My Customer's Air Conditioner isn't keeping the beer cold!

In the market that I service there are numerous medium temperature applications utilizing typical air conditioning condensing units. Upon visiting a prospective customer who asks that I review the equipment that he's utilizing, I frequently come across the "Rheem" beer case condenser.

In most cases, the installer has gone into the condenser cabinet and modified the piping in order to install a fan cycle control and squeeze a receiver into the cabinet. Other times, the receiver is sitting on the roof next to the cabinet.

I do not hesitate to tell Mr Customer, that if he has a failure of an air conditioning condenser in a medium temperature application, that he must be prepared to replace it with a "real" medium temperature condenser..........because I will not do him the disservice of repairing it.

I have communicated with several manufacturer's engineering departments. All indicate that their equipment applied in such a manner is void of any warranty or liability, and furthermore that the equipment is not designed for such an application. However, no one has yet to explain to me in a technical manner by what criteria that the machine is ill-suited for the application (aside from the lack of low ambient controls, receiver, etc.... which Johnny Jackleg seems to remedy himself in the field).

One fellow with ArcoAire was getting around to explaining some relationship between the THR of the condenser and the evaporator NRE. Also he was concerned with decreased refrigerant volume returning to the compressor and possibly affecting motor cooling in hermetic applications. These criteria as related to a 45degF S.S.T. (air conditioning application)vs. 22degF S.S.T.(medium temperature application).

I dare say, that regardless of the manufacturer's warnings regarding warranty status for the "misapplication", that millions of dollars a year are rendered in compressor warranties for these applications (by others). I have a customer that lost a 5 HP scroll within the first year warranty on the dairy "air conditioner". The customer said "That compressor is still under warranty".

I said, "No, it's not"

Anyway, can anyone shed some technical light other than the obvious, which I deal with regularly, on whether or not the utilization of air conditioning condensers in medium temperature applications is bad practice.

An air conditioning condensing unit operating on a medium temp refrigeration application? High superheats, liquid slugging, oil return problems...

A few obvious questions come to mind when trying to assess the potential problems you might experience:
1.) How do they match the condensing unit to the evaporator load?
2.) What is used as a metering device?
3.) How are the suction and liquid lines sized?
4.) What ambient temperatures are the condensing unit exposed to?
5.) Crankcase heater?
6.)Superheat settings???
7.) Liquid injection? Hot gas bypass? EPR?

Then again... Nevermind answering the above questions! The very idea of using an air conditioning condensing unit sounds like an expensive way to save a few bucks on a properly designed and matched condensing unit!

Yes, Gibson. As you state, those are the obvious questions and/or problems.

(1) As far as condensing unit matching, I suppose that "Johnny" is using the rule of thirds

(2) In all applications, the expansion device is a TEV, but typically the TEV(s) are over sized, because "Johnny" often specs a valve or valves based on the nominal rating of the valve

(3) Line sizes have typically been correct

(4) In central Texas, the maximum ambient that I have actually measured on a roof is 120degF, entering air into a condenser

(5) Crankcase heater, etc., perhaps if factory provided. Of course that would be highly recommended, because there is NEVER a PDS (LLS) installed in these systems.

(6) Typically, I know that the TEV(s) in such a mess is wrong, so I usually start at the TEV replacement and LLS installation while waiting for my condensing unit to be delivered.

(7) No EPR's or unloaders. Condenser fan cycle control typically Mickey-Moused into the unit.


Of course all of these above issues are what I catagorize as the obvious.

My question however, is even if the air conditioning condenser was actually installed into a system with a 20degF design SST in a manner conducive to good refrigeration practice (aside from using the air conditiong condenser), is there some inherent characteristic of the design of an air conditioning condenser which proves it ill-suited for medium temperature appplication?

herefishy...
1.) A heat pump with a condenser rated at 20deg SST would be operating in the heating mode. I think you could rule that suspicion out.

2.) As ambient temperature falls, condenser cap increases. As SST falls, compressor capacity drops.

3.) What is the evaporator capacity? Are you refering to oversized TXV's with relation to the nominal rating of the A/C condensing unit or the evap coil capacity?

By DOA you mean what? A burnout or not pumping or siezed?

Gibson, thanks for again responding.

(1) In regard to Trane making the reference to a consing unit capacity @ 20degF SST, I was inplying that perhaps "Andy" was referencing some information on the operation of perhaps a heat pump in the heat mode. Again, I don't know the source of his information.

