Aquastat "jumper" keeps frying....

dhsmithh

Have owned my house for 2 years and am now on my 3rd aquastat... First time the hvac guy told me over the phone to try jumping the thermostat screws to see if it would do anything, and it didn't. Long story short, according to him it was a bad aquastat so I ordered another identical one off of supplyhouse.com and before I installed that, took a picture of the aquastat to make sure that I hooked everything back up exactly how it was currently.

Lasted about 2 days and I noticed that the temperature in the house was about 50 degrees. I go down and look and tank was full so i wasn't out of oil. So i check the breaker and it was off, out of curiosity I take the cover off the aquastat and the jumper on it had completely fried the board.

I sent that one back thinking it was faulty, and they sent me another one with no hassle. Installed that the same exact way and it lasted all winter until march or april. We had a couple random really cold days and I noticed that the heat wasn't kicking on so i checked and it burnt out in the same spot.





I have a new one sitting here at home in a box but do not want to install it if the same thing is going to happen again.

Aquastat is a Honeywell L8124C 1003 Triple Aquastat Relay Line Volt burner control 120v 60hz

lchmb

you need someone to come in and diagnose what is going on before you have a fire...imho...

STEVEusaPA

Yeah something isn't right--maybe bad neutral or something grounding. I've never seen that in my 30+ years. If it tripped the breaker, it's serious.
By the way, you never should jump T-T on the control without removing at least one of the thermostat wires.

EdTheHeaterMan

Contact your fuel dealer. If they do not have a service man, then they have a sub contractor or have an independent contractor that they refer their customers to. You need someone who is good at control wiring and understands oil heat. that person is rare in some areas.

billtwocase

You need to have your voltage, amperage draw, and neutral/grounds checked. Also make sure that L-1 is actually power, and not crossed with L-2 which is the neutral/ground

dhsmithh

Should I be contacting an hvac guy or an electrician??

Leon82

an electrician first. the wire should be traced back to make sure its not pinched or cut or spliced improperly

Jamie Hall

Leon82 said:

an electrician first. the wire should be traced back to make sure its not pinched or cut or spliced improperly

And that all your grounds and neutrals are really solid...

ChrisJ

Something in the circuit is drawing excess current for some reason and personally, I doubt it has anything to do with neutrals or grounds. Questionable neutrals on the equipment would do the opposite of this (no power consumption, not excessive) and grounds would have zero effect.

If the building had a neutral or a voltage issue a whole lot more would be burning up than just this Aquastat. An open neutral to the pole is a very very bad thing and doesn't just effect one circuit.

You need to get someone in to check the heating system out. Any thing that draws power through that Aquastat (oil burner, pumps etc) as well as the wiring related to the devices could cause this.

delta T

Yeah you have something else wrong for sure, never seen an aquastat do that before. Definitely start with an electrician, if they say all is well up to the boiler, then get an HVAC company out to check the control wiring.

Not trying to bash electricians, but most have little experience with the intricacies of control wiring and I would guess they will have little insight on the problem if it is in the boiler controls somewhere. Some electricians do though, so you may get lucky.

Definitely don't turn anything on again until you have a solution, fire hazard for sure (obviously).

Paul48

That should have been repaired correctly after the first aquastat burned up. As a homeowner, you have to recognize when things in the house are telling you there's a problem. This is not meant to chastise the OP. It is a lesson that all homeowners need to learn. If all the lights in the house start flickering, it's not an indication of bad bulbs.

I had an aquastat burn up, as the result of a shorted nozzle heater on a Carlin EZ-1 burner.

EdTheHeaterMan

Hatterasguy said:

I have seen this before on the L8124.

There is most likely nothing wrong with your house wiring. It only supplies voltage to the control. If anything that is powered by the control draws excess current (circulator or burner), you'd get a circuit breaker trip before any damage occurred.

Likewise, there is no ground fault or neutral fault. They cannot cause excess current to be drawn by the control.

So, what do we have left?

All the amperage to the control passes between the wire and the terminal of the control beneath the screw.

If you take a close look at the wiring beneath the screw, you find that there are no wires beneath the screw. The wiring was done by a homeowner who cannot quite get the wire beneath the screw and the majority of the wire is outside the terminal and outside the screw head. Usually folks call this "good enough".

Well, it is likely not good enough and there is localized heating beneath the screw which causes further degradation of the contact surface. Eventually, there is insufficient contact surface for the current and it actually destroys the terminal due to heat.


It is tempting to cut corners with that control due to the difficulty in wiring it, but it is intolerant of mistakes by the installer.

Come to think of it, I have a customer with a similar problem. The L8124 fried in a similar way near the L1 terminal. It was only 3 years old so I started to research the difference between the L8124 and the L7224U, (I use this as a replacement for both the L8124 and the L8148) to see if he can expect the same in a few years. Im guessing NOT

The difference is the wire terminal is more user friendly with the square washer to allow for better connection to the terminal

Paul48

Hmmmm........Isn't that a wire lug?

BobC

Wire lugs solve a lot of problems and can make the install look more professional.

Bob

ratio

Stak-Ons are your friend...

ChrisJ

Bend the wire, put it around the screw in the direction the screw tightens, after it's around it, close it more using your needle nose. Tighten screw.

Come on guys, it's not that complicated.

billtwocase

If this was happening to the B-1 terminal, I would look into a burner component, but line in tells me otherwise. Excessive draw "should" pop the breaker or fuse

Fred

It's a"Jumper" What is it jumped To?

Paul48

B-1 terminal becomes a direct connection on a call for heat from the lo-limit. A short will burn the weakest point in the circuit. Based on what we see, you can't discount anything.

bob_46

MH shows that's a 1/4"male tab terminal. My experience is Sta-Kons are not reliable with solid wire. I question OP use of the term jumper.

dhsmithh

I say jumper because the wire that toasted is soldered to the board and comes out and goes right back into it. I will check tonight to see if the wire is solid or not

ChrisJ

It could be just me, but it looks like a whole lot more is toasted than just the jumper. I suspect some traces on the PCB likely also took a hit.


And yes, we would call that a jumper.

Something in the circuit drew way too much current through that.

dhsmithh

It was just that jumper, it looks like more because I broke the terminals off trying to get the L1 & L2 wires off

Jack M

come to any final conclusion on this aquastat installation? Was it the wiring?

ericmmff

Those Honeywell aqua stats suck. They suck to wire and I've had to resolder brand new ones to get them to work. If the power side checks out,have your electrician add surge protection . Then install a digital Hydrostat. No proven track record, but better all around as far as wiring ,accuracy and price are concerned.