HVAC experts: question on detecting coolant leaks

[sheepfarmer]

I have new Fujitsu heat pumps put in last October so this is first season for cooling. One outside compressor and three different Halcyon inside units. On one of the wall mounted units, I thought it smelled like antifreeze yesterday when it was running on "dry" mode. It seems to happen when it pauses in blowing cold air for a while, and blows warmer air for a few minutes. The coolant is R410A. I called for service since I'd like to know if there is a small coolant leak, or if I am smelling something from it being damp in there. The gal taking the phone call didn't seem to think they had anything to detect the coolant in a gas phase. Using my not so good nose seems like this could be an exercise in frustration. Is there a detection device?

 

[RCW]

I’m no expert at all, but I know detectors are used routinely for AC leak detection....I just assume something exists in regular use for your system?!?!

 

[Poohbear]

R-410A is detectable with modern electronic leak detectors. There are also liquid detectors such as " Big Blue " or just old fashion soap bubbles. I believe based on half my life fixing HVACR equipment you are smelling something other than refrigerant as leaks do not fix themselves. Not etching in stone not a leak , especially since mini splits have been notorious for leaks on evaporator. The flare nuts big culprit also as young techs just don't make them properly or tighten correctly.
Now , IF your system is actually leaking R-410 , then you need to be aware. R-410 is an azeatrope refrigerant meaning it's a blend of refrigerants with different size molecules & per centage of total. Simply put when it leaks what's left is not true 410. Require them to recover all refrigerant then recharge with new 410.

 

[sheepfarmer]

R-410A is detectable with modern electronic leak detectors. There are also liquid detectors such as " Big Blue " or just old fashion soap bubbles. I believe based on half my life fixing HVACR equipment you are smelling something other than refrigerant as leaks do not fix themselves. Not etching in stone not a leak , especially since mini splits have been notorious for leaks on evaporator. The flare nuts big culprit also as young techs just don't make them properly or tighten correctly.
Now , IF your system is actually leaking R-410 , then you need to be aware. R-410 is an azeatrope refrigerant meaning it's a blend of refrigerants with different size molecules & per centage of total. Simply put when it leaks what's left is not true 410. Require them to recover all refrigerant then recharge with new 410.

Thank you. I turned it off when I smelled it, and then spent a lot of time trying to eliminate other things, cleaned filters, trying out the other heads, and sometimes I think I just smell damp, and sometimes something sort of sweetish. I think my nose is not the best tool.

 

[i7win7]

A/C Heating companies should have leak detectors or UV dye and UV light to locate leaks.

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www.thedrive.com

Helps to know what refrigerant is used. Think a trained technician is needed.

 

[North Idaho Wolfman]

Really simply, if it's working it's not leaking, if it was leaking enough to smell anything, then it would have quit working already.

 

[sheepfarmer]

Th

Really simply, if it's working it's not leaking, if it was leaking enough to smell anything, then it would have quit working already.

Thought that might be the eventual outcome, but wanted to know before I inhaled a bunch of R410a. Good to know! We have a hot spell coming up. Thanks, we'll see if the guys show up with a detector and prove my nose wrong. Hope so.

 

[North Idaho Wolfman]

If it is leaking I'll have egg on my face... But it won't be the first time that's happened.

 

[pendoreille]

If it is leaking I'll have egg on my face... But it won't be the first time that's happened.

I am sure I have seen you with cake on your face!

 

[sheepfarmer]

Well the service guy just left and he couldn't smell it. Said what you guys said, if it was leaking it wouldn't work. Said you cant smell the R410a even when it was boiling off. Didn't know what it was. Didn't have anything to check for coolant leak. Seemed to feel that running the kitchen unit on "dry" and turning it off when not needed at night was at fault! The funny smell occurs when it pauses to defrost or something. He couldnt tell me how it worked. My current theory is it gets mildewy in there, and I only smell it when it heats up to defrost. Recommended putting all the units on all the time on "cool". This goes against my lifestyle, I like having my bedroom windows open at night to smell the honeysuckle...and then we have 4 or 5 days at a time when we have the cool Canadian air and a high of 72.

I could smell something burning on the unit in the living room this morning, and not cooling very well. He couldn't smell it when I could. Dragged him up to unit for living room which is in attic crawl space, and he poked around. The tape was falling off the ducts so insulation not covering them. Didn't have any of the right kind of tape on his truck. I will try regular duct tape.

I will consider what he said, but I am not sure if I wasted his time or he wasted mine.

 

[Poohbear]

Well the service guy just left and he couldn't smell it. Said what you guys said, if it was leaking it wouldn't work. Said you cant smell the R410a even when it was boiling off. Didn't know what it was. Didn't have anything to check for coolant leak. Seemed to feel that running the kitchen unit on "dry" and turning it off when not needed at night was at fault! The funny smell occurs when it pauses to defrost or something. He couldnt tell me how it worked. My current theory is it gets mildewy in there, and I only smell it when it heats up to defrost. Recommended putting all the units on all the time on "cool". This goes against my lifestyle, I like having my bedroom windows open at night to smell the honeysuckle...and then we have 4 or 5 days at a time when we have the cool Canadian air and a high of 72.

I could smell something burning on the unit in the living room this morning, and not cooling very well. He couldn't smell it when I could. Dragged him up to unit for living room which is in attic crawl space, and he poked around. The tape was falling off the ducts so insulation not covering them. Didn't have any of the right kind of tape on his truck. I will try regular duct tape.

