Heat Pump refrigerant lines
I live on the second floor of a three story condo buildingin Fairfax, VA. Its about 20 feet from my evaporator/indoor-coil/air-handler Unit to the chase which runs another 20 feet down to the outside condensing Unit. I had a contract to replace my broken 10 Seer Unit but they couldn't use the existing refrigerant tubing (5/16 rather than the 3/8 required. They were going to run all new refrigerant and return tubes but couldn't. They tried to snake down through the existing chase so as to thread a new 3/8 refrigerant line but got stuck between between floors.
Although my downstairs neighbor will allow me access to the chase from her unit, the vendor wouldn't go that route because of liability issues.
I have found a contractor that is willing to attempt to run a new refrigerant line by using my neighbors unit for access but I have some questions concerning the 20 foot run above my ceiling.
Can the 3/8 tubing lie free on the ceiling studs and/or insulation with no clamping except possibly at the ends. The things I'm worried about are 1) is the heat from the refrigerant tube capable of starting a fire 2) are there building codes requiring clamping and 3) vibration problems or potential damage to tubing.
I've been told the free run of refrigerant tubing is not a problem by the contractor wiiling to do the work (and sell me a new heat pump), its not a problem. I'm looking for a second opinion.
I agree with #1. not enough heat to cause any problem. there shouldnt
be any vibration issues..
60 here in Portland,OR
There is a issue with refrigerant tubing that touches wood or other bldg. materials. Transmission of noise associated with the refer traveling through the lines and vibration.
Mfg.'s don't want the tubing touching floor joist,ceiling joist etc.,your neighbor might not like it either.
If tubing doesn't touch anything, is there any noise problem? Can the 3/8 tubing be insulated like the return line and would it take care of any noise problem? The current tubing has the 5/16 tubing taped to the insulation of the return line.
Originally Posted by captube
Last edited by jrogers41; 06-10-2008 at 12:54 AM.
Reason: forgot possibility insulating of 3/8 tubing
You could insulate the new 3/8 line, but if they are already having issues pulling the liquid line due to space there may not be enough room for the insulation.
Also, the problem that they are running into between floors may be due to a fire stop. Generally, individual units and floors are seperated by fire rated structures and running piping through this fire rated structure without proper sealing would result in breaking fire codes. This would allow flames to spread through the building much quicker and could endanger lives.
If this is a fire stop try and make sure that your contractor seals any penetrations they make with approved materials.
Too late now, but next time, get other quotes. There are I believe to manufacturers that still use 5/16" line on some of their units.
You may want to pass that along to your neighbors.
Your going to want the 3/8" line insulated/wrapped to help prevent noise.
I'd want it fastened to something.
The original contract was voided. I have no existing contract, only a commitment to install the line if feasible along with an installation of any unit I chose. What manufacturers/units still work with 5/16 and would they still be warranteed to at least an efficiency of 13 Seer. I have had contractors who would use the 5/16 tube but want a waiver and this is using R22. I would like to move up to R410A and I been told that requires 3/8 because of the increase in pressure.
Rheem/Ruud. Someone else too, but I forget who.
R410A does not take larger lines. The brands you have been quoted probably use 3/8 for R22 units in the same size.
If it's R410A refrigerant, I don't think so. For my system, the hottest the R410A gets is about 125°F - see chart below:
Originally Posted by jrogers41
This is about the same temperature as a hot water pipe gets to.
I don't know if the comment is different if it's an R22 system.
If you he used the existing lines what kind of problems would happen
If they are the right size nothing.
If they are too small, you lose capacity.
Well, could make a 2 ton 14 SEER operate about the same as a 1.75 ton 11 SEER.