Honeywell L8148J Aquastat bulb seized.

Twilt

Can anyone tell me how to remove the bulb from the well. Mine is seized. The conductive compound appears to have hardened. I have tried to dig it out and not making much headway. Right now I am soaking it in WD40.

These aquastats are really garbage. My boiler is 20 years old and this is the fourth one I have had to install. (maybe more) The first two I had serviceman install, but it came to the point that I knew the symptoms so I did it myself. Saved a service call and the markup on the part.

Alan (California Radiant) Forbes

If the bulb has seized, what else can you do? Replace the well, no?

Aquastats aren't garbage, you just have to deal with them. As the French say, "Get over eet.".

HVACNUT

^^^ Yes, replace the well, in which case you need to cut the capillary. So it's a good time to upgrade the aquastat to one that offers LWCO, ODR, etc.

STEVEusaPA

You could try some heat, maybe it will melt the paste, but you should replace the well.
In my almost 30 years I've probably replaced 2 dozen aquastats, and never the same one twice.
I think something else is going on-bad install, bad ground, bad voltage (spikes or shorts) or the well is limed up inside the boiler and not sensing temperature correctly.
You didn't say why it failed.

rick in Alaska

That is also the reason that the heat conductive past is not recommended to be used. The stuff hardens and the probe is stuck. I don't think it makes very much difference at all by using it, so you are better off not.
And yes, you are either going to have to drill it out, which won't get it all out, or replace the well.
Rick

GBart

Agreed, after killing myself trying to get a probe out of a well with the paste it in I never used it, ever.

Tim McElwain

There is new stuff in a tube that does not harden. Sorry I do not have the brand name but I believe it comes from Honeywell or White Rodgers.

jlyonsmith

Just thought I would add a late comment here as I just went through this exact problem. Firstly, heat and WD40 don't work. The compound is really thick but WILL release if you use enough pressure. What I did was to use a thin flat blade screwdriver to loosen to carefully loosen the compound to about halfway down the thermostat. Don't twist the blade, just push it down firmly all around. Then, cut the copper wire off the bottom of the L8148 unit leaving it as long as possible. Wrap the wire around a long stiff metal bar. Place a 1" piece of wood under the end of the bar, then slowly and carefully use the leverage of the bar to pull the thermostat out. Good luck!

SuperTech

Don't replace that aquastat with another L8148J. I would install a Resideo L7224U or Hydrolevel 3250. Both are superior to L8148 and have features that will improve the boiler efficiency and help you save money on fuel. And they are both less expensive than a L8148J.