Boiler fired up without a call

Jersey2

Today my boiler fired up without any zones calling for heat. The boiler ran for about two minutes and then shut down. I do not believe the circulator ran. It is the first time its done this, I monitor its runs. Since then it is running normally, it went on for the indirect water heater calling and fired up and turned off like normal. Any thoughts?

HydroAirJoe_2

If it's not a cold fire boiler, that is normal operation controlled by the triple aqua stat LL/LLDF setting

EdTheHeaterMan

Today my boiler (insert description here) fired up without any zones calling for heat. The boiler ran for about two minutes and then shut down. I do not believe the circulator ran. It is the first time its done this, I monitor its runs. Since then it is running normally, it went on for the indirect water heater calling and fired up and turned off like normal. Any thoughts?

My first thought is that there is not enough information the answer your query

Today my Weil McLain WTGO -3 boiler with tankless coil L7224 aquastat relay Beckett burner with GeniSys primary control that has 3 zones valve zones operated by a Taco ZVC-405 and a bronze TACO 006 connecting the tankless coil to the 30 gallon storage tank fired up without any zones calling for heat.

If you hade a more specific "Boiler" and control system, like my example statement, I believe we could help

Your query is like asking if you can tell me whats wrong with car from these pictures?

Can you even tell me what kind of car it is?

Grallert

Yes. More information is needed.

Jersey2

It's a Slant/Fin Senitnel cold start cast iron boiler with a hydrolevel hydrostat control model 3200. It has three heating zones, one zone is an indirect water heater with a Resideo aquastat. It has 3 Honeywell zone valves, and one Taco circulator. When it did the phantom ignition, the digital temperature did not change, only after it turned off did the temperature start to climb. The water pressure was about 18 since the boiler was pretty cool at the time. This is a video of the run

https://www.youtube.com/watch?v=9Uj4VubtWW8

LRCCBJ

The indirect water heater called the boiler. It probably has a small differential (7F?) and the boiler only needs to run a short period to satisfy it.

Jersey2

If the water heater called, it would have made the water get cold to 61 degrees.

Jersey2

It seems like the boiler does a short run when its temperature drops to 60 for some reason, even though low limit is turned off. I never noticed it doing that before. I will check the low limit value to make sure it's off.

HVACNUT

https://forum.heatinghelp.com/discussion/comment/1822928#Comment_1822928

What make and model thermostats?

There will be a little Green light in the bottom right hand corner of the temperature display if the Hydrostat is receiving a heat call. I can't tell in the video because it's microscopic. If it is, check to see which zone valve is open, and why. Which brings me back to the thermostats. Are the thermostats are 4 letter word?

EdTheHeaterMan

The nasty 4 letter word thermostats are to blame, even if you don't have them. 🤣 LOL

My thoughts.

1. Water heater tank stratifies and the cooler water near the bottom creeped up just enough to operate the zone valve.
2. The valve opens and the end switch causes the boiler to go through the startup sequence of operation.
3. The hot water in the DHW tank HX coil is pushed out of the tank while cold 60° boiler water is pushed into the tank HX
4. The water temperature change in the DHW HX causes some convection flow in the DHW potable water side of the tank.
5. The hot water from the DHW HX enters the bottom of the boiler and mixes with the boiler water that is 61°
6. The heat from the flame starts to affect the water temperature in the boiler.
7. Both the HX warmer water and the boiler water that is near the flame move closer to the aquastat temperature sensor
8. "Meanwhile back at the Ranch" the slight temperature change of the water on the potable water side causes the DHW aquastat to be satisfied.
9. The burner stops at that time.
10. The circulator stops moving boiler water out of the supply and into the return.
11. That boiler water then starts to stratify causing the sensor on the boiler aquastat to measure the increase in temperature.

I am looking at your piping configuration in my mind's eye and thinking what would water do in this case. I can't really see your piping configuration but I will bet you dollars to donuts that you had a brief call for heat from the DHW tank.  That call for heat was unnecessary and actually wasted fuel but over all the indirect tank is a better way to heat DHW compared to a tank that is connected to a chimney or otherwise vented. 

Jersey2

I don't have the dreaded nest, I have a simple non programmable Honeywell Home Pro 1000. The mystery burn happens so infrequent, and is so quick it will be hard to catch it in action to check if one of the zones is calling.

Ed those are some good thoughts!

PS Happy Thanksgiving to everyone

Jersey2

Thinking about, if there is a call it would have to be the hot water tank because I have the thermostats upstairs set on the chilly side. Cold water might just reach the aquastat on the HWT as everything cools down while the upper water in the tank is still hot. I really have to try to catch it when it does it and check the zone valves.