ReplyWe also have the SMAN2 that doesn't include a micron gauge if you prefer to have a stand alone micron gauge.Originally Posted by mgenius33
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I know there was an old thread on this, but now that changes have been made to improve them and many more techs have had time to test them, which one is the better?
From the posts I've read, I'm gathering;
pricing is near the same
physical durability goes to SMAN3
accuracy might lean toward the 550, I think they might use better sensors like thermistors instead of type k thermocouples, etc..
reliability is about even. Do the SMANs have any static discharge issues? Are they tolerant of light water contact?
customer service goes to FP
SMAN has the micron gauge built in, before anyone says 557 that adds $200 which puts them into a different class.
I'm really not interested in digicools or any other meter you have to hook up to your own manifold for the same price as a nice unit that comes all in a package.
So, from those who have tested these units, what pro/con chart, or Testo/FP chart would you write for this head to head shootout?
Last edited by mgenius33; 07-09-2011 at 05:10 PM.
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We also have the SMAN2 that doesn't include a micron gauge if you prefer to have a stand alone micron gauge.
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We have 4 Testo 550's in the truck. The hanging hook is week, but Testo keeps sending them to me so it's not a big issue. Love the durability of the unit itself and the price.
I did learn that the hook is not a press-fit installation like I thought. Under the battery door, under the serial number label is a screw and insert in the plastic back that removes for easy hook replacement.
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I would be interested in sman3 owners have to say too. I'm running digi-cools, and the other guys at work are showing interest in going digital also. I'm not real happy with the temp sensors on the 1250, hardly usable.
sman3 k thermocouples are field calibratable aren't they? No big deal if all you have to do is drop em into icewater ocassionally. I wouldn't buy it for the internal micron gauge, because what if you hook up to a trashed system? I just don't see it holding up, but if they're cheap enough maybe it could be considered a bonus.
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There are now several threads on the SMAN3 with many, many users out there. I've had one for several months and recently suffered a failed high side valve. I made on telephone call to Field Piece and without hesitation was told a new one would be on the way by overnight Fed/Ex and I should have it by morning. Well they fibbed a little. The sent it by UPS overnight and I had it by 10:15 AM. And the sent two valves, not just one! So how could I even begin to complain about the valve failure. That's customer service par excellance, IMO.
I've had otherwise an excellent experience with my SMAN3. It did get weird with the micron gauge but that was, I'm sure, a result of the stuck high side valve. Otherwise it's made me quite lazy. I get the IWB using another thermometer and manually load it into the SMAN. I just use the high side pipe thermometer for the OAT and it loads automatically. Once that's done, I hook up my two clamp thermometers (included with the manifold purchase) and I've got instant target SH, actual SH and SC, as well as pressures, T1/T2 temps, hi and lo saturated temperatures and can switch between refrigerants with one button push. R-22 and R-410A are right next to each other in the data base.
As for calibration, there are 4 options. One is to calibrate the gauge set to a known source or you can calibrate the gauge set to atmospheric. Then there are two calibration screws for the K2 thermometers. It does not come with refrigerant line sets but that's minor. I rate the unit a 10 on a scale of 0-10, 10 being the highest.
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I also am very happy with my sman3 but don't use the micron gauge function.
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Well, being a skeptic on the whole digital gauges thing, I can now say I was wrong.
I have been using my SMAN's for 3 days now, and yes I am happy with the results. Did the clamp calibration by clamping on to a couple of ice cubes. Dunking them in icewater doesn't read as low as straight up ice.
I also thought that I would only use them for diagnostics, and use my old analogs for daily use. Now that I have them, I use them, and I think, damn my analogs are now backups!
It's so nice using these gauges for pressure testing.
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I too give Sman3'S a big thumbs up. They are the bang for the buck. I have used mine now for a few weeks and love them. I might just buy another pair for back up.
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FWIW ice out of your freezer can be much colder than 32˚F
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I would agree if the type k thermocouple were a pyrometer reading the core temperature of the cube. However, 32° is the temperature at which ice melts. So, the surface temperature would be 32°, as it was run under water before clamping, inducing the melting process.
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Water can be supercooled and superheated.
This is a property of water
more common than you may think if you've thought about it before
not to mention impurities.
Water is not black and white
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Glad you like the SMANs. Keep letting us know how they are going!
Just to clarify the calibration procedure. You should have a bucket filled with Ice and the water filled just up to the top of the ice so the ice isn't floating too much. Then stir as you set the temp. Ice itself can be colder than 32 and this may throw off your measurement.
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Ice itself IS colder than 32°. The melting point of ice is 32° for pure water. Distilled water is close enough for testing.
Water mixed with ice will not get down to 32°, but it will also get close enough for testing.
The icecube that has begun to melt is insulated by a thin layer of water, this water is in contact with the probe.
Water and ice is not that complicated either. The only factors that will cause water to boil or freeze at different temperatures other than ~ 212° and ~32°, are impurities, and pressure change. That's it, there is nothing more to it.
The only reason people believe in the "superheated" water b.s., is due to the violent eruption when impurities are added. Just as hot oil will erupt when water is added. The water never reaches the temperature of the oil, it simply bounces until vaporization or mixture occurs. Pure water simply cannot absorb any more heat in liquid state. Nor can it release any more heat without being altered by impurities or pressure change.
If you believe so, please explain the alternatives.
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If you can fit the lack of nucleation somewhere in between pressure and impurities I will concede SH,SC H2O = BS
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I find my temps form the clamps to be right sometimes and off other times i adjust them they work but i still grab my amp probe and use it seems more on the money and i have other ways to take temps just the k type dont seem to be as up to par as they should...
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LOL! I think I will concede aswell...
I dunked them in stirred icewater and found to be 6/10ths to 8/10ths difference. It seems, I've wasted too much time on thermocouples that aren't that accurate anyway...
Enjoyed the education on nucleation. Not sure it exists with the melting point though?
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I've had the same issue, that's why I've wasted so much time on the calibrating thing.
I did find that using the same clamp on the same port keeps the temps more accurate. I labeled them I and II to keep them plugged into the corresponding ports.
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At 32˚F is where I see it the most SH H2O seems like a rare occurrence IMO hence the BS opinion. Ever see a slushed up ice machine?
It could be possible that the initial clamping of the ice would melt and form the water like it does but as the sensor is cooled to 32˚F and if your ice cube is still colder than 32˚F it is possible to supercool that water and sensor below 32˚F.
As far as the OP goes the temperature sensors are one of the major difference between the two units. The 550 sensors are very accurate with very little drift over time. On the SMAN once you notice them starting to drift and you are futzing with your one 32˚F reference point you will most likely notice them drifting out at other temps. It is best like you said to mark the sensors and calibrate them closest to the temp you are using them for like a dedicated suction and liquid.
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i have them marked as well and still same problem also still have the high side valve not always wanting to open if i let it set and try again it works...Has anyone else ears came lose where u put the clams mine have but easy fix.
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