FAQs about proper installation of insulation on refrigerant piping.

This article series explains why refrigerant piping insulation needed and discusses the types of insulation are used on refrigerant tubing sytsems & where can the insulation be purchased and how it should be installed.

Q&A on Proper Method for Installing Insulation on Air Conditioning & Heat Pump Refrigeration Lines & Condensate Drains

These questions & answers about refrigerant piping insulation were posted originally

at REFRIGERANT PIPING INSULATION - so please be sure to also check out the refrigerant piping insulation specifications and snafus described there.

Is the foam insulation on the AC lines supposed to continue into the foundation ?

Is the foam insulation on the AC lines supposed to continue into the foundation or just on the exterior of the home? Thank you - ROD

Reply by (mod) - do not run bare refrigerant piping through concete (nor underground)

Rod,

You do not want to run refrigerant piping bare through concrete. Corrosion and damage and leaks are serious risks.

Here's an example code citation from the UMC as adopted in Utah:

1107.2.1 Piping in Concrete Floors

Refrigerant piping installed in concrete floors shall be encased in pipe ducts.

The piping shall be isolated and supported to prevent damaging vibration, stress and corrosion.

 

OK to run coolant lines inside of a laundry chute?

Can air conditioner coolant line be run down a clothes shoot? - On 2018-05-25 by Elsene -

Reply by (mod) - NO; also, possible problems with very tall vertical refrigerant piping runs

Can, physically, sure. Within very specific total vertical height limits and refrigerant pipe diameters that need to be reviewed with the manufacturer of the air conditioning equipment.

Good idea? No.

Dumping clothes down a laundry chute risks damaging lines, causing a leak, or knocking off insulation. If there is room to route the refrigerant lines through the clothete I'd expect the installing contractor to make sure the piping is protected from damage, perhaps enclosing it in a suitable conduit.

There are vertical height limits for refrigerant piping. That's because vertical refrigerant piping can run into limits on its ability to move droplets

Source: Air Conditioning Clinic - REFRIGERANT PIPING [PDF], Trane, Belgium, retrieved 2018/05/25, original source: http://www.tranebelgium.com/files/book-doc/20/en/20.aqerykdx.pdf
A copy can also be found at InspectApedia.com at

Excerpt: The minimum velocity required to carry oil droplets up a vertical riser is higher for a larger diameter pipe than it is for a smaller diameter pipe.

This is due to the velocity profile of the refrigerant flowing inside the pipe.

In a smaller diameter pipe, the higher-velocity refrigerant is closer to the inner walls of the pipe than it is in a larger-diameter pipe.

For instance, while the minimum allowable velocity in a 2 1/8 in. (54 mm)-diameter suction riser is approximately 1,000 fpm (5 m/s), the minimum velocity in a 1 1/8 in. (28 mm)-diameter riser is only 700 fpm (3.6 m/s).

While the old minimum-velocity limits were easy to remember, they may lead to the unnecessary use of double suction risers.

The recommended maximum-velocity limit of 4,000 fpm (20 m/s) has not changed. A higher velocity inside the suction line may cause objectionable noise for those nearby.

 

On 2018-05-03 by Kumar - why do we insulate the suction line?

Why we providing insulation in low pressure side

Reply by (mod)

To stop condensation and related water damage in the building. Also insulating the line increases the system efficiency, thus reducing energy costs.

On 2017-04-26 by Lisa - shade lines on plaster walls near refrigerant tubing

I have solid plaster walls, split system Fujitsu airconditioner cooling/heater system installed 1.5 years ago.

Now seeing 'shade' line on inside plaster wall from airconditioner down to floor level. The outer part of the airconditioner is installed on the solid brick wall directly behind the internal airconditioner section (second level of house).

This could be condensation/moisture and will your article above may be the answer. We are calling the installers back to investigate and will ask questions from your article. Thank you for publishing this information.

On 2017-04-26 by (mod) - if shade lines mean moisture, investigate further

Lisa:

Refrigerant piping run in an insulated wall cavity ought to be insulated not just by its own insulating jacket but also by the wall insulation itself.

If those were omitted or if there were air or water leaks into the wall would I expect a problem along the refrigerant line piping route that would show up as mold or moisture stains.

I have also found wall and ceiling cavity leaks along the route of improperly-sloped or otherwise leaky condensate disposal lines from the wall-mounted split system indoor unit whose condensate has to drain to the outdoors.

I'd like to see photos of the staining you're seeing - use the page top or bottom CONTACT link;

Also I'd consider modest invasive inspection (cutting a small opening say 2x4" to inspect for wetness or mold or leaks in the most-suspect areas along the stain; Sometimes a moisture meter or thermography can help find leaks too but those are not foolproof since if used at a time when the wet area has dried they'll not see a thing.

If you have photos of the system being installed those can help pinpoint the actual routing and insulation on refrigerant piping in walls, and they can help show if the condensate disposal drain runs in the same area and whether or not it is sloped properly. A drywall screw or nail puncturing a refrigerant line will be discovered right away but a puncture of a condensate drain may not show up until later.

 

On 2016-08-04 by King - is it ok to only insulate 1 of the 2 refrigerant lines?

Insulating one line is it bad

Reply by (mod) -

Best practice is to insulate both refrigerant lines, though for different reasons, and practices vary by climate and local practice.

Insulation on the suction line (the larger diameter pipe) reduces the risk of condensation and water damage inside the building

Insulation on the high pressure line on a cooling-only system is sometimes omitted by some installers as that line is normally warm - not a condensation problem. But in a heat pump system insulating both lines makes more sense as refrigerant flow swaps direction dependin on whether you're in cooling or heating mode.

 

On 2016-06-19 by Eshanya - why is there no insulation between the suction line and the charging valve

Why Doesn't insulate Suction line Between compressor & Charging Valve

On 2016-06-19 by (mod) -

The line between compressor and charging valve in a cooling system contains warm liquid refrigerant; it doesn't present a problem with condensation.

I think installers thus consider this energy improvement optional

On 2015-06-02 by N - need parts for Evcon 2T Evaporator Coil

Hi there -silly question... I have an Evcon 2T evap (A coil) that has a 1/2 tube with what looks like a 13/16" female connection.

I beleive the adapter to allow the flowrator stub is missing. I need to adapt from the coil fitting to a 3/8 flare or I need a male fitting with a 3/8 stubout so I can braze the flowrator assy in... Surely this must be more common that I'm finding... The evap is spec'd fine for replacement aside from the goofy fitting...

I would cut it off but it appears to be made for the flowrator insert forward of the regulator to the cap tubing/circuits....
Thank you,

N

Andrew.

On 2015-06-02 by (mod) -

N. The question is certainly not silly. It's those guys who bully their way through who are IMO silly.

My NY HVAC supplier used to keep a smart guy (Dave Ferris) on payroll (he retired): it was wonderful, I'd just give Dave a call and over the phone he could usually help me out. Your supplier might be that good. If so give that a shot. I'd do that before risking coil damage by cutting off or brazing on a fitting that maybe I didn't need. Sorry I don't know more.

Use the Add Image button at the bottom of this page to submit some photos for approval & view.

I'd give the supplier / manufacturer a call:

The Evcon Evaporator A coil is available from
Johnson Controls Unitary Products
5005 York Drive
Norman, OK 73069

web: johnstonesupply.com

You'll see several contact numbers depending on where you live.

On 2015-05-16 by Gopal Ramakrishnan - some of my split tubing insulation isn't re-sticking

During installation of insulation on refrigerant piping for air conditioners, I used the split insulation.

I did not know there was plastic on both sides. Therefore I removed the plastic only from one side before sticking together. It seems to be stuck well but will it be ok in the long run ?

Or should I open and and remove the plastic from the other side and join again ? It is sticking quite well and in 4 places I have tape around the insulation also. Thanks for your help.

On 2015-05-18 by (mod) -

If you can not easily separate the insulation to re-stick it properly you may be able to improve the installation by adding a suitable weatherproof tape over the seams.

On 2014-12-11 by Jameel Pasha - sending your refrigerant insulation article to our plant manager

I have visited a plant having uninsulated refrigerant piping .This topic do discuss the application but i would like to forward the plant manager the document showing losses due to uninsulated piping.
Kindly for forward it on my e-mail pashatherm@yahoo.com
JAMEEL PASHA

On 2014-12-11 by (mod) - printed copy of articles at InspectApedia

Jameel

You are welcome to either make a printed copy of articles at InspectApedia that you can give to the plant manager, or you can simply give a copy of the web link to this page

https://inspectapedia.com/aircond/Refrigerant_Insulation.php

On 2014-09-09 by NYCitizen - Refrigerant tubing insulation comes in standard sizes

Oh, it looks bad.
I checked plumbing supplies in my area, nothing seems to fit right.

There is a large amount of caulking used and it is overall not done neatly. I have to come up with something to cover it all (pipe and caulk) and provide some sort of drip edge above the opening.

