Horizontal Right Installations

8/17/2019 Horizontal Right Installations

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Report on problems encountered in the installation of equipmentand suggestions on how to achieve better performance in thedepartments of installation and service

Service tech: Renan Gonzalez.


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Subject: Report on problems encountered in the installation of equipment and suggestions onhow to achieve better performance in the departments of installation and service

When I arrive at the company, six month ago, I was surprised because the amount of problems I encountered in thesystems installed. There was on the one hand the incorrect installation of the equipment, and on the other hand improperadjustment in the air flow amount or in refrigerant level in air conditioning systems.

For a long time the company has been facing the following problems:

Need to change the thermostatic expansion valves due to restrictions, showing excessive subcooling andsuperheat.

Need to change Evaporators due to freezing up.

Poor efficiency in the performance of work by the air conditioning unit.

I came from companies in which I normally worked with equipment that had been working for some time in the right way,and then this had one or two problems to be diagnosed. For a service technician in this context it is easy to diagnose andfix these problems.

However, when I comes to Capital Air it was hard for me to see the whole picture. I could not understand how it was thathad so many problems in just one unit. So I began a study of how the company has been installing air conditioning unitsand its effect on these problems.


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Bit by bit I understood that the main problems are related to incorrect installation and adjustment of the air conditioningunits. I gave myself the task of studying the installation manuals of the units used, and manuals manufacturer's productdata. I was finding data that have helped me to reach a conclusion that will show in this report to the management of thecompany.

I'll try to explain my findings in the most understandable way possible, while I makes reference to the manufacturers'manuals to prove that my conclusions are correct. I hope to help solve these problems we have been facing for sometime, and that make the company lose considerable amount of money

To simplify my report I will make a list of the literature used to test my conclusions. To cite this literature has used thefollowing format:

"Quote of the document" (1, p. 12). This means that the document cited is the first the reference list, page 12)Due to the technical nature of the information, sometimes I will make an explanation of some concepts in order to help

the company understand these concepts in a simple way. I apologize in advance for my English, because as you all knowit is not my principal language.

To honor honesty I must acknowledge the invaluable help of Armando Caballero, service technician, who shared withme their data service calls and very timely observations which helped me to see the whole picture.

First scenario: Restricted thermostatic expansion valves with readings of subcooling andsuperheat too high.

Some well-known in the field of air conditioning is the fact that on a Evaporator Coil with TXV as a control element, a

high superheat with a high subcooling is the possibility of a restriction on the high pressure side of the system.However, before arrive To the conclusion that the problem is a restricted TXV it is important to follow the following

procedures:

The technician should take the temperature before and after the filter drier. If there is a difference of morethan three degrees then the restriction is in the dryer. If there is no significant temperature difference thentechnician should:

To take the temperature in the liquid line in front of the condenser unit and in front of E. Coil. If there is adifference of more than three degrees then there is a kink in the liquid line, so technician should search it andcorrected it. If there is no significant temperature difference then:


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The technician must ensure that the air flow through the evaporator is correct, because an improper amountof air flow can lead to the evaporator to have a very large temperature drop and that makes to the TXV closes toomuch. If the TXV closes too much the result is a very high subcooling and superheat, but not a TXV with restriction.If it is found that the air flow is appropriate then:

The technician must measure the temperature inside the house. If the temperature inside house is below 70degrees, then technician must heating the house with the heater unit, or diagnosis should be left for a warmer day.If the temperature if over 70 degrees then the technician must make sure the TXV sensible bulb is attached andinsolated properly. If there is not any problem with sensible bulb, or none of the problems described above arethere, then we can ensure a high degree of certainty that the TXV is restricted.

When I started my work in Capital Air one of the managers referred me to the many problems they have had with theTXVs. Throughout these months I found some TXVs, and pistons, who have been restricted and showing foreign materialclogging TXVs. This shows that in some cases there is an improper installation procedure. A few months ago in aconversation with a manager I mentioned that in my experience, the filter dryer should be installed in front of the

evaporator so that any foreign material in line liquid is captured by the filter drier before the material arrives the TXV. Thisway can help us to avoid a high percentage of blocked TXV.

The following reference prove that I am right in saying that filter driers must be installed in front of the evaporator if youwant to avoid many of the problems we have had with the TXVs:

“Place liquid filter dryer near ID1 unit to reduce the r isk of debr is clogging the valve .” ( 2, page 2)

My recommendation in this regard is that the company begins to install filter driers in front of the E. Coils to avoid thisproblem in the future. Any foreign material that could cause an obstruction to TXVs will be trapped by the filter drier,avoiding a problem that has affected high costs to the company.

