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ServiceF1rst
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 Posted: Fri Aug 24, 2007 5:18 pm Post subject: Return of the J/B DM-2 Digitals [FieldTest Thread] |
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Wanted to start a new thread on the DM-2 to update everyone as to the status of the set and where we are at the moment with them. The set has been returned to J/B to be evaluated as to the cause of failure - early indications are that it may have at least started with exposure to a strong DC current field - but that is preliminary at this point. Irrespective of the cause of failure the set will be corrected by J/B technicians and returned to us to resume evaluation at the earlest possible date. In all likelyhood the evaluation will resume either in the extreme southern states or possibly California because as we a ll know old man winter is just around the corner.
I will make any updates as they become available here in this thread. My apologies for the delay.
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least.
Last edited by ServiceF1rst on Sat Sep 29, 2007 9:34 pm; edited 2 times in total |
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ServiceF1rst
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| Posted: Sun Aug 26, 2007 10:09 am Post subject: |
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A little technical information on the DM-2 that we are field evaluating:
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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Maineiac
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Location: Middle of nowhere,3 feet from hell and 20 miles from water
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| Posted: Sun Aug 26, 2007 4:06 pm Post subject: |
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any word when we can get them back in the field?
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ServiceF1rst
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| Posted: Sun Aug 26, 2007 4:37 pm Post subject: |
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| Maineiac wrote: | | any word when we can get them back in the field? |
Not a definitive date yet, apparently they wanted to make an evaluation as to the probable cause of the failure, it was I think Friday when they called and asked about the DC field current - I have not spoke with them beyond that point. My feelings were at least at the time that it would not be an especially long wait - perhaps we will find out more tomorrow.
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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ServiceF1rst
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| Posted: Fri Aug 31, 2007 5:06 pm Post subject: |
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Instead of paraphrasing the status of the DM-2 I will just copy and paste the email I recieved from Tony this afternoon:
| ReliPro wrote: | Tony,
Good news for the long weekend. The gauge has been repaired and is en route to us.
Apparently, the salesman I had working on this was told by JB that the transducer failed.
I'll let you know when it arrives and contact you for instruction...
Tony |
We should have them back home sometime next week, we will determine how we will procede with the evaluations at that time.
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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ServiceF1rst
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| Posted: Fri Sep 07, 2007 6:47 pm Post subject: |
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The DM-2 was shipped out to my address yesterday, probably have them either this weekend or very early next week. When they arrive we will regroup and decide if we need to ice this evaluation, at least in the northern states and move on to combustion analyzers that I am in the process of acquiring for eval. We might just keep the digital gauges in the southern states and ship the CAA's out across the northern states. As soon as I have them back we'll get something figured out and make an announcement here.
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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Maineiac
Global Moderator~Keeper Of The Flame
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Location: Middle of nowhere,3 feet from hell and 20 miles from water
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| Posted: Fri Sep 07, 2007 8:02 pm Post subject: |
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We are still running no A/C calls here in the Bangor area. I have many accounts and schools that have to have heat on , on or before Sept 15.
I have gone 2 days now with out putting referigeration gauges on. The combustion analizer has been out of the van on almost every call.
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ServiceF1rst
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| Posted: Fri Oct 19, 2007 11:56 pm Post subject: |
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Ok guys here's what we're going to do with the DM-2. First I'm going to repost in the form of a quote all of the posts made to the original J/B DM-2 thread that were pertinent to the fieldtest being run. At the conclusion of these reposts we will open the boards back up to any member that wants to participate in this evaluation.
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ServiceF1rst
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| Posted: Sat Oct 20, 2007 12:12 am Post subject: |
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Reposted Evaluation Notes:
| Freezon wrote: | The set arrived today in fine condition. I opened the package to check things over, found a small problem with the fittings being loose. I read the directions not too complicated in fact kind of simple. I played around with the different features cycling thru the options of the various keys. I was quite impressed with all the refrigerants in memory. I’m going to grab a bite and if its still daylight I’ll put some hoses on and hook them up to my home system.
