[kremlin]

Hi - desperate for some help on a yearly AC leak.

Have a Bryant system, attic install from 2007 - 17 SEER condensing units model 187ANA024, 2 tons, 2 speed compressors.
R-410 A (or what they call Puron)

First year Spring startup 4yrs ago and got a low pressure switch fault - no cold air coming out. Original contractor came out, no 410a in the system. Put the system under pressure and left for a few hours - no drop in pressure. Shrugged shoulders and refilled - worked for the season.

Second year - same thing on spring startup. Had a different carrier contractor come out - looked over system. No 410a in system. Pressure tested and left overnight. No loss of pressure. Put a "sealant" of some sort in (I know, not the best idea but bit desperate). Refilled system, worked for the summer.

Last year - same thing on startup. Had a different carrier contractor come out. No 410a in system. Pressure tested. Maintained pressure again! Refilled system, replaced caps on Schraeder valves hoping maybe that had something to do with it.

Today - same thing on startup. Low pressure switch, no cold air!

Guys - HELP! 3 different bryant/carrier contractors - What are we missing? The 410a is going somewhere!

1. Could it be the winter cold causes something in the unit to contract and then it leaks?
2. Does the pressure test not include some part of the system - does that give any indication as to where the leak may be?
3. The thermostat on this unit is a Carrier and in winter gives "Emergency Heat" notifications (even though this isnt a heat pump setup) - could that have anything to do with it? (I have an identical unit installed same time with the Braynat therm that doesnt do this and no issues whatsoever w leaks)

I know leaks are hard to find but this is crazy - any suggestions would be HUGELY appreciated - so so frustrating!

Thanks in advance!

Chris (in CT)

 

[firecontrol]

You keep mentioning that they pressure tested the system. After the pressure test did they put a vacuum pump on the system and tell you that it also held vacuum?

 

[Gunslinger]

Did they measure pressure with a digital type manifold?

 

[kremlin]

Hi guys. Thanks. Sorry. Yes it held vacuum as well. The first guy used a mechanical gauge the second a digital and the third mechanical.

 

[pacnw]

While thermostat plays no part in the leak, it should not display emergency heat.

If they are pressure testing the entire system and evacuating it and it holds under both conditions, has anyone thought about vandalism?

It is possible that there is a minute leak that is not detectable.

 

[Bazooka Joe]

http://hvacsurplus.net/wp-content/uploads/2018/02/Technical-Specifications-7.pdf

If this is your unit, possibly it's leaking by the service valve stem caps ( page 7 shows the valve stems and caps ) not to be confused with the schrader caps where the gauges hook up to.

Possibly after the cooling season is over, you can have a HVAC Contractor install a stubby short pressure gauge(s) on the manifold gauge ports then have them turn in both valve stem tightly closed and reinstall the valve stem caps tightly securing them to isolated the OD unit refrigerant from the refrigerant in the lineset and indoor coil. Note what the outdoor ambient and indoor room temperatures are along with the static refrigerant pressures.

Then spring time when you get similar OD and ID temperatures compare the pressures. If there is no pressure at the pressure gauges, your leak is starting at the lineset to the indoor coil section. You can open the service valves, if there is no leak at the OD unit your gauge pressures should increase.

If there is good refrigerant pressures at the gauges, then have them open both service valves and see what happens to the pressures, if they drop noticeably, your leak is in the OD unit somewhere.

The trick is to not have any leakage at the gauges/hose assembly itself, while doing the test and have the valve stem caps tightly secured.

Certainly you want to deenergise the OD section from accidentally coming on during test mode..

Have them check the inside of the valve stem caps to see if they have a gasket inside there to help with the seating. Some do some don't. Also have them look at the valve stem itself to see if there is excessive oil formation around that area, to me that would indicate a leak by the packing gland, if that's the set up you have.

Didn't they change the drier as you seem to indicate system was bone dry at least one time?

 

[kremlin]

Thanks Bazooka so much! what a great response - will share this with the next guy to come out. No, don't believe they did anything with a dryer, will ask that as well! Crazy, just feel like ripping the whole thing out and starting over!

Any thoughts on replacing the line from the unit to the wall at the house and give that a shot before recharging - I know its a shot in the dark but man, this is getting old.

 

[Bazooka Joe]

Actually you don’t have to leave the gauges on. Less potential of leaking through the gauge assembly. Just need to know the static pressure with the gauges on, note the pressures and OD temperature. Remove gauges, then turn the valve stems in tightly, ( they should hold being the unit is 4 years old ? ) then tightly secure the valve stem caps and Schader caps. Springtime at similar OD temperatures hook up the gauges.

If your system has a crankcase heater on the compressor may want to deenergise power to OD unit in the fall, as that may throw off your pressures a tad in the OD section.

When all is said and done ( valves open ) energie OD section for 24 hours to energize crankcase heater....

Not sure what your talking about replacing the lines by wall.

If the stems don’t hold a more expensive way would be to cut the lineset ( both lines and valve stems open ) near the OD unit and install a access schrader taps in the liquid lines then crimp and braze the liquid and suction lines and add nitrogen, to each side.