At other times the problem of high superheat and subcooling is solved by simply finding the right air flow for the unit2 inquestion. The following reference may help us understand how the manufacturer of evaporators see this:

1 ID means Indoor. It’s a reference to Evaporator Coil. 2 I will not describe the procedure to find the right amount of airflow to avoid extensive. I just want to refer that to do it, it is important

the proper use of the air flow chart of the manufacturer and the instrument known as Magnehelic. There is not another way to knowthe air flow in the unit. You can see this in any air flow training from the manufacturers.


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“Airflow Air f low amou nt and distr ibut ion are vi tal to adequate system performance . Problems that can be experienced with

incorrect airflow include:

low system performance

restr ict ed TXV frosted coil

poor humidity control

water blow—off “ (2, page 2)

This is the reason why sometimes adjust the air flow to the correct amount helped me to solve the problem while Iprevent unnecessarily removed the TXV.

However, on other occasions, after following the above diagnostic procedures and even after replacing the TXV

problems continued just like at first to diagnose the system. This led me to ask myself what the relationship is betweenthis and other problems in the equipment installed by the company.

Second scenario: Evaporator coils freezing up, poor equipments performance, poor humiditycontrol. Another problem that was referred to me by one of the managers is the fact that the company had replaced a significant

amount of evaporators because these froze. At this time the company had changed TXVs and continued freezing units.Here enters the scene service technician Armando Caballero.

Armando starts to work about a month and a half after I, recommended by me. He is a technician who had experience

as an installer for the same company for which I worked, ARS Rescue Rooter. On his first day of work was assigned tochange a flow evaporator up with tech. Upon arrival Armando observed that the evaporator was installed in the wrongposition. The installation was performed leaving a portion of the coil without airflow so heat transfer was very poor and theevaporator would freeze. You can see how it was installed in the image below. This image is taken from Reference 3,page 4, fig. 4


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As we can see, the position of the evaporator is indicated by the manufacturer as incorrect. Armando try to avoid

installing this evaporator reasoning with her partner but could not prevent the replacement of the same. By Armandoconsult my views on confirmation that effectively the evaporator was installed improperly. This fact was reported to themanagement of the company avoiding that more evaporators were installed incorrectly and helping the servicedepartment to properly diagnose this problem.


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The illustrations above are valid ways to install these types of evaporators. (3, page 4, fig.4)

This corrected one problem that has wasted a lot of money to the company. But two significant problems still remained,poor efficiency and poor humidity control in some of our equipment.

During my diagnosis I found a curious fact. After adjusting the air flow and the refrigerant level appropriately manyequipments began to work properly and with excellent performance. However on other equipments, even when theappropriate adjustments were made, the efficiency of the equipments was really poor. This has brought the complaint bysome customers that their electricity bill is high when these are equipments that should have high efficiency.

Here I must explain a procedure, little-known for service technicians that is necessary to understand if we want to knowthe efficiency of air conditioning equipment. It is necessary to explain some concepts which, being little known, should beexplained.


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We all know that there are some important parameters that allow to a service tech to diagnose an air conditioning

system properly. They are the superheat, the subcooling and the delta t. But with respect to Delta T there is a wrongconcept. There is a rule of the thumb about delta T: Delta t should be between 17 and 21 degrees Fahrenheit. Although

this rule may be useful it is limited. The delta T Wet depends directly on the wet bulb and dry bulb in the return air. As anexample:

We have a return air with Wet bulb 68 degrees and 74 degrees Dry bulb. What would be the appropriate delta T in thiscase?

In this case, to measure delta T, the technician will find that delta t is 14.1 degrees. If we go by the rule of 17 to 21degrees for delta t, we are going to diagnose that delta t is wrong and that the system is working badly. That would be amajor mistake. As shown in table’s manufacturers with this wet bulb and dry bulb in the return air, target delta t shouldbe.... 14.1 degrees!!! So using the above rule we would be wrong diagnosis.

How this fact influence the efficiency of the equipment? Well, there is an additional parameter that a few technicians useto diagnose an air conditioning system, this parameter is enthalpy delta. Enthalpy is defined as the amount of total heatthat is in an air mass. The enthalpy includes the amount of sensible heat and latent heat in an air mass. Delta enthalpy isthe difference between the total heat air entering the evaporator and the total enthalpy heat or leaving the evaporator.How delta t can help us to know the efficiency of a system?

Suppose we have an equipment of 5 tons. That means that this equipment is capable of removing 60,000 BTUs, whenworking on cooling mode. This system should have an air flow of 2000 cfms, 400 x ton. We adjusted the blower to deliver1978 cfms, it is near the cfms required for the system. We've loaded the system with refrigerant subcooling and adequatesuperheat. Now we can use the following formula in order to calculate whether the system is working with due efficiency:

Btu = DH x 4.5 x CFM.

Here Btu means the amount of heat being removed and it should be as close as possible to the equipment's ability, in thiscase 6000 BTUs. DH means enthalpy delta is the difference between the total heat return and supply of equipment. 4.5 isa constant that reflects the air density with this enthalpy. This value is used as a constant because the air density changesinsignificantly and an approximate 4.5 is to simplify the use of the formula.


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Let’s see the next pictures. In the first we can see that dry bulb is 74 degrees and wet bulb is 68 degrees, the same asthe previous example with delta t 14.1. The point on the psychometric chart shown the air entering the return and itscharacteristics. If we look at the column on the left of the illustrations we can see the value marked with the letter h, this isthe value of the enthalpy with this wet bulb and dry bulb. Enthalpy with this values is equal to 32.4. Now we are to locate

the next point in the psychometric chart.

We have in this equipment 14.1 of delta t. Its dry bulb is 74 degrees. 74 degrees minus 14 = 60 degrees. It is the drybulb for the air leaving the evaporator. In this case we know delta t is the correct at this wet and dry bulb. So the system isworking fine, and with a supply dry bulb at 60 degrees, the wet bulb will be 59 degrees. If we locate in the psychometricchart both values, supply dry and wet bulb, then we can find the enthalpy for the air leaving the evaporator. Here we seethat 60 of bulb and dry bulb wet 59 h, enthalpy at supply air, has a value of 25.8

Now we can determine h delta, delta enthalpy, to use the formula and see if the system is working properly or notefficiency.

Delta H = Return H – Supply HDelta H = 32.4 – 25.8 = 6.6Now using the formula to calculate BTUsBtu = DH x 4.5 x CFM.Btu = 6.6 x 4.5 x 1979 = 58,776 BtusThe system is removing 58,776 BTUs that means the system is working with an efficiency of 97.96 %. So although we

are reading a delta t of 14.1 degrees, the system is actually working with very close to its maximum efficiency. There isnothing to correct a system with these features.


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I ask, please forgive me for such a complicated explanation but it is necessary to understand what I meant to say that Iwas studying the efficiency of the systems in the past four months.

As I said, in my analysis of the systems I have found that, after adjusting the air flow and refrigerant charge, many

systems start to work with proper efficiency. At the same time I found that some of these systems are not working properlyeven with correct refrigerant charge and adjusting the air flow adequate.

This opened my mind an important question, why? To facilitate and speed up the research results, I trained to Armandoin using my methods of analysis and began to collect data to help us determine the cause of inefficiency in some systems.

Comparing the data collected, I began to notice a pattern of behavior defined and find the following results:

When the evaporators and furnaces coincide in the size of their dimensions, then adjusting the air flow andrefrigerant charge, significantly improves the efficiency of the system.

When the evaporators and furnaces don’t coincide in the size of their dimensions, then adjusting the air flow

and refrigerant charge, significantly improves the efficiency of the system only when the system is installed fromleft to right, as shown in next picture


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When the evaporators and furnaces don’t coincide in the size of their dimensions, then adjusting the air flowand refrigerant charge, don’t improves the efficiency of the system if the system is installed from right to left, asshown in next picture

The illustrations above are taken from reference 1, page 2.

This manual shows the installations may be performed properly in both directions with furnaces and evaporators that donot have the same dimensions. Unfortunately this seemed to contradict the findings that Armando and I have found in ourstudy. What we did not know was that this manual is an older version and there is a second edition of the manualinstallation for these coil, as we will see.

It seems that the installation from right to left was something wrong but the manufacturer's manual seemed to indicatethat the installation was correct as the company was performing. The question I had in my mind was, is that theevaporator at the facility from right to left should be level with the furnace at the top of both?

Although my search for information on the subject I found nothing that could confirm my suspicions. One day Armandowas assigned to work with Joe in the modification of a previously installed system. Arriving to the place Armando saw that


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the evaporator, which was up flow, was installed in the wrong way, so Armando explained to Joe what the problem wasand why the Installation was poorly made.