(2) I understand the effect of variances in ambient and SST, which are the factors that I beleive are crucial in the decision to NOT employ any A/C condenser in any other application than an air conditioning application (45degF SST).

(3) by oversized TEV's, I mean in relation to the design load and evaporator capacity. "Johnny Jackleg" employs his TEV's according to the nominal capacity of the condenser. If the compressor has a "5" on it (5 H.P.), Johnny makes sure his valve had a "5" on it (i.e. GVE-5-C).

D.O.A. = Dead On Arrival. Electrical and mechanical failures are discovered.


But all that is neither here, nor there........


*My question is if there is some characteristic in the design or construction of an air conditioning condensing unit be it the condenser coil, the compressor, or the relationship between the two, which make an A/C condenser ill-suited for operation at a 20degF design SST?*

I understand that compressors employed in air conditioning applications may be rated for adequate capacities at varying SST's (applications). **But is it mechanically detrimental to employ an air conditioning condensing unit in a medium temperature application which is 60% of the rated capacity of the unit's design in the application that it was intended for? And if not, for what what mechanical reason(s) ? **

Mind you, the answer could be that ,as mickey mouse as it may seem if you do it right it'll be just fine and dandy. Well, I ain't ever seen it done right before, so I wonder. :rolleyes:

herefishy,
*In a word, YES!
In three words, YES! YES! YES!
In five words? *S*

Hi to the both of you. I should have known it was either Texas or Florida where this is somewhat common.:) Here's my two sense worth:

All aforementioned comments regarding controls and heaters are, of course, to the point. But let me simply point to the hermetic compressor as an issue:

A high temperature compressor has a matched motor to the compressor displacement.... all hermetic or semihermetic compressors have a motor designed to operate within a somewhat narrow band of temperature and pressure limitations.

In the case of taking a high temperature compressor down to medium temperature duty, you are providing less cooling to the motor than it was designed for. Take it to a further extreme and the imminent failure of the compressor will be assured. Try running the high temperature compressor at -20 deg F. You will have a burnout in short order.

Not nearly enough "wind" blowing over the motor to keep it from overheating. The same mistake can be made in reverse by taking a compressor rated for low temperature and attempting to operate at high temperatures. Now you have plenty of "wind" but not enough motor to do the work of high pressure evaporation.

All compressor manufacturers have limits in their rating data that will not show the compressor performance at conditions considered outside the compressor's parameters for this reason.

In your examples, Herefishy, it is possible that the compressor is rated down to 22 deg F. But what does pumpdown to 10 deg F do in the long run?

Also, keep in mind that the condenser fan assists in the compressor body cooling and the placement of components by the manufacturer of the a/c unit were considered adequate only for an application that assumed suction return cooling at higher mass flows.

The biggest problem with a/c units doing fridge duty is that they sort of work and are 30% cheaper than a proper system.:)

Thanks Dan,

I understand you to say that the decreased suction temperature with a properly sized and adjusted expansion device producing a "colder" return temperature would not compensate for the decreased mass flow compared to the design application (of the air conditioner). Is that right?

herefishy,
Yes, there is something inherent to the design of an air conditioning condensing unit that will reduce the life expectancy of the compressor. Dan has hit on the lack of cooling to the compressor motor windings that will lead to a burnout.

This begs the question; have you ever measured the temperature of the hermetic compressor casing under the conditions you describe?

Second and subsequent yes's were that it is detrimental to operate an air conditioning condensing unit outside of it's normal ratings. An air conditioning condensing unit could be made to work but the modifications would be so expensive that it's better to use a condensing unit designed for the application.

Gibson, and Dan - Both

I have been preaching the misapplication of these machines to my customers, and continue on a month to month basis to throw these applications into the street, literally.

I find it frustrating however, to see that "Johnny Jackleg" is out making 3 million dollars a year installing this c**p, and making a killing on keeping it running. When I get there, I throw it into the street, install properly engineered and installed equipment, and I don't see it again for twenty years, because it works!

My motto is: "A well informed customer is the best customer".

I don't mind inundating the fellow with the scientific or mechanical facts. I just want to be sure that I'm not blowin' smoke up the fellow's butt, just because I don't like the A/C coolin' the dairy case thing.


Thanks for your insight.

...the fish

see ya'

This is an INTERESTING thread!

