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Honeywell L7224U err3 Erratic Behavior


Walleye Hunter's Avatar
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11-11-17, 11:05 AM   #1 (permalink)  
Honeywell L7224U err3 Erratic Behavior

Hi folks, thanks for letting me in. I have a Weil McClain (SP?) oil hot water system with summer winter hookup. A couple of years ago I installed a Honeywell L7224U and until now have had no trouble with it. Started the furnace yesterday and one of the circulators was frozen up so I replaced it with a Taco 700. After installing the new circulator I am getting err3 message and the burner starts, runs for a short period of time, maybe 2 seconds, maybe 30 seconds, one time it even ran up to temp before cutting off. I have looked around here and found nothing on it so I post new thread. I did find one thread that suggested holding < > I for 60 seconds and I tried that. Tried for 2 minutes and no good. While holding the buttons it reads err for the whole duration of the hold. The circulators do run.

While I am mechanically inclined electronics is out of my wheelhouse and I don't know where to go with this, what do I do?

Thanks for any help,
Mark

 
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11-11-17, 11:16 AM   #2 (permalink)  
Welcome to the forums.

When you post on a help forum.... it's always better to start your own thread. This way all the replies are about your problem. Referencing an older thread can be helpful too.

I work on boilers but I'm not the pro.

When I look at the list of fault codes for that Honeywell aquastat I see.....
err 3=Hardware fault, replace the control.

That would appear to indicate a failure of the control board. Before I recommend replacing it we'll see if someone else has further information.


~ Pete ~

 
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11-11-17, 11:42 AM   #3 (permalink)  
I've been using an L7224U for about 10 years now, and have experienced many false alarms where I began calling around to price a replacement, and still came back to find that I could resolve the problem without replacing the unit . . . . I have replaced the sensor probe as a component and had the ERR Codes direct me to a failing electric burner motor and a bad motor/pump union; but don't think I've ever had ERR 3.

ERR 3 does sound rather conclusive; but I would first disconnect the power and let the unit rest for 5 minutes or so while I double checked my installation of the replacement circulator pump. I might even loosen and re-tighten all of the basic connections on the L7224U while I waited.

Then, after those few minutes, I'd supply power again and see if the condition persists. These units seem to be more than a little forgiving . . . . hopefully you'll be back in business right off; or you'll get a different return code which will help you diagnose the true underlying issue.

 
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11-11-17, 01:06 PM   #4 (permalink)  
Thanks for the help. I have shut it off overnight hoping that it would at least clear the err in the event of a glitch. I found the circulator pump to be simple to install, white wire to white wire, black to a different colored wire (I forget what color it is) and ground to ground. I have disconnected and reconnected the pump and worked it with the thermostat and all seems good there. Checking all of the connections sounds like a good step and I'll give that a shot. At least with the old aquastat I could always make the thing run.

 
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11-11-17, 04:11 PM   #5 (permalink)  
I just found it very odd that the appearance of your ERR 3 would coincide with the recent replacement of a Circulator.

Do you have the Honeywell L7224U Installation/Service Manual readily available ?

I know mine isn't the most recent (Oct 2004), and the Troubleshooting section is a little weak, but it doesn't seem.to anticipate the exact conditions you're experiencing.

I do note however that the on-line manual describes ERR 3 with a little more detail:

Excessive electrical noise or frequency out of range. Hardware fault; replace controller.

In case it would be more up-to-date than yours, here's the link to that manual:

http://manualzz.com/doc/3213548/hone...-user-s-manual


Last edited by Vermont; 11-11-17 at 04:32 PM. Reason: Added link
 
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11-11-17, 05:44 PM   #6 (permalink)  
I do have the manual and did find that part about electrical noise and hardware fault, etc. I agree that it seems odd that it would happen at the same time the circulator went but it did take me about 15-30 seconds to figure out that the old one was frozen and it could have caused a problem by sucking more electricity than it should have for that time. However, both circulators are spinning now. It does say in the book that everything will shut down except the circulators (that's what I got out of it anyway). Then it comes on and goes off. I'm wondering if there's a bad sensor somewhere? I doubt that it's the eye that determines it's running or not because it doesn't behave like that's the issue.

 
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11-11-17, 06:20 PM   #7 (permalink)  
As I recall it now, when my burner motor began acting up, I think the L7224U told me I had "noise" on the L1 Circuit; but didn't tell me where or what component . . . . I had to deduce it. Swapped out the motor and all was well.

 
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11-12-17, 06:56 AM   #8 (permalink)  
After thinking about your situation overnight, I reviewed some of my recent boiler issues and just wanted to throw out one last possibility that came to my mind.

You noted that you had just replaced a Taco Circulator 700, which I interpreted to mean a Taco 007-F5 or 007-F3. I recently replaced such a unit, and encountered a problem which I documented in the following thread:

https://www.doityourself.com/forum/b...your-flow.html

I don't recall whether my directional mix-up last November ever presented itself as a ERR of any kind on the L7224U; but it did prevent the boiler from distributing heat. A simple reversal of the Pump Housing corrected that matter; but I don't know if the Taco would have produced similar "noise" on the L1 Line when it was unable to move water backwards because of the Taco Flo-Chek.

If your system contains a Flo-Check (or equivalent), then this could be an additional consideration in diagnosing your problem.

