circulators come on in low limit when 2 minute timer is active

 
cardinal
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Post by cardinal » Wed. Dec. 22, 2021 10:27 pm

EFM 520 STOKER SETTING 200 HIGH 160 LOW 10 diff
Stoker with 4 zones and two zones calling for heat,
stoker keep running below low limit (ok)
circulators shut off at 150 and come back on at 160(ok)
Digital timer runs 2minutes every ½ hour (ok)
Honeywell Aquastat L7224
TACO SR503 3 ZONE Switching Relay

Need Help
The Problem starts with stoker running on low limit and the circulators shut off, (at 150)
for some reason during the low limit, power is getting to the circulators only when the 2 minute timer comes on, and the circulators shut off when timer shuts off after the 2 minutes . When stoker is idle and timer comes on it does not affect the circulators and everything is normal .This problem is cooling down the boiler below the 150 and it only does this when 2 minute timer is active as the boiler heats up 150 rising to 160, after 160 circulators power back on and everything is OK
Could it be the TACO SR503 3 ZONE Switching Relay (ice cube relay look ok )
ZR wire on taco relay goes to ZR in Aquastat and to ZR on to 2 minute timer
Note : don't know what is wrong it ran good for 11 years Thanks


 
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Rob R.
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Post by Rob R. » Thu. Dec. 23, 2021 6:30 am

Are you sure this is not something that you just have not noticed before? It sounds like it is not wired properly.

 
Holdencoal
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Post by Holdencoal » Thu. Dec. 23, 2021 6:43 am

It could be wiring or priority settings. You could also have a relay sticking.

Pictures of wiring would be the best.

 
cardinal
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Post by cardinal » Thu. Dec. 23, 2021 10:22 am

I changed aquastat also put in new digital timer from marks supply in Shenandoah pa

Noticed one thing prior to this, (When everything was ok ) the boiler would be in low limit rising up to 160
at 160 boiler you would hear a click (switching sound)and boiler would shut off for a fraction of a second then another click and boiler would restart and circulator would come on.
Now at 160 boiler keeps running and circulators come on but there is no clicking sound and no switching off for that fraction of a second .Its wired the exact same way checked and recheck ,One more thing I changed the aquastat because , when there was a call for heat, boiler would run normal then when the boiler would reach 160 it would cut off the thermostat and the thermostat lights on the taco zone relay would shut off then 10 minutes later thermostat would come back on and it would run normal ,because it was above the low limit of 160 . Also put in a used aquastat got from plumber said it was OK, I wonder if used aquastat is doing this. maybe I should put old timer back on and go from there.

 
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Rob R.
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Post by Rob R. » Thu. Dec. 23, 2021 11:43 am

Your Taco relay is not wired correctly.

Do you use the tankless coil in your EFM?

 
cardinal
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Post by cardinal » Thu. Dec. 23, 2021 4:02 pm

The Taco relay was wired when boiler was installed always worked, maybe something wrong with taco relay. Never changed any wire in relay it looks to be wired ok and the ice cube relays look to be ok ,
I don't think its one bad relay cause it happens with both zones so two relays would have to be bad at the same time . Also yes on tankless coil I use for hot water. I'am going to wait till holidays are over before I mess around .I Probably will change taco 503 relay first . then install new aquastat but First I want to remove new digital timer and put the will-burt timer back on, its not going to last cause switch is loose. If you guys can think of something or let me know what you think I should do , please let me know, Thanks for your help and Merry Christmas

 
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Rob R.
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Post by Rob R. » Thu. Dec. 23, 2021 4:16 pm

Before you throw a bunch of expensive parts at it I would spend some time with a meter and see what is going on. My guess is that your Taco relay is wired off ZR/ZC in the aquastat and the power is interrupted when the temperature drops below the low limit setting.

I have found it is less complex to keep the zone relays independent from the aquastat. My circulators run regardless of boiler temperature. There are pros and cons to this, but it works well for me.


 
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Retro_Origin
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Post by Retro_Origin » Thu. Dec. 23, 2021 7:36 pm

Rob R. wrote:
Thu. Dec. 23, 2021 4:16 pm
My circulators run regardless of boiler temperature. There are pros and cons to this, but it works well for me.
This is how the plumber originally hooked mine up, I changed it back because the boiler struggled so much to make heat. Can you expound on that a little and highlight the main reasons why or why not someone might not go this route? Thanks!

 
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Rob R.
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Post by Rob R. » Thu. Dec. 23, 2021 8:46 pm

Sure - it really depends on how much of a load your zones put on the boiler, and also how you produce domestic hot water.

Also - if your heating zones really make the boiler struggle, it likely that some sort of bypass piping is needed, and/or the flow rate through the zone is too great.

 
Pacowy
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Post by Pacowy » Thu. Dec. 23, 2021 10:08 pm

Or maybe crank up the stoker?

Mike

 
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Retro_Origin
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Post by Retro_Origin » Fri. Dec. 24, 2021 8:29 am

Pacowy wrote:
Thu. Dec. 23, 2021 10:08 pm
Or maybe crank up the stoker?

