240V60A Breaker Failure - Lost a Leg

[larry4406]

Had a new failure mode to me.

Did some maintenance on the heat pump. It has internal breakers as the disconnnect. Turned them off and did my work.

Unit would not run after turning disconnect breakers back on. WTF?

Checked line side breaker lugs at each breaker (there are 2 - one 60A and one 30A) and both have 240V. Checked load side lugs and zero volts for the 60A and the 30A has 240V. WTF? Cycled the 60A breaker and no change.

Killed the main panel. With both disconnect breakers "on" checked for continuity of the legs thru the breaker. Sure enough, left side leg on the 60A breaker no continuity. The 30A breaker checks fine. Odd.

Check the tightness of the line side lugs. Interestingly, find that I could turn the left side lug on the 60A disconnect breaker ~2 turns. Still no change...

Ordered new breaker. These are odd Square D QOUQ260 breakers. Odd to me as they bolt down via metal clamps and the load side lugs are actually 1/4" spade terminals. Not available local, so jungle store to the rescue.

Popped new breaker in, trimmed leads to fresh ends, tightened by hand to what felt right. I then used my 1/4-drive torque wrench to torque to 45-in/lbs. I was actually surprised how much tighter it needed to be to be per spec; I think it was 4-5 additional turns!

Unit fired right up.

I concluded that the loose lug somehow fried the internals while no overt heat damage of the breaker.

So lesson for all - use your torque wrench on the lugs!

This breaker was installed with the heat pump 11 years ago.

 

[micromind]

I've seen dust enter the top of the breaker and rest on top of the contacts. All is well until the contacts are opened then the dust falls down between them and when they are closed again, the dust gets between the contacts and they don't close.

 

[manwithtools]

I then used my 1/4-drive torque wrench to torque to 45-in/lbs. I was actually surprised how much tighter it needed to be to be per spec; I think it was 4-5 additional turns!

I think many people would be surprised to see how tight the torque spec is on many breakers; if they actually put a torque wrench on them.

 

[dave*99]

Perhaps a bit of heat discoloration?

 

[mm08822]

Keep the new one in place.

Take the old one and try to blow it out from every direction possible. Cycle it several times and see if you get continuity back.

That entire cabinet should be blow out.

 

[larry4406]

Perhaps a bit of heat discoloration?

I actually saw that today when I went to post the picture. Didn't notice it under the normal basement lighting but its clipped off now. Not sure if it was real or the phone camera.

 

[larry4406]

Keep the new one in place.

Take the old one and try to blow it out from every direction possible. Cycle it several times and see if you get continuity back.

That entire cabinet should be blow out.

I did keep the breaker. Might try that.

Yes we need to get the entire system cleaned. We have been here 11 years. We had the duct work cleaned after we gutted the basement, completed the first set of first floor renovation, and had the new heat pump installed. Since then we have done a kitchen addition, hall bath renovation, and basement bath addition.

Current thinking is after the master bath addition is completed (on week 2 of permit review) will have the entire system cleaned again.

 

[PCustoms]

Current thinking is after the master bath addition is completed (on week 2 of permit review) will have the entire system cleaned again.

You paid to have the electric system cleaned?

 

[manwithtools]

You paid to have the electric system cleaned?

I believe he's referring to the HVAC "system", not the electrical "system".

 

[larry4406]

You paid to have the electric system cleaned?

I believe he's referring to the HVAC "system", not the electrical "system".

We had a company come and clean all of the hvac ductwork, returns, etc.

The house was built in 1987. Had been a rental for who knows how long so house was rather nasty when we bought it.

Reading comprehension is strong with @manwithtools .

Regarding electrical cleaning, I power wash it monthly. I make sure that there is water on the floor, I’m in bare feet, and then crank it up. Copper is nice and bright afterwards. You know the cleaning is good when your balls start to tingle.

 

[mm08822]

We had a company come and clean all of the hvac ductwork, returns, etc.

