# Thread: Digital gauge manifold

1. Originally Posted by XcelTech
2.) You need to spend time getting not just accumulated with analog gauges but proficient with using superheat sub-cooling. I don't mean learn the math, I mean you understand what it truly is, how it helps you, and the physics of what you can't see.
Although digital gauges do not prevent you from learning this stuff, knowing how to use the rudimentary tools precisely comes with a very strong understanding that will make you a confident self-aware technician.
I disagree completely with this.
Using digital gauges, that give a direct saturated temperature conversion, will help new technicians to think in terms of saturated temperature, instead of pressure.
Thinking in terms of saturated temperature makes understanding superheat, subcooling, and other things going on inside the system much more intuitive.

When you think in terms of saturated temperatures, it doesn't really matter what refrigerant you are working with, as the saturated temperatures will usually be close to the same for a given application, regardless of the refrigerant used.

The only reason we even look at pressure is to convert it to a saturated temperature.
Having to read pressures, and do PT conversions, is a distracting, diagnostically useless step, that doesn't do anything to enhance the understanding of the refrigerant cycle.

5.) By the time you are really ready to use these tools and have your own van something better will have replaced them on the market.
As with all things technological, if your reason for waiting to make a purchase is because something better will be coming along in 6 months, you will be stuck with not experiencing the benefits of the technology for that period, and in 6 months you will again be faced with the dilemma of knowing that something better will be coming out in 6 months.

6.) Make sure any digital gauges you purchase have a respectable micron gauge. A bad micron gauge setup will turn your would upside down on large equipment like chillers.
A micron gauge in the manifold is a fluff feature that I find pointless and annoying that I have to pay for.
The fastest evacuations are had with no refrigerant manifold or hoses involved, and it is best to have the micron gauge connected to the system, as far from the pump as possible.
This is doubly true on "large equipment like chillers."

Having said that, if a new guy is mainly doing start-up of new residential systems, etc., pulling a vacuum with a service manifold and hoses doesn't take that long.
If having a micron gauge built into the gauge set gets some people actually paying attention to micron readings, and proper evacuation, that otherwise have not ever done so, it is a good thing.

2. Originally Posted by mark beiser
When you think in terms of saturated temperatures, it doesn't really matter what refrigerant you are working with, as the saturated temperatures will usually be close to the same for a given application, regardless of the refrigerant used.

The only reason we even look at pressure is to convert it to a saturated temperature.
Having to read pressures, and do PT conversions, is a distracting, diagnostically useless step, that doesn't do anything to enhance the understanding of the refrigerant cycle.
Realizing that the pressures aren't what matter was the biggest revelation I made in my apprenticeship. The saturated temperatures and their relationship to the actual temperatures are what is really important.

Keeping this philosophy, it doesn't matter what refrigerant the system uses.

I teach this religiously to apprentices working under my now. The digital gauges make it even easier to show and explain.

For the record, I use Yellow Jacket digital gauges with the external micron sensor.

3. Originally Posted by mark beiser
I disagree completely with this.
Using digital gauges, that give a direct saturated temperature conversion, will help new technicians to think in terms of saturated temperature, instead of pressure.
Thinking in terms of saturated temperature makes understanding superheat, subcooling, and other things going on inside the system much more intuitive.
I disagree with this because digital gauges bypass the saturated pressure completely. As is, I have come across several 5 year HVAC techs who know what saturated temperature is but do not know what that means. Most believe the PT chart shows what the actual temperature of the refrigerant is at that pressure, which we know is not correct. By using digital gauges, the new techs bypass those numbers completely. How is a tech gonna figure out that someone dropped R-22 in a R-407c system or how to check the refrigerant in a recovery cylinder if they do not understand how to use the PT chart.

Originally Posted by mark beiser
As with all things technological, if your reason for waiting to make a purchase is because something better will be coming along in 6 months, you will be stuck with not experiencing the benefits of the technology for that period, and in 6 months you will again be faced with the dilemma of knowing that something better will be coming out in 6 months.
You miss interpreted what I said. I said why buy something expensive now when you are not efficient with it if you can buy something better when you really know how to use it. I would love to own a crane but that doesn't mean I know how to use it properly.

