Condensate + attic install + gravity = bad

[Giantsean]

Hey All,

Those who may remember my post about my HVAC installers being hacks... we now have another hacktastic milestone in their road to hack nirvana. They just can't stop topping themselves.

So long story short we have an attic mounted Trane/AS hydro air handler which services the 2nd floor. It sits in a sheet metal catch pan bent and sealed by the Hack Bros. Tonight my daughter alerts me that the paint on the wall outside her room is bubbling. Uh oh.

So I go up the attic stairs to find the pan full, the drain pipe filled to level of the cleanout, and a whole bay full of sopping fiberglass. Fortunately the hacks installed an overflow cutoff to prevent this very situation. UNfortunately they apparently don't know how to seal the corners of the pan when they build them, because it was happily dripping it's contents out of the lowest corner (which of course was the least accessible one... of course).

I shut everything down, dried what I could, and tried forcing the water down the drain in a variety of ways (none really good) and eventually it seems to have worked as it returned to the trap weir level and stayed there.

Luckily the damage was not TOO bad. I will have to fix and repaint a good sized area but the drywall still feels hard, so I it could have been much worse. Still, why wouldn't the float trigger? Unless it was a vicious cycle of on/off due to the dripping pan? What causes drains to clog in the first place? We are still doing a lot of construction upstairs (wood and drywall dust) though I am changing the filter regularly and shutting off the system when we do anything super dusty. Could dust be washing off the coil and jamming up in there? Finally, the pan is not actually UNDER the drain cleanout and there was no water directly under it. If it backed up, where would it actually leak from? the air handler itself?

Thanks for letting me vent, and for any info!

 

[Jadnashua]

When you have a pan like that above living space, a useful technique is to have a secondary drain a bit higher than the 'normal' one. The odds of both of them being clogged is much less. It's handy if the outlet is where you might notice, so you could tell there was a problem. A float or moisture sensor would need to be tested periodically to verify it is still working. It would also be handy if it were hooked up to either an alarm or an indicator light placed somewhere you'd notice.

 

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[WorthFlorida]

From you description it's not sure to me that there are two drain lines. One from the unit and one from the drip pan. Below is written for anyone with a similar problem.

All attic installed units will have a drip pan with a drain but this drain if for overflows only. The condensation line should be going out of the attic space on its own pipe. Should this main drain plug, the Safety Switch on this condensation line would switch off the 24v AC to the thermostat and shuts the whole thing off. Looks like it did work for you. In no way should the condensation drain go directly to to drip pan then out the attic on one drain pipe. Condensation lines plug up all the time in the south because after 11 months of continuous use slime build up the and it will plug up the drains. At least twice a year you need to check the drains and use a water hose or compressed air to blow out the drains. A shop vac on the outlet of the drain pipe on the outside of the home can be used to suck out any crud. There are safety switches made for drip pans. Click on the blue.

In this picture you can see the drain line from the unit on the left. It cannot be seen but the drip pan should also have its own drain line. Occasionally look at the overflow drip pan drain line on the outside of the home, if you see water coming out then you know there is a problem.

 

[Giantsean]

Thanks for the replies guys.

Far be it from Hack Hackster & Hack HVAC Hack service to even seal the pan properly, much less install a 2nd drain line. The secondary pan is bent sheet metal sealed with some sort of sealant (maybe silicone but I can't tell). Unfortunately it leaks, hence the issue. Ultimately though it does not have it's own drain port.

I actually also do have a float switch but for whatever reason it didn't work, or worked poorly. I think the switches you suggested will work well, someone else suggested a water detector placed in the lowest corner. Ironically the pan does not even extend far enough under the pan main drain to catch any overflow that happened to come out the cleanout, if it can even get that high. I actually have another drain hole in the air handler (TAM 7) that I'd be happy to use if it's wise to do so.

What I'd really like to do though is sh*tcan that metal secondary pan and put a plastic one-piece pan in it's place. Are those any good?

 

[WorthFlorida]

I think you will always find metal pans. Ok your safety switch didn't work. With the AC running, pull out the safety switch and push the float into the head of the unit. The unit should turn off if it is installed correctly. All it does is open the 24v's. it can be on the output of the 24 volt transformer or to the thermostat. If is doesn't turn off the system then check for correct wiring. If that is OK open one wire to the safety switch. If it shuts off then it is a bad switch.

If it does turn off on the first test, then it is not in the correct location so when water backs up, it does get high enough for the float. Sometimes it just takes moving the pipe it is connected too down a little so it is level to the drip pan inside the air handler. The air handler has two or three locations for the condensate lines. It is common to get a PVC nipple (may come with in the original packaging) and remove one of the drain plugs and insert the safety switch into the new location. If you google safety switch pictures for drain lines you'll find different ways with different type of switches.

 

[Giantsean]

Thanks again. Yes it actually does test properly (I had to re-wire it after they screwed THAT up too) and it just opens hot to R when triggered. but I think they main reason was the placement. I think it would go through a stop/leak/go vicious cycle, leaking all the while. It is one of these BTW:

https://www.amazon.com/Aquaguard-Ma...911968&sr=8-7&keywords=hvac+condensate+switch

Doesn't seem bad overall, just probably not ideal for my setup. If I was to keep my current setup I'd for sure have to re-seal the pan and place the switch in the spot it backs up, at the very least. The leak is what concerns me the most... I could have a dozen switches and drains but if the stupid pan leaks it's all for naught. I will definitely look into using the 2nd drain plug for a switch as well. Certainly could't hurt.

If I want to retrofit the secondary pan with a dedicated drain, do I just use a uni-bit or is it then worth just getting a pre-made one?

 

[WorthFlorida]

Without a pic to see your pan it's hard to say. As long as the pan covers the air handler just siliconized the seams and punch a hole for a drain and run a pipe. Just get a drip pan water sensor and keep an eye on the main condensate drain that it is cleaned out once a year. At the same time check the Safety Switch. You have the Safety Switch wired correctly now so the problem may never happen again. About now you're done with your AC season and you may only use your AC three or four months a year. Very little use compared to south Florida living. It takes a lot of maintenance on the AC since it runs almost every day but I never have to get the oil furnace serviced or worry about delivery in the coldest time of the year.

 

[JerryR]

Here is a picture of one of my setups. The Pan is a commercially available pan, not home made.

The condensation drain safety switch is installed in the second drain line on the left.
The metal drip pan safety "AquaGuard" switch is in second picture.

My unit is installed in garage. There is no drain for the drip pan, just the Aquaguard switch.

Every 6 months the condensation line gets serviced by connecting a wet vac on the pipe outside the house and sucking out all the slime and crud. With the vac still running, a diluted vinegar solution is poured into the pipe that has a unglued cap on it to flush out more crud. We run about a quart of solution through it. Once it is done the vac is disconnected and a little water is poured in to fill the trap.