I would break down the condensing unit, look at the manufacturers specs on that particular compressor model number and look for similar model numbers comparing the differences... voltage... relays... capacitors etc.

I have found on MANY commercial refrigeration applications that the compressor used on a medium temperature application is ACTUALLY spec'd as a HIGH temperature compressor. And to top it off... the condensing units are built by the compressor manufacturer in many cases as well!

I have a unit in my garage right now that has dual specs... changing the start components can make a world of difference sometimes! "Kinda puts a new spin on it"... think about it. On some units the start components aren't even changed... everything comes down to mass flow.

Yes indeed.... this is an interesting topic! :p

Dean,

You are right. Most often, if you reference the model number of the compressor of the "beer case air conditioner" in the compressor manufacturer data, you will likely find that it has some rating down to say 20 or 10degF.

However, in a properly arranged medium temp application, if you reference the compressor mfgr data, and compare it with the specs of the condensing unit manufacturer which is employing the compressor, you may find a variance in the spec capacity of the assembled unit to be sometimes 5% difference between the two ratings. This I assume is due to condenser coil construction or other accessories.

Furthermore, if a compressor is an OEM, perhaps the condensing unit manufacturer has specified some special requirements for the component, such as the reed valve alloy, or some other characteristic which may not be suitable for any other application than air conditioning, because you know specifically what application the A/C condenser is going to be utilized in, right?

Often, even though the numbers on the tag are the same, the off-the-shelf component may not be the exact same creature.

thanx

I agree, usually the C.U. has a lower capacity is what I have found. But I have to wonder, as you said... if it is due to the smaller condenser coil dims?

Here is an example of some OEM condensing units with High and Medium Temp applications: (some might even work for retarding units?)

Copeland C3DD-1001, 10 hp unit: R-22 refrigerant.

45 degree SST has a rating of 151000 Btu/Hr
25 degree SST has a rating of 106000 Btu/Hr
10 degree SST has a rating of 78500 Btu/Hr

Copeland C3AH-0100, 1 hp unit: R-22 refrigerant.

45 degree SST has a rating of 12200 Btu/Hr
25 degree SST has a rating of 8220 Btu/Hr
10 degree SST has a rating of 4450 Btu/Hr

Both are condensing units.... LOL! :D

How much refrigerant vapor is stuffed into a cylinder on each downstroke of the piston depends on the pressure stuffing it in there, thus the compressor pumps more refrigerant (has higher capacity) when the SST is higher.

Subzero.....

I'm not sure if I follow your point. As Gary states, the relationship of the compressor capacity to SST is termed VOLUMETRIC EFFICIENCY. That is understood I'm sure, by anyone interested in this subject. And furthermore Volumetric Efficiency is a key consideration in all the implications, I would say.

My comment in regard to the compressor capacity rating verses the C.U. capacity rating is illustrated by the following examples:


(1) Trenton MN: EH500H2@ 20degF SST @95degF CONDENSING = 33,238 BTUH
UTILIZES COPELAND CRN5-0500
COPELAND SPEC CRN5-0500 @ 20degF SST @ 95 degF = 34,800 TO 35,500 depending on power supply

(2) Trenton MN: EH400H2 @ 20degF sst, 95degF ambient = 29,028
UTILIZES COPELAND CRM3-0400 same conditions = 27,800 to 27,900 depending on power supply


(3) Trenton MN: EH300H2 @ same conditions = 20,409
UTILIZES COPELAND CRJ3-0300 @ same conditions = 18,700 to 19,500


SUB -

You were comparing different C.U.'s to each other. I don't get your reasoning unless you work for Cornelius Ice Machines service non-support line!... then I understand.
:p



So in regard to just referencing the compressor manufacturer data to determine the system capacity, or appropriate application, my point is that you cannot ignore a very significat part of the equation and that being the assembled unit in which it functions!

thanx,

.....The fish

Point being is that those Condensing Units I picked were capable of serving more than one application based on SST... nothing more.

Your original post was in regard to a high temperature application system being used for a medium temperature application.... and perhaps the system would operate at an obviously lower capacity. Now if I were going to install a system like that.... I would base the TXV on the approximate capacity understood using the rule of thirds which you mentioned, and then I would probably use a balanced port valve at that... just a thought.

Now don't go off on a tangent thinking that I would do that, but your original question begs exploration. How often do you see such things and how old are the systems when they fail? What is the cause for failure?