I will consider what he said, but I am not sure if I wasted his time or

Well the service guy just left and he couldn't smell it. Said what you guys said, if it was leaking it wouldn't work. Said you cant smell the R410a even when it was boiling off. Didn't know what it was. Didn't have anything to check for coolant leak. Seemed to feel that running the kitchen unit on "dry" and turning it off when not needed at night was at fault! The funny smell occurs when it pauses to defrost or something. He couldnt tell me how it worked. My current theory is it gets mildewy in there, and I only smell it when it heats up to defrost. Recommended putting all the units on all the time on "cool". This goes against my lifestyle, I like having my bedroom windows open at night to smell the honeysuckle...and then we have 4 or 5 days at a time when we have the cool Canadian air and a high of 72.

I could smell something burning on the unit in the living room this morning, and not cooling very well. He couldn't smell it when I could. Dragged him up to unit for living room which is in attic crawl space, and he poked around. The tape was falling off the ducts so insulation not covering them. Didn't have any of the right kind of tape on his truck. I will try regular duct tape.

I will consider what he said, but I am not sure if I wasted his time or he wasted mine.

Not much of a so called service tech they sent out.
Is this system a heat pump with backup auxiliary electric strip heat ? If so you might be smelling the new heat strips comeing on as it's a musty/burning smell . If thermostat set to cool those strips should not be on so you have a problem

 

[Russell King]

Please don’t use what most people call duct tape to seal duct work. It will fall off. Use a foil back tape or brush on duct sealing compound that is like thick paint. It is messy but works well and is available at most hardware stores in gallon tubs.

 

[sheepfarmer]

Not much of a so called service tech they sent out.
Is this system a heat pump with backup auxiliary electric strip heat ? If so you might be smelling the new heat strips comeing on as it's a musty/burning smell . If thermostat set to cool those strips should not be on so you have a problem

I don't think so, but I don't know for sure. I have read the owner's manual, but they also left installation manuals, so I can look for more info there. He "assured" me that any electrical problem and the whole system would shut down. I imagine Torch might have a comment about the safety of electrical systems.

 

[sheepfarmer]

Please don’t use what most people call duct tape to seal duct work. It will fall off. Use a foil back tape or brush on duct sealing compound that is like thick paint. It is messy but works well and is available at most hardware stores in gallon tubs.

Service guy said it was much more expensive tape, but it was only being used to hold paper backed insulation in place around the sheet metal ducts. The ducts look to be fine, but the insulation was not in place, so if tape is falling off after less than 6 months I am not impressed.

 

[michigander]

I have new furnace/central air 2019 using existing duct work. My cold air return in attic is constructed of plywood and wasn't insulated. The hottest day we had last summer I was up there adding 6" insulation.
We had cooling issues Sensi thermostat I messed up a setting on service guy was back and reset.

 

[ACDII]

What you smelled was the dust and other things floating around that goes right past most filters and sticks to the fins. When the fins are cold they condense the moisture in the air, which falls down into a collection tray and drains off. When the system cycles and refrigerant stops moving, the fins dry off from the warmer drier air flowing across them, releasing the odors. Not much different than in an older car that hasn't had working AC for a while and then gets repaired. They usually need a good cleaning in that case, but in yours since it was new, it was probably something during the winter. You mentioned kitchen, is this one in the kitchen? If so, that could very well be why it only smelled from that one unit. Kitchen odors can get into a lot of places you never think of.

Those of us with gas furnaces know what this is like, every winter the first start up has a distinct smell because fine dust sticks to the heat exchanger and burns off on first lighting. Ours has one of those fat 5" thick HEPA filters and we still get that dust smell. It's nothing like when using the stringy looking cheap filters, but still some dust gets through it.

 

[DaveFromMi]

I used to work in automotive HVAC. We did assembly plant audits for refrigerant leaks.
Get a black light (UV) and yellow colored work glasses. The compressor lubricating oil, some of which circulates, will be set off at the leak site by the black light.

 

[Daren Todd]

We've been fighting with some AC issues at our house. Tech came out, checked the unit and found it low on freon.

He added a die to the unit. Then ran it for a bit and checked to see if it showed up any where. Unit ran fine, then started up within 12 hours.

Outside unit was running continuously and wouldn't shut down. Air handler would come on sporadically. Sometimes for 10 seconds or so, then stay off for a few minutes, then kick on and not shut off till it reached the desired temperature.

When switched to emergency mode (running on heat strips only), it would operate fairly normally. Occasionally you would get the 10 second run rime, then off for a minute or so, the kick on and heat the house back up.

Until yesterday, when it crapped out completely. Woke up to the house being a balmy 63° air handler would kick on for 10 seconds about every 20 minutes.

Tech came and unit worked normally for him. Got home from work and tried it, and unit was back to only operating on the heat strips.

Called the company back out this morning. They tracked it down to a bad fan motor in the inside air handler which they replaced. So far so good and the unit is operating normally since the fan motor replacement.

 

[DustyRusty]

I have new Fujitsu heat pumps put in last October so this is first season for cooling. One outside compressor and three different Halcyon inside units. On one of the wall mounted units, I thought it smelled like antifreeze yesterday when it was running on "dry" mode. It seems to happen when it pauses in blowing cold air for a while, and blows warmer air for a few minutes. The coolant is R410A. I called for service since I'd like to know if there is a small coolant leak, or if I am smelling something from it being damp in there. The gal taking the phone call didn't seem to think they had anything to detect the coolant in a gas phase. Using my not so good nose seems like this could be an exercise in frustration. Is there a detection device?

R-410A is a Hydrofluorocarbon, ( HFC), made up of hydrogen, fluorine, and carbon atoms.
This video might help you determine where to look for a refrigerant leak. It isn't referred to as "coolant". Coolant is a water-based product, not a gas.

 

[xrocketengineer]

Is this another old thread revived by a new user with no useful information in the reply?