Unit Testing Question -Goodman Package Heat Pump

[ntjock]

Hello,
I need some advice from some more experienced folks. I've got a Package Heatpump from Goodman. 5 Ton unit. It is a used unit and was acquiredon Ebay and shipped in. When we connected it up we can get things running, but it didn't cool. So we put a set of guages on it. The guages say it's empty. (like completely empty 0 low and 0 high). I thought that was suspicious and did a double check test because it was a new guage set. A momentary press on the low side confirms it was empty. At this point I have an empty system that needs charging. I decided to get a vacuum pump and put on it to see if it is empty because it leaks, or if it's empty because whomever pulled it off stole the freon out of it. (I'm betting on the latter).

Here's my question. How long should it take to pull a vacuum and then what sort of vacuum should I look for it to hold?

With the guages hooked up, high closed, low open, mid open and mid port hooked to vacuum pump it shows 20 to 30 hg of vacuum. I say 20 to 30 because tinkering with the low valve tinkers with the guage reading. Closing the low side causes the vacuum to drop to 4 hg of vacuum. It doesn't budge from 4. I understand that I should probably have a electronic guage.

BTW, I'm not planning to charge this myself. I have several A/C's and several refrigerant dryers. So I wanted to invest in some basic diagnostic equipment because I like to work on my equipment on the weekends. Most techs don't like to work on the weekends. I also enjoy the satisfaction that comes from a properly installed and running system. My goal at this point is to make a fix, junk, charge decision on this unit. If it holds a vacuum then charge. If it doesn't hold a vacuum I may try to locate the leak. Otherwise I may cut my losses and ditch the unit for a different one.

[ntjock]

Forgot to mention a few xtra tidbits.

Guage reading while drawing vacuum is either 24 or 26 Hg depending on the low side of the guage. If I crank it to mechanical dead stop it's 26. Otherwise it seems to be 24. When I close the guage it goes to 4 then to 3. Seems like a leak to me. But it doesn't seem to go lower then that.

In theory it should hold the guage reading with the guage closed. However, I know vacuums take time to establish... and there was/is stuff in the system (oil, maybe some moisture in the drier, etc). That stuff should vaporize as you lower the pressure. That could account for the replenishment of the system when I close off the vacuum pump. Advice would be greatly appreciated.

[sparks]

Call a HVAC company and have someone licensed to open a system come out and check your unit. That’s about the best advice I can give you!

[ntjock]

That unfortunately is not the type of advice I was looking for. Perhaps you might care to share some intelligent remarks like answering the vacuum related question. The last time I called a 'licensed' 'professional' I wound up junking a perfectly good unit because the idiot missed something simple. He swore that it was a bad compressor when in fact it turned out to be too much voltage drop to the unit. I will admit that the big national company that the 'professional' was employed by did have the courtesy to issue a refund on the service call. But it backed up my assessment that as long as I follow the refrigerant laws I can do most of my own maintenance.

In fact, to continue about the last HVAC tech... he didn't understand why we had mounted the unit at 9' off the ground on a specially made stand. Even after we explained that it shortened the ducting and put the unit where the heat was he was still confused by it.

At any rate, I don't have a problem calling a licensed tech to charge the system. But I want to be able to diagnose my own equipment. To draw a parallell this is like working on and diagnosing a car. I like to troubleshoot it, but I usually take it to a mechanic to have it worked on.

Going back to the original post, I'm trying to decide if the unit has a leak, and if so if it's worth the hassle of trying to locate and fix it. And as a side note regarding licensing.... unlike some repressive states Texas allows building owners to service their own equipment. The 608 exam is really not that challenging. Frankly, if you can't pass an open book at-home test you shouldn't be allowed to touch a screwdriver let alone a AC unit. (type 1 exam only).

[badboy]

Fortunately,that is the advise you should take.
Sparks is looking at your questions and has detirmined that calling an hvac tech is in your best intrest.

