LS6 Tommy
Well-known member
Congrats! Keep in mind, that only allows you to work on motor vehicle A/C systems. You still can't buy refrigerants at an HVAC supply house.
Tommy
DIY A/C Refill/Recharge
- Thread starter bmarshall1
- Start date
Congrats! Keep in mind, that only allows you to work on motor vehicle A/C systems. You still can't buy refrigerants at an HVAC supply house.
Tommy
LS6 Tommy
Well-known member
Guys, I will keep saying this every time I read advice to see if a unit holds a vacuum before charging-
YOU CANNOT USE VACUUM TO PERFORM A LEAK CHECK
Tommy
YOU CANNOT USE VACUUM TO PERFORM A LEAK CHECK
Tommy
bczygan
Well-known member
In 40 years nobody as ever asked to see that certificate
Still useful to have the knowledge.
You never needed it to buy refrigerant?
Bill
bczygan
Well-known member
Agree on the knowledge gain.
Yes, purchased refrigerant in quantity........nobody has ever asked for it.
Joe Blow can buy small cans 134a at Menards.
In the automotive AC vacuum check is the standard practice. We seem to mixing Mobile AC and HVAC.
Rusty Fords
Well-known member
First off they should be treating all customers as family but keeping in mind you have to make a living. Replacing units was the last thing I wanted to do it creates a lot of work.
The refrigerant piping is brazed with silver solder not plumbing soft solder I have had good success with patching coils, the tech needs to be willing to do it instead of replacing units. I have always used a micron gauge sure helps with continued leakers. Never want a tech out that gets paid commission as well!!
I use Nitrogen with soap bubbles to locate leaks start around 25-30 psi moving up about 25 psi each time I don't find one. In 26 years never seen a Nitrogen leak detector. Usually leave about 5psi in system of refrigerant as a tracer to locate with a Refrigerant leak detector if I can't locate with soap bubbles.
Great job
Might add a lot of capacitors blow on first hot day of the spring and also have had a lot that one fuse has blown in a disconnect ( always replace both when this happens with time delay fuses)
Some of these require new POE oil which cleans all the old refrigerant out real well and some types of seal swell from the old mineral oil so when the new POE oil cleans the mineral out the seals shrink causing more leaks. ( Most all you new compressors come with POE oil any more as well)
I have never been asked other then when going to a new supply house.
The refrigerant piping is brazed with silver solder not plumbing soft solder I have had good success with patching coils, the tech needs to be willing to do it instead of replacing units. I have always used a micron gauge sure helps with continued leakers. Never want a tech out that gets paid commission as well!!
I use Nitrogen with soap bubbles to locate leaks start around 25-30 psi moving up about 25 psi each time I don't find one. In 26 years never seen a Nitrogen leak detector. Usually leave about 5psi in system of refrigerant as a tracer to locate with a Refrigerant leak detector if I can't locate with soap bubbles.
Great job
Might add a lot of capacitors blow on first hot day of the spring and also have had a lot that one fuse has blown in a disconnect ( always replace both when this happens with time delay fuses)
Some of these require new POE oil which cleans all the old refrigerant out real well and some types of seal swell from the old mineral oil so when the new POE oil cleans the mineral out the seals shrink causing more leaks. ( Most all you new compressors come with POE oil any more as well)
I have never been asked other then when going to a new supply house.
firebirdparts
Well-known member
Let me add another idea, in case you're totally unfamiliar with the control systems.
With an air conditioner, you need 2 fans and a compressor to come on. There are three relays that do this. The control wiring is 24 volts AC, which is provided by a little transformer usually mounted with the indoor fan, but I suppose there could be variations on that, because it doesn't really matter where it's mounted. The relay that pulls in the compressor is a great big double pole thing that cuts off both legs. it might have open air contacts. One failure I have seen on this is a bug got between the contacts and met with an unfortunate end. Luckily I could see him. The fans are turned on by two little teeny cheap relays. The thermostat simply connects these three things to each other and to the transformer, but in this day and age these units probably have a "brain board" in there that makes the indoor fan run for 30 seconds extra. If that board goes bad, you might ignore that problem simply bypassing the indoor fan relay. In fact, I have to admit I bypassed it in my own house about 2 years ago, and I'm not even thinking about fixing it. But in any case, you need to make sure all these came on.
