L7124 Aquastat Problem or Not?


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Old 12-20-08, 10:12 PM
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L7124 Aquastat Problem or Not?

Hello All,
I was lucky to stumble upon this forum. I have concerns about my Aquastat not working properly and contacting Honeywell was a complete waste of time as they offer no technical support for this product.
As a layman, I will try to describe the problem as best I can.
After my programmable thermostat has gone into sleep mode at night and is no longer calling for heat, my main circulator (C) of a 3 circulator sytem will open and start sending heat. The TT led on the Aquastat is off so I know the Thermo is not making the call.
The Disable LED on the Aquastat is blinking in 4 blink intervals during this time. Since the burner is off and the circulator is on, the water temp will go way down past the Low Limit. After several minutes the circulator will close and the Disable LED stops blinking. The burner then comes on to bring the water up to the Hi Limit. Once the water hits the Hi Limit, the process starts over again.... No call for heat, circulator on, blinking Disable LED. I can't watch it all night, but I know this only happens sporadically, most of the time the Aquastat works normally. That is why I am not sure if this a problem or some kind of self-adjustment by the Aquastat. You would think if it was defective, it would be defective all the time. If anyone can shed some light on this problem, I would really appreciate it. I have a Peerless WV-05. Aquastat set to 180/160 w/15 diff. Thanks for your help.
 
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Old 12-21-08, 08:30 AM
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I'm looking for some info on the error LED's on your 'stat...
haven't found any yet, but there is some info here...

http://customer.honeywell.com/techli...0s/71-3213.pdf
 
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Old 12-21-08, 09:45 PM
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Thanks Trooper, I really appreciate your help. Just to clarify one thing, the Disable LED that I said is blinking 4x's is more commonly refered to as the LL(Low-Limit)/DSBL LED.
I don't know how familiar you are with the L7124U, so I thought I would mention this.
Thanks Again.
 
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Old 12-22-08, 03:46 PM
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Never seen one... have seen the younger brother 7224 ...

Don't know what the 'blink codes' are for that a'stat, and can't find any references for it.
 
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Old 12-22-08, 05:02 PM
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Hello Trooper,
I read somewhere that 4 blinks of the LL/DSBL LED means "Safety relay has welded, Device requires replacement"
This doesn't make sense to me because if something is "welded" isn't that a permanent condition that would prevent the Aquastat from ever running properly?
Please give me your thoughts on what this error message means and also if you think I should replace the unit.
Thank You.
 
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Old 12-23-08, 05:09 PM
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That aquastat is obsolete. Go to Catalog and type in your aquastat number and search. There will be a page that points you to a replacement. At the bottom of the replacement page there are .pdf files that tell you anything you want to know. Download them and save 'em.
 

Last edited by NJT; 12-23-08 at 05:35 PM.
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Old 12-23-08, 05:19 PM
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The list below is an example of the problems. Your codes may vary, but this is the current list.




Error Code Cause/Action
Err1 Sensor fault; check sensor.
Err2 ECOM fault; check EnviraCOM. wiring.
Err3 Hardware fault; replace control.
Err4 B1 fault; check B1 wiring/voltage.
Err5 Low Line; Check L1-L2, 110 Vac.
Err6 Fuse; Check ECOM wires, Replace fuse.
Err7 EEPROM, HL, LL, Hdf, Ldf, Reset to default values.
Err8 Repeated B1 fault (voltage present at B1 when
output is turned off); check B1 wiring/voltage.
 
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Old 12-23-08, 05:44 PM
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OK, those codes are the ones that are displayed on the 7224 display... CT3 said it, but just want to make it clear that these are probably NOT the same as your unit.

Pod, do you think you can find where you read that?

Yes, i would think that welded contacts would not 'clear' themselves... welding tends to be somewhat permanent!

It's inconceivable to me that I can't find a list of the 7124 blink codes on the internet...
 
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Old 12-23-08, 10:36 PM
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Originally Posted by NJ Trooper View Post
OK, those codes are the ones that are displayed on the 7224 display... CT3 said it, but just want to make it clear that these are probably NOT the same as your unit.

Pod, do you think you can find where you read that?

Yes, i would think that welded contacts would not 'clear' themselves... welding tends to be somewhat permanent!

It's inconceivable to me that I can't find a list of the 7124 blink codes on the internet...
Correct, the listed codes are for the new replacement 7224aquastat.
 
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Old 12-24-08, 08:59 AM
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There is a site that will answer your question. Just answers.com. It will cost you $9-$15.00.
 
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Old 12-24-08, 09:53 AM
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Trooper-

This is from the L7124U installation guide: (I knew I saw it somewhere)

L7124U UNIVERSAL OIL ELECTRONIC AQUASTATĂ CONTROLLER
TROUBLESHOOTING
When attempting to diagnose system performance,
references to the LED can help to identify specific areas
not working properly. The LED are:
PWRˇON indicates 24 Vac power present.
CˇON indicates circulator relay energized.
TSTATˇON indicates thermostat call for heat.
ZCˇON indicates power to zoning.
BˇON indicates burner relay energized.
LL/DSBLˇ
´ ON indicates Low Limit function selected.
´ OFF indicates Low Limit disabled.
´ Flashing indicates error. See Table 3 and
Troubleshooting Guide, Table 4.
Table 3. LED Error Codes.
.
Number
of Blinks Cause
2 Sensor Error (Open or shorted sensor.)
3 System error(s); e.g., setpoint POT failure.
4 Safety relay has welded, device requires
replacement.

As you can see, Honeywell does not provide a wealth of information here. My LL/DSBL

LED is blinking 4X, but WHEN during the cycle does this indicate a problem? Does the

LED have to blink continuously to indicate a problem or is sporadic blinking enough?

All I know is the LED blinks sometimes and the Aquastat misbehaves, while the rest of

the time it does not blink and the Aquastat functions properly.

Which brings me back to the question, doesn't "welded" indicate a permanent fault

condition in which case the Aquastat would never run properly?

Anyway, Trooper, if you would like to see the complete guide, I could email it to you.

Of course, any other input you may have would be greatly appreciated.
 
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Old 12-24-08, 10:35 AM
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When relay contacts 'weld' it is basically that they stick closed. How stuck depends upon how welded they are (duh), which is affected by the current and whether it is AC or DC power.

A bump or vibration can cause the contacts to un-stick. Which may be what is happening. OTOH: it may be a false alarm. In which the uproc thinks that the contacts are welded when in fact they are not.

What bothers me the most about all this is the lack of information on that aquastat (the L7124). I get the feeling that there are problems with this model which is why it is superseded along with having very little info out there on it. Honeywell has quite a bit of information on their other products. But not this one, almost like they want to forget it ever existed.

I too searched the 'net for information on it when you first posted. The only thing I found was a 3 page summary that didn't have much information at all.

Al.
 
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Old 12-24-08, 11:07 AM
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Sure... the micro-P doesn't know if they are WELDED welded... or just 'stuck' welded... and maybe after it tries the relay a few times, they 'un-stick' ... could happen ... I've seen quite a few 'sticky' relays in my time. (and my share of WELDED ones too!)

I was thinking the same thing Al... maybe they really screwed up royally and are sweeping it under the rug ...

I think if my system was acting up like that I would consider replacing the aquastat with something else ... maybe the 7224 ... but who knows? maybe Honey will sweep that one too...

pod, no need to send the whole thing, that's pretty much the info I was looking for.
 
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Old 12-24-08, 01:15 PM
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Trooper,

I've decided to replace the Aquastat. I purchased the L7224u1002 from Amazon. I should have it in a few days. Even though Honeywell says it should only be installed by a licensed heating contractor, I'm going to try installing it myself. The wiring is the same as the L7124 so all I need to do is swap it out.
My only concern is installing the Sensor in the immersion well. I'm hoping the sensor is the same size and will not require installing a new well or using thermal compound.
If you think only a professional should install this let me know, otherwise any tips or tricks you might have for me will be welcome. Thanks.
 