Later Freezon
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| Freezon wrote: | | ServiceF1rst wrote: | Great, glad you got them Free. Curious about your thoughts on the method they used to attach the hook to the manifold. Just thought it was sort of a different design.
Edit
Forgot to add, appreciate the images, any that you have the time to take over the next few weeks in use would be appreciated also.  |
Ya, I like the way they have the hook thru the middle of the display out of the way but firmly attached. I noticed the directions say "turn the set on with out pressure" well I use loss fittings so does this mean I have to bleed the hoses every time I turn them on? I also would like to see a fast reacting air temp sensor for measuring the condenser air inlet temperature as I use the superheat chart from Jim Wheeler to charge orifice units. Maybe I'll have to start measuring indoor WB every time, but for now I'm trying to compare Wheeler's chart to the WB one that came with the instructions. I would also like to see the wet bulb socks closed at one end, as they tend to slip off the sensor and down the cable. The phone's a ringing gota go
Later Freezon |
| ServiceF1rst wrote: | | Freezon wrote: | | ServiceF1rst wrote: | Great, glad you got them Free. Curious about your thoughts on the method they used to attach the hook to the manifold. Just thought it was sort of a different design.
Edit
Forgot to add, appreciate the images, any that you have the time to take over the next few weeks in use would be appreciated also. |
Ya, I like the way they have the hook thru the middle of the display out of the way but firmly attached. I noticed the directions say "turn the set on with out pressure" well I use loss fittings so does this mean I have to bleed the hoses every time I turn them on? I also would like to see a fast reacting air temp sensor for measuring the condenser air inlet temperature as I use the superheat chart from Jim Wheeler to charge orifice units. Maybe I'll have to start measuring indoor WB every time, but for now I'm trying to compare Wheeler's chart to the WB one that came with the instructions. I would also like to see the wet bulb socks closed at one end, as they tend to slip off the sensor and down the cable. The phone's a ringing gota go
Later Freezon |
Most of the guys here seem to valve off the head side of the manifold and allow the suction side to pull the residual into the system. With that said however, as a result of the logic in some of the other threads here dealing with this subject matter I have gradually shyed away from using the low loss fittings as exclusively as I once did. I didn't look closely at the WB socks but I would concur that a closed end would be an advantage for the reason you noted. |
| Freezon wrote: | Used the set quite a bit today lots of residential a/c and a few rooftops. I'm thinking what is the advantage of digital gauges? For me at this point just the fact that the information needed to do this type of work is much more convenient. A regular gauge set can give you the same information, but you have to work a little harder to get it, so for now convenience is the major benefit I see.
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| ServiceF1rst wrote: | Absolutely no doubt that convenience is a positive aspect of digital manifold gauges. Expanding on that fact is the additional fact that this convenience can be translated into instrument application efficiency or simply put they will reduce time required to acquire system operating information, and subsequently diagnosis time. I've personally found that I can trim about an hour to an hour and a quarter combined at the end of the day, that's 5 to 6.25 hours a week - nearly a full day or at the least half a day. This became especially true after I became acclimated to using the DRSA.
Another key component, actually IMHO a critical component in the digital equation is repeatability - something that despite intentions cannot be obtained with conventional analogs. So while I agree with your contention that you can extract the same information from analogs, PT charts and digital thermoms in a more greatly exaggerated time period - digital instruments and in particular the 523 and the 1200 offer laboratory quality accuracy, while analog cannot even approach that statement. So you take 5 technicians, given identical conditions, using identical techniques and you will likely have 5 different indications of essential operating parameters with analog instruments - under the same circumstances using digital instruments the operational parameters recorded should be repeated across the board.
