Steam Boiler - Won't shut off even if thermostat temp is met / nothing calling for hot water

zeth07

We have had numerous problems with our boiler and have replaced various parts because of leaks. After the leak problems were solved we ran into issues with it overfilling which seemed to be the tankless coil. After that was replaced we ran into our current problem which is that the pump will not turn off automatically even after the thermostat temperature is met and nothing else is running that would be calling for hot water.

When the other problems were addressed the boiler guy replaced the primary, but apparently that was not the correct one we needed and we were told by people on here that it could be the problem. When we replaced the tankless coil it came with a new aquastat and apparently that also was not correct. So we put the old aquastat back on and got the new primary as suggested but are still having the same problem.

At this point it feels like it would be just a simple wiring problem but we aren't sure what the issue actually is. My brother even completely reran the thermostat wiring and bought a new one.

So we got the R7284U as recommended. Would anyone know how the wiring of the R7284U is supposed to go in regards to a L4006A1009 Honeywell Aquastat?

This is the old Aquastat:
https://www.supplyhouse.com/Honeywell-L4006A1009-High-or-Low-Limit-Aquastat-100-240F-range-5F-Differential-4585000-p

Here is the install instructions of the Aquastat:
https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1249544835101/Honeywell_L4006A1009_Installation.pdf

And this is that primary:
https://www.supplyhouse.com/Honeywell-R7284U1004-Universal-Digital-Electronic-Oil-Primary

Here is the install instructions of the primary:
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/R7284-INSTALL.pdf

Most of it is color coded which is easy enough for my brother, but we're confused about how the Aquastat is supposed to connect to it. There are two wires coming off the Aquastat, so are they supposed to go into Limit and L1? Or something else entirely?

Previously the Aquastat was hooked up to the T / T on the primary along with the thermostat wires together. Do we do that again or do they go somewhere else as mentioned?

We just need clarification because otherwise my brother can handle doing it.

We cannot figure out why the boiler will not turn off now even though it has been running for an extended period of time long after the temperature would be met on the thermostat.

Jamie Hall

I replied to your other thread.

zeth07

Jamie Hall said:

I replied to your other thread.

I didn't see a new reply. I added another post to that thread which is why I was trying to get more information with posting again.

Basically based on what was recommended previously we went ahead and got that new Primary and put the old Aquastat back in since that at least was the proper one and maybe not the problem compared to the new Aquastat that came with the tankless coil which you or the other person said were wrong.

So we are thinking there's just a wiring mixup that we can't figure out, but it seems more like a common sense instructions thing that just isn't working.

My brother tried tapping on the solenoid and it went from like ~800 ohms reading to a ~500-600 ohms reading, so now we think that maybe it is the problem and it's somehow getting stuck open when it's called for heat.

At this point it just doesn't make sense why it would do it.

Erin Holohan Haskell

Since this is a double post, I'm going to close this thread and continue it here: https://forum.heatinghelp.com/discussion/181990/steam-boiler-not-turning-off-after-everything-is-heated
Thanks.