kitchen problem

[bernie]

I've got to replace some beat up condensors. They are located in a kitchen on the cooks line. These are 12 drawer, 4 evaps, 1 condensor prep tables in a kitchen. There is also condiment section on top of prep table.
Problem is these are 404a units and the ambient is 100F continually.
The condenser coils are damaged and blocked with grease etc.
Liquid temps are at 115 - 120F.
Need to replace two of the condensers but Im thinking there is a better refrigerant for this application.
R-22 would be ideal but space is a problem. This being the case I have to come up with a better control strategy. Each evaporator has its own solenoid and thermostat. These are high use coolers. Obviously the is a need for better frost control and I see the need for suction/liquid heat exchanger to keep liquid temps down.
The units were manufactured by becca equipment, and the condensers are labeled omnitemp.. I'm on my own here and I'd like to know what the professionals here would do.
Thanks Bernie

[herefishy]

Originally posted by bernie
Problem is these are 404a units and the ambient is 100F continually. The condenser coils are damaged and blocked with grease etc. Liquid temps are at 115 - 120F. Need to replace two of the condensers but Im thinking there is a better refrigerant for this application.

The refrigerant is not the problem. The system was intended for use with 404A, and that is what should be used (in the existing). So you should absolutely forget about "changing refrigerants" as an answer to your problem. If you change refrigerant (and keep the original design capacity), the condensing temperatures will still be the same. What is the ambient ? Is it a hot kitchen?

If it is a hot kitchen, perhaps employing a C.U. of 6%-10% more capacity would compensate for the higher condensing temperatures. Typically "indoor" self contained units are rated at no more that 90F ambient (Condenser entering air temp)

Is the kitchen 100F? Or is just the area around the C.U. 100F? Maybe the dirty coils, and the poor airflow is compounding the temperature at the C.U. Have the coils been cleaned?

I have to come up with a better control strategy. Each evaporator has its own solenoid and thermostat. These are high use coolers. Obviously the is a need for better frost control

Don't eliminate the solenoid valve... In regard to temperature control, if the existing is an "air sensing" control, get rid of it!!!! Are like your everyday walk-in stat fitted in some manner to control temperature? You should employ "coil sensing"
cold controls which sense coil temperature. For refrigerators, you would want a cut-out at about 20F (for TEV apps) and a cut-in of about 38F to 40F. A dependable control that I use (and it never fails me), I purchase from Refrigeration Hardware Supply, stock #60-260

Other controls that come to mind are:

Delfield pt.#219-4224
True mfg pt#800306

These are all the (previously manufactoured by Hubbell?) 953IN line that Ranco recently purchased. any of the above pt #'s, you will be able to install and forget about. They will ensure positive coil defrosts. The "pigtail" you will insert into the coil fins at the oulet of the coil airflow. Do not get one of those Ranco fits all's. You will inherit a career getting it to work

I see the need for suction/liquid heat exchanger to keep liquid temps down.

Forget it, you're just going to increase your compressor superheat. I wouldn't go there. Again, is the high head due to the dirty and damaged condeners? If the kitchen is 100F, when you replace the C.U.'s, see if you can fit something rated at the proper capacity, at the ambient it will be in.



PS: for cleaning those greasy kitchen condensing coils, that "pink" coil cleaner is useless. get the "alkaline" cleaner 4-X or X-4? that you can purchase at Johnstone supply. It really does a number on grease.


PSS: Make sure "Cookie" has all the holes filled in on the condiment rail. If a section of the condiment rail is not required for product, an empty pan should be in the "hole" anyway !!


PSSS: If the kitchen is 100F, maybe someone should start working on the d*mn air-conditioning. I hate to eat at a restaurant, when I know the cook's sweat is dripping into my meal

[Andy]

Hi Bernie,
I would look at some ventilation, first, then A/C, if you can't talk the customer into either, re-design the fridge systems with larger condensers. I know of a 15 hp condensing unit struggling in a roof space, I friend of mind, lost the head and bolted another condenser he had second hand, the same as the first, just directly above the other. Then piped them in series, pressure drop thru the condenser was not ideal, but the unit started to run well, matter what the ambient.
Kind Regards. Andy

[bernie]

Well said herefishy!!
The kitchen is actually conditioned well, problem is the condensers
are accross from the gills, ovens etc. What these units are picking up is radiant heat off the cooking equipment.
I don't intend to do away with the solenoid valves, my intent is to use a robertshaw electronic temp controls for each evaporator.
I'm also kicking around adding a time clock for night time air defrosts.
This info was from a survey for a service contract we have.
I havn''t done any maintenence to them yet.
I like to use a product called grease strip, its made by ecolab.
Its a "clingy gel" that liquifies the grease and allows you to rinse away with water. I'm not familiar with the products you referenced, but i'm all for a better mouse trap.
Thanks Bernie

[herefishy]

Originally posted by bernie
my intent is to use a robertshaw electronic temp controls for each evaporator.

