line set question

[94yj]

i am getting a new hvac system installed and had a few questions the unit i have now is a 4 ton straight a/c and may be going to a 4t hp and my question is will a 4ton trane system work on 3/8 and 3/4 38 ft run if that far as one of the people i talked to said i need to change from 3/8 3/4 to 3/8 7/8 is it that much of a problem staying with what i have now or is it okay to use what the size i have now on the new system all help greatly appreciated

 

[94yj]

also the one person said i may have had a smaller unit 3 ton maybe since their is a reducer on the 7/8 line down to 3/4

 

[Ohmthis]

The manufacturer will state the required line set sizing. They have done the R and D and know what is best for their equipment. Look there first. It won’t hurt to over size, but undersized will drop the efficiency of the equipment or drop the sizing (will only do 3 tons of works versus its true sized 4) of the units, or both. The last HP I put in was a 4 ton and it required a 7/8” suction line and 3/8” liquid line. We had to go about 50’ and that required we upsized the suction to 1 1/8”. Is running a new line difficult to impossible or you just want to save the money?

 

[brewchief]

Is the lineset someplace that it can't be replaced? I can't say that I've ever seen a 4 ton unit with 3/4" suction line

Sent from my XT1254 using Tapatalk

 

[justinjoyal]

Does your old system work on R410a ?

 

[samss]

One other thing to consider...
What's the condition of the suction line insulation?

 

[LS6 Tommy]

The manufacturer will state the required line set sizing. They have done the R and D and know what is best for their equipment. Look there first. It won’t hurt to over size, but undersized will drop the efficiency of the equipment or drop the sizing (will only do 3 tons of works versus its true sized 4) of the units, or both.

^^This.^^
If your old system is R22, you have to replace the line set when you replace the unit if it was not brazed.

Tommy

 

[Jackfre]

Follow the manuf recommendations, sorry, directions. You are making a substantial investment and potentially creating warranty support issues for the future by trying to retain components.
Years ago I represented a unitary equipment manuf. One day I got a call from a dealer who said, I didn't have the spec'd line set size so I put in this one. How much additional refrigerant do i need to add to make up for it? I called engineering and their answer was, "Tell him to put in the correct line set." Period! Their point was, why do we want to encourage this? I called the guy back and he hit the roof. "I will never install another piece of your equipment." I said, "good, do we understand each other?" I finally had to sell the business. I was running out of customers to fire

 

[94yj]

Is the lineset someplace that it can't be replaced? I can't say that I've ever seen a 4 ton unit with 3/4" suction line

Sent from my XT1254 using Tapatalk

yes it is run through the brick on the side of the house one company was going to run a new line st up the wall and into the attic then to inside unit and it is 3/4 but i think this house had a 3ton in it at some point in it life

 

[94yj]

Does your old system work on R410a ?

no sir r22 that is another reason i am upgrading it as the Freon would kill me if i had to replace it and the o/s unit was made in 2005 if i remember right

 

[94yj]

One other thing to consider...
What's the condition of the suction line insulation?

that i do not know if you are talking about what is inside the walls i can only say the outside has about 2ft of insulation on it

 

[94yj]

Follow the manuf recommendations, sorry, directions. You are making a substantial investment and potentially creating warranty support issues for the future by trying to retain components.
Years ago I represented a unitary equipment manuf. One day I got a call from a dealer who said, I didn't have the spec'd line set size so I put in this one. How much additional refrigerant do i need to add to make up for it? I called engineering and their answer was, "Tell him to put in the correct line set." Period! Their point was, why do we want to encourage this? I called the guy back and he hit the roof. "I will never install another piece of your equipment." I said, "good, do we understand each other?" I finally had to sell the business. I was running out of customers to fire

i am getting the whole hvac system replaced total electric and it is the trane dealer that wants to flush out the old lines and reuse it for the new system which i agree if someone wants a new system why would i want the old tubing used i have a call in to him now but being the weekend i will not hear from him till Monday i do like the trane xr 16 better even though it is higher in price as the other one wants to sell me a carrier comfort series which so far from what i have read seems more like a builder grade setup

 

[bobbyjean]

where is the reducer you mention? if at the condenser...remove it for sure,has the system ever needed refrigerant? if so....going with new line set may be best

 

[LS6 Tommy]

i am getting the whole hvac system replaced total electric and it is the trane dealer that wants to flush out the old lines and reuse it for the new system which i agree if someone wants a new system why would i want the old tubing used i have a call in to him now but being the weekend i will not hear from him till Monday i do like the trane xr 16 better even though it is higher in price as the other one wants to sell me a carrier comfort series which so far from what i have read seems more like a builder grade setup

You CANNOT reuse the old tubing if it was not brazed at every connection, but if they're absolutely positive the line set has no soldered joints and their plan is to cut it off at the ends, then reinstall on the new equipment, that would be OK. If the line set is accessible it's more cost effective to replace it rather than do a proper flush and reusing it.

Tommy

 

[94yj]

You CANNOT reuse the old tubing if it was not brazed at every connection, but if they're absolutely positive the line set has no soldered joints and their plan is to cut it off at the ends, then reinstall on the new equipment, that would be OK. If the line set is accessible it's more cost effective to replace it rather than do a proper flush and reusing it.

Tommy

it is behind a brick wall on the side of the house and only about 2 ft if that much is outside the wall and that is 3/4 and mated to a 7/8 to 3/4 reducer so it has been soldered at the condenser and the air handler at those points but unsure of what is inside the wall as it is hidden by Sheetrock

 

[Trey T]

The suction line is quite critical. 3.5ton - 4ton is where you have to step up to 7/8" suction line. The idea is that if you use 3/4" suction line instead of the recommended 7/8", you risk condensing the vapor back into liquid (or vapor supersaturated w/ liquid) causing your pump to stall when the condition is right (and it will happen). First of all, stick to the recommendation by the manufacturer. If not, you need to find a competent person to determine if an accumulator needs to be installed inline w/ the suction line prior to the compressor.

What I'm offering is more of an academic value than practical application; again, stick w/ the recommendation.