I don't know if you actually have a heat pump there, but there are 2 controls that convert an air conditioner to a heat pump:
1. a 4-way valve that allows you to put the flow in "reverse"
2. The ability to defrost.
With an air conditioner, you need 2 fans and a compressor to come on. There are three relays that do this. The control wiring is 24 volts AC, which is provided by a little transformer usually mounted with the indoor fan, but I suppose there could be variations on that, because it doesn't really matter where it's mounted. The relay that pulls in the compressor is a great big double pole thing that cuts off both legs. it might have open air contacts. One failure I have seen on this is a bug got between the contacts and met with an unfortunate end. Luckily I could see him. The fans are turned on by two little teeny cheap relays. The thermostat simply connects these three things to each other and to the transformer, but in this day and age these units probably have a "brain board" in there that makes the indoor fan run for 30 seconds extra. If that board goes bad, you might ignore that problem simply bypassing the indoor fan relay. In fact, I have to admit I bypassed it in my own house about 2 years ago, and I'm not even thinking about fixing it. But in any case, you need to make sure all these came on.
I don't know if you actually have a heat pump there, but there are 2 controls that convert an air conditioner to a heat pump:
1. a 4-way valve that allows you to put the flow in "reverse"
2. The ability to defrost.
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Rustypigeon
Well-known member
You can take all the 608 tests at once and get a 608 Universal certificate. 608 Universal has to be at a proctored location, but it is not difficult. I did mine at a local refrigeration distributor. I used free self study materials online and the total for all 4 tests was about $65.
theoldwizard1
Well-known member
Congratulations !
You can make a lot of money in your back yard with just a few tools.
bczygan
Well-known member
Decided to add the EPA Section 608 Type I Certification by taking the 2 25 question tests.
Bill
Bill
Jim greengo
Well-known member
What he said.
pizza
Well-known member
Decided to add the EPA Section 608 Type I Certification by taking the 2 25 question tests.
Bill
photoshop your name on there and get you some R22
LS6 Tommy
Well-known member
Decided to add the EPA Section 608 Type I Certification by taking the 2 25 question tests.
Bill
Now you're cooking with gas. Keep studying and get your Universal.
Tommy
bczygan
Well-known member
Now you're cooking with gas. Keep studying and get your Universal.
Tommy
I just might!!!
Bill
OP
bmarshall1
Well-known member
- Joined
- Dec 5, 2015
- Messages
- 54
Hey Guys, sorry to go dark but I had a few other items needing attention, so...... here's the results. Living in SW FL there are a lot of sketchy contractors and I have had my share of them. I was not looking to dismiss anyone's trade or knowledge, but I can see now a few people on here have taken it upon themselves and were successful. I did not want one of the $29 "Check Up" guys to come out and upsell me (they recently busted a very large company for fraud in just this manner, predatory lending etc...).
I was able to get a referral for a 'good old boy' and that's what I was looking for. I paid $85 x 2 for the service call and am always willing to pay for performance and value.
One unit was almost empty and had a leak from the tube coming out of the compressor, it also had a bad time blower time delay circuit board. He bypassed the delay with a relay and brazed in a new section of copper. The second unit had about 2/3 charge and he could find no leak, so he charged it and tried again after a little searching he discovered when the high and low pressure lines were brazed on they did not protect the schrader valves against the heat and they were the leak (they also had no o rings in the caps either). He then changed out a buzzing set of contacts and talked me through things as he went. Total bill was $529, which was under my personal estimate.
But wait, there's more. He told me that on my home unit the power wires were 10 GA and should have been 8 GA and that could be the reason for the lights dimming when it powers up.
And lastly, his bill seemed too good to be true so I recalculated the numbers and he shortchanged himself 1 hour labor and $90 in R22. I called him and told him I will be sending a check for the difference.