After that Armando will explain this matter to Joe, Joe began to make some changes in some units installed horizontally,from right to left so that the level of evaporator and Furnace coincide on top. He observed a significant improvement inthese changes and shared with me the results. Their findings coincide with observations that Armando and I had beendoing to study the systems above, so this seemed to confirm that the manufacturer handbook was wrong.

The missing piece turned out to be the last version of this installation manual. This presents the appropriate optionswhen installed from left to right and from right to left with an evaporator and furnace mismatched in size. So I couldunderstand that as the company had been installing some systems flow up incorrectly, also it had been installedincorrectly horizontal furnace from right to left when they are of different size evaporators.

The following illustration shows how the coils can be installed in various combinations: from right to left and left to right,with furnaces that match or do not match in size. (2, pages 3)

HORIZONTAL RIGHT INSTALLATIONS Acceptable for Air Conditioner andHeat Pump Applications

HORIZONTAL LEFT INSTALLATIONS Acceptable for Air ConditionerOnly Applications


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The following table shows how to combine furnaces installed from left to right and right to left with coils that match or donot match in size.

Let's see a practical example of how to use this information. If we use a furnace 58PHB045 whose width is 14-3 / 16inches, with a CNPHP2417 coil, whose width is 17-1 / 2 inch and install from left to right then we can use the followingcombinations: B, C, D, E. If we use de same combination but from right to left then the right combination will be: G, H, I, J.


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Now see the following figure.

This installation is from left to right and the coil and furnace are level at the bottom.

However on applications from right to left, this installation it is not correct. In this case the coil must be level with the topof the furnace, or in the center thereof, or a transitions to permit the passage of air through the entire coil.


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This shows that the way the company is installing this combination of furnace is incorrect. The question is why? Theanswer to this question lies in the following illustrations (1, page 3):


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Here we can see that the design of the coil on the left side allow the passage of air through all sections of the coil so thatthe heat transfer becomes effective. In this case has no effect that the furnace is installed at the bottom level. That is the

reason to adjust the air flow and the refrigerant level, the system could work at an efficiency above 93%. That meansfewer complaints from customers and an electricity bill less expensive for them.

But now let me show you what happens when installed from right to left with the furnace and coil at the same level at thebottom. (1, page 3):


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Notice now that on this side of the coil design is totally different. Now the furnace is at a level in which a section of thecoil cannot receive air. This makes the heat transfer lower, causing the system efficiency falls below 81%. This brings thenumber of customer complaints and their electricity bill will be higher. This is exactly what Armando and I have found inour studies of installed systems in this way.

Below I have made a table with the possible combinations3 of furnaces and coils that we are currently using. This tablecan help technicians determine if the facilities are made correctly or not, in systems that are diagnosing.

Of course there are other findings that are related to the distribution system in which air must be improved, but this willbe the subject of another report that will in the future. In this speak about my concerns regarding the return ducts, the sizeof supply pipelines, as well as in the selections of the bypass dampers in the zone systems.

3 You can get reference about the values on this table in the product data and installation manuals for Evaporator and coil.


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58PHBfurnace

Width of thefurnace

EvaporatorCNPHP

(Width)

Tons S. Pressure4 CFM withproper S. P.5

CombinationsforInstallation.6

045-12 14-3/16 2417 (17-1/2) 2 4/ 0.5 – 0.7 855 - 770 B, C, D, E, G,H, I, J

045-12 14-3/16 3017 ((17-1/2)

2-1/2 5/ 0.5 – 0.7 1080 – 1010 B, C, D, E, G,H, I, J

070-12 17-1/5 2417 (17-1/2) 2 4/ 0.4 – 0.6 850 - 750 A, F

070-12 17-1/5 3017 ((17-1/2)

2-1/2 5/ 0.4 - 0.6 1055 - 960 A, F

070-16 17-1/5 2417 (17-1/2) 2 This combination is not recommended because it wouldhave to use the blower speed or static pressure very low.

070-16 17-1/5 3017 (17-1/2) 2-1/2 3/ 0.4 – 0.7 1075 - 940 A, F070-16 17-1/5 3617 (17-1/2) 3 4/ 0.4 – 0.7 1250 -1125 A, F070-16 17-1/5 4221 (21) 3-1/2 5/ 0.4 – 0.7 1475 - 1350 B, C, D, E, G,

H, I, J

090-14 17-1/5 2417 (17-1/2) 2 This combination is not recommended because it wouldhave to use the blower speed or static pressure very low.