Also as a matter of personal opinion respective to the DM-2 while they appear to be pretty solid initially and we will find out as this evaluation thread progresses, they are essentially entry level - at least when compared to the capabilities of the DRSA 1200 and the RSA 523 each respective analyzer incorporates technology and functionalities that the DM-2 cannot offer.
Appreciate the updates Free.
One thing I was curious about that I didn't get the chance to look into before I sent them out to you is the record function on the DM-2 have you had the chance to use it yet, and if so what is it's capabilities? |
| Freezon wrote: | | ServiceF1rst wrote: | | One thing I was curious about that I didn't get the chance to look into before I sent them out to you is the record function on the DM-2 have you had the chance to use it yet, and if so what is it's capabilities? |
Ya, I used that feature to test a pesky leaking coil another tech removed. I pressurized the coil left it over night, the next day I was able to see the High, Low, and Average pressures during the test period. Guest what? I found no leak so he’ll be going back sooner or later.
Freez
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| ServiceF1rst wrote: | | Bustawrench wrote: | | gonefishing wrote: | $443.00 Includes case, probes and 6' hoses. Those on e-bay are
already overpriced with no hoses. The miracle of competion 
GF |
I'd like to see those, got a Link?
Thanks. |
Busta we have arranged for some special pricing available to PROTech members at HVACRTools [their link is on the homepage, left column. Click their logo to go to the site.] Below is a recap of the DM-2 Model breakdown as well as the pricing available in conjunction with the evaluation.
| Reliable Procurement wrote: | Tony, here's the breakdown on the prices for PROTech members:
DM2-3 - $449.99 (regular price 524.99)
DM2-5 - $437.99 (regular price 509.99)
DM2-8 - $409.99 (regular price 469.99) |
If you have any trouble with locating the gauges on their site or are interested in taking advantage of the pricing, let me know I'll put you in touch with the company owner. |
| Freezon wrote: | Well I’m on my second week with the new gauge set and I can’t think of one thing bad to say about them. There’s allot of information at your fingertips, all you have to know is how to apply it, and if you do, you’ll probably love a digital gauge set. Then again you might want to check around to see what’s available. Many companies offering digital gauges are coming out with products that have advanced features that I would like to know more about. I will, at some point, own a set of digital gauges is J/B the set? Maybe, but I’ll wait and see what you other guy/gal’s think about them.
Who’s Next? |
| gonefishing wrote: | O.K. folks, now back to the topic of this thread, the J/B-DM2 manifold.
A little information straight from Bob Johnson, engineering department with
J/B Industries.
"The J/B-DM2 incorporates Rapid Refresh Technology which gives the display
a 0.75 to 1.00 second refresh rate."
That should put an end to that part of the debate.
Later.........GF |
| gonefishing wrote: | | Maineiac wrote: |  WHO HAS THE JB DIGITALS? AND WHAT DO YOU THINK OF THEM. |
Not sure where the Evaluation set is but................
I have a good friend who has been carrying a set for about 2.5 months now.
He loves them, and is the only set he uses. Hung on the tool bin in the back of
his service van with his analogs. Thats where they have been since he bought
them.
He left them on one system over-night on a problem unit. Was able to see with
the high/low pressure log that the condenser fan motor went off in the night.
Replaced the motor, problem gone. I have asked him to write me an evaluation
on them so I can get it posted.
Later........GF |
| gonefishing wrote: | | absolutehvac wrote: | I believe that all the fancy stuff in the world wouldn't be of any use if you don't know what you're looking at. With all of the changes happening with technology nowadays it's hard to keep up with what's current but I don't care how much money you spend on something... if you don't know how to interpret the information you are getting it's useless.
I personally, refuse to buy anything "new" until it has been proven to be useful to me.. whether that be by a few years of testing or what have you.. I'm not one to go out and buy the newest thing just because someone says that it's the best and you gotta have it. If what we currently have and use and know works just fine for what we need it to do why would I go spend the money on something else? I have to justify the cost before I purchase something like that.
ttfn
abs. |
I agree to a great extent abs. The one primary advantage I see to this
technology, is for example, the installation tech who does the basic start-ups,
but does not do any actual service. With a set like the J/Bs, the installer
can hook up the gauges, set "both" temperature probes and log the pressures,
superheat and sub-cooling as reported by the manifold, and turn this information
in to the service supervisor. Knowing this data was given from a set of digital
gauges, the information can be evaluated and given to the field service representative
on a dispatch to make final test and tune on the new installation. Data can
be gathered by the installer in a matter of minutes.
Just one of the many advantages to the technology.
GF |
| Reeferman wrote: | | Reeferman wrote: | J/B digitals arrived here late Tuesday afternoon. I checked them and they seemed to be in working order. I familiarized myself with them and hooked them up to a vacuum pump to see if what they would do.
J/B claims that they compenste for altitute and barometric pressure. With a micron gauge hooked up also, at 150 microns the low side read 26.3"hg and the high side read 26.0" hg. They do not adjust for altitude.
The next day I hooked them up with a t- fitting on the high and low sides so I could use another gauge set to compare readings and hooked this up to a mobile a/c unit. Before hooking them up to this system I turned them on with no pressure as per the instructions and purged both gauges. With the unit running the low side was off by 6 psi and the high side was off by 10 psi compared to my digitals. I tried both of my digital gauges to make sure it was not one of them and both of my digital gauges read the same. I even tried a set of new Yellow Jacket brass 1% analogs and they seemed to read the same as both of my digitals.
I had to remove the refrigerant to proceed with repairs and started to remove refrigerant. Thats when I noticed the low side of the J/B digitals was reading 1672"hg( not 16.72"hg) the high side was at 95lbs psi and both high and low on my digitals were at 85 lbs psi. I had only removed about one pound of refrigerant.
I checked the batteries, both were ok but put new ones in anyways. This did not change anything. I then removed the J/B digitals, removed hoses and tried turning them on and off but made no difference. There are no trouble shooting instructions or phone number to call for problems.
I contacted Tony about this and he is going to get ahold of J/B to find out what to do.
So I have not really been able to test drive these gauges but will say this.
!) The display screens are too small for me. They are very hard to see in the bright sunlight. There is no backlight which would make seeing in the dark even harder.
2) They do not compensate for altitude or barometric pressure as they are now.
3) Having to push buttons to display pressure, super heat, subcooling, satuaration, temperature and what refrigerant it is set for is not something that I like. Not something I would want to do when it is 10 feet off of the ground on a reefer unit and my hands are covered with dirt and oil.
4) I compared the temp readings to my Fluke 52 11(which I had calibrated by Fluke a month ago) and they were pretty much bang on.
5) I like the temp probes and leads that come with it but like the digitals I have are a pain in the ass having to have wires to read temps. They need to have wireless temp probes.
6) I don't use or like 2 valve manifolds. But if J/B makes a 4 valve manifold like this one I would buy it. It seems to be very well made and the valve action is very smooth.
So that is where I have gotten with them and will have to wait until Tony or someone from J/B gets back to me on how to fix the problem. |
After the J/B digital seemed to start working again something was bothering me about the inside of it when I changed the batteries.I think a few of you will remember this.
So I took it apart and and this is what is inside.
I then opened up the J/b digital and this is what is in it.
Now I am not a electronic wizard but they sure look to be about the same to me. The old Imperial however has the wires covered at least. I think that the problem I had with the low side doing what it did is due to the fact that these are unshielded milli volt sensors and the electrical system in the tractor I was working on did something to them.You can't see it in the J/B picture but the low side has 4 wires just like the high side.
I started the next day on a tractor a/c and hooked them up like this.
I purged all of the gauges and hoses and the static pressures all seemed to read the same. I then started the unit and the readings on all gauges were too close to see any difference in them. I did start to see a pattern develope between 250psi and 305 psi on the high side. The J/B digital would start to read between 20psi and 30psi lower than both of the other digital gauges about 3 times out of 10. The low side seemed to all read the same. I then removed the refrigerant and all readings on all gauges read the same down to about 15"hg. I had pictures of this but they were unseeable due to the sunlight.
I lost all convidence in the J/B unit after this and did not see any use in hooking them up to any other units. I was not able to get a picture of the J/B unit when the low side was stuck as in the post above due to not having a camera when it did this you will just have to take my word on this.
Which brings me to the conclusion that I would not recommend them for any type of work that I do or to anyone else. J/B has a good manifold but has along way to go with their digital gauge. I would not want to work in any rain or snow with these as there is no protection to stop water from entering the case or thru the temperature probe jack plugs.
I was very careful when using the J/B digitals and would be very concerned to use them daily in the conditions that I work in. I am around hot dirty engines with electrical interference, moving belts and pulleys, major vibrations and extreme temperature changes.
Could they have been damaged in transit I don't know but they were very well packed with paper in the shipping box and it did not appear to have been damaged when I got them.
I then sent them out to Doug Lockhart as per Tony last Monday. |
| Doug Lockhart wrote: | I have had a chance to use the JB dig. gauge set briefly and have the following comments. It is a nice small, light unit that will appeal to those wanting an easy unit to run up onto a roof without a lot of complicated connection needs.
-hose blank offs are not drilled therefore your hoses never seal and with POE/moisture concerns this could be a concern.
-low side failed and never could get it to work
-high side tracked VERY SLOWLY and settled out 3-6 psi on a 185 psi system off of actual as compared to DC DRSA.
-minimal information right in front of the tech to help as well as train the tech. If you always see your SCT/SST under your corresponding pressure then you'll start to remember pressure/temps and help you in troubleshooting. The temps being present all the time gets you to understand the relative refrigerant glides.
-Without R being displayed constantly you have a chance with cell phones/customers/etc of forgetting to reset....without the temps you really have a problem then when you switch over.
-temperature sensors are uncomplicated and plug in at the front without a sealed dust/water cap
-case is very minimal with no boot for impact protection.
-hook is easy to use and small as well as compact.
-buttons are minimal and give most of what tech would want.
-manifold is a nice compact smooth operating manifold
Very basic and since lowside was not operational could not see the performance in that area.
Suspect lower accuracy easily EMI affected pressure sensors used instead of transducers with EMI enclosure and EMI shielded cable as questioned by Reefer. Good unit for basic troubleshooting and basic startup only.
Let me know who/where I should ship this but since the lowside is non functional it will not be of much value to the next reefer tech. |
| gonefishing wrote: | Just to up-date on the J/Bs in this area. 4 sets out in the field with techs I know,
two over 2 months now, and everyone is very happy with them. I would not
like to have to make a choice right now, that's for sure.
GF |
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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ServiceF1rst
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| Posted: Sat Oct 20, 2007 12:22 am Post subject: |
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OK that's done, so with the essential evaluation and opinions recaptured in the above post - in summary for those members who may not have been here during the period that this portion of the fieldtest transpired.
The initial member to fieldtest the J/B DM-2 liked the instrument and logged his evaluation.
The second and third members to test the instrument had issues that required the set be retuned to J/B for in warranty repair. To date there is no single source able to provide a definitive evaluation relevant to the instruments failure - so we are just going to skip that whole area of the discussion to begin with because it leads to a dead end anyway.
I do however think it important to include this note on the failure. J/B Industries resolved the issue quickly and returned the instrument at no cost in a very short, reasonable period of time. Customer support was absolutely a priority as was customer support, so J/B gets an "A" in that department.
That brings us full circle for the most part. the set is ready to begin new fieldtesting. Members who might be interested in fieldtesting the DM-2 should reply to this thread and we will make the necessary contact and arrangements to facilitate shipping.
As always thanks for your participation in these fieldtests.
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Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least. |
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