveway and took it apart and found the HX had a spot that was never welded.

Returned that one and picked up another new one.

When that happens, you get a bad taste in your mouth. A lot of time wasted.

HVACNUT · January 21

https://forum.heatinghelp.com/discussion/comment/1836702#Comment_1836702

I appreciate the lesson, but I've already been schooled in Miller furnaces. Vent and combustion air kits have been used for years. If the primary is hot to the touch, there's something wrong. There's probably positive pressure over fire.

EdTheHeaterMan · January 21

Just answering your question @HVACNUT

Screenshot 2025-01-21 at 1.47.07 PM.png

HVACNUT · January 21

https://forum.heatinghelp.com/discussion/comment/1836827#Comment_1836827

It was rhetorical.

EdTheHeaterMan · January 22

@HVACNUT said "It was rhetorical."

Golly, I had to google "Rhetorical"

And I was wondering if your were trying to be Overelaborate or Bombastic?

So I googled those two words, and since your comment was so short, I figured that you were not trying to be Excessively elaborate, you must be trying for Bombastic.

I will try to use this information in the future when reading you comments.

🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄🙄

njsmith · January 22

Air flow is open from below and burner is not over firing. As we have said its a Miller and the burner compartment can get very hot in some installations. Intake air temp is typically in the 40s-50's this time of year as that location has a full basement that is insulated. The units fires for hours in the deep winter (like these -20F nights) without issues with the WR.

The Genisys 7565 has a separate set of terminals for the purge value, the motor, the igniter, the CAD cell and the AC input. Not so easy to 'remote' locate it. The test was to pull the door safety switch and leave the door open for the cycles. Had a run at about 2 hours bringing temp up from 42F with no issues with the door open. Fairly certain it is an overtemp safety cutout in the Genisys. At least the microcontroller and bluetooth are still functioning as I can connect but everything is reporting as normal. Not a very good system if this type of fault isn't recorded / indicated.

Next time I'm at that location I'm going to put the WR back in service. Technically nothing wrong with the function. I didn't want to add a separate 24VAC transformer if I could avoid it. Would have been easier at this point.

I have a Trane / Beckett at my other house and the Genisys should be a better fit for that application.

Let me know your idea for a C wire tap from the WR. I suspected the one side of the CAD cell might suffice but I never metered one out.

Thanks for the insight.

EdTheHeaterMan · 12:30AM

So your manufactured home is on a foundation with a basement. Your test shows the the temperature in the burner compartment IS the cause of the lockout. You have two potions for mounting the control outside the burner compartment.

Mount it on the front door
Mount it in the blower compartment.

Either one will get the control out of the hot burner compartment.

You may also want to check that the vent is clear and properly installed. If there is a downdraft after the call for heat is satisfied, then that will cause that burner compartment to overheat. If that is what is happening, then other burner parts may begin to fail.

Beckett Genisys 7565 - Recurring LIM indicator lockout

Comments

Categories