Good luck

[freezone]

He can help.:D

[seaboard]

Originally posted by ntjock
That unfortunately is not the type of advice I was looking for. Perhaps you might care to share some intelligent remarks like answering the vacuum related question. The last time I called a 'licensed' 'professional' I wound up junking a perfectly good unit because the idiot missed something simple. He swore that it was a bad compressor when in fact it turned out to be too much voltage drop to the unit. I will admit that the big national company that the 'professional' was employed by did have the courtesy to issue a refund on the service call. But it backed up my assessment that as long as I follow the refrigerant laws I can do most of my own maintenance.

In fact, to continue about the last HVAC tech... he didn't understand why we had mounted the unit at 9' off the ground on a specially made stand. Even after we explained that it shortened the ducting and put the unit where the heat was he was still confused by it.

At any rate, I don't have a problem calling a licensed tech to charge the system. But I want to be able to diagnose my own equipment. To draw a parallell this is like working on and diagnosing a car. I like to troubleshoot it, but I usually take it to a mechanic to have it worked on.

Going back to the original post, I'm trying to decide if the unit has a leak, and if so if it's worth the hassle of trying to locate and fix it. And as a side note regarding licensing.... unlike some repressive states Texas allows building owners to service their own equipment. The 608 exam is really not that challenging. Frankly, if you can't pass an open book at-home test you shouldn't be allowed to touch a screwdriver let alone a AC unit. (type 1 exam only).

To get an inteligent answer you need to ask inteligent questions. If the unit is completely out of refrigerant you should leak test in before assuming someone "stole" the refrigerant. I would hate to be the service tech or auto mechanic that you call. Regarding putting the unit on a 9 foot stand. If the ductwork were properly sized and installed, putting the unit where it could be serviced more easily would have been what most professionals would have done. That tech that did not catch that the compressor was not defective (wire causing voltage drop). Did he wire that unit or was that some of your handywork. By assuming that you can buy a set of gauges and a few tools and call yourself a technician you are insulting the inteligence of all the HVAC techs I know. The #1 sign you don't know what you are doing- You bought a used Goodman!

[Edited by seaboard on 07-17-2004 at 06:29 PM]

[ntjock]

Rather then flame and debate you.... I'm editing the post.

Let's remember that the site is for HVAC discussion not obstruction, criticism, etc.

I think I asked a valid question. If you don't like it (or the thread) don't respond. Read the site rules if you are confused.

I have a unit that I no nothing about. In trying to make it work I discovered that it has no refrigerant. I validated that the guages were not defective. The first logical place to start is by leak testing. I'm using a vacuum pump and my guage set to analyze the unit. However, I'm getting a reading that doesn't make alot of sense.

Please don't response with call a contractor. If you willing to help me understand the situation then please *do* respond.


[Edited by ntjock on 07-17-2004 at 06:55 PM]

[dchrbac]

To properly leak check the unit would require purchasing expensive equipment.
It would really be to your benefit to call a tech with the proper eqipment to test for leaks and repair any he/she may find.
Were you tring to save money by purchasing the unit on e-bay? If so, you wont be saving if you run down and buy the equipment to properly leak check the system.
Honestly.... Calling a tech like the others told you is the best option.
There is a possibility that the person you purchased the unit from removed the refrigerant due to the shippers rules or maybe he holds a EPA licence and wants to protect it.

[ntjock]

I will agree that perhaps they removed the refrigerant for shipping reasons. And yes, we did save a bundle getting the unit used. Ebay is an excellent venue for buying used equipment if one is careful.

Part of the reason I'm posting is to learn more about HVAC. The other reason is that I do have several pieces of equipment that use one type of refrigerant process or another. It's handy to be able to rule out the simple things on my own.


At any rate, my original question stands. Can a leak test be performed with a vacuum pump? My goal was to do a quick and simple leak test. Not a find the leak test.