Originally Posted by mark beiser
A micron gauge in the manifold is a fluff feature that I find pointless and annoying that I have to pay for.
The fastest evacuations are had with no refrigerant manifold or hoses involved, and it is best to have the micron gauge connected to the system, as far from the pump as possible.
This is doubly true on "large equipment like chillers."
I agree with this statement except that I can do exactly what you just said with my digital gauges and I now have one less item in my van and one less expensive tool to purchase.

Originally Posted by mark beiser
Having said that, if a new guy is mainly doing start-up of new residential systems, etc., pulling a vacuum with a service manifold and hoses doesn't take that long.
If having a micron gauge built into the gauge set gets some people actually paying attention to micron readings, and proper evacuation, that otherwise have not ever done so, it is a good thing.
Here Here! I will drink to that, sir!

4. Originally Posted by XcelTech
I disagree with this because digital gauges bypass the saturated pressure completely.
Huh?

One of the best things about digital gauges is that they display that they do the PT conversion automatically, and display it directly on the gauge.
Digital gauges are like having a real time exact PT chart, with no interpolation between the lines.

I agree with this statement except that I can do exactly what you just said with my digital gauges and I now have one less item in my van and one less expensive tool to purchase.
Except that if we were both tasked with say, changing a compressor on a couple of systems that were side by side, and we both completed the replacement and started our evacuation at the same time, using my vacuum tree and oversized hoses, I'd finish the evacuation faster, have the unit charged, and possibly be packed up and on my way to my next call before you finished with the evacuation through your service manifold.
If it was a couple of big chiller systems, I might be sitting at home drinking a beer before you had it evacuated.

5. Originally Posted by mark beiser
Huh?

One of the best things about digital gauges is that they display that they do the PT conversion automatically, and display it directly on the gauge.
Digital gauges are like having a real time exact PT chart, with no interpolation between the lines.
Don't get me wrong I have 2 digital gauges and wouldn't trade them for anything.
However, I never see the saturated pressure or temperature on digital gauges, just the calculated superheat or sub-cooling. It is becoming comfortable with those numbers purpose, not memorizing them just understanding them, that I am referring too.

Originally Posted by mark beiser
Except that if we were both tasked with say, changing a compressor on a couple of systems that were side by side, and we both completed the replacement and started our evacuation at the same time, using my vacuum tree and oversized hoses, I'd finish the evacuation faster, have the unit charged, and possibly be packed up and on my way to my next call before you finished with the evacuation through your service manifold.
If it was a couple of big chiller systems, I might be sitting at home drinking a beer before you had it evacuated.
I apologize for not completely explaining myself. I have the same over sized hose set up and connect my gauges to read the microns not to pull vacuum through. Sorry for not being clearer.

6. Originally Posted by XcelTech
Don't get me wrong I have 2 digital gauges and wouldn't trade them for anything.
However, I never see the saturated pressure or temperature on digital gauges, just the calculated superheat or sub-cooling.
One of the things I like about my Digi-Cool gauges is that the saturated temperatures are always displayed.
I wish there was an option to make my Testo and Fieldpiece gauges display the saturated temp, instead of the pressure, when viewing the SH and SC.

I see where you are coming from now, I'm just not necessarily on board with it.

I've got the older Digi-Cool products, but one really nice thing about the AK900 is that it shows both pressures, both saturated temperatures, both probe temperatures, SH, SC, and temp difference between the probes, all on the same screen at once.
They are also tough enough that even the worst newbie klutz would have to try hard to destroy them, and I mean really hard.

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Originally Posted by jbeckham
Ha, this is hilarious...

Lets parlay and add full retail market price for each others gauge set...

I'm gonna be laughing about the gig all the way through, but unless you just turned over a fire engine red quarter... You, probably not so much...
My digi-cools are fairly new at just over 3 years old. I've replaced the battery a few times. Otherwise, I turn them on and go to work.

Analog quality has dropped so radically that I couldn't even bring myself to trust a 1% gauge for much more than a week.

As far as your durability tests go, you might wanna re-think your bets. The DC is drop proof, hammer proof, water proof under normal and most abnormal service conditions (I wouldn't service an AC system on a submarine while SCUBA diving, but that type of equipment really doesn't exist, so the point is rendered moot.

Originally Posted by mark beiser
Using digital gauges, that give a direct saturated temperature conversion, will help new technicians to think in terms of saturated temperature, instead of pressure.
Thinking in terms of saturated temperature makes understanding superheat, subcooling, and other things going on inside the system much more intuitive.
Yep. I had fallen into the 'trap' of thinking in terms of pressure rather than temperature. Now, I barely glance at the pressure portion of the display unless I'm leak testing.

