Air Conditioning - Air Conditioner Gas Manifold

Our service person has told us that our 20 year old roof-mounted a.c. unit with gas deck is showing its age and that the gas manifold is developing pinhole leaks from the heat. He said that it is OK right now but will soon need to be replaced ($$). He did say that some people use high temp epoxy to repair them but he suggested its replacement. This, of course, led to a discusssion about replacing the entire unit. (Later, this, of course, led to a discussion about reroofing... selling the house... moving to another state, etc etc etc!!). But I digress.

1. Do manifolds develop pinhole leaks over time?

2. Is the use of high temp epoxy viable/recommended in this situation?

3. Can I do this myself?

Thanks, Larbo

lost :confused: do you mean the heat exchanger in the unit??? 20 year old unit out in the weather yes get a new one for sure, better SEER and AFUE on them.

ED ;)

Copper tubing? I have seen it happen. Usually due to environmental conditions. Epoxy is a band-aid at best & not likely to hold up long. In order to effect any kind of repair, the refrigerant would have to be pumped out & federal law requires this to be done by an EPA certified person.

After re-reading the original post, I'm not clear on if this is just A/C or a gas fired heater & A/C package unit nor if the leaks are in the fuel gas or refrigerant side. Can you clarify, please?

Sorry for the lack of clarity.

This is a package unit with a natural gas heater (as opposed to a heat pump). The manifold I believe is where the gas is ignited and burned (wrong term, right?). I did not see it personally so I don't know if it is made of cast iron or aluminum, or just steel.

Thanks a lot, Larbo

Clear now, :) , thanks. I think I would have to agree with Ed on replacement. A 20 yr. old gas pack is probably a goner. They just don't last like furnaces indoors. Nearly all of the gas packs I've worked on which were over 15 yrs. old had holes in the heat exchanger. Most looked like they had been hit with a shotgun, holes everywhere. I know this is not what you wanted to hear, but...
Shop around, talk to friends, neighbors, relatives, co-workers, etc. about whom they have used for similar work & how satisfied they were.

Thanks Grady.

I'm pretty handy. Is this something that I could do? It sounds pretty "mechanical" in nature.

Larbo

If the heat exchanger has holes in it, the unit is shot (sorry, no pun intended). You probably could remove the metal skins & inspect it your self if you are so inclined but it would be best to have an experienced tech do it.

Just for the sake of (financial) clarity, when you say the "unit" is shot, do you mean the whole package unit or just the heat exchanger (combustion chamber thingee) unit?

That old I dont thing you can get parts for the furnace like the heat exchanger to keep it going. Id say all new is the only way you can go. At 20 years on it do get a new one AC and heat.

ED ;)

20 years old??? It should have been replaced years back most likely... There is a good chance you've been breathing carbon monoxide :alarm: in lighter concentrations that would give you head aches and chronic fatigue. :eek: Even if you sell it, the price of a replacement will be deducted from the selling price at a much higher price than you would have paid yourself. Get the unit replaced, you get to enjoy it, and it becomes a selling feature rather than an excuse NOT to buy the house. :)

OK, so it's got to go. Our CO detector has been very silent so that is a comfort.

Is it necessary to replace the distribution ducting, too?

The ducting in our shallow 30" "attic" is flexible insulated ducting with a vinyl skin. Some of outer skin has torn or ripped. Can it just be rewwrapped?

Thanks again! Obviously, cost is an issue and we have no plans to sell the house for at least another 10 years.

Dont know where you are. But for 10 years more here. long run on AC go for a SEER of 14 to 16 .long run on furnace go for a AFUE 90%.

ED ;)

I'm in L.A.

No it cannot be re-wrapped. It needs to be replaced. Flex is not expensive.

replacing them will also remove the dirt , dust and other contaminants. Tape unfortunately is glue on a textile backed vinyl strip.... the glue adventually lets go, especially when subjected to heat.
:wall:

Sorry for the lengthy response time. Been swamped, hence.. lost track.

Thanks for the info on the a/c and ducting replacement. You guys all seem to be in the know. Once I looked up AFUE and SEER, I got the picture that standards are much improved for efficiency. :thumbup:

Minimum SEER rating next January is 13.