Questions About Internal AC Coils

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I understand all that work is needed to get at the coils to clean them, but to me its not worth the trouble, plus you risk damaging your coil trying to make some kind of access to get to it. If you ae going to go through that trouble, wait until the A-coil craps out and replace with a new one.
I agree with the other poster. If there is at least 17-20 degree or more difference in the return plenum and supply register, the system is fine. And if the return line of the refrigerent line is cold and sweaty, thats a good sign too. If your house gets to the proper temp with the compressor regularly cycling on and off throughout the day ( about 2- 3 times/hour), I would leave well enough alone.
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1. 5 years ? They need to be cleaned, even if you changed your filter religiously stuff will still build up on the coils... Even if you think they look clean...
2. You can't see in there very well and probably wouldn't see the tiny stuff which builds up in the coils anyway... Once people can be able to "see" dust on the coils the have been wasting energy in their cooling system for quite a long time... Dust insulates the coils making the system work harder to provide the same amount of cooling capacity and provides a nice convenient medium where any excess moisture in your home from humidity can condense and freeze, icing up the coils... (which is *not* a good thing)
3. Irrelevant questions, your condensate drain clearly does not directly connect to a sewer line or it would have a trap in its drain line -- nor does it drain directly outside...
As far as the coil being shipped charged with Nitrogen that is how the coils are protected from damage during shipping and installation... All of that gas would have been recovered and evacuated from the system before it was charged prior to the pressure testing which is done before any refrigerant is added, without refrigerant your AC wouldn't cool your house at all...
To answer your question about how to get at the coil, here is your answer:
You need to obtain a proper pair of steel metal shears to cut the cover panel down in a straight line from where the refrigerant lines exit the duct box to where the condensate line is located... You would then need a piece of heavy gauge flat stock and some gasket material... One side of the flat stock gets attached to the larger piece of the cover panel permanently... With the additional joint you create you can remove the cover from both sides of flue vent pipe without disturbing it's integrity which would cause a hazard, and if you properly gasket and seal the new joint line you create in the cover plate with real foil duct tape you will not impact or change the level of static pressure in your duct work...
Want to keep your AC working at peak performance for years ? Clean your inside coils with proper coil cleaner every year before cooling season starts -- don't forget to do the same with the coils in the outside heat pump unit, all sorts of things can obstruct the cooling fins in the coil outside from dirt to things left by bugs, plants or animals... If the cooling fins in the outside unit are dirty or have lots of stuff clogging them, then the fan can't induce a proper draft to transfer the heat into the outside air and the system won't run very efficiently wasting energy...
That looks like a very nice and neat install on your furnace and AC coils, the only thing your installer overlooked was how on earth the next guy was ever going to be able to open the cover up to service or clean the coils without having to cut out and remove the vent pipe and repair the same every time someone needed to open that cover plate...
~~ Evan
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Thanks for the info.
Seeing that the exhaust port on the furnace and the cutouts on the panel came that way from the manufacturer, how could the AC unit been installed differently such that "the next guy" (me!) was going to be able to remove the panel?
The only way I could it happening would be to have reversed the AC unit (if that is even possible) so that the panel was opposite the vent. That of course would have meant a vent pipe coming out of one side and the drain and refrigerant pipes pipes coming out of the other. That would have ended up being a very ugly installation.
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Please. I'd bet that 95% of the coils in central AC systems have never been cleaned, ever.

Some manufacturers call for a trap to be installed without regard to where the drain terminates. Not sure of the reason for this. One could be to reduce air loss through it or keep bugs out.

You don't recover nitrogen.

It would be interesting to hear from Derby if he thinks that's feasible.

I'd like to see a manufacturer that recommends doing this. And if it's so important, why don't the manufacturer's have a design where you don't have the huge problems Derby is having?

I'd say it wasn't the installer that overlooked anything. It was the manufacturer. That install looks exactly like the typical install instructions from the manufactuer. Every one of them I've seen shows the exhaust glued to the stub, and glue joints the rest of the way to the outside. The manufacturer designed the furnace and the cased coil. So, if they wanted access, they could have planned for it. I agree it would be a good idea to have access, but you have to deal with the hand you're given. And what I see here is the typical situation.
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Looks like the installer was lazy......The vent pipe should connect with an elbow so the pipe is out of the way or should be removeable if that is not practical.
Jimmie
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I don;t see that the installer has any choice. The typical exhaust fitting is PVC female glue type at the top of the furnace. Putting an elbow in doesn't solve a thing, you then just have the elbow in the way. Also, manufacturers spec out the max number of elbows allowed, and less is better.
And short of not gluing it, I don't see a way to make it removeable. To make it removeable, which would be a good idea, would require the manufacturer to do so.

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How would an elbow help? The panel goes all the down to the top of furnace housing.
If an elbow had been used, the elbow would be in the way.
The only way the vent will not be in the way is if it is removed from the exhaust port completely.
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On 5/28/2011 8:17 PM, DerbyDad03 wrote:

I believe the trap prevents blowing the slightly higher pressure discharge air out the condensate drain pipe.

The nitrogen definitely should have been removed so there is only refrigerant in the system. The whole system is pumped down - evaporator coil, lines, outside unit.
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That was my thought too. But then you still have the overflow drain outlet that even if it had a trap, the trap would soon dry out and be useless. I guess having 1/2 as much air loss is better though.

Most of the nitrogen just escape to the atmosphere when the factory plugs are removed. Then you're supposed to flow nitrogen through the tubing while brazing. Then that nitrogen gets vacuumed out. The outside unit, ie condenser, is usually shipped pre-charged with R410A so that does not need to be pumped down.
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On May 29, 8:46am, "Stormin Mormon"

What do you think the reason for this is? I know Rheem at least says you should always have one in the drain line. But then they don't say anything about putting one in the aux, ie overflow line for the coils. And even if you did put one in there because it's only for an overflow, the trap would soon dry out. Hence, if you have one drain line that is open, why not two? Also, some installs I've seen they put a trap in, others none. More common is none from what I've seen.
My thought would be they would be most concerned if the drain line was routed to a sewer drain, which makes sense. Other than that, the trap would prevent the loss of some conditioned air.

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DerbyDad03 wrote:

A p-trap on the condensate line serves the same purpose as a p-trap on a sink: it blocks sewer gas from infiltrating your A/C system.
Your question can be answered with another question: Does your house sometimes smell like a privy?
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He's dumping the condensate into a sink.
If he was going into a drain, he'd need a trap for the reason you stated. If he wad going outside to the ground, he'd want a trap to keep bugs from crawling in. I don't see any need for a trap in this case.
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..
Your answer can be questioned with another question:
How are sewer gases going to get into a piece of flexible tubing that hangs over a utility sink?
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On 5/30/2011 7:23 AM, DerbyDad03 wrote:

Here (and probably everywhere else) condensate drains are an "indirect waste" and go through an air break to a sink or floor drain. They can't connect directly into a sewer system.
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bud-- wrote:

My bad. I thought his condensate drain went to the sink's vent pipe (mine does).
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