Heat Pump Failure (who's fault?)

[hurk27]

I appreciate the comments you have made. As far as this particular customer is concerned, whether or not the system is designed correctly or not isn't really their issue. Even though I feel this wasn't our fault and shouldn't have happened, I can't make my customer pay for it either. I ran a report today and we have accumulated ~$58,000,000 in revenue during the past 8 years without a single liability claim against our insurance. Given the thousands and thousands of dollars we shell out to our insurance company every year, I think this is probably one of those cases where it makes sense to let the insurance company and their lawyers handle it. They will probably get allot more attention from the HVAC manufacturer than we would anyway.

Those of you who are contractors, please take this as a cautionary tale and tell your journeymen about what happened as we sure as heck are going to.

One final comment, to the person who mentioned the T-Stat as the interlock device (which is a good point, by the way), my employee was smart enough to find two thermostats and turn them off, but it turned out that there were three thermostats controlling this particular unit. On any designs that I personally handle in the future, I will be making sure that some type of electrical interlock is in place.

Well it sounds like a wise decision, and to go one step farther, you do have the right to require from your insurance company an investigation, to make sure they don't pay out just because it is the easiest route to take as many will do, that is up to you not them, you are their boss as you pay them, but it is also wise to listen to them as they are in this business, and are good or should be, at determining which way to go with it, I took over a house fire that our old company was supposed to have caused, and our company liability insurance want to just settle with the home owner, I told them in no way was that going to happen when we knew we did not cause the fire, so they did launch an investigation and to their surprise found that the home owner did in fact do some wiring on the house by changing connections in a junction box which caused a circuit being tied to two breakers on the same leg in the panel, and also wrongly tied a switch in place of a receptacle which caused a dead short in this same circuit with two 20 amp breakers that didn't trip, causing the circuit wire to over heat and burned the house down, well not only did we not have to pay, the home owner had to pay for the investigation and all cost of attorneys fees, and to top it off his own insurance refused to pay for the house, but that part was reversed in court.

So you can control what your insurance pays out, just know and learn as much as possible to which way to go.
also ask questions, like the one I stated before, are manufactures allow to make a system self destructive just because of a failure of one part? I would think not. like you said too many reasons that the evaporator fans that can become inoperable should not allow this to destroy the compressor.
And no the owners of the unit should not be left paying either, if there was installation deficiencies, it should fall back to between the manufacture and the original installer of the unit.

ever wonder why generator manufactures put so many fail safe in them, low oil, water, over voltage, under voltage, and many more, because they will be left holding the bag if it fails for something that could have been prevented in the design.

 

[Electric-Light]

The facts and theories be what they may, but, my stance would still be that I'm not responsible unless and until it's proven that I am, and not the other way around.

Civil claim is different from criminal cases. It's not your fault/their fault,but a degree of fault on each party.

Say there are two lanes in each direction on the road we're turning into.
I turn right on red into right lane after making sure it is clear of anyone else with right of way.

You're in oncoming lane and turn left on a protected green.
We turn at the same time and we collide in right lane.

Obviously, we wouldn't have collided if we didn't turn at the same time but who's fault is it?

I would argue that it is your fault, because you did not have a right of way into making a wide turn, thus I did not fail to yield to anyone with right of way and that you have caused the accident by making a wide turn/unlawful lane change.

You might say otherwise, especially if you had liability only insurance.

 

[LarryFine]

Obviously, we wouldn't have collided if we didn't turn at the same time but who's fault is it?

That would depend on who's side of the lane-division line the contact occured. The location of debris on the road might be the compelling clue. What's the evidence here?

If it is clear that the AC damage occured because the outside unit ran when the inside unit stopped, I'd ask what the manufacturer and/or the installer did to prevent that.

If it's not electrically or mechanically prevented, then were was the warning labeling? If it should be "common knowledge," then where's the evidence? Professional witnesses?

 

[Electric-Light]

That would depend on who's side of the lane-division line the contact occured. The location of debris on the road might be the compelling clue. What's the evidence here?