My thinking was that the unit has to be vacuumed out anyhow. So let's vacuum it and see if it can hold the vacuum. If it can then that means it's intact. If it can't, then we need to do a leak test with either a nitrogen/R-22 mix or a dye based system. Personally, I like the dye based systems better as you can see the problem. Being a package unit there aren't many places for the leak to hide. Furhter, the system doesn't show any obvious signs of damage. i.e. no bent fins, dented coils, kinked tubing etc. System appears to be in good condition.

I will respond to an earlier post about putting the equipment down lower. In my area of Houston there are lowlifes who will steal your unit for the copper or who will steal the unit period. Perching the unit on a stand makes it less inviting to steal. It also prevents vandalism of the coils which is common by underprivelaged misbehaved children (laugh). Seriously though, we have two units mounted on stands. In the back of the building it facilitates access to the back of the building and to an air compressor. In the front it protects the unit from bad drivers in the parking area. It also shortens the duct runs and provides the unit with a steady supply of hot air to be cooled with a minimum of ductwork. I've always been a proponent of roof intakes in hot climates. It stands to reason that a system will operate more efficiently if you provide it with the hottest air to be cooled.

[sparks]

You want my honest opinion, I don’t care which state you live in. I spent 20 grand going to school to be a Liscened Commercial Service technician and countless hours in manufacture seminars. More countless hours spent reading and studying every aspect of this trade. You wanted free advice you got it. If you want me to fix your problem for you then you will pay for it. You are the fool who was too cheap to by new equipment from a contractor. Not me. If you are so smart than fix the dam thing. Since the test is so easy right?? Take it and fix it. *******!!

I supose your the guy who takes his own food to expensive resturants and have them cook it for you too!

[dschwab9]

Originally posted by ntjock
The 608 exam is really not that challenging. Frankly, if you can't pass an open book at-home test you shouldn't be allowed to touch a screwdriver let alone a AC unit. (type 1 exam only).

Last time I checked, the 608 exam was not an open book test you take at home.

[ntjock]

Like I said.... the 608 exam is simple. It's open book. It really shouldn't be, and it should be much more difficult. I take pity on you if you spent $20K for a technical certificate. You could have gone to college for that amount. At any rate, if you don't make assumptions about me, I won't make them about you. Better yet, if you treat me professionally I'll do the same for you.

I didn't ask you to fix my system. In fact, I wouldnt' hire you because you have a bad attitude and are exactly the type of contractor or customer that I try to avoid. Life's too short to be so hateful.

I asked a simple, straight-forward question based on a situation and the tools I have on hand today. I honestly expected three different kinds of responses:
1) You can't to do it with those tools, you need to do X.
2) You can do it with those tools, you are seeing X which means Y.
3) Additional information is required to answer the question.

[sparks]

Obviously you can’t read either!


Do-It-Yourselfers - not here.

This site is for industry professionals and folks seeking HVAC/R advice and knowledge. Please do not ask for step by step instructions on purchasing, installing or repairing your own HVAC equipment, that is our job and our livelihood. We are generous, but not to a fault.

Questions of this type will not be answered and may be deleted.

[ntjock]

I was wondering why you were so hateful. I looked at your profile and then I realized it was because you are in NJ. Read the other rules and get a life. Try reading the one where it says not to post if you don't like the subject.

Maybe you can explain why it is that people in NY and NJ are so rude and quick to cuss and yell when they don't agree with you? I deal with people all over the world in my profession. I've found that people in NJ and NY are the absolute worst. They are the first to cuss you out and misbehave. The only people who come close are the Candians in Quebec. They simply hate everyone.

I didn't ask for step by step instructions. I asked a specific question about doing a leak test.

Visit http://www.epatest.com if you want to take the 608 exam. The type 1 certification *is* open book which degrades the purpose of the certification.

[sparks]

What ever, I'm done with this post. You are wasting my time and are not worth it. Good luck getting the help you need. I am sure you'll need all the help you can get.

