Troubleshooting Triple Aquastat L8124A, Circulator circuit (LONG!)

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CoalisCoolxWarm
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Stoker Coal Boiler: Keystoker KA-6
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Other Heating: Oil Boiler

Post by CoalisCoolxWarm » Mon. Dec. 20, 2021 10:34 am

Having a bit of odd behavior with my primary loop circulator and believe I've traced it to the Triple Aquastat, but not sure what internal components switch where. Perhaps someone can look over this and check me/give suggestions?

I've attached pdfs with my wiring and components. Two SR504's, separate circulators on each zone using closely spaced Tee's. One main loop circulator going into boiler.

Two separate power switches for boiler, including main loop circulator; and Zone controls, Tstats, zone circulators

Normal Behavior:
SR504 relays handle thermostats and trigger TT on Triple Aquastat (TA).
Upon call for heat, stoker, fans, and main loop circulator run.
Upon timer pins, heat, stoker, fans, and main loop circulator run.
4006, if over high temp, runs main loop circulator

Bad Behavior #1:
I turned up upper limit on TA to 190F from 180F
Last week the main circulator stayed running. It was 60F outside.
Living room zone constantly received heat, even with it's TStat off and zone circulator off.
I believe this one zone does not have a flow-check and was doing gravity feed. (I want some of this behavior later, but haven't set it up). Not 100% sure as neighbor replaced it while I was in hospital.
I added LED light to main loop and Living Room zone circulators after testing with DVOM to simplify troubleshooting
Stoker and fans cycled on and off with timer. No zones calling for heat on the zone controllers.
Even powering off Zones main power (controller, Tstats, zone circulators), main circulator stayed on

Troubleshooting:
I power cycled boiler and zones. No change
I turned up 4006 to 210 from 200 and verified boiler approx 190F
I triggered timer switch manually to confirm operation
I removed wire nuts at circulator, tested voltage, installed 120v LED
TT at Triple Aquastat was shorted (?) but not from zone controller (internal to TA?)
Physical check of TT wire from zone controller to TA for damage. Perfect condition
Manually pushed relay in TA a few times to cycle it (only buzzed at me, lol)

Living room at 80F, shut down boiler, figured it was too warm


Bad Behavior #2:
Re-lit boiler last eve
Stoker and fans run normally
Zone controllers and zone circulators properly indicated calls for heat
Main loop circulator wasn't running. Waited until boiler temp was within the TA setting (160F-190F)

Circulator still wasn't running. LED was off. I removed LED and tested just the wiring. Zero volts. Reinstalled LED and wiring

Manually tripped timer, no change
Manually pushed relay on TA, no change
Verified zone controllers calling for heat, even though stoker was running
Turned 4006 up and down. Could hear the physical snap at approx temp of boiler and then unsnap as I turned it up to 210F (just in case)
DVOM to confirm C1 and C2 didn't have voltage
Verified all wiring connectors in TA. Wiggled other wires in TA.
*Realized I don't know what the TA does to trigger C1 and C2 ??? (the internal relay, something else?)

Walked around basement a bit. Checked draft as I haven't cleaned the stove pipes yet this year. Wondered if I wanted to wire that circulator up constantly now using a physical switch until I work something else out. Thought about when would be a good time to view the comet, it should be coming up higher on the horizon soon...

Put some coal in the bin while thinking. Should I try to swap the TA with the one in the old oil boiler. It looks similar, but I don't have that kind of heat paste on hand. I may have smacked or tapped...ahem...I mean "gently attempted physical stress relief of circuitry" LOL

I made 2 short pieces of wire in order to shunt power directly to C1 + C2 terminals to test pump and wiring....but...

Suddenly, I look over again and the LED is on and the circulator is running!

Hmm....

So I *think * the TA may be having problems. The upper limit dial was off about 10 degrees forever and feels a bit...wiggly. I'd like one that indicates digital temp, but there have been reported problems with those, so stuck with this one.

I don't know if there was a problem BEFORE adjusting the upper limit, but there was afterwards.