By the way... I wasn't comparing the 1 hp to the 10 hp C.U.... too funny! LOL!

Okay Dean....


I understand the spec operating ranges of C.U.'s...... I live by them, and apply them appropriately.


But please!.......... don't explain your reasoning behind the "balanced port" expansion valve subject (reference sporlan publication #201), because that design terminolgy is a major problem in the application and service of refrigeration. Any expansion valve has only one capacity at any given application or conditions...... don't get me started...!

The misapplication of "Balanced Port" TEV's (by others) is a major source of my income. sporlan puts 1/3 thru 500 tons on the box, and "Johnny Jackleg the servicer" comes into the supply house and thinks one valve does it all, and "Johnny Jackleg the countersalesman" recommends it to him! NOT!

But we need to start a different thread on the Balanced Port TEV subject...... but I might put myself out of business!

This thing is going in a circle..... would someone please offer me privilage of assuming that I know SOMETHING.... aside from the question I ponder?

WHERE IS PROFESSOR SPORLAN?????!?!?

thanx,

.... the fish

Herefishy et al. I wrote a wonderful response last night that now resides in the electronic junk mail room of the troposphere.

I did not mean to imply that a sensibly colder suction return does not make up for less mass flow, because it does offset things..... But how much? How cold?. Perhaps I meant that field design is problematical, and cannot compare to factory design - guesswork versus thorough testing and measurement.

Further, most compressors rated for a/c duty are rated for 20 deg F duty.

The point is, however, that most jackleg installs I see down my way use the low pressure control for temperature control, or the pumpdown setpoint is way too low.... jackleg setups on jacklegged engineering, etc. When they are not jumped out or operating in a vacuum. The initial philosophy of misusing equipment continues on into the setup of everything.

Jackleg, or cost-cutting installation feeds upon itself. It distorts the customer's mind. "First you try to charge me too much for my equipment, and it works for 3 months. Now you cannot fix it, and you charge me too much!"

I can understand how this situation exists to the degree that it does.

What does a 4-ton high side a/c unit cost compared to an equivalently sized refrigeration condensing unit? My guess is about 1/2. Please correct me if I seem off base.

That leaves a lot of room for a creative and profitable jackleg installation. Where we see it in Florida most often is independantly and easternly owned/operated convenience stores and restaurants. It is understandable that these stores choose to save money on equipment costs and even more understandable that word of mouth encourages the spread of such applications. In Florida, this is a tight-knit society.

I still discourage it. Here are some other reasons:

Closer fin spacing on the condensers. Requiring more preventive maintenance, or more likely resulting in energy efficiency losses due to high discharge pressures, and even more likely resulting in system failure because of that "cost" thing, when it comes to service and maintenance.

Total lack of factory support. Even if you cheat the compressor or a/c manufacturer (which bugs me) there is not going to be a proper user manual nor wiring diagram nor service manual, nor 800-number to help.

Accidental application engineering. Who is sizing this equipment and how? Most likely it is gosh and bygosh and word of mouth. What I hate most about such applications is that it sort of works. "Hey, it worked on my 10-door reach-in, why doesn't it work on my 15-door reach-in?"

There is no more devastating equipment for a service tech to work on than the equipment that "sort of works."

The service tech gets into a netherworld of tweaking expansion valves and control settings... spending much too much "creative" time trying to make it work right and likely incurring callbacks when something changes, and proffering a single service bill that exceeds what the customer saved on his equipment installation. No happiness.

Warranty. Any warranty claim is fraudulent. I cannot go there.

Underwriter's laboratory liability. UL shares liability with the manufacturer in case of catastrophic equipment failure. All bets are off with this equipment. Yep. The owner and contractor are part of that sad story if something catches fire. Sadly, it becomes into a deep pocket search.

Building codes. Even in Texas and Florida, such installations are against code. Well maybe not in Lubbock or Lutz, but most everywhere else.:)

Energy consumption. I could make a convincing argument, but I am not now sure I can support it.

I go back to the original post: Refuse to work on them and quote a proper system. It's what we do in Florida. If it is a more economical way to cool the beer, then shame on me and more power to the novel a/c application. If after a year or two it is not, then call me.

Dan

Dan....

You are the MAN!!!

You are too cool under the collar for this thing.

I did not imply, that you implied, the cooler suction temperature thing,........ I just asked.