There are some products that would enclose the wall opening properly and hopefully still look good. I came across some wall sleeves that seems to be applicable even post-installation, and also some flat wall covers and escutcheons that might provide decent cover and divert the water from the opening (diversitech is selling them in bulk, I got to see if I can find the small amounts I need).
Thank you

On 2014-09-12 by (mod)

NYC

Refrigerant tubing insulation comes in standard sizes to fit standard tubing or piping sizes. It's bound to be available. But if the insulation is slightly oversized that ought not matter.

I agree that better treatment of the point of penetration of refrigerant tubing through walls is a smart idea.

On 2014-05-02 by NYCitizen - decorative covers & escutcheons for refrigerant piping outside of a home - at an entry

Are there any decorative covers/escutcheons to use for the outside entrance point of the piping into a house? Contractor used black caulking of some sort and it is very ugly.
Any suggestions?

On 2014-05-02 by (mod) -

Sounds ugly NYC.

Measure the diameter that the escrutcheon has to fit around - the diameter of the pipe.

Then you'll probably have to end up with a stainless steel (or paintable plastic) add-on escrutcheon of the sort used around pipes indoors. These are hinged so that they can be opened, then latched around the pipe.

You'll want a weather resistant material so don't buy chromed steel. It'll rust.

On 2012-10-25 1 by Carol - refrigerant pipe insulation goam was painted, now cracked and shedding - how to repair?

It appears the foam cover has been painted but it's cracking and there are small chunks missing from the foam cover. There are several lines.

What the best way to repair this? Tape over all of it; remove the foam and replace it with new covers (if so what do you recommend); coat it with some kind of coating? ETC.

On 2012-11-08 by Anonymous - Snap around foam insulation for refrigerant pipes

Carol,
Snap around foam insulation in sizes for refrigerant piping is widely available, eg at home depot. Loews, HVAC suppliers, and is inexpensive. Just replace that which is damaged, deteriorated, or incomplete. Take note of our advice at REFRIGERANT PIPING INSULATION about how to attach without over tightening

On 2012-09-02 1 by Batt Insulation - safe to run refrigerant lines together in a stud bay?

I have a normal house with the unit outside, and the other in the attic.

The piping runs from my attic, through an outside wall, to outdoors. 1 line is insulated, the other is not. they are tied together in the same stud bay.

My question is can i have fiberglass insulation batts in that bay? The non insulated line felt pretty hot, so I didnt know if it was safe to use the fiberglass insulation in that bay. Let me know. Thanks

On 2012-09-06 by (mod) -

Andrew,
If the leak you describe was condensation on the outside of a cold refrigerant line, re-insulating the line makes sense and should stop the problem. If you are still seeing leakage, your next step is to find and fix the source.

On 2012-08-06 by derek terveer - recommended insulation of the liquid and vapor lines for a HP that is primarily used for heating in a cold-weather area (MN).

What about recommended insulation of the liquid and vapor lines for a HP that is primarily used for heating in a cold-weather area (MN). The large line was insulated at install-time (and I added another layer, and a loose fitting, flexible aluminum dryer hose over that for protection against the sun and environment.

But, should the small line also be insulated? 99% of the run-time on this unit, it is heating.

On 2012-08-08 by (mod) -

Derek

Interesting question. Considering that at times the heat pump is trying to send heat from outside into the building, it would make perfect sense to insulate all of the refrigerant piping. In my OPINION I would definitely do that.

But, though I've worked in Minnesota, I'm not a MN super-cold weather (we've seen -20 in Two Harbors) HP expert - I'd also ask the local HVAC techs.

On 2012-08-08 by derek terveer - I insulate the suction line only

I tested which lines the HP uses for heating and cooling and in both modes the vapor line is used for sending heat into the building (heating mode) and cool into the building (cooling mode)

So, that works out nicely - I insulated the vapor line only. I made some calculations based on 1 meter of uninsulated and poorly insulated copper tubing (3/4" in my case) and it worked out to 51 W/m for uninsulated and I guesstimated 10W/m for the partially insulated pipe.

After insulating, I estimated that I had brought that value down to 1.5W/m.

The savings was on the order of 15 seconds of running of my furnace, per hour.

That was around 0.16% (not 16%, but point one six percent) of my furnace capacity (at -7C). So, given the savings, at least percentage-wise, I'm not surprised that my local contractor didn't bother insulating more.

...

Continue reading at REFRIGERANT PIPING INSULATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• REFRIGERANT GASES & PIPING - home
• REFRIGERANT PIPING INSTALLATION
• REFRIGERANT PIPING INSULATION

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REFRIGERANT PIPING INSULATION FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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