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Old 12-24-08, 02:48 PM
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I woulda just drove over to Plainview and picked it up at Patriot... maybe too far for ya ...

You won't have any trouble at all. Should be pin for pin, plug and play. Take yer time and take pics or and label the wires ...

Take a look at the old one, there should be 1 screw that operates the well clamp mechanism. I'm 99.99% sure that the mechanism on the new one will be identical.

Let us know how ya do!
 
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Old 01-03-09, 03:48 PM
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Smile L7224 is installed.

Well, the deed is done. I installed the Aquastat this afternoon.
It was an easy job but I think I could have done it better had I paid more attention to installing the temperature probe. I say this because the LED read out on the Aquastat of the boiler temp is 20 deg. higher that the temp guage on the side of the boiler. I have to set the high limit to 200 to get a 180 degree reading on the boiler guage.
Maybe the probe isn't seated just right.
Do you think a poorly seated probe could cause a 20 deg difference?
I guess a better question would be. .. in the real world do these two readings ever match or come close? And which temp should I go by? I'd hate to waste oil keeping the boiler temp too high.

The difference in the two temperature readings occurred while the thermostat was calling for heat thru-out the day and the circulators would come on. Would I get a more accurate reading checking these temperatures at night when the system is idle and just maintaining water temp?

Last but not least, since I am trying to adjust the water temp to 180/160, now that I have changed the high limit to 200 does it necessary mean I have to raise the low limit to 180?

Sorry for all the questions. All responses will be much appreciated.
 
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Old 01-03-09, 05:39 PM
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If I trusted either gauge, it would be the one in the new aquastast. BUT, there are often temp differences between two points in the boiler. I would set up the 7224 for 180 HIGH... start with a 15 differential on the high. That should give you reasonable cycle times. If you notice that there are burner cycles lasting less than say 5 min or so, you can increase the DIFF on the HIGH setting and that should give longer cycles.

I forget, was the old a'stat set up with a LOW setting also? And you are heating your domestic with a tankless coil in the boiler? If so, I would start with the LOW setting at 140 with a 20-25 DIFF.

If the old a'stat was a COLD START... meaning that it didn't keep the boiler hot for domestic hot water use, then you should turn the LOW setting OFF.

Last but not least, since I am trying to adjust the water temp to 180/160, now that I have changed the high limit to 200 does it necessary mean I have to raise the low limit to 180?
No, most definitely not.

A few more words about the LOW limit setting.

The LOW setting is the temp that the boiler maintains in the absence of a heat call. The boiler is kept warm/hot to meet demands of domestic hot water use. If you push that LOW limit up to 180, and you do NOT have a tempering valve on that domestic coil, you run a very real chance of seriously scalding someone... 180 water is NOT something you want touching your (or anyones) skin for even a split second. 160 is bad enough... most codes these days specify that there MUST be a tempering valve installed, and it must be set no higher than 120 ...

So, do you have a domestic coil in your boiler? and do you have a tempering valve if you do?
 
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Old 01-03-09, 09:05 PM
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L7224 installed

Hello Trooper ...Thanks for your reply.

When you say you would trust the Temp reading on the new Aquastat over the boiler guage, does that mean you don't think I could have effected the Aquastats accuracy in a significant way by improperly seating the Temp Probe? By the way, I did use the heat conductive compound in the well because there was already compound in there from the old Aquastat.

Also, I have a separate oil-fired hot water heater. So, how should I set the High and High diff and the Low and Low diff for heat only?

Thanks
 
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Old 01-03-09, 10:10 PM
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Trooper, I read thru your last reply again and I believe you already answered my last question about Aquastat settings.
If I don't use the boiler for domestic hot water, I think you recommended HL- 180 w/15 diff, and LL-OFF. Is this correct?

