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-   -   A/c Line sets (http://www.diychatroom.com/f17/c-line-sets-116128/)

coconut sunrise 09-03-2011 09:32 PM

A/c Line sets
 
I am installing two 4 ton A/c units on the roof of my all concrete flat roof
what would be a good product to run the line set thru ? was considering using a 4 inch pvc plastic pipe for each unit, that way I should be able to replace line set rather easy should i ever have the need too. what is the industry standard ? if i avoid 90 degree elbows and only use two 45 degree
for gentle turns do you think I could pull line set 45 feet ? if the line set was all wraped and lubricated and complete pulling all at once ?

Thanks in advance

Coconut sunrise

Master of Cold 09-03-2011 11:07 PM

How long are these linesets (on the roof section), and where do they go down?

Doc Holliday 09-03-2011 11:35 PM

Quote:

Originally Posted by coconut sunrise (Post 720703)
I am installing two 4 ton A/c units on the roof of my all concrete flat roof
what would be a good product to run the line set thru ? was considering using a 4 inch pvc plastic pipe for each unit, that way I should be able to replace line set rather easy should i ever have the need too. what is the industry standard ? if i avoid 90 degree elbows and only use two 45 degree
for gentle turns do you think I could pull line set 45 feet ? if the line set was all wraped and lubricated and complete pulling all at once ?

Thanks in advance

Coconut sunrise

Do not run it through anything.

coconut sunrise 09-04-2011 07:14 AM

Thanks DOC
however I dont want to have the Concrete poured around the line set
where it goes thru the roof. I want to be able to pull a new line set in the event that I ever need to along with insuring no water leaks,

Master
these line sets will only go thru 8.5 inches of concrete roof to the A/c unit
before that they will run in a drop ceiling one will be 45 foot run and the other one will be about 20 feet

this drop ceiling is drywall so wanted to engineer a race that i could easily replace line set without tearing out drywall to replace line set should i ever need to

coconut

Master of Cold 09-04-2011 09:16 AM

I think the first step would be to see what local codes apply in this situation. I don't think I have seen pvc used in a roof penetration. Its usually a gooseneck sheetmetal fitting that has been flashed on the bottom, and then tar or foam into the top. I think spray foam deteriorates with the sun light and is not good at stopping water intrusion.

Don't take my word as gospel here. Anyone that knows me knows that I am mysteriously absent during installs.I will tear 300 black wires out of a unit and replace them all, but installation isn't for me :).

NoHax 09-04-2011 09:26 AM

1 Attachment(s)
How about this roof jack device?

MODEL No. 353 Roof Jack for Refrigerant Lines


No affiliation with company.

Master of Cold 09-04-2011 09:29 AM

Yes..that's a "gooseneck" around here

Doc Holliday 09-04-2011 09:35 AM

Called a "dog house" around here.

Master of Cold 09-04-2011 10:22 AM

I thought "doghouse" was the cover over the ductwork of a residential package unit....

Doc Holliday 09-04-2011 02:48 PM

Quote:

Originally Posted by Master of Cold (Post 720906)
I thought "doghouse" was the cover over the ductwork of a residential package unit....


My fault, I thought that's what was pictured. That's just a regular roof jack.

coconut sunrise 09-04-2011 02:52 PM

here in the salt water air I think it would be gone in 2-3 years Pvc pipe with stucco would last longer IMHO

Coconut

Doc Holliday 09-04-2011 03:39 PM

Quote:

Originally Posted by coconut sunrise (Post 720809)
Thanks DOC
however I dont want to have the Concrete poured around the line set
where it goes thru the roof. I want to be able to pull a new line set in the event that I ever need to along with insuring no water leaks,

Master
these line sets will only go thru 8.5 inches of concrete roof to the A/c unit
before that they will run in a drop ceiling one will be 45 foot run and the other one will be about 20 feet

this drop ceiling is drywall so wanted to engineer a race that i could easily replace line set without tearing out drywall to replace line set should i ever need to

coconut

Roof jacks are very common for roof top units. In fact it is code to use one for line sets around here as you can not just leave a gaping hole through the roof. Go with that.

Master of Cold 09-04-2011 08:05 PM

If you seal the jack on the inside and paint the outside with an elastomeric coating, corrosion shouldn't be a problem.

COLDIRON 09-05-2011 06:39 AM

Use the 4" PVC if you want to just put a 45deg ell on the vertical after you run all your line sets, thermo, power,etc. before the final hookups then fill in the end of the 45 with some type of sunlight resistance foam or equal.

PS: Use a roof vent boot stack to seal the roof and push the PVC through the rubber just like you would in a regular roof.

REP 09-06-2011 03:26 PM

I agree with COLDIRON.
Even cement roofs normally have common plumbing vents run through them.Those would be common 2",3",or 4" pvc.
Just call a local roofing wholesaler for the fitting.Should be fairly simple.


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