Can't find aquastat?

SDJ88

So, first real cold day of the year here and the baseboards weren't providing enough heat to hit what I set the thermostat at. I looked at the temp on the boiler which was roughly 140 degrees and figured maybe it needed adjusting up. Starting searching for an aquastat but I couldn't find one. From what I've seen online, these are usually pretty obviously attached to a pipe or right near the boiler, but 1st time homeowner here so everything is kind of new to me.

Anyways, I popped the front fascia off the boiler and found this probe just kind of floating freely:
http://i65.tinypic.com/5b3dc5.jpg

When I moved the probe from resting on the boiler door, the temperature gauge on the boiler immediately started dropping closer to room temperature, which doesn't seem right. What am I missing?

The prior homeowners left a bunch of paperwork which included some on the Hydrostat Model 3250 plus, although they did replace the boiler this year so no idea if that was with the current or old boiler. Looks like a pretty obvious unit with digital displays and LED lights, so I don't think I'm overlooking it. Can you even run a boiler without an aquastat?

rick in Alaska

I would suggest shutting it down right now and getting a father away picture for us. It looks like that is the temperature probe for the aquastat, which should be in an immersion well. Without it in place, the boiler has no control and can overheat dramatically. Dangerous situation if this is what I am seeing.
Rick

SDJ88

Here's a few extra pics:

Entire Setup (electric water heater, not an indirect or anything like that)
http://i67.tinypic.com/29oho5v.jpg

Profile View of Boiler:
http://i65.tinypic.com/x3fuv5.jpg

Closeup of Boiler (looks like the probe goes in at the bottom of the boiler, but the other end is just floating freely, attached to nothing)
http://i65.tinypic.com/2vbwxlx.jpg

BBros

Since no one has responded... I'll give it a whack (as a hack).

Yes, that probe looks like it should go in the brass well at the upper part of the boiler door. It's almost impossible for me to believe there is a reason a temp sensor would be hanging loosely against the door. If it were me, I would put it in and see what happens.

The Hydrostat 3250 is a newer unit, I think they started making it in 2013 or so. I would guess this boiler utilizes that if you have the user manual for it in you homeowner packet.

Standard configuration has the black plastic box that you're seeing on the documentation. With what looks like that's an oil fired Riello burner, I would have anticipated the Hydrostat mounted on the righthand side of the boiler.

However... it appears that boiler has the controls built into the top of the case, and I know that is an option on some boilers. I'm not a pro, and haven't the expertise or experience to tell you anything about that unit. The burner electrical whip seems to disappear into the case, and that is an indication that the aquastat and relays you're looking for are in there (as the burner gets power from the control). I would guess it's still digital, and there are controls somewhere under cover that you're not seeing. Try pulling the top off the boiler.

As an added note, the Hydrostat 3250 often combines the temp and low water cutoff in one sensor if used with a proper well. That means your boiler *might* be operating without that safety if indeed that probe is what I (we) think it is.

In any case... 140F is way too low for that system to be running at.

Good luck.