Your response, Furthermore does not reside in junk mail. I find you the most familiar with my question, and value very much, your input. I think these Yankees and Canadians have no idea what we're talking about. No offense is intended, but the thread seems weird to some of the responses.

My question is not hypothetical!!!!!

Dan... in regard to to your other points..... You're preachin' to the choir, because I'm singin' it, boy!!!!!!!!!!!

:o ("singin")

You seem to be comfortable with your position, as I WAS...... but the jackleg activity has increased so much her, in Austin, TX.... that I'm losing my temper at seeing the public fleeced to the extent that it is.

thanx for the most informed and direct response.....

.... the fish

later


"The problems you inherit last much longer,...... than the smile on your face when you pay the low price."

herefishy,
"come on........ I really want some in-depth scientific input".

Not to be rude but I don't see much in the way of technical nor scientific information in dan's post? But I guess the two of you share more than your opinion on misapplied equipment! They say that about people from the south! (Just funnin ya'all)

Seems to me that your concerns are common with most, if not all of us who frequent this place.

We have similar problems here with contractors using residential A/C condensing units modified with condenser fan cycle controls and crankcase heaters to cool server rooms and other critical applications through ambient temp's. from 95F to minus 30F to save a buck.

Truth be told, the main reason these systems fail and lose compressors is the method of head pressure control.

The primary difference between a commercial condensing unit, designed for operation in low ambient conditions is the Liquid floodback control, ie. Alco's Headmaster or Sporlans Limitrol.

I bet if you modified the residential A/C condensing unit by adding a liquid floodback headpressure control, properly selected heated receiver, txv, pumpdown cycle, crankcase heater with all controls set properly it would last forever!

Then again, like I said before, it would probably cost more than a properly selected commercial refrigeration condensing unit!

Hi Gibson,

I got corny. But I was referring to Dan's response as scientific or technical, but I am impressed by his insight into the potential liabilities to the customer, and "Johnny".

I dunno, Maybe it is fine and dandy to do it right (aside from using the A/C C.U.) and have an A/C condensing unit service medium temperature applications (aside from all the practical ramifications).

So,

I have come to the conclusion that the application of A/C condensing units in medium temp applications can be done by the "scientist" who has all the information to determine the capacity at system design SST, and modify the equipment with all the appropriate accesories to perform the desired task.

But, everyone seems to agree that it is a lot of work for nothing, except for someone whose labor is cheaper that the right equipment for the application.


....... Buyer Beware.........?

Agreed! If someone has all the time in the world and enough supplies to make something work... then I think anything can be made to work. LOL!!

What about a heat pump system used for medium temp? I have no intend on doing this. This is the first I have heard of this and it has peaked my curiousity.
I have seen many high temp compressors running 20 degree evaps. Every water cooler does this. What is the difference?

Warranty, perhaps? There are no clear lines one can distinguish between where something designed for one thing either fails or succeeds to accomplish another thing under differing circumstances.

The manufacturer bears a responsibility to its customers and itself to insure that their product works without fail within design parameters.

Answering another way, there are infinite combinations of motor input versus compressor output versus superheat versus evaporator and condenser sizing and restriction devices and expected air return and supply ..... maybe not infinite, but long enough.

Best answer: Most consumer designed a/c or refrigeration units are specifically designed for their purpose because all extraneous cost must be removed to compete for the selling of the product.

Likely, therefore, your stretching limits are thin and you are pretty much on your own. If you don't mind being on your own, then go for it.

I looked into this the first time I lost a winery job to a competitor who built his chiller from an a/c condensing unit instead of the "real thing". The unit in question was not rated nearly low enough for the chiller temperatures needed.

As stated earlier, it primarily comes down to the published operating limits of the compressor which the manufacturer determines will provide sufficient motor cooling.

Refer to the ASHRAE Fundamentals volume and you can take enthalpy, density, etc. of any refrigerant at a given condition and calculate a hypothetical cooling profile to compare with the same refrigerant at any other condition.

There are too many variables to get very accurate (lower suction = less horsepower required but less efficient operation, so not that much cooler, colder refrigerant but less mass, less velocity, etc.)

I like the idea mentioned earlier of just recording the crankcase/case temperatures of these cheapos and comparing them to the same units used as a/c units. (Now why didn't I think of that?)

I also agree that I don't like the fin spacing and the potential low ambient problems.

