Air Conditioner Fixed, Problems with Cabon Monoxide

[gregg687]

I had a blower in my AC unit fixed in my rental property by a company and was over charged.  I needed it done ASAP for my tenants.

12 hours later the carbon monoxide detectors were going off, and the fire department showed up stating there was a very high level of carbon monoxide in the air.  I'm having the company come back to check it out.  From research, it appears that AC units don't produce carbon monoxide so I'm very confused.  This has never been an issue in almost 10 years of owning this house.

Does anyone have any advice?  Could the repair company have messed something up to produce this?

Thank you in advance. 

[Jon Bon]

Woah that is a big deal! I would have a different company come back. Is it possible for you to drop by and check it out?

Honestly I have no idea, I am NOT an HVAC tech or anything. I have a hypothesis but I'm not sure its even possible. The scale of Eff up is impressive if they did.

You really should only have 2 sources of CO in your house, Furnace and hot water tank. So your furnace should not be running as its summer, so that leaves the hot water tank. Possible you have a gas dryer?

They could have knocked something loose and jarred the exhaust from the HW tank off. But even a tank really does not produce that much CO. I am not sure if its possible but if they REALLY messed with your wiring is it even possible they cross the AC and the Heat up? So the furnace was running? AND somehow  created some blockage?

Both of these are pretty far fetched and I dont you could even do this on purpose if you wanted too!

Let us know how it turns out.

[Wrenchturner]

Perhaps something to do with air circulation.  Your presumably central AC is probably pushing the CO around now, which it wasn't before.

[gregg687]

Thank you for your responses.  This forum makes dealing with this stuff much easier.

The company came out and said the air conditioning was now circulating CO around from the water heater (great hypothesis Wrenchturner).  They were able to get this problem fixed and the CO is not doing this anymore. 

They are now saying that erosion from the AC is causing problems with my furnace and that it needs to be fixed, but that its worth it to .  My furnace is only 10 years old and has never had a problem.  They are giving me estimates today.  I know I need to get more opinions if this is the case. 

It has been a really frustrating week dealing with this.  I'm hoping I have better experience with a different company. 

[Jon Bon]

I have heard that this can happen, but again they must have really messed this up.

So before you had AC and hot water tank both running correct? You did not have problems with CO before that?

SO they did something.... Basically they must have had the blower drawing air from the basement. So the blower is sucking the air OUT of the HW tank exhaust pipe and then blowing it into the house. Is there MASSIVE holes in your cold air return in your basement? I guess its possible but hot water tanks have relatively small BTUs and shorter run times. But your situation could be different from what I am thinking.

Very strange, the part that sticks out to me is you did not have any CO problems until after those turkeys left your house.  Find a new company ASAP.  I mean these guys could have killed people.

[robartsd]

Carbon Monoxide is formed when combustion is incomplete due to lack of oxygen. You might want to look for problems with the make up air supply for the water heater.

[Wrenchturner]

Erosion?  Furnace AND water heater, after fixing an AC?

I have heard that this can happen, but again they must have really messed this up.

So before you had AC and hot water tank both running correct? You did not have problems with CO before that?

SO they did something.... Basically they must have had the blower drawing air from the basement. So the blower is sucking the air OUT of the HW tank exhaust pipe and then blowing it into the house. Is there MASSIVE holes in your cold air return in your basement? I guess its possible but hot water tanks have relatively small BTUs and shorter run times. But your situation could be different from what I am thinking.

Very strange, the part that sticks out to me is you did not have any CO problems until after those turkeys left your house.  Find a new company ASAP.  I mean these guys could have killed people.

+1, hire someone else to fix this, if they're skilled they can probably tell you exactly what went wrong and if it was caused in part by the last guys.  An AC shouldn't be pulling air out of the furnace room, it's supposed to recirculate.  Maybe they did a shit job installing the ducting after changing the blower motor.

[gregg687]

Correct, Jon Bon, I had never had a single problem with CO prior to them changing the blower motor in my AC unit. 

They came and fixed it and told me it was completely corrected.  Then gave me an estimate for a new furnace.  And 24 hours later the CO levels were back up (to 53 this time which is less than before) and fire department had to come again.  I'm going with a new company that does great work and is checking it out this morning.  Thanks again for the help, this whole situation is scary.  I'm grateful those CO detectors work. 

[gregg687]

So it was a flue pipe problem.  It's being replaced now and is a rather inexpensive fix.  I don't know how the other company missed this.  Should I file some sort of formal complaint or something with them?  This issue is something serious.

[Wrenchturner]

So it was a flue pipe problem.  It's being replaced now and is a rather inexpensive fix.  I don't know how the other company missed this.  Should I file some sort of formal complaint or something with them?  This issue is something serious.

The first company shouldn't have fixed it incorrectly, but it still may not have been their fault originally.  Was the AC out of use for a long period?  The flue issue could have developed during this time and only become severe when the blower motor for your AC was functioning again.

What specifically was wrong with the flue?

Good on you for providing CO detectors btw.

[gregg687]

The first company removed the flue for some reason or another.  When they came and "fixed it", instead of installing a flue, they used silver tape.  The tech who replaced it showed them that the chimney was now working correctly.  My tenants are still convinced that something is wrong and want another chimney inspection which I am working on getting now.

[Jon Bon]

Holy shit man that is scary! Glad you at least figured it out.

Now, here is what I do know. In 100% of the hot water tanks (that I have seen) the HVAC blower is NOWHERE NEAR THE HW FLUE! So that like yeah I was putting new tires on your car but somehow drained all the oil out, oops my bad :)

As far as the first company, I would demand my money back AND dispute all charges. I would investigate legal action. What those guys did was incredibly dangerous. If you had not been the responsible party here (CO detectors) horrible things could have happened.

To use the car analogy again, if you dont know how to change brakes on a car, maybe you should not do it? Because the consequences of getting in wrong can be deadly!