Recharging an A/C my be a somewhat straightforward process, but his experience allowed him to know where the leaks would be, braze a lines then and there (tools & supplies on-hand), the proper way to Evac, proper charge(s), common issues with different brands, R22 compatibility (He used 407 on the empty one) etc... it was all well worth the price,
So there is the end of My Air Conditioning Story.
Up Next - who wants to join me for a Septic Tank thread? =)
I was able to get a referral for a 'good old boy' and that's what I was looking for. I paid $85 x 2 for the service call and am always willing to pay for performance and value.
One unit was almost empty and had a leak from the tube coming out of the compressor, it also had a bad time blower time delay circuit board. He bypassed the delay with a relay and brazed in a new section of copper. The second unit had about 2/3 charge and he could find no leak, so he charged it and tried again after a little searching he discovered when the high and low pressure lines were brazed on they did not protect the schrader valves against the heat and they were the leak (they also had no o rings in the caps either). He then changed out a buzzing set of contacts and talked me through things as he went. Total bill was $529, which was under my personal estimate.
But wait, there's more. He told me that on my home unit the power wires were 10 GA and should have been 8 GA and that could be the reason for the lights dimming when it powers up.
And lastly, his bill seemed too good to be true so I recalculated the numbers and he shortchanged himself 1 hour labor and $90 in R22. I called him and told him I will be sending a check for the difference.
Recharging an A/C my be a somewhat straightforward process, but his experience allowed him to know where the leaks would be, braze a lines then and there (tools & supplies on-hand), the proper way to Evac, proper charge(s), common issues with different brands, R22 compatibility (He used 407 on the empty one) etc... it was all well worth the price,
So there is the end of My Air Conditioning Story.
Up Next - who wants to join me for a Septic Tank thread? =)
Sounds like you found a good guy, keep his number.
The wire on one unit being to small is possible but many HVAC guys don't understand some of the exceptions in the code that allow smaller wire then is normally seen for a given size circuit, if you post a pic of the rating plate it's pretty easy to determine the proper wire size.
Sent from my SM-T510 using Tapatalk
The wire on one unit being to small is possible but many HVAC guys don't understand some of the exceptions in the code that allow smaller wire then is normally seen for a given size circuit, if you post a pic of the rating plate it's pretty easy to determine the proper wire size.
Sent from my SM-T510 using Tapatalk
Rusty Fords
Well-known member
What he said, Not saying this is your case but I have seen where a over charged unit in a brand new house caused lights to dim when the outdoor unit came on. I was the second tech out and I was sure to give the first an ear full!!!
LS6 Tommy
Well-known member
I told ya to check the schraders…
Glad you got it squared away. Did he change the filter driers and swap to POE oil?
Tommy
Glad you got it squared away. Did he change the filter driers and swap to POE oil?
Tommy
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LS6 Tommy
Well-known member
In MVAC it's common, not "standard", and it's also still wrong. Using a vacuum pulls seals tight, so the leaks don't show. Once the system is charged, the loose connection/bad seal leaks.
Tommy
OP
bmarshall1
Well-known member
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- 54
I told ya to check the schraders…
Glad you got it squared away. Did he change the filter driers and swap to POE oil?
Tommy
Tommy - I'm not certain about the POE oil, or even what it is. I know he totally vacuumed the one unit and added 407 and I *think the 407 had oil in it because as he disconnected the lines some fluffy looking foam came out and he stated it was the oil.
The other unit had 2/3 charge and he added new R22, does it come with oil? The fellow seemed very knowledgeable and never mentioned either one of those items. I had also let him know these units are for my outbuilding and only will be run a few hours on the weekend a few times a month. Maybe this played into his decision, or maybe through his diagnosis he decided these items weren't necessary?
Can you give me a quick explanation on these two things you mentioned, if they are important I can have him come back out in the future and take care of it, would either of these affect performance?
lbpd716
Well-known member
^^ what he said.
Pulling the vacuum is more for the refill process - allows for the voids to be filled..
Pulling the vacuum is more for the refill process - allows for the voids to be filled..