..................

The best idea, anyway is to re-establish the original manufacturer's configuration and use the same parts for replacement, assuming that the machines have not already been Re-Engineered.

I'm also kicking around adding a time clock for night time air defrosts.

This is the greatest misapplication of defrost ever !!! ... and I see it all the time. Why do you want to cycle defrost at night?? No one is in it, no product is entering, and it will be "off" on the t-stat, anyway. When you would want to apply a defrost, is when the load is so great, that the thermostat won't satisfy and there is not enough off time for air defrost (lunch rush or shortly thereafter).

The cold controls that I described will assure positive defrosts at all times. You in effect would be affecting a "temperature initiated" defrost cycle, whereas when the frost builds up on the evaporator and the airflow decreases, the evaporator temperature falls. The cold control senses the fall in the coil temp, and cycles off, until the coil temperature reaches the cut-in setting, which is ideally the high end of the desired temperature range.

Doesn't that seem much more impressive and concise than.... a clock?


I don't think the the 4-X will outperform your Grease Strip.... stay with it.

[condenseddave]

Bernie: Is this "toptech"? Just curious...

[bernie]

Originally posted by herefishy
..................

The best idea, anyway is to re-establish the original manufacturer's configuration and use the same parts for replacement, assuming that the machines have not already been Re-Engineered.



This is the greatest misapplication of defrost ever !!! ... and I see it all the time. Why do you want to cycle defrost at night?? No one is in it, no product is entering, and it will be "off" on the t-stat, anyway. When you would want to apply a defrost, is when the load is so great, that the thermostat won't satisfy and there is not enough off time for air defrost (lunch rush or shortly thereafter).





The cold controls that I described will assure positive defrosts at all times. You in effect would be affecting a "temperature initiated" defrost cycle, whereas when the frost builds up on the evaporator and the airflow decreases, the evaporator temperature falls. The cold control senses the fall in the coil temp, and cycles off, until the coil temperature reaches the cut-in setting, which is ideally the high end of the desired temperature range.

Doesn't that seem much more impressive and concise than.... a clock?


I don't think the the 4-X will outperform your Grease Strip.... stay with it.

Sorry it took soo long to reply,
The original manufacturer now only manufacturers outdoor
barbeque grills. That should give you an idea as to how well it was designed.

The ranco control I referenced I installed as a cold control.
I love the digital display and the programming options they provide. I feel they are far better than the #$@% control that came with the box. They were also installed in the return air stream. The new ones I buried in the coil, this should help.

*The time clocks were added also to effectively shut down the compressors a night a few times to give them a break. Cooks
dont always close the doors, box of bacon too long for the box
etc.*


*I love this site, you defenitley have to bring your A game here.*
As always great responses.*

[bernie]

Originally posted by condenseddave
Bernie: Is this "toptech"? Just curious...

whats up dave!

[condenseddave]

Not much, man, I kinda quit posting at the "other place" for awhile. Some of the utter ignorance was really getting on my nerves...

[herefishy]

Originally posted by bernie
The ranco control I referenced I installed as a cold control....*The time clocks were added also to effectively shut down the compressors a night a few times to give them a break.

What is your cut-in and cut-out?

[bernie]

Whats up fish,
Set @ 20F out
40 in
Been back to check on it all seems well, Cooks think I'm
a magician.

[bernie]

Originally posted by condenseddave
Not much, man, I kinda quit posting at the "other place" for awhile. Some of the utter ignorance was really getting on my nerves...

The politics post on that site really can drag you down,
I like it here cause half the time I have know idea what the
hell their talking about and can learn alot.

[herefishy]

Originally posted by bernie
Whats up fish,
Set @ 20F out
40 in

That sounds good.