Sorry that my pictures in the other thread no longer appear . . . . that's a problem due to photobucket holding them hostage until they can squeeze some blackmail money out of me.

 
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11-12-17, 07:32 AM   #9 (permalink)  
I think I have the flow direction right, I checked that out during the process and matched it to the Taco circulator for the other zone sitting right next to it. But...I was thinking as well, there is a high pitched buzz that I noticed coming from the relay area and I will go over there and follow that and see what I find. Thanks for the input.

 
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11-12-17, 12:31 PM   #10 (permalink)  
OK, no go on disconnecting the relay or my circulators. I have a guy helping me out who has suggested that I unhook everything but the power to the board and see what it does so I'll do that tomorrow.

 
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11-13-17, 01:07 PM   #11 (permalink)  
As per tech's instructions I disconnected everything but the power to the controller. I still got the err3 and he tells me that it has to be the controller. I feel a little better about spending the money expecting that the one part will fix the problem, if it doesn't I won't feel so good about it. Will report final disposition for future users.

 
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11-13-17, 02:02 PM   #12 (permalink)  
Before you start shopping for a replacement, I'd check the Sensor Bulb in the Well of the Boiler; the earlier models seem to have corroded prematurely . . . . I had to replace mine AFTER some erratic intermittent behavior which DID NOT generate an ERR Code until the tail end. They're only about $17.00 and the newer design seems more likely to last.

How old is your L7224U ?


Last edited by Vermont; 11-13-17 at 02:38 PM. Reason: Fixed spelling error.
 
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11-13-17, 03:31 PM   #13 (permalink)  
I only had it for about three years. I can check that sensor, do you have any tips on how to test it?

 
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11-14-17, 06:00 AM   #14 (permalink)  
No, I think the test equipment would be more expensive than a new L7224U; but since you're replacing it anyway, you could pull the sensor (carefully) and visually check the bulb and leads for corrosion.

Here's what a NEW Sensor looks like compared to my old one after 8 or so years in the Well:

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I had to dig the Bulb out of the Well; that's why I say CAREFULLY.

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Because it's a thermistor, its electrical resistance varies with the temperature. Someone else may know if there's a simple way to check this unit for functionality but I don't think it can be done with simple commonly available tools or test equipment;


Last edited by Vermont; 11-14-17 at 06:29 AM. Reason: Fixed Photos
 
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11-14-17, 08:48 AM   #15 (permalink)  
All you need to test most sensors is a simple ohm meter. Connect ohm meter to sensor leads. Put sensor is cup of warm then cold water. Wait a minute or two and resistance should change. A similar one I have reads 10,000 ohms at 75F , 7,300 at 90F and 2,500 at 140F.

Important thing is resistance varies with temp change. A fixed very low or high reading indicates a defect.

Here is a typical sensor used in heating systems: 071 - Tekmar 071 - Universal Sensor (1' wire)


Last edited by doughess; 11-14-17 at 09:06 AM.
 
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11-14-17, 05:42 PM   #16 (permalink)  
For some reason I was thinking that you were talking about the eye that senses whether or not the burner is lit. The burner temp reading was working properly. I got new unit in today. For some reason it has a spade on on it at the B1 location. I haven't checked to see if it is removable or not but it looks like it might be. Why would they put a spade connector there?

 
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11-15-17, 08:32 PM   #17 (permalink)  
All Finished Up

Replaced the controller and all is working as it should.

 
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11-16-17, 03:42 AM   #18 (permalink)  
Too bad we can't determine what failed about it . . . . after only three (3) years, while mine still works after eleven (11)) ?

I'll have to look up what Honeywell offers as a Warranty on these units.

PS: I just read that the Warranty is a mere 1 Year; that's only one heating season . . . . maybe I should have a spare on hand.


Last edited by Vermont; 11-16-17 at 03:56 AM. Reason: Added PostScript
 
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11-16-17, 06:08 AM   #19 (permalink)  
I hear ya, I asked the tech who helped me out if the carcass had any value, if they repaired them or anything and he said, "Nope, just pitch it, maybe save the temp sensor". I wonder if the frozen circulator didn't cause the failure somehow.

Edit: Oh, and for future reference, if you disconnect everything but L1 and L2 (power to the board) you can determine if it's the board or something else. Then you can reconnect the burner and circulators one by one and figure out where the problem lies if it isn't the controller itself.

 
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11-16-17, 06:38 AM   #20 (permalink)  
I'd wonder if Sid Harvey bothers to re-condition the L7224U the way his Company re-buillds other triple acting Aquastats like the L8124 and others ?

Then they sell for a hair over 50% of what new ones sell for.

 
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11-18-17, 09:11 PM   #21 (permalink)  
Don't Just Replace L7224U Aquasta, Upgrade to Out-Door-Reset for Quick pay back.

The Honeywell L7224U handles 3 funtions: aquastat control of burner, low voltage control of circulator by thermostat and transformer to provide souce of 24 volts.

The original problem was the aquastat function. A $160 ODR is a full feature aquastat and provides long term on fuel costs savings of 10% to 20%. That is only $30 more than a new L7224 and payback would be less than one year.

ODR's have many features and benefits not available on older on-off type aquastats.

$160 Tekmar 256 - Tekmar 256 Boiler Control - One Stage Boiler - Tekmar - SupplyHouse.com


$132 L7224U1002 - Honeywell L7224U1002 - 120 Vac Oil Electronic Aquastat

 
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