Rusty Fords
Well-known member
I have seen this happen a multiple times hold on vac doesn't hold on pressure. My journeyman always told me just because it holds on one doesn't mean it will hold on the other!!
mrobins297aaa
Well-known member
Decided to add the EPA Section 608 Type I Certification by taking the 2 25 question tests.
Bill
Congratulations Bill
LS6 Tommy
Well-known member
The R22 units use mineral oil, which is incompatible with the Polyol Esther oil used with R407C, so the old mineral oil should be removed and the same amount of POE oil installed.
You sometimes get a little oil foam when you take the gauges off, so that doesn't mean any was added.
If all h did was add R22 to the other system. there shouldn't be any need to add oil.
It sounds like you had a good tech, I bet he did things right.
Tommy
bczygan
Well-known member
So is there a standard pump and procedure for putting pressure on an automotive system?
Bill
Yes......it is vacuum to 500 microns ..........hold 500 microns for period of time ..........Charge by weight ......Temperature and pressure checks.
The typical ROBINAIR machine does it all in one package.
None of which involves nitrogen in automotive. While it’s done on occasion....it’s not a standard procedure.
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OP
bmarshall1
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Hi Tommy - quick question - The only issue I had with the entire project was when he found the leaking copper line coming out of the compressor, it was a 1/2 inch line, unfortunately he was out of 1/2 in. and used 3/8 pushed inside the 1/2 and brazed. He showed me that in other places there were other 3/8 lines seemingly to indicate that the added line reduction/restriction would not be an issue (He stated I would get like 95% efficiency). That unit does not seem to cool as good as the other unit, but there are a lot of other variables that could account for that. How big of a concern is this for a unit that will only be run for a few hours on the weekends now and then.
fitter30
Well-known member
bczygan
Well-known member
bczygan
Well-known member
I was asking about what pump is used to apply PRESSURE to a system for checking for leaks.
Bill
Bill
High pressure bottled gas............
Terry D
Well-known member
Its not a pump. It is a tank of nitrogen used to pressure test a system
Sent from my SM-G960U using The Garage Journal mobile app
LS6 Tommy
Well-known member
IMO that restriction could cause high discharge pressure. Id like to see what the operating pressures and current draw is.
Tommy
Rusty Fords
Well-known member
I have converted multiple larger Commercail/Industrial systems from R22 to R407c. I've had leaks develop after making these conversions as well as plugging up filter driers. The POE cleans the system out and that gunk gets caught in the filter drier or the metering device. The Mineral oil causes the rubber seals to swell and the POE cleans on the mineral oil out causing the rubber seals to shrink and start leaking.
They say there is a slit reduction in capacity but I never noticed much.
You are correct about the seals and i don't know anyone that uses vacuum to perform an actual leak test. But i have never met an automotive or hvac tech that after vacuuming down a system did not ensure that their aren't any potential leaks such as a bad braze or such. By making sure it holds for a few minutes
danski0224
Well-known member
I was told the opposite, that the seals and Schrader valves are designed to seal against pressure.
LS6 Tommy
Well-known member
Same idea, different view. I was talking about the seals on the compressor and quick connect line fittings. A vacuum can pull a Schrader open, too. Realistically, if your gauges are on the system to pull a vacuum, the schraders can't leak. I usually remove the cores to evacuate anyway.
Tommy
OP
bmarshall1
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@Tommy - the technician brazed the 3/8 line into the 1/2 line it now creates a whistle in that spot, like fluid moving through an orifice or valve. Also, that unit gets about a 15 degree drop whereas my other unit gets a 25 degree drop. Since I only use this unit sparingly, is this a big deal? Lastly, if I choose to have him come back out. Can he vacuum the charge and save it, and return it to the system so I don't have to purchase a complete recharge?
slow
Well-known member
depending on where the repair is, a technician can pump down the system into the outside unit, do the repair and then open the valves on the outside unit without ever having to recover the refrigerant with recovery machine, obviously if the repair is between the 2 valves, that is not an option, but they should have a machine to recover it. It is illegal to intentionally vent a system into the atmosphere