Honeywell L8148A1017 Immersion-Type Controller

Last piece to get the furnace running again after a lightning strike.

replaced old controller. working fine. controls my oil fired furnace boiler. reasonable price.

Had issue with the burner not staying lit on the boiler which resulted in no heat. Had a service person come to the house and he said that the aquastat was bad and gave a quote of over $1000.00 to fix it. Well looked around and found this exact replacement for the bad one on the boiler. Read the install directions and change out was very easy. Adjusted the high temp cutoff to be the same as the old one that was removed, hooked up the wiring and was good to go. Heating system works as it should. Saved close to $800.00 DIY!!

I was perfectly comfortable with the idea of replacing this myself except I was not sure about how to properly remove and install the probe. So I called my HVAC relative and glad I did. After 25+ years the thermal compound in the well was rock solid. He ended up breaking the well trying to get the old probe out and water spilled out of the boiler. Fortunately, I had the original installation manual from the boiler for the P/N, we got a new well and it was all good after that. (Honeywell 123870A for my Burnham water boiler. Your boiler might be different.)

Quality control on the L8148A is terrible. The one I received did not produce 24 VAC at the TT terminals when shorted together. I immediately requested a return which Amazon handled very well. Just before returning I looked at the backside of the circuit board. Sure enough, one of the tabs to the transformer wasn’t even soldered. Other tab was very lightly soldered. There’s no way that would have passed a test. I’ve seen poor solder joints on these causing early failures on the contactor too. Be advised to check the underside of the board!

The device has a design flaw which results in the leads on the relays burning off in time. If you are buying a replacement, this is probably why. The connections are left far too long from the factory and can flash over to other parts of the board, and a few of the traces are light on solder.Pull back the four metal tabs holding the IC board in, lift the board out. Dab a soldering iron on any funky looking joints and trim back terminals to the board with a pair of end cutters. If you have a hot glue gun, slather the whole back of the Ic board with about 1/8" of glue. With any luck it will be the last replacement you ever have to buy.

Even though I'm giving this five stars, I just want to mention that the little "doors" on the end of it are a bit of a pain to open, and there are some sharpish edges on the thing that you could cut yourself on. Since it's not a toy or something you'll use all the time, but a boiler part, I suppose it's to be expected that you might have to be a bit careful with it and/or wrestle with it. That aside, it's a solid unit that isn't at all flimsy, and we managed to put it onto our boiler ourselves in short order. This is our second winter with it in place and it's working like a champ. No issues with it and we'll happily buy another when/if we need it.

Was not a Honeywell but it is the brand that took over Honeywell. So its a direct replacement. Came packaged well and was half the cost compared to HVAC and plumbing stores near me. Fast shipping and was easy to install and working great!! Didnt give 5 stars because it says Honeywell and its NOT a honeywell. I would still buy it again!