090-14 17-1/5 3017 ((17-1/2)

2-1/2 3/ 0.5 – 0.7 1065 - 975 A, F

110-20 21 4221 (21) 3-1/2 1400 - 1335 3/ 0.4 – 0.5 A, F110-20 21 4821 (21) 4 1655 - 1545 4/ 0.6 - 0.8 A, F

4 S. Pressure (Static pressure that can be used in this combination) 4/ 0.5-0.7 means blower speed # 4 Static pressure between 0.5 to

0.7 water column inch. The distribution duck work must be calculate to warranty this S. P. in this particular Evaporator-Furnacecombination.5 It is the Cfms that the blower is going to deliver if there is the recommended S. Pressure.6 See the table in pages 12 -14 of this report.


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110-20 21 6024 (24-1/2) 5 2040 – 1920 5/ 0.5-0.7 B,C,D,E7

58PHBfurnace

Width of thefurnace

EvaporatorCNPHP

(Width)

Tons S. Pressure CFM withproper S. P.8

Combinationsfor Installation.

110-20 21 6124 (24-1/2) 5 2040 – 1920 5/ 0.5-0.7 B,C,D,E9

135-20 24-1/2 With this furnace there is not available any good combination. Only can be used bywidth with E. Coils 6024 and 6124 but the air flow needed for 5 ton is only deliveredin a Static pressure too low with this furnace 5/ 0.1-0.3 W.C.I.

In my research I have found it very important in the selection of equipment to keep in mind which is the pressure drop ofthe various components that are installed, such as air filters, evaporators as well as the system of air distribution to ensureadequate static. This can ensure that the blower deliver the required amount cfms per tonnage. This situation will be

explained in a future report and will be based on the findings in the manuals D and J of the ACCA.

Conclusions:

For a long time the company has been questioning the productivity and high cost of the Department of Service. Althoughat first I thought that was indeed the situation, after two months of work I began to point out that the main source ofdifficulties for the company consists in the low quality of the installation of equipment.

The fact that the installation manuals have information from the manufacturer, which coincides with my findings in the

field, is a clear indication that the company has been installing equipment without proper understanding of how to do theinstallation properly. This has been the result of ignoring the manufacturer's instructions for not dedicate time to studyingthe installation manuals.

7 With this combination the furnace never can be installed on right side!!! 8 It is the Cfms that the blower is going to deliver if there is the recommended S. Pressure.9 With this combination the furnace never can be installed on right side!!!


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It is important to help the installation department establishing appropriate installation policies and training installers inthem. At the same time it is important to provide the superintendents of a checklist of installation in which it shows theelements that they should inspect in each occasion. This would help prevent the service department have to put in longhours of work to find the weaknesses and correct them. As a result, we can focus on the COD calls, which will bringadditional money input to the company on service calls, as well as a better performance pay for service technicians.


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References for this report

1. CNPHP, CNRHP, Cased N Coils. Horizontal, Heating—Cooling, Carrier Enterprise, First edition. (Internetlink, http://dms.hvacpartners.com/docs/1009/Public/0F/IM-CNPH-02.pdf)

2. CNPHP, Cased N Coils. Horizontal, Heating --- Cooling, Carrier Enterprise. Second edition. (Internet link,http://dms.hvacpartners.com/docs/1009/public/04/im-cnph-07.pdf )

3. CNPVP, Cased N Coils, Upflow --- Downflow, Heating --- Cooling (Internet link,

http://dms.hvacpartners.com/docs/1009/public/09/im-cnpvp-06.pdf

http://dms.hvacpartners.com/docs/1009/public/04/im-cnph-07.pdfhttp://dms.hvacpartners.com/docs/1009/public/04/im-cnph-07.pdfhttp://dms.hvacpartners.com/docs/1009/public/09/im-cnpvp-06.pdfhttp://dms.hvacpartners.com/docs/1009/public/09/im-cnpvp-06.pdfhttp://dms.hvacpartners.com/docs/1009/public/09/im-cnpvp-06.pdfhttp://dms.hvacpartners.com/docs/1009/public/04/im-cnph-07.pdf


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Appendices I. Air flow table for 58PHB Furnaces


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Appendices I. Cabinet dimensions for 58PHB furnaces

Documents

Horizontal Right Installations