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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22515
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Im having trouble with a brand new system . Installed new

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I'm having trouble with a brand new system . Installed new coil and new condenser (2 ton HEIL 410-A) last year. The line set was not replaced. This year the coil froze up with a big icicle. The filter was dirty but not extremely and that was replaced. I had a service call and they diagnosed low on freon (missing a little over a pound of freon) and that the joints were not braised and are soft soldered. I sprayed the joints and could not find a leak at the joints. The system was still working at this time but I decided to have it filled to eliminate further problems. I had someone fill it with 3/4 pd but it looked like he was having trouble with the gauges and he did not use a scale but told me he filled it with 3/4pd of freon. About 24 hours later the system is now blowing hot air. The same guy came out to check and the gauges are not making sense...reading 28 degrees...and he thinks it is freezing somewhere but last time it froze I still had cold air. Why the sudden change air temperature output. i dont know if I have a leak, moisture or if I'm talking to the wrong people. The guy that installed the condenser and coil did not evacuate the line with the tank but just let what freon was left out. We initially changed the condenser and coil (30 years old) thinking that was leaking since I had to fill it 2 times. Please help.


The system was never prepared correctly. You could have a leak, or you could have blockage in the freon system due to contaminates.

R410A is VERY picky about how it is set up. The system must be vacuumed 3 times...but that is after the existing lineset is flushed and cleaned thoroughly to remove traces of old oil and refrigerant. They do not mix well at all.

R410a must be vacuumed and the system totally free of air, moisture oil before releasing the refrigerant. The oil in R410a will absorb moisture instantly and be ruined.

Whether you have leaks or will never be able to proceed in a corredt fashion until the unit is reclaimed, vacuumed and purged with nitrogen.

At the time it is pressurized with nitrogen is the time to leak test.

After all is confirmed tight with no leaks you can then charge with NEW R410a.

I apologize if this is not what you were planning on....but it is the right way to proceed.


Customer: replied 3 years ago.

a the time of install the guy said he checked the line with putting nitrogen in. does that still mean that its still not clean???

and why the sudden change with putting more freon in??

i really appreciate this there is just too many bad tech out there

If you reused the old lines, just pressure testing with nitrogen is insufficient.

I am at a disadvantage since I do not know what process was or was not used...but I can tell you that it is absolutely critical with R410a that the system be totally free of air, moisture, previous oil and/or refrigerant.

I have seen many techs chase their tail for years on a ac call when thet should have just reclaimed, cleaned, leak checked and recharged.

With your description you have either:

A serious leak, which should be evident with an electronic leak detector. have blockage of the system resulting in a low suction pressure.

You see I recommend starting at the beginning to make sure no preexisting issues come back to haunt you.

You can clean, leak check and balnce charge all in one service thus eliminating all those options as supect.


Customer: replied 3 years ago.

could the new coil or condenser jeopardized already from that


That is why compressor failures were so prevalent in R410A equipment.

They were prone to failure when the proper procedure was not followed at install. Everyone who installed R22 systems thought they could use the same protocol on installs. But the failure rate of new R410 systems was directly tied to incorrect installation procedures.

The oil used in R410 is 100 times more hygroscopic than R22 oil.

This means if exposed to air/moisture it absorbs 100 times what R22 would.

This is turn gells the oil...affects the compressor...and leads to burnout

Customer: replied 3 years ago.

i'll tip you @the end.

if this procedure gets done right (start from beginning evacuate etc and clean) should I I still worry about the soft soldered joints and leaking? I just found out that it is now shooting cold air again. When you say burnt out compressor does that mean complete failure or will it work again.

I mean complete failure.

I do not like soft solder joints ESPECIALLY with R410a.

The pressure of 410a is twice that of R22. An R22 unit could run 265psi on a hot day...and 410a over 500 psi. Now I am not saying you need to is just my opinion that they should not have been reused..especially with sof solder and 410 is just begging for leaks.

Plus I never approved of soft solder because of flux in the system...vibration leaks etc..

My company only uses braze rod. Braze melts at 1400 degrees F compared to 400 f for solder. IF.....the system had a blockage..or was could be tripping off on high pressure or low pressure safety. Once recovered, it will start up again.

I recommend a new pair of eyes with proper equipment that works.
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Customer: replied 3 years ago.

Since, we had the line leak tested for 24 hours with no leaks. Once reconnected with now braised joints it was again leak tested as a whole. Result--no leaks. Then system was vacuumed for 4 hours, recharged with new freon. The gauge continues to read too low on the low side. The system is working right now with cool air showing 55 degrees or less out of the vents but what is causing the low pressure readings.