[Luiyo]

I'm having the same problem but in this case I'm the restaurant manager and I'm looking everywhere to solve my big problem the people that are working on my kitchen drawers and cold tables set everything just fine it works for six hours then the evaporator starts to freeze and the tempeture starts to raise until no tempeture I'm having this health department visits and I should be done in a couple of days . The refrigeration guy told me he could solve this problem changing the "tev" for capillary and control it with the existing white rogers controll. There are 4 of this equipments with this problem all are the same "jade refrigeration " I can find nothing for this on internet . They area 1/4 horse condensing units with ranco low pressure controll located at the roof of the restaurant charge with R-22 gas and in the kitchen is the evaporator unit that consist on 2 fans the coil and new sporlan "tev" . This guy also wants to change the refrigerant with 408a because he sais is cooler than the r-22 please help me with that I don't want my restaurants to colse because of these problems.Please tell me something it is the control that I'm using or what??? Some tech told me once that I should switch for low temp condensing units and adjust to my desire temp (32-38)F

[herefishy]

I just don't know where to start.

You stated that there is a "new" Sporlan TEV. New, huh? I would guess that it's wrong, and likely the key to your problem.

Assuming it's wrong, I'll bet it is a "1/4" valve since the condensing unit you state is a 1/4 horse. That would be wrong, however typical of a shop that would address your problems as described.

"The equipment is only as good as the service it receives". Yours isn't working very well, huh?

If the White Rodgers control has an adjustable differential of up to 30 degreesF or so, the sensing bulb could be inserted into the evaporator coil and set at 18degF cut-out (off) and 38degF cut-in (ON). OR the original control configuration of the equipment should be re-establish (if it is already butchered). In these type of boxes, air-sensing controls are not very effective because of high rate of air exchanges.

Are the gaskets in proper order? With a coil-sensing temperature control, it wouldn't make that much difference, anyway.

[Luiyo]

what is the smart beacon II computer could this solve my problem.

The white rodgers bulb is located in the back wall of the unit it would be better to located at the coils??

What about the gas should be switched to 408A??

Do you know somebady from puerto rico that could solve my problem I' district manager in Denny's restaurant Puerto Rico we have 10 restaurants here and we are paying for somebady to fix our problem. SOON We have the same problem on all our stores and the bad part here all the equipment is new. but it freeze.

[Gary]

No matter what controls are used, the key to solving the problem is the coil temperature at which the compressor starts. The coil must be defrosted before the compressor starts, then it must shut the compressor off when the desired temperature is reached.

Go to my website and buy the "ACR Trouble Shooting" book. Give it to your refrigeration service technician. This will make life easier and more profitable for both of you.

[Dan]

Louiyo, you might call Raulito de Pedro with Refrigerama. He is the service manager, and I have a high regard for him.

[Luiyo]

Thanks Dan I have his number and I already talk to him in case the people are working now can't give me the results I want , The next choice would be Refrigerama ( Raul's Company) You know him from this forum??/

[Luiyo]

Today I buy a low tem 1/2 horsepower condensing unit and install it and the complete drawers where at 26F so next step would be adjusting that tempeture to 32-38. If this works for 48 hours without problems I would be switching all my units to low temp 1/2 condensing units.

[Dan]

I have known the de Pedros for close to 25 years through their relationship as a distributor for our company. Their service capability became much stronger under Raulito's direction. Tell them I said hello!

[Luiyo]

Ok I know he is a big distributor in the island of some of the best refrigeration trademarks here also he is the only one that works with my hoshizaki icemachines parts. If I talk to him a will send your greetings!!

[tony_rich]

kitchens are HOT many copressors die to soon poor maint # 1 they need a lot more when in side the other is oil break down from the High heat this is why I jest remote them basment, roof or out side wall.

[tony_rich]

had call. I did want to say just like HEREFISHY when there greese you need a good cleaner. I like new bright, but I dont clean them in the kitchen I take the condenser out side to clean it may seam like a lot of work but the way I see it is. only one dop of that cleaner is needed to make somone sick, say your on a reach in this stuff will get into the box even if you clean out the food you still have all those cooks and staff runing by like there on crack. pluse the fact you can't flush the cleaner well it rots coils. after that hit it w/ blast off 3 time yr. never need to clean it.
blast off works on mild greese. It takes 3hr but I sleep well...