So right now your suction line (the large line) is insulated with some type of foam? And the liquid line and t'stat cable is tie wrapped to the insulation?
You're not going to accomplish anything measurable by further insulating the ref lines. If you have the sectional foam that's split along its length, and it hasn't been glued at the splits and **** joints then you should use contact cement to glue those up to prevent the suction line sweating.
If you have armaflex (the black foam rubber stuff) as normally comes installed on the suction line of a tubing package, then you shouldn't need to do anything. Even if the line is bare and you insulate it, you're still not going to see any measurable efficiency gains.
The largest gains in efficiency in the all too common ram 'n slam residential HVAC installation can be realized by installing a decently constructed and properly sized duct system.
The general terms of hvac codes from state to state are very similar, and typically limit the use of flex duct to runouts from the trunk as well as limiting the allowable length of each piece of flex to 10-12 ft. Unfortunately, way too many of the morons who inspect stuff will piss and moan about a convenience outlet that's located 2 inches too far away from a condensing unit while ignoring a "duct system" consisting of nothing more than a couple truckloads of flex half-*** taped together with the cheapest tape the installer can find within a 5 state area.
The unknowing customer gets screwed and the inspectors enable incompetent hacks to move right along to the next job where they install a similar pile of **** rather than having their license removed and their companies barred from the trade as a public service.
Thanks for taking the time to write all that. Yes, it looks like armaflex in sections running the length of the suction pipe. Now that you mention armaflex, It's been a while... I believe I used that product when redoing auto AC unit line. (then wrap with header tape and foil tape). There is no slit down the length of the foam and the **** joints are not glued/taped.
The AC was installed without a permit so no inspection. It was the prior homeowner's brother-in-law who did the install. There is no convenience receptacle outside however I don't believe one is required (nec 2017) for residential.
The reason why I say the AH is backwards or the whole system is backwards, is because the return (in the house) is way down at the opposite side of the AH and supply plenum. Everything (supply and return) is flex ducts coming off the main supply plenum and return inlet by coil. The supply flex ducts go out to the ceiling registers and then the return flex duct runs the length of the plenum and AH, wedged between the AH and the rafters, somewhat crushing the flex supply ducts against the attic floor joists. It's a disaster.
I'd like to switch over the system to same size hard-lines so I can re-use the R-5 insulation wrap around the flex ducts. I realize that will change things (potentially a lot) because hard lines will be shorter and they flow better. If I keep the AH exactly where it is, except rotate it 180-degrees, the return inlet (by coil) would be so close to the ceiling register that a 90-degree bend and maybe a 6"-8" section of duct would be all that's needed to pipe the return directly to the AH. Doing that would also accomplish two more things: First it would significantly shorten the supply ducts and second it would straighten the runs. Only thing I'm not confident with is how that would change the system. I haven't even looked at the AH board yet so not sure if it has fan speed jumpers or similar. I know changing the AH, bringing attic into the envelope, going with solid lines, etc. will make a huge difference, but don't know what that will do to sizing the system, etc. I can do hydronic heat btus, etc. but no clue about air.
I own two recovery tanks, vacuum pump, set of hoses & gauges (and several hot shot tanks in various colors... don't ask). I've done cars but never evacuated an existing system. All the cars I've done have been restorations or conversions where the old system was broken (no refrigerant in lines). I know I have more than enough of the correct refrigerant but not sure I'd be comfortable trying to DIY unless I had someone with a clue helping/teaching me.
With the way the AH is laid out in the attic, I'm not sure there is a reasonable way to bring the return from the register to the AH with a hard line. There is already a hard bend 180 where the return meets the AH and it's wedged in so tight between the small triangle that is the roof rafters, side of AH and attic floor joists. I can try and grab some pictures next time I'm up there. Would love some suggestions on how to deal with it.
Thanks.