Question I have:

1. Are C1+C2 always energized by TA when the stoker circuitry is, or is it separately controlled?
2. There are extra wires within the TA that connect to itself (ie face of dial area), not sure of their function
3. Anything on the back of note? I've never removed one from the case
4. Components? I can test, replace, etc a number of electronic components (on a good day)
5. I am very perplexed why the (initial problem) stoker would be disengaged (no calls for heat) but the circulator would be energized? Aren't they bonded together, or what controls them separately within the TA?
6. Is there a failure that would affect C1 + C2 and TT at the same time?
7. I only see the one relay, or it would be simple? What does that relay do? Does it have inspectable connectors?
8. Anyone ever tear one apart?
9. Any other suggestions?


We do have heat at the moment, but it seems only a matter of time before a bigger malfunction...

Thanks for reading.

Attachments

Keystoker KA6 wiring Page 1.pdf
.PDF | 4.7MB | Keystoker KA6 wiring Page 1.pdf
Keystoker KA6 wiring Page 2.pdf
.PDF | 5.4MB | Keystoker KA6 wiring Page 2.pdf

 
lzaharis
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Post by lzaharis » Mon. Dec. 20, 2021 11:27 am

You need to hire an electrician for an hour's work to fix this that is all you need.

 
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CoalisCoolxWarm
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Post by CoalisCoolxWarm » Mon. Dec. 20, 2021 11:34 am

I think my limit switch/dials are bad


 
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Rob R.
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Post by Rob R. » Mon. Dec. 20, 2021 12:15 pm

There is a simple way to diagnose this. If you find that your primary circulator is running when you think it should not, verify that there is power across C1/C2 in the L8124 with a meter. Assuming there is, remove one of the wires from the TT terminals in the L8124, then recheck for power across C1/C2. If there is no longer power across C1/C2, the L8124 is likely working as intended and the issue is with one of your other controls.

Through the process of elimination you should be able to figure it out.

 
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McGiever
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Post by McGiever » Mon. Dec. 20, 2021 12:36 pm

CoalisCoolxWarm wrote:
Mon. Dec. 20, 2021 11:34 am
I think my limit switch/dials are bad
Are you referring to the timer box?

 
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CoalisCoolxWarm
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Posts: 2323
Joined: Wed. Jan. 19, 2011 11:41 am
Location: Western PA
Stoker Coal Boiler: Keystoker KA-6
Hand Fed Coal Furnace: old Sears rebuilt, bituminous- offline as of winter 2014
Coal Size/Type: Anthracite Buckwheat
Other Heating: Oil Boiler

Post by CoalisCoolxWarm » Mon. Dec. 20, 2021 1:07 pm

Thanks. I think the high/low dials on the L8124a isn't reading true or contacting where/when it should.

If the low wasn't accurate, the circulator wouldn't run until it was up to temp.

If the high wasn't accurate, it may think temp is too high and run just the circulator, with the occasional timer running the stoker.

I do need to test the TT. I don't remember if I have it shunt or 24vac. I'll have to test it to see.

I foresee a new Triple Aquastat in the near future.

L7224U had some mixed experiences when I asked about it a while back and the CoalTrol, too. Any updates on L7224U reliability?


 
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McGiever
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Coal Size/Type: PEA,NUT,STOVE /ANTHRACITE
Other Heating: Ground Source Heat Pump and some Solar

Post by McGiever » Mon. Dec. 20, 2021 9:14 pm

CoalTrol isn't for boiler application so cross that one off the list.

 
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CoalisCoolxWarm
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Posts: 2323
Joined: Wed. Jan. 19, 2011 11:41 am
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Stoker Coal Boiler: Keystoker KA-6
Hand Fed Coal Furnace: old Sears rebuilt, bituminous- offline as of winter 2014
Coal Size/Type: Anthracite Buckwheat
Other Heating: Oil Boiler

Post by CoalisCoolxWarm » Tue. Dec. 21, 2021 12:56 am

McGiever wrote:
Mon. Dec. 20, 2021 9:14 pm
CoalTrol isn't for boiler application so cross that one off the list.
Well, I just learned something. LOL.

Thanks :yes:

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