The house was built in 1987. Had been a rental for who knows how long so house was rather nasty when we bought it.

Reading comprehension is strong with @manwithtools .

Regarding electrical cleaning, I power wash it monthly. I make sure that there is water on the floor, I’m in bare feet, and then crank it up. Copper is nice and bright afterwards. You know the cleaning is good when your balls start to tingle.

Next time ur powerwashing the electrical, make sure to dose in an Epsom salt solution. The copper will be brighter and the tingle will be quite the tickle instead.

 

[PCustoms]

We had a company come and clean all of the hvac ductwork, returns, etc.

The house was built in 1987. Had been a rental for who knows how long so house was rather nasty when we bought it.

Reading comprehension is strong with @manwithtools .

Good for him, maybe he can read you cleaning contract. Does the duct guy clean the electrical side too?

You know the cleaning is good when your balls start to tingle.

Whatever gets you going on the morning

 

[larry4406]

Does the duct guy clean the electrical side

The ductwork was cleaned at the time the heat pump was replaced. So 11 years ago the electrical side was new at time of cleaning as the heat pump was brand new.

I have an idea, go right now and send us a picture of the electrical side of your hvac without cleaning. Be honest.

 

[PCustoms]

I have an idea, go right now and send us a picture of the electrical side of your hvac without cleaning. Be honest.

I'll grab one a few minutes.

But I think you may be missing the point. Pretty sure this

That entire cabinet should be blow out.

Was in reference to the dusty cabinet and failed breaker. Somehow from there we went off into duct cleaning land...

 

[Dagny]

That problem happens often here only its asian beetles. Showed up about 20 years ago and crawl into the breaker till its chock full then when you turn it off a couple dozen fall between the contacts and when you turn it back on nothing. sometimes if theres only a few you can here them cooking in there.

 

[PCustoms]

@larry4406



Not sure if I cleaned the burner last year and due for a filter change, so thanks for the reminder

 

[Wrench97]

I started reading that and thought Square D, I've seen it on Square D disconnects before and sure enough scroll down and there a picture of a Square D breaker.....

 

[larry4406]

I started reading that and though Square D, I've seen it on Square D disconnects before and sure enough scroll down and there a picture of a Square D breaker.....

I guess I don't mess with HVAC much.

Are these type of breakers with load side spade terminals more common than I think?

 

[manwithtools]

I guess I don't mess with HVAC much.

Are these type of breakers with load side spade terminals more common than I think?

Larry, those are application specific breakers made for the HVAC industry. There are also application specific relays and motor contactors made for the HVAC guys too. The big players in that world have enough buying power that allows them to specify components that allow lower cost and faster assembly times with low skilled workers.

 

[dave*99]

@larry4406 I have not worked inside many systems like yours, but I am surprised at the amount of dust in the electrical compartment. Where is it coming from? The return air ducts in the house? Or the room where the unit is located. The photos are zoomed a little tight for me to see the air path into the electrical compartment.

I've worked inside many gas fired heaters and they look like PC's unit. I find some dust in the blower compartment, but the burner compartment is not very dusty.

Is there a cover plate that goes under the hex head screw in the lower left corner of this photo? It looks like much of the dust builds up near the slit bottom left. Is the blower sucking air from the utility room and bypassing the furnace filter?

 

[larry4406]

@larry4406 I have not worked inside many systems like yours, but I am surprised at the amount of dust in the electrical compartment. Where is it coming from? The return air ducts in the house? Or the room where the unit is located. The photos are zoomed a little tight for me to see the air path into the electrical compartment.

I've worked inside many gas fired heaters and they look like PC's unit. I find some dust in the blower compartment, but the burner compartment is not very dusty.

Is there a cover plate that goes under the hex head screw in the lower left corner of this photo? It looks like much of the dust builds up near the slit bottom left. Is the blower sucking air from the utility room and bypassing the furnace filter?