The hypothetical situation is that the left turning vehicle encroached into the right lane by making a direct turn into the right lane rather than the left lane he was supposed to turn into. Realistically I'm assuming the insurance representing both drivers would just share percent liability. A costly investigation may not happen unless one of the vehicle involved was a van with 7 kids and all of them died.

Whoever has the greatest legal resource is obviously at an advantage.

 

[petersonra]

IMO, this may well be one of those cases where it is best to let a 3rd party (like your insurance company) fight it out with their insurance company.

Most of the time they are able to work it out between them, and you are not even really involved much.

It is why you pay for insurance.

I am not at all surprised the manufacturer replaced the compressor. Most of the time it is more cost effective to just do so than to try and figure out what really happened. Especially in this case where it may well be that the manufacturer failed to supply (or at least require) adequate interlocks to protect the system from this kind of thing.

I wonder who is going to pay to add in the interlocks now that a catastrophic failure mode has been found?

 

[markstg]

If I was the owner I'd be concerned that the compressor's protections, Hi and Low coolant pressure cutouts, do not work.

 

[Mgraw]

If I was the owner I'd be concerned that the compressor's protections, Hi and Low coolant pressure cutouts, do not work.

Why? There is nothing in this thread to indicate the refrigerant pressure controls do not work.

"petersonra"
"Especially in this case where it may well be that the manufacturer failed to supply (or at least require) adequate interlocks to protect the system from this kind of thing.

I wonder who is going to pay to add in the interlocks now that a catastrophic failure mode has been found?"

Just about every manufacturer makes units similar to this one. They are wired the same way. Do you think they are going to change the design because of this failure? I doubt it. They have not changed in the 35+ years I have been installing them. They all say they need to be serviced by qualified personnel and I believe they still put labels on them that say more than one disconnect may be needed to disconnect power.

 

[Electric-Light]

I wonder who is going to pay to add in the interlocks now that a catastrophic failure mode has been found?

Who is going to pay for data center downtime caused by factory unapproved, field improvised interlock that creates a false trip? If its an engineered system and you tamper with it, original engineers are going to blame whoever that modified it.

 

[petersonra]

Who is going to pay for data center downtime caused by factory unapproved, field improvised interlock that creates a false trip? If its an engineered system and you tamper with it, original engineers are going to blame whoever that modified it.

What owner is dumb enough not to deal with the a known issue like this?

I am not suggesting an electrician just cobbling something up one day on his own. But it would be foolish not to fix a known issue like that.

It might be as simple as putting a sign up somewhere.

 

[Mgraw]

The best way in my opinion is to add a sail switch. It goes in the return of the air handler. The one I use kicks in when the air movement gets to 300cfm. It is wired between the y terminal wire going to the t-stat and the y terminal wire going to the condensing unit. If there is no air movement the condensing unit will not run. They cost about $50.00 and take about 15 minutes to install.

 

[LarryFine]

The hypothetical situation is that the left turning vehicle encroached into the right lane by making a direct turn into the right lane rather than the left lane he was supposed to turn into.

I got that. I was just pointing out the possibility that the right turner was the one not turning into the proper lane properly.

 

[Electric-Light]

I got that. I was just pointing out the possibility that the right turner was the one not turning into the proper lane properly.

Even if it was staying within its own lane, he's probably held to some percentage of responsibility for turning right on RED at the same time as a left turner on protected green.

 

[Sierrasparky]

I've seen this conversation go so many directions
What I don't understand is that why is the system not protected for this in the first place. Why did't the pressure switches catch the fault.
If power was cut to the FAU why was the Stat calling for air.

Why is the breakers or disconnect's not labled for this.

 

[Mgraw]

As with most areas of construction COST. Everybody wants the cheapest price. It is not required by code so why do it.
The low pressure control is not there to prevent refrigerant from flooding back. Its purpose is to shut the unit down if it has a leak.
On light commercial units the 24v transformer is in the condensing unit.
Labeling the diconnects is not required.