I don't take such a hard line with my customers, though. I give them the replace/repair options with strong recommendations, but if they are struggling along and still willing to pay my rates, I'll get them running again if that's all they can afford. (Okay, I refused to replace a compressor once, but the case was a real piece of junk!)

FYI, that winemaker struggled to make it those first few years and is now quite successful. IMO he gambled hugely with an entire year's crush depending on that crappy chiller. But he's rich and I ain't!

Rog

I have done this many times and the units work just fine, with proper modification. I think the reason foir the Manufacturer to say it voids the warrenty is due to the fact that regular medium temp cost more money but use the same compressor. Also I like the AC condensor because the condensor is larger and in high ambient will handel the load better.
I do a lot of cascade work and all compressor manufactures say "you can't do that". Wana bet! I have had Copeland tell me I couldn't get -100f out of a 20 hp compoud water cooled condensor on 404A but I did and the unit has been running since 1993. I invited them to come see it but they never did. Of course the evap is in a vacum chamber which helps. I have been told that you can't use that refrigerant in that compressor, Wana bet. They only want you to do what they have tested and approved. Object...Sell more expensive compressors.

Quote:

---

They only want you to do what they have tested and approved.
Object...Sell more expensive compressors.

---

I disagree that that is the motivation from the manufacurers. I see manufacturers as simply attempting to control warranty replacements, which is a huge cost already with misdiagnosed failures and abusive applications of their equipment.

On the other hand, I know exactly your joy when you just go ahead and do the surprising thing all on your own. The joy is that you did it successfully without anybody else's permission.:)

Re: Mr. Lester's post:

The other day I serviced a system with a compressor that has worked continuously for 27 years. That's my idea of a great design.

Physics is physics. Motor winding insulation breaks down as a function of time and temperature, among other things. The higher the temperature, the shorter the time.

When I read a compressor rating chart, I know that the unit has been tested and found to be reliable under the given conditions. In addition, a successful manufacturer is going to build in a great deal more reliability than his warranty guarantees. No one wants the reputation of failing just outside the warranty period.

If you ignore the tested ratings, you are skating on thinner ice. The unit may run great and an individual unit might run a long time. But a statistical analysis is the only true measure of the design. How many units have you produced? 100? 1000? What is the average compressor life?, etc.

I agree that successful compressor manufacturers are market-driven. It was their competition to sell compressors that produced the narrowly-focused, inexpensive A/C compressor. If your view were correct: that the ratings are intentionally restrictive to force the purchase of more expensive machines, it seems to me that at least one of them would have abandoned the conspiracy and captured the market for midtemps merely by publishing wider ratings.

It's easy to do things cheaper. It's much harder to do them better. Show me better and I'll do that.


Rog

Gee, I wish I could have said that.:) Well spoken, Rog.

A resident in the business park that I just moved into walked into my shop and introduced himself. He owns a specialty (leather) dry cleaning business located a few doors down from me. He has a problem with his 10hp chiller that condenses evaporated chemical from the clothing as it is in the dryer.

I walked with him over to the equipment, and an air-conditioning condensing unit was serving the chiller unit. As usual, I began to bemoan the application, and explain to him my concerns (which are already apparent in this thread). The unit was fitted with low ambient control, and all the "necessary" accessories. The required repair was a refrigerant leak related to some previous service (by others), a crummy weld.

A couple of months later the compressor failed. Due to the condition of the unit (aluminum oxidized and condenser coil ready to fail) I suggested replacement of the entire condensing unit.

To my surprise, I discovered that the chiller manufacturer was fitting the A/C condensers himself, and providing them with his chiller barrel/evaporator/control/pump assemblies, which mind you are very excellently built and engineered! Well, how do you think that I felt about that? The chiller manufacturer is warrantying the stuff, so it's not (necessarily) my liability. I supplied the original manufacturer's equipment for replacement.

Yesterday I called the same chiller manufacturer for information on an application that I am working on for a semi-conductor testing oven (approximately 45,000 watts of dissipation from operating product in 125degC oven temp). We decided that we were looking at about 20hp of (air conditioning condenser) for approximately a 15.68 ton load. Mr. manufacturer indicated that he would spec four 5hp A/C C.U.'s, instead of (what he might have usually spec'd) two 10hp A/C C.U.'s.

............The reason, he said, "I have been having an unacceptable failure rate of my 10(ton) condensing units."

hmmmmmmmmmmmm :rolleyes: