Which detail from Heart of Darkness shows the ineffectiveness of the colonizers. What is the answer to this logical question pumara ako sumakay ako umupo ako sumandal ako bumaba ako anong dala ko? All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. Hottest Questions. Previously Viewed. Unanswered Questions. Needs a Topic. What is the low side pressure of a freezer using RA refrigerant?

Wiki User Related Questions Asked in Technology What is the correct suction pressure when charging a freezer using Refrigerant a?

Negative 30 psi should do it. If your talking about an Orifice tube? As the blower motor pushes warm air thru the evaporator, the refrigerant turns from a liquid to a gas which cools the air.

Asked in Chemistry, Evaporation and Condensation To maintain 40 degree evaporator coil temperature what is the suction pressure? It depends on the refrigerant you are using, for R it's 72 psