Reply to Thread

do alot of you guys have tools for airflow that mainly do commerical refrigeration? i don't mean to ask a dumb question or hijack a thread. i'm just curious, always trying to pick up knowledge from knowledgable people.

I have an Alnor Velometer Jr.

I'm looking into a Testo 410 anemometer, though.

What Alnor instument do you use?

Originally Posted by jpsmith1cm

Iceneck,

To hijack my own thread, I think you are wise to stay clear of ECMs in MOST refrigeration applications.

One plugged drain and all that fancy, EXPENSIVE technology goes right down the drain, so to speak......

I've 'retrofitting' ECMs with 9w and other appropriate sized motors for years.

Jps,

Didn't mean to hijack your thread...I thought it was along the same lines as the problem you posted, though.

As far as what you said about ECMs, EVERY tech and EVERY salesperson at the supply houses have told me the same thing you did.

Thanks again...

Iceneck,

To hijack my own thread, I think you are wise to stay clear of ECMs in MOST refrigeration applications.

One plugged drain and all that fancy, EXPENSIVE technology goes right down the drain, so to speak......

I've 'retrofitting' ECMs with 9w and other appropriate sized motors for years.

I learned a lot from this thread. There is a company that keeps coming to the market I work at selling "energy rebates" for refrigeration. We've actually done quite a bit of business with them--got a bunch of LEDs installed in glass door cases, floating head pressure controls, etc. for great price--but now they want me to buy and install ECM motors for all of our cases and walk ins. Keep in mind these guys are NOT refrieration mechanics and can be kind of pushy salespeople. So I was like, "uhh, guys...I think these fans need to be spec'd just right for the cases. Like, CFM and the like?" They just dismissed me. I was like, well, can you supply me with data that the rpms of the motors will be exactly the same? They couldn't, so I scrapped the program.

Engineerdave,

Yes, the store has the ability to switch from med to low at will with a key switch. They only do so for a week at the holidays, though. To date, no more complaints on the case.


As far as the motors are concerned, this particular manufacturer (who has reps on this site so I'm not naming names) uses a unitary motor design. Basket, motor and blade are one large assembly. Can't remove the blade, so you aren't likely to swap in the wrong part. The parts in place were OEM, so you do the math.


Oh, yeah, due to the age of the case, the manufacturer went back on the verbal agreement to send me new motors and the operation of the system remains unchanged as the customer has also refused to pay for the parts.


As far as the company we inherited this mess from......... I love taking over their accounts. They always lead to good, educational problems like this.

I think there are still questions.

1) Does the customer switch the unit from MT to LT for Seasonal promotions, such as turkeys for Thanksgiving?

2) The other guys you inherited the store from... are they reputable?

The reason for both these questions why / how did the wrong fans get in there? Was it an oopsdammit (guys just stocking & selling 9wt motors) or were they trying to beat a different problem?

It's been several months now, should be warm & humid there, how's that system running now?

Nice find either way. Not sure I would have used anything more accurate than the back of my hand to check airflow.

Originally Posted by KB Cool

Wow!!! who would have thought too much air flow on a refer case. I usually just check to see if the coils frozen, motor is working and spinning the right way. Nice find though and glad you shared it with us. I'll have to keep it in mind. May need it someday.

Same here!

Originally Posted by jpsmith1cm

TXV was wide open at the time this picture was taken.

All heating vents were already checked and aimed away from this case. (Yes, it is an open air single-deck type case)

Not to be a jerk, mccool, but how would low airflow contribute to this problem?


Ok. Time for another hint. It hasn't worked right in a very long time if it ever worked right. Our company didn't install it, but we got saddled with the repairs.

*Keep in mind that I'm reading as I post..

Hmmm... Maybe not all the components aren't manufacturers and has been retrofitted?

Originally Posted by jpsmith1cm

Hopefully the picture I took of the DRSA is adequate to provide all refrigerant side data.

Problem is this:

Dual temp single deck case would NOT hold temp in LT mode. Did a 'fair' job in MT.

Tech#1 was out and condemned the powerhead and when that did nothing, replaced the whole TXV. When THAT didn't work, I was called in.

Cut in a pressure tap and SG on the liquid line to confirm quality of liquid and the pic I posted gives the results. Sightglass was perfectly solid.


So. Fire away.

So, what's the low end temperature of the suction line where the sensing bulb of the powerhead is located? Maybe the superheat is off.

we used to have to check each case temp and rack pressures now we go on the computer and look at every thing That control system even calls your cell or computer if something is not right. Nice to set coil td and not have to take gages or temp probe out of the truck. The new controls will not brake the bank no more frozen food case full of product that the juice is liquid.

Originally Posted by Herb1025

After 18 months who had to trash all that ice cream or did they sell the frozen product as new might look at fed reg on the food

For most of the year, they run this case as a medium temp case. In that mode, it holds reasonably well.

There has been no product loss.

Originally Posted by Texas-Tech

Looks like he had it right

No. he did not.

The problem WAS airflow related, but the case had 3 times the airflow that was required, not low airflow as he suggested.

[quote=jpsmith1cm;858382

Not to be a jerk, mccool, but how would low airflow contribute to this problem.[/quote]

Looks like he had it right

After 18 months who had to trash all that ice cream or did they sell the frozen product as new might look at fed reg on the food

Originally Posted by Herb1025

So is the factory going to pay ? I have had store ref people adjust fan blades to adjust air flow but to replace fan motors and blades just can not buy it Should look at case history

I wish I had the full case history.

I don't know about payment or anything, I just want this case to work properly.

As I said before, my company did not install this case. We took this store over about 18 months ago and this is the first that this problem was brought to our attention.

Originally Posted by mccool

Oh now I see the high superheat on your guages...don't own a fancy set like that,,,,,but would have caught the problem before case was even started, when I noticed the wicked pitch on the fan blades.....just kidding.

Is OK. What you are looking at in that picture is the new AK-900 coming from Digicool. Once you get used to the display, you can absorb all of the system information at a glance. They're AWESOME!

If I started the case, I'd have caught it, too, when I set the SH. Apparently, not all companies do this.

Originally Posted by icemeister

What a great lesson JP.

Now I get your hint about how the HVAC guys might get the answer right away.

I totally missed the airflow aspect...even after I posted a comment about using the Testo 410 for case velocities just yesterday.

DUH....

That is EXACTLY why I posted this and why I milked it along as long as I did.

It seems that, as a market guy, I tend to ignore airflow as a potential problem. If a case is delivering a decent air curtain, then the airflow is fine. Nothing more need be checked. I *ASSUME* that it is correct. I have the instruments to measure it, I just don't.

I can just about promise that this one won't slip by me again.

I think that the 410 just crawled a few slots up the tool list...

Wow!!! who would have thought too much air flow on a refer case. I usually just check to see if the coils frozen, motor is working and spinning the right way. Nice find though and glad you shared it with us. I'll have to keep it in mind. May need it someday.

Originally Posted by jpsmith1cm

The assumption is that there was something wrong with the refrigeration circuit.

I called Tech support and when the guy called me back, I laid out the scenario that has been outlined for you guys.

He asked me this question:

"What is your AIRFLOW?"

I took the Alnor and checked air velocity. Read 600FPM at several spots across the Honeycomb. I did this with him on the phone and read the readings off to him.

Case airflow is rated at 220 FPM.

I choked off the return air to provide as little airflow as possible (got it down to 300FPM) and all readings dropped to normal.

With the higher airflow, I was lucky to see 10 degrees supply air temperature. When I choked it off, it dropped so fast that my Fluke could barely keep up with it.


Apparently, at some point in this case's history, the wrong fans were installed....

What a great lesson JP.

Now I get your hint about how the HVAC guys might get the answer right away.

I totally missed the airflow aspect...even after I posted a comment about using the Testo 410 for case velocities just yesterday.

DUH....

Originally Posted by jpsmith1cm

TXV was wide open at the time this picture was taken.

All heating vents were already checked and aimed away from this case. (Yes, it is an open air single-deck type case)

Not to be a jerk, mccool, but how would low airflow contribute to this problem?


Ok. Time for another hint. It hasn't worked right in a very long time if it ever worked right. Our company didn't install it, but we got saddled with the repairs.

Oh now I see the high superheat on your guages...don't own a fancy set like that,,,,,but would have caught the problem before case was even started, when I noticed the wicked pitch on the fan blades.....just kidding.