It is a Goodman upflow heat pump. The return is on the left, connects under the unit, encounters the A-coil, blower, then up thru the heat pack, and on to the supply plenum/ductwork.

There are filter grilles at the 3 house returns.

The disconnect breakers are located within the cabinet up at the top and there is a window in the cabinet cover with black fuzzy dust seal like **** around the protruding breakers. In retrospect, I think there should be a piece of weatherstrip at the horizontal divider between the blower and electrical section.

I will check that "slit" you noticed to see if it is indeed open to the blower box. If so, I can seal with mastic or UL listed foil tape.

 

[dave*99]

Sure looks like dust is coming into the unit from the utility room.

 

[Bert_]

There is supposed to be a clear flexible plastic cover over the circuit breakers. Since it's gone you are sucking unfiltered air through the gaps around the breakers.

I have put in a few of that exact same air handler.

 

[larry4406]

There is supposed to be a clear flexible plastic cover over the circuit breakers. Since it's gone you are sucking unfiltered air through the gaps around the breakers.

I have put in a few of that exact same air handler.

Interesting.

I will study the parts list to see if I can find the plastic breaker cover or an alternate.

Been like that since day one 10+ years ago.

I always thought that arrangement was wonky.

 

[wyliesdiesels]

I concluded that the loose lug somehow fried the internals while no overheat damage of the breaker.

That is not possible. Purely coincidental.

Basic Breakers (non-GFCI non-AFCI) have 2 components- magnetic trip for ground fault & short circuit incidents and bi-metal trip for overcurrent incidents. A loose lug would in no way be able to affect either component.

 

[larry4406]

There is supposed to be a clear flexible plastic cover over the circuit breakers. Since it's gone you are sucking unfiltered air through the gaps around the breakers.

I have put in a few of that exact same air handler.

Interesting.

I will study the parts list to see if I can find the plastic breaker cover or an alternate.

Been like that since day one 10+ years ago.

I always thought that arrangement was wonky.

Bert for the win!

541 is the schematic number which is part number 0161A00073 for the circuit breaker cover. Search that and it has a plastic clear cover! Spendy at $34! Although the breaker was $50 with $10 in shipping and 5 days without AC so maybe a bargain?

Very odd. The piece I have looks like it was a simple blank with an outline for razor knife to cut it at one or two 2-pole breakers. Razor cuts are still evident.

I wonder if that was the actual part 10+ years ago. The company that installed it was highly qualified. Unfortunately, the father had cancer and passed, the younger son ran it quite successfully (who I dealt with), but then in his late-40's he had a stroke and sold the business around 5 years ago.

I will say that the people's that live here (wife and 2 daughters) insist that the blower run 24/7/365 as they like the air flow and the white noise (they don't care about the electric bill, but I know from past house 15 years ago it was $25-30/month to run the fan! I know this cause at 10 years that fan STB and I said no-more).
So, we have 10+ years of basement dust getting sucked in it appears. As that region is above the blower box, I would think it should be under positive pressure, and with the returns filtered, I am still surprised.

Reminds me, I think I should look into a spare blower fan sooner than later...

 

[larry4406]

That is not possible. Purely coincidental.

Basic Breakers (non-GFCI non-AFCI) have 2 components- magnetic trip for ground fault & short circuit incidents and bi-metal trip for overcurrent incidents. A loose lug would in no way be able to affect either component.

Keep the new one in place.

Take the old one and try to blow it out from every direction possible. Cycle it several times and see if you get continuity back.

That entire cabinet should be blow out.

Thank you!

So perhaps the theory that dust/**** got inside and gunked things up is valid. I will use an air hose tomorrow to blow the failed breaker clean to see if it restores.

I was trying to wrap my head around how a loose line lug would fail the breaker continuity.

 

[larry4406]

Interesting, plot thickens.

This is the cover my unit appears to have shipped with. Can see the razor knife outlines for the breakers.