[dschwab9]

Originally posted by ntjock
Visit http://www.epatest.com if you want to take the 608 exam. The type 1 certification *is* open book which degrades the purpose of the certification.

No thanks. I already have 608 universal and 609 (have for years).

If you had read about the 608 certification types, you would find that type I only allows you to service small appliances with less than 5lbs charge. To work on your package unit, you need a type II.

[seaboard]

OK, OK Lets get down to business. There is a tool called a micron gauge that hooks up in parallel with your vacuum pump. That gauge is a very sensitive test instrument that won't even start to read the vacuum level until your regular gauges get past 29" of vacuum. There is no set time to evacuate the system. The only way to accurately leak check a system using a vacuum pump is with a micron gauge. Often people don't give enough information on their posts however you perhaps gave enough to show you have no business servicing HVAC equipment. Don't be too offended by our sarcasm however people in any profession would be insulted by a novice thinking he can but a few instruments and do anything the professional can do. When you go to the doctor, do you tell him exactly what's wrong with yourself? If so, why do you go?

[Boss]

enough ntjock. take a break for tonight, maybe you can come back with a more understanding attitude tomorrow.

Thank you

Boss

[beenthere]

Don't leak check with a vacuum pump, if it has a leak you just draw in more contaminants.

Use nitrogen for leak checking.

[ntjock]

Thanks to the last two folks for answering my question.

You are correct in the contaminant point. I hadn't thought of that one.

Seaboard - I wasn't out to charge my own unit or fix any leak I found. However, I don't want to waste money calling a tech out on a unit that I'm going to junk. I have a vacuum pump for something else and I have guages because we own 9 or 10 refrigeration/hvac units (counting window units, air dryers, package units). It's often handy to hook guages up to understand what's going on inside the unit before you call a tech. And yes, when I go to the doc I tell her as much info as I can about what's bugging me. It makes her job easier. Imagine going to the doctor and saying only "it hurts." He or she would have a difficult time fixing things. At any rate I appreciate you answering my question.

I'm just a bit confused about the guage readings. I think I had the guages hooked up and configured right for a vacuum reading. With the pump in the system the vacuum reading was predictable. However, with the pump isolated the vacuum fell which seems to indicate a leak. However, it didn't fall to zero which is confusing. Even so, shrader (sp?) valves aren't designed to hold pressure..... They seal against pressure from the inside not the outside. At any rate, I can't think of a situation where a system leak would result in partial loss of vacuum.

Do you think it's worth fixing? I only have around $350 into this unit including shipping and time it took to install. The net problem is that this is the hottest time of the year. We acquired this unit to try and bring enough cooling into our production environment. I have a t-shirt printing company and we have a 1500s/f space that has a 125Kbtu gas fired curing unit in it. When we built the space we didn't have the gas fired curing unit. We had a much smaller unit. In addition, we try to keep the shop environment below 95 degrees. While I realize there are people who work in temperatures higher than that regularly, I don't think it's right. I also don't like to make my employees work in such temperatures. We have one 4 ton unit that can't even keep up. We ran enough duct work (flex) to bring the A/C to the people. That made it tolerable but it's still not enough cooling. If the temp is 98 degrees and we turn off the exhaust fans and shut the doors and turn on the AC the temp climbs to 105 with lower humidity. At least sweat evaporates.... But it's still hotter then I want it to be. We scrounged around for this unit so we could put more cooling on the employees. I'd love to just run out and buy new units, but frankly we have so much overseas competition that it keeps our margins razor thin. As such we have to balance costs wherever possible. The ironic part is that the amount of A/C for this size building is off the chart for a standard load calc. And making matters worse we have 'spot' heaters that are each 8,000 watts and that fire an average of a quarter of the time when they are running. There are two for each of our two presses.

While yes, we could have tech or contractor come in... honestly they are going to be doing what we are. That is evaluate the situation, look at the resources available, and then make modifications. As our production capacity and heat load has grown our cooling needs have changed. Fortunately we only run the AC for about 10 weeks in the summer. Just when it's the absolute worst. The rest of the time we use fans. We have a blower fan salvaged from a 7.5 ton AC unit that we use as a shop exhaust. It does an excellent job of pulling heat and lint and fumes out of the bldg. Most t-shirt printers don't bother to AC their shops because it generates so much heat to print them.

[dschwab9]

If the vacuum is rising, there is either a leak or moisture in the system. You're going to have to do a pressure test to ever find out which.

[seaboard]

That unit either has a ton of moisture in it or has a large leak. Your vacuum level is falling off when you valve the unit off. You say it levels off at 4" of vacuum and slowly falls to 3". Picture it this way, when the unit begins leaking, it leaks faster when the pressure in the system is higher and slower as the pressure differential gets lower. It will be the same when you pull the system in a vacuum. You're not going to be able to simply watch the gauges go to 0 over the course of a few minutes. It's tough operating a small business nowadays and I understand you're trying to provide your employees with some better working conditions. Don't even try to compete with the overseas guys. Invest in a web-site and get set up with UPS or Fed Ex to ship them to your customers overnight. Push the angle of fast turnaround and you can charge more for it. Get the computer software to enable your customers to see examples of the product and import their logo onto it.







Are you thinking "I've been in the T-shirt business for years, who does this guy think he is!" Just trying to put the shoe on the other foot.

[ntjock]

I've decided to hunt around for someone to come out and pressure test the system next week. However, it's important to me that was able to figure out that thing doesn't likely have a gash inside (no vacuum). My biggest nightmare is would be to spend $300 or $400 on this unit and discover it's unrepairable. My only rationalization is that I've personally looked at both coils and not seen any fin damage that would indicate an impact or gash. It could easily be something stupid like a bad scrader valve seal. What little I know about the unit is that it was installed in a commercial building. It was removed when the tenant was evicted for not paying rent. The management company then sold the unit to recoup some cash. Or so the story goes. It's actually not that old of a unit at something like 8 years old. My neighbor works for Goodman in their plant that is down the street and I asked him how to decode the serial #s. He doesn't do anything special there, just a line worker. But I can say that they take good enough care of their people that him and his wife and kids have a nice house and a couple of nice cars. The one thing that impressed me the most was how much more efficient it was then my old 4 ton. I have an old 4 ton Carrier (I think a 58 series) and it cranks out the cool. But it draws 30A at 230V 3 Phase. The 5 ton goodman is rated at 40A 230V 1 Phase. While the 5 ton draws more juice it's only an additional 240 watts for the extra ton. That statement assumes a power factor of 1.3 for the 3 phase wattage calculation. It's not exact, but it's close enough to see that the 5 tons use less then the 4 tons. I can't imagine where else one of these things could leak. With a RTU the opportunity for leaks should in theory be lower.

I realize it may sound silly, but I would hate to call a tech out here and find out the thing is hopeless. It still might come to that, but I want to make sure that if it's something stupid and obvious that I'm able to eliminate the causes. I know I hate being asked to do menial computer things. Example my bookeeper will say the printer isn't working. I'll ask her what she thinks is wrong. She'll say it's out of paper. I'll say well, gee what should we do about it? She'll say put paper in. I'll say do you think you can handle that? She'll say sure. I'll say great I'm glad you solved that problem. In reality, I'd rather not get involved. I'm sure that most good techs feel the same way. They would rather be called for a problem, not something stupid like leaving the furnace door off, or a tripped breaker.


As for T-shirts..... previous to starting a t-shirt company I worked for two large software companies. I hated the way they ran their business. I especially hated the lie to make a sale attitude in sales. After 9/11 I decided I didn't need to be on an airplane 250,000 miles a year. So, we are as close as we can get on the computer stuff and as a result we are extremely efficient and do a good job delivering value to our customers. With time it will turn a profit and I won't have to dink with A/C units, air dryers, air compressors, and a myriad of other mechanical headaches like pneumatic operated automatic presses. However, I don't want to offshore the work. I actually am firmly convinced that large companies have screwed America by offshoring work that should be done here. If we all do it, nobody will have money to buy. American workers do it better, faster, and smarter then most countries. Our culture is fundamentally different then China, Mexico, or island of slave labor (wherever they go next). And yes, we do offer 2 day service, 5 day service and standard 10 day service to our customers. Probably the same as you offer weekend and holiday and drop what I'm doing service to your customers. I do actually appreciate suggestions and we listen very very carefully to our customers to make sure they stay our customers next year. I envy one aspect of the HVAC business. Your customers can't take it to China to have it fixed. And as of now, the Chinese can't come here to fix it. Not that the Chinese are bad, but we'll throw darts at them because they won't feel it or notice it. At any rate, we can probably agree on one thing. It's great that people can be Enron, Citibank, and Microsoft presidents. However, it's more important that people are employed in jobs that create value. While the above mentioned companies can siphon value from the economy they don't make tangible goods that create value. Most trades, manufacturing, and hands-on services create tangible value and therefore will always have a place in the world. I'll end on the note that if more people would go back to making things America would be a far better place. Unfortunately most people want to sit behind a desk and order other people to make things. We have only our leaders to blame for that one. There is nothing dishonorable about using your hands to earn a living. In fact, it can be a rewarding life and there is something that's just fundamentally good about looking at a product that everyone understands and appreciates the value of. Contrast this against my former life where I installed Active Directory enabled migration integration software suites for the Windows Business computing environment. Right like what the f*ck is an active directory integrated bla blah is what most people answer. I always had to sum it up with, I'm in the computer business.

Lastly, I do really appreciate you answering the questions. I'm a very hands on sort of guy and while I won't do major repair on my HVAC equipment, I do like to troubleshoot it, do the minor stuff, and understand it well enough to carry on an intelligent conversation. By minor stuff I mean like hanging flex duct to move a outlet. Or installing a register. Or replacing a thermostat. I also find it just flat out fascinating as well.

[dschwab9]

Have you asked the person you bought it from if they recoverd the refrigerant for shipping purposes or something? Seems like that would be a start.

[ntjock]

That's a good idea... but honestly it's one of those projects that never got done in a timely manner. We bought it last August. We started to install it in September, and then it cooled down. So we shelved it until the spring. I doubt that the seller would remember anything.

[h2045]

Interesting thread....... The crack about buying a used Goodman was the BEST!!!!!!!

[hackmaster]

My mother could pass that freon test and she passed away a few years back. If your serious about fixing your own equipment your gonna have to go to school and buy all the expensive stuff like the rest of us did...no free lunch and no shortcuts in this field.

[h2045]

That about covers it

[sadwoman]

Since you have already pulled several vacuums, the unit has no refrigerant in it and you may legally work on it, although you broke the law if it had freon in it the first time you put your gauges on it.

I do not understand your attitude re Canadians from Quebec. I moved to Quebec from Europe and find that Quebecers have managed to combine what is best in Europe and north America.

I understand your problem and I realize that sometimes you have to do what you are doing because otherwise you can do nothing.

You need to invest in a nitrogen tank and pressure regulator (about 100$). The unit should hold a pressure of 50 psi for several hours. If not, use soap and water to find the leak. Now you need a certified tech to repair the leak, evacuate and charge. I do not think that 4" vacuum can be due to water in the system. 4" vacuum is about 12 or 13 psia, and at this pressure water needs to be heated to about 200F to boil.

I know I will be flamed for what I am going to say next. If 100$ is too much to invest in nitrogen, use a clean source of compressed air, you should have it available in your shop. I know I know, compressed air is loaded with humidity, but you can pull several vacuums after the system is sealed, and a liquid line drier filter is a few bucks and you will need one anyway.

See, Canadians from Quebec are not so bad after all.