A far as Temp guage accuracy, I am still unsure which guage to go by.
My old 7124 was obviously in the same position as the new Aquastat, as is the boiler temp guage. Yet, in the past when I set the HL on the old 7124 it was always within a few degrees of the temp reading on boiler guage. This tells me the 20 deg difference I get now is not due to the guages location on the boiler.
Bottom line..Now I have to set the Aquastat to 200 to get a 180 reading on the boiler guage wheras before 180 on the Aqauastat = 180 on the boiler guage. I can't figure this out unless like I said its a problem with the new probe.

Anyway, please let me know if I understand your HL/LL settings correctly and if you think the probe could cause a 20 deg. temp difference. Thanks Again.
 
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Old 01-04-09, 12:13 AM
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pod, did the old aquastat keep the boiler as a warm start? i.e. maintain a temperature? or would it go cold if there were no heat call? Sometimes a boiler that has spent it's life as a warm start will weep water if allowed to go cold...

If it's always been a cold start, then go ahead and turn OFF the LL. If it's always been warm start, turn it off, but monitor closely for signs of leakage. If any is seen, then turn the LL back on but set it to the minimum temp and diff.

Yes, 180 HI, start with 15 DIFF and check the cycling... if short cycles, increase DIFF.

If the new a'stat is reading a HIGHER temp, then it's not likely a problem with the seating of the probe. If the probe wasn't seated properly, it would read LOWER, OR have a SLOWER response time. Improper seating can't make it read HIGHER.

There are several possibilities...

1. The boiler gauge AND the old a'stat were BOTH off the same amount (reading 20 low).

2. The new a'stat is off (which I'm skeptical of).

3. ALL are off.

4. There IS a temp difference between the two locations, and either the old a'stat was off, or the boiler gauge is off.

Pretty much the only way to verify any of the above would be if you had a known accurate thermometer that you could use to verify.

If you are uncomfortable about the seating of the probe, go ahead and check it ... maybe even clean the old compound out and put the new stuff in. But like I sed, if the new one is reading HIGHER it's pretty much certain that the probe is 'in there'.

How about this... do the two readings 'converge' several minutes after the burner shuts down? Or do they ALWAYS read differently? It's possible that the new a'stat is able to respond FASTER than the mechanical gauge ...
 
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Old 01-04-09, 07:42 AM
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Trooper, The boiler has always been a warm start, although when oil prices went sky high a couple of years ago, I started disabling the Aquastat for a month or two in the summer. I figured I would take maximum advantage of having a separate HWH. I only did this for two summers and I never had any leaks as a result.
I'm happy to hear what you said about the probe not being a problem. Your logic makes perfect sense to me. I guess I was feeling a little guilty about not paying enough attention when I installed the probe.
I know the manual type boiler guage takes longer to respond than the digital probe, but the two temps never do converge.

I guess the thing for me to do is to try going with the probe temp. If I notice the house is struggling to reach the thermostat set point, I can set the HL higher.

I still have to decide about about turning the LL off. It seems to me, if I did turn it off, in the summer the boiler would never come on because there would be no call for heat. I don't want to risk damaging the boiler. Seals drying out causing leaks,etc.
I read that there are boilers specially made to be "cold start" boilers. I don't think my Peerless is one them.
Oh well, let me know what you think.
 
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Old 01-04-09, 08:00 AM
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If the boiler doesn't leak when it goes cold, I don't see a reason why not... you will save fuel. Why not call Peerless and ask? I'm pretty sure the WV I looked at last summer was a cold start. Perhaps others on here will weigh in with opinions? Grady?

The temps are easy enough to change... so yeah, start at 180 and see what happens. You'll probably be pleasantly surprised to find it heats the home just fine, and you'll save some fuel to boot!

Turn the LL all the way down with min DIff if you don't wanna turn it off. There is absolutely no sense at all to run it any higher if you aren't heating domestic water. The min temp will be enough to keep the boiler warm...
 
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Old 01-04-09, 02:42 PM
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Thumbs up Thank You, Trooper

Just wanted to say thanks for all the valuable information you have given me.
Like I said in my first post, I was lucky to find this forum. And even luckier to find someone like you who is willing to help.
Thanks.
 
 

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