Perhaps the "blank" shipped with the base unit. The dual breaker setup comes with the optional heat pack kit which they included. Perhaps when you order the heat pack kit, one is supposed to upgrade to the plastic cover version.

 

[PCustoms]

Cheapest blank cover I've ever seen....

Went to get some for my panel a few years ago, was cheaper to buy a breaker to fill the space

 

[Bert_]

You could just tape over the breakers too. Wouldn't look as nice but would accomplish the goal.

If you want you should be able to adjust the speed when you are running fan only.

You have to download the coolcloud app then you can set airflow. I wouldn't mess with the heating or cooling settings unless you know what you're doing.

 

[dave*99]

As that region is above the blower box, I would think it should be under positive pressure,

I don’t think so. The dust says otherwise. And you would need air leaking where the heating elements sit in order to have positive pressure.

Easy enough to check. Hold a tissue in front of the breakers.

 

[larry4406]

I don’t think so. The dust says otherwise. And you would need air leaking where the heating elements sit in order to have positive pressure.

Easy enough to check. Hold a tissue in front of the breakers.

Well the tissue paper proved air in-leakage around the breakers! Also observed a large intentional wire management hole from the electrical compartment to the blower compartment below. Wire hole is behind the circuit board.

I used 2" blue painters tape, 3 slightly overlapping pieces, to cover up the breakers. I did turn off the unit, remove the cover, and vacuumed while I dusted with a fine paint brush.

I also used my compressor air gun to blow out the old breaker and cycled it repeatedly. No change of condition so I am concluding it is dumpster food.

 

[dave*99]

If the breakers and the cover panel are sealed from drawing utility room air, you probably don’t need to worry about the wire management hole. There will be no airflow from the room into the electrical compartment. But it won’t hurt to seal it.

 

[mm08822]

I was wondering about the dust infiltration too, all along. This section should be positive pressured, I thought. if not atmospheric..........unless it leaks into the negative section.
The red area is where weatherstripping could help based upon a single cover. Just throw duct seal into the grommet to seal that too.

 

[madison069]

One of the reason we hated touching those breakers, they will fail randomly due to sand, dirt, insects, and other items that can get inside the breaker and would wait for the breaker to be tripped and fall between the contact. Then they would get cooked or melted into the contact on the next flip and cause a poor connection. We kept those breakers on the truck due to replacing them often during diagnostic or general service.

 

[mm08822]

One of the reason we hated touching those breakers, they will fail randomly due to sand, dirt, insects, and other items that can get inside the breaker and would wait for the breaker to be tripped and fall between the contact. Then they would get cooked or melted into the contact on the next flip and cause a poor connection. We kept those breakers on the truck due to replacing them often during diagnostic or general service.

It seems to be the victim of poor sealing between the vacuum side of the blower and the electrical compartments. Mfr did not fix root cause but put a band-aide on the problem with the cb cover.

 

[madison069]

It seems to be the victim of poor sealing between the vacuum side of the blower and the electrical compartments. Mfr did not fix root cause but put a band-aide on the problem with the cb cover.

For us it was just the high wind and sandy desert. No matter how good the seal is, there was going to be sand and dirt located on the inside of these units. If it can be opened, it wasn’t going to be sealed 100% to fight the wind and sand.

 

[larry4406]

It seems to be the victim of poor sealing between the vacuum side of the blower and the electrical compartments. Mfr did not fix root cause but put a band-aide on the problem with the cb cover.

and apparently did not include the band-aide circuit cover for my installation.

 

[mm08822]

and apparently did not include the band-aide circuit cover for my installation.

Maybe they were learning on your vintage!

 

[dave*99]

and apparently did not include the band-aide circuit cover for my installation.

However you achieve it, the issue is eliminating unfiltered utility room air entering the system.
Filtered air moving between compartments is less of an issue.
If the breakers, cover door and electrical cables and any other penetrations entering the cabinet from the utility room were sealed, dust is diminished.