Mike
I'm pretty underimpressed with Keystoker's design and operation manual. "turn up the feed until you have 2" of ash after a long run", nothing to do with air, nothing to do with firebed height. It takes at least 45 minutes to get a solid fire that can keep up with the circulator. My house is about 1800 sq ft heated by finned baseboard, and the basement just benefits from the radiant. The whole house is one zone, so that probably doesn't help, I would be happy to post pictures of the routing of the pipe if that would help dictate how useful bypass piping would be.

I'm currently doing some testing on different settings. I will be starting a thread in the feature but for right now I don't want to highjack this one with it.'

 
lzaharis
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Post by lzaharis » Fri. Dec. 24, 2021 9:30 am

Hello Retro_Origin,

The manual for the keystoker does leave a lot to be desired.

When was the last time you vacuumed out the air passage under the fire grates?? When was the last time you cleaned the ash build up out from behind the removable baffle at the flue breech-I found out about this the hard way as it was never described in "their" owners manual.

My entire house is one zone and I have a Honeywell L8124L and a single Bell & Gossett NRF 25 circulator for it with 225 feet of fin tube baseboard.

I also have a Bell and Gossett RB-122-E Low Water Cut Off wired as the first control for the boiler that will kill the power to the
boiler if a low water condition is detected by the immersed conductor; this is something I will never be without.

The high limit is set at 170 degrees Fahrenheit and the low limit is set at 150 degrees Fahrenheit.

The dump zone which is the heating loop is set to operate at 190 degrees Fahrenheit.

I have a 50 plus year old honeywell mercury thermostat in the dining room to control the heat for the home.

My bypass piping is shut off and the stoker is set with 12 threads out for the feed rate.

It's simple and it works which is what I want and what I need, I have slept very well since I replaced "their" "OEM CHINESE"
digital controls.

 
Pacowy
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Post by Pacowy » Fri. Dec. 24, 2021 9:53 am

RO, the 2" of ash shows you have a good fuel-air mix - enough air so you aren't putting hot coals in the ash pan, and enough fuel that you aren't blowing cooling air through dead ash on the burn plate.

I haven't seen a KA-6 for years, but IIRC you can adjust the feed rate via the travel of the pusher and/or the thickness of the bed, and the air via a slider. Fully cranked up, it can produce output somewhat higher than an EFM 350 or AA 130, and somewhat less than an EFM 520, all pretty serious heating machines.

If it's one of the newer models, it may be slow to respond at least in part due to the [insert expletive] secondary blower. In making the ash look better, that blower consumes the coal on the grate when there is not even a call for heat. This forces cooling air into the combustion chamber and adds to the time required for the stoker to achieve a good burn. To me, it's much better to rely on timer settings and the thickness of the bed to control the fire at idle, even if you get a little more unburned coal.

I'm not much of a hydronics guy, so I'll leave it to others to give suggestions on reworking your piping, but I'd start by making sure you're getting the most out of your stoker.

Mike

 
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Post by LTStorm07 » Fri. Dec. 24, 2021 10:49 am

Rob R. wrote:
Thu. Dec. 23, 2021 4:16 pm
Before you throw a bunch of expensive parts at it I would spend some time with a meter and see what is going on. My guess is that your Taco relay is wired off ZR/ZC in the aquastat and the power is interrupted when the temperature drops below the low limit setting.

I have found it is less complex to keep the zone relays independent from the aquastat. My circulators run regardless of boiler temperature. There are pros and cons to this, but it works well for me.
This is also how I run my zone setup. The aquastat is trigged by TT out of the zone panel, and the ZR is triggered by the timer. Pumps will run no matter what the boiler temp is. To help combat the initially hard drop of a large zone, run an extra tooth to help the recovery.

 
cardinal
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Post by cardinal » Fri. Dec. 24, 2021 12:58 pm

EFM 520 STOKER SETTING 200 HIGH 160 LOW 10 diff
Honeywell Aqua stat L7224
TACO SR503 3 ZONE Switching Relay

Stoker with two zones calling for heat, connected to taco SR 503 switching relay .Boiler temp at 165 thermostat calls for heat, boiler running and circulator runs till low of 150 , now circulator shuts off ,
the boiler keeps running goes to 160 then shuts off and thermostat also shut off, It doesn't want to run past 160 ,161 then 15 minutes later thermostat comes back on , and it does the same thing 3 zones connect to taco switching .

At ZR in switching relay there is power as temp drops 165 to 150 circulator working
From 150 rising to 160 no power at ZR circulator off till 160
at 160 -161 red light for thermostat go off and boiler shuts down cause it reached the low limit of 160

The zone that connects to aqua stat in (C1- C2) is fine that works in the low setting till 150
and on the rise of heat will come back on at 160 plus

The problem seems to be the taco switching relay won’t run circulator past 160 or something is shutting off thermostat in the switching relay at boiler setting of 160. I check and recheck all wiring everything OK .Taco switching relay been working for 11 years . It not just one zone it will do this with two zone running at the same time


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