 

[pecmsg]

Have a contractor inject UV DUE into the system. Clearly label it. Run for 24 hrs and begin leak checking

 

[kremlin]

Thanks everyone, much appreciated. Bazooka - the unit was installed in 2007, just started leaking 4 years ago.

I just meant replacing the lines between the OD unit and where it enters the house to eliminate that as a leak source bc it seems pretty straightforward. But thats me the non-professional thinking.

Again, u guys are great, thanks!

Not sure whether or not permitted but if anyone here has an hvac rec in southern CT NY metro area, would be appreciated. if recs not allowed, apologize, please ignore

Thx

 

[martyinlincoln]

Uv dye as mentioned will find every leak. If it's the service valves leaking in the winter it won't show until after it leaks but you'll have an answer.

 

[martyinlincoln]

Is the insulation on the line set white by chance?

 

[pecmsg]

Thanks everyone, much appreciated. Bazooka - the unit was installed in 2007, just started leaking 4 years ago.

I just meant replacing the lines between the OD unit and where it enters the house to eliminate that as a leak source bc it seems pretty straightforward. But thats me the non-professional thinking.

Again, u guys are great, thanks!

Not sure whether or not permitted but if anyone here has an hvac rec in southern CT NY metro area, would be appreciated. if recs not allowed, apologize, please ignore

Thx

We have a Contractors Locator Map.
Also Heating Help dot com is also a help.

 

[pacnw]

I just meant replacing the lines between the OD unit and where it enters the house to eliminate that as a leak source bc it seems pretty straightforward. But thats me the non-professional thinking.




Thx

This is a waste of time and money, unless they can prove it is leaking there.
Doing this will add potential leak points.

 

[garyed]

Am I understanding correctly that you've had three different contractors out & they all found virtually no gas in your system & not one of them ran a any type of leak detector to get an idea where its leaking? Pressurizing the system to check for leaks has it's place but it's got to be a leak big enough that it's not going to last a month or so or it's probably not going to tell you much. Since the system is doing the same thing for the last 4 years it's probably been nothing new but the same slow gradual leak that shows up every year. If you figure your system with a 50 ft. line set holds around 7.5 lbs or 120 oz.. Divide that by 365 days & you come up with roughly 1/3 of an ounce in a 24 hr. period. You can lose more gas than that by just taking your hoses off the system. I can't imagine it leaking out that evenly over exactly a 365 day period but even if it all leaked out twice as fast in a 6 month period it would still be hard to tell by doing a pressure test. Anyways my guess is if someone comes out with a good electronic leak detector & pressurizes your system with some refrigerant they'll find the leak. Don't be surprised if it ends up being in the indoor coil too because that would be the first place I would look.

 

[kremlin]

Gary (and all) thanks! Thats really helpful to put it in those terms and will have that done next.

no, no leaks test other than some bubble spray. along the lines and the outdoor condensor unit. thinking they just wanted to recharge and again the next year as easier for them?

 

[pecmsg]

Gary (and all) thanks! Thats really helpful to put it in those terms and will have that done next.

no, no leaks test other than some bubble spray. along the lines and the outdoor condensor unit. thinking they just wanted to recharge and again the next year as easier for them?

It is a shame your paying for sud standard work.

 

[Poodle Head Mikey]

Does your system have locking caps on the gauge access ports?

Have then tried using fluorescent dye in the system? And if not; why not?

A total charge leaks out in less than a year? Come on now.

What leak checking / leak locating methods are they using exactly?

PHM
-----------

Hi - desperate for some help on a yearly AC leak.

Have a Bryant system, attic install from 2007 - 17 SEER condensing units model 187ANA024, 2 tons, 2 speed compressors.
R-410 A (or what they call Puron)

First year Spring startup 4yrs ago and got a low pressure switch fault - no cold air coming out. Original contractor came out, no 410a in the system. Put the system under pressure and left for a few hours - no drop in pressure. Shrugged shoulders and refilled - worked for the season.

Second year - same thing on spring startup. Had a different carrier contractor come out - looked over system. No 410a in system. Pressure tested and left overnight. No loss of pressure. Put a "sealant" of some sort in (I know, not the best idea but bit desperate). Refilled system, worked for the summer.

Last year - same thing on startup. Had a different carrier contractor come out. No 410a in system. Pressure tested. Maintained pressure again! Refilled system, replaced caps on Schraeder valves hoping maybe that had something to do with it.

Today - same thing on startup. Low pressure switch, no cold air!

Guys - HELP! 3 different bryant/carrier contractors - What are we missing? The 410a is going somewhere!

1. Could it be the winter cold causes something in the unit to contract and then it leaks?
2. Does the pressure test not include some part of the system - does that give any indication as to where the leak may be?
3. The thermostat on this unit is a Carrier and in winter gives "Emergency Heat" notifications (even though this isnt a heat pump setup) - could that have anything to do with it? (I have an identical unit installed same time with the Braynat therm that doesnt do this and no issues whatsoever w leaks)

I know leaks are hard to find but this is crazy - any suggestions would be HUGELY appreciated - so so frustrating!

Thanks in advance!

Chris (in CT)