Best Of

As @109A_5 indicated, you have a series 1 boiler with standing pilot so this is your wiring diagram

I wouldn't be surprised if that is not posted on your boiler somewhere. I have a red circle on this diagram where the thermostat is supposed to be connected on the diagram. Here is that connection on your boiler.

In your case that is not the thermostat wire. Possibly because there were 2 zones at one time and each zone had a switching relay to operate each separate circulator. Since you no longer have two zones that control is not needed. The fact that it is still there means that you have more than one place to look for your problem. That thermostat wire has 5 or 6 conductors. Only the red and the white are used and they connect to the switching relay where @109A_5 indicated in this picture.

1. The place to start looking for the problem is in the TACO SR501 switching relay.
2. With the power off to the boiler and the boiler cold, remove both the red and the white wire from the SR501 in the red circle.
3. Power up the boiler. The burner should not operate.
   1. If the burner operates then the problem is not in the SR501.
   2. If the burner stays off, then the problem is in the SR 501.

Based on your findings, we can take the proper steps to solve the problem.

Looks like your boiler is the Williamson GWA series 1 and it should not behave as it does (similar to a warm start configuration). The boiler and the circulator should follow the thermostats command.

Looks like the Taco SR501 is wired correctly.

To start to determine troubleshooting direction start where @mattmia2 stated.

As @EBEBRATT-Ed stated the relay inside the boiler "CR" (Red Arrow) could be stuck, contacts welded, coil energized, or other mechanical defect. Note on your unit the connection plate on the transformer is spun 180 degrees compared to this image.

Thanks, Ed! I’ll go down and post some photos right now. I can make a video too and upload it to my YouTube and post the link

@FrankMaraschino, So, I just looked at the wiring diagram for the Williamson GWA series 1

and the GWA series 2 boilers

There is no provision for maintaining any temperature, 140° or 180° or any other temperature, in either diagram. I think it is a good thing that you found your home like a sauna and that caused you to come here for some advise. You would not have found out that you are wasting fuel by maintaining 180° in the heating season. During the fringe seasons when the call for heat may only last a few minutes, your burner may not even allow the water temperature to reach 150° before being satisfied.

Every minute your boiler is operating at 180° without a call for heat, you are venting lots of heat up the chimney… even with a vent damper closed while the burner is off by the high limit, because that damper does not have a 100% closure. there is always some leakage past the closed damper, and the damper is open more that it is closed whet the weather outside is very cold.

Can you find out why the boiler is maintaining 180° all the time? If you open up the control compartment and post some pictures of the wires inside there, like this:

I can usually see what was done incorrectly and maybe even get you back to a more efficient cold start design as the manufacturer intended. Please try to make the photo as clear as possible by not moving the camera when taking still photos. A video can also help however, there is more involved to post a video and not everyone has the ability to do so.

Also, tank more than one angle so I can see behind stuff that may be blocked in the first pic you take

I understand that wiring diagram can be intimidating to a layman. (and some of the professionals too) But take my word for it, you can fix this with just a minor adjustment and your utility bill will drop by 15% or more.

Yours Truly,

Mr.ED

i burned myself on that water heater vent just looking at that picture

Your fuel bills may go down (even during the heating season) if the warm start is disabled.

IMO Extrol wants the vertical position so air is not trapped on the water side of the diaphragm. Air on the water side of the diaphragm against the steel housing may lead to premature failure and property damage.

When there's time and you have someone who knows what they're doing, the thermostat/pump/boiler can be wired in series so that the boiler will only come on when the thermostat calls for heat. As it is currently wired, only the pump responds to the thermostat.