8. Originally Posted by mark beiser
The reading still changes with the angle it is viewed at, or which eye you are squinting at it with.
Then there is the PT chart interpolation error.

With digitals, you don't even have to look at pressure, you get a direct saturated temperature reading, which is what you really need.

There is a 9 year span in instrument ages in this picture. They are from 3 different manufacturers, use 4 different types of pressure transducers, and 4 different types of 3 different technologies of temperature sensors.
There is only about a 1.5 psi difference between the lowest and highest pressure reading, and 1.1&#186; difference in the temperature probe readings among the 4 instruments that have temperature probes. The BTD-1000(top left) has no temperature probes.
Attachment 384431

I'd put some money on the table that says my Digi-Cool DRSA-1250 would still work fine. The manifold it is mounted on may need to be replaced though.
My BTD-1000 has survived such a drop, onto concrete.
You've obviously invested more in this than I have ever even considered...

I'm not going to continue an argument with you over how accurate or robust the equipment you own is, because I don't own any of it...I can't see any significant relevance for it.

If it's what you say it is, that's fine. I just think you're putting way more resources than what is really required into the task...

Kind of like a doctor telling me that he is positive what is wrong, but he's going to recommend a CT scan anyway... All this while he is looking over my chart and x-ray...

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Originally Posted by jbeckham
, because I don't own any of it...
^^THIS^^

Is a significant part of most tech's argument against digital equipment.

That and they don't want to invest in their own careers.

I don't know many techs who buy cheap wrenches or screwdrivers. We buy the best hand-tools money can buy because tools are our trade and our career and our livelihood...

When it comes to measuring instruments however, the "good ol" stuff is good enough because it was good enough for gran-pappy and pappy and it's good 'nuff fer me.

Just sayin... Don't make a lot of sense when you step back and look at it.

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In my opinion its a ton of money for a lot of information that is right in front of you, and some simple mathmatics. In my area I think the testos are the popular ones and many people like them. I personally don't want to lug them big things around.

11. Originally Posted by jpsmith1cm
^^THIS^^

Is a significant part of most tech's argument against digital equipment.

That and they don't want to invest in their own careers.

I don't know many techs who buy cheap wrenches or screwdrivers. We buy the best hand-tools money can buy because tools are our trade and our career and our livelihood...

When it comes to measuring instruments however, the "good ol" stuff is good enough because it was good enough for gran-pappy and pappy and it's good 'nuff fer me.

Just sayin... Don't make a lot of sense when you step back and look at it.

I work with a lot of digital equipment.

Wrenches and screwdrivers get lost or stolen, and digital gauges look an awful lot like overkill to me.

Spend your money where you think you need to, but don't sit around telling people that you're somehow better at what you do because you've spent three times more on your kit...

And "the best" has, and always will be, subjective...

12. Originally Posted by jbeckham
I work with a lot of digital equipment.

Wrenches and screwdrivers get lost or stolen, and digital gauges look an awful lot like overkill to me.

Spend your money where you think you need to, but don't sit around telling people that you're somehow better at what you do because you've spent three times more on your kit...

And "the best" has, and always will be, subjective...
That isn't the case at all. Everyone who has been spirited in this is trying nothing more than to make sure you see the benefit of it. It's like a cell phone. I didn't have an IPhone for a long time because I thought it could do just fine without it. Come to find out I've found used for it I never anticipated. If nothing else I would urge you to let someone you know who has them let you try them out and show you the features. 4 guys I work with have bought gauges after seeing mine in use and how I'm able to use them. If you don't choose to use them, then it's all fine.

13. Originally Posted by mark beiser
Huh?

One of the best things about digital gauges is that they display that they do the PT conversion automatically, and display it directly on the gauge.
Digital gauges are like having a real time exact PT chart, with no interpolation between the lines.

Except that if we were both tasked with say, changing a compressor on a couple of systems that were side by side, and we both completed the replacement and started our evacuation at the same time, using my vacuum tree and oversized hoses, I'd finish the evacuation faster, have the unit charged, and possibly be packed up and on my way to my next call before you finished with the evacuation through your service manifold.
If it was a couple of big chiller systems, I might be sitting at home drinking a beer before you had it evacuated.
While I agree ,my question is are you getting paid by the hour. Oh by the way I am building a tree for myself. Don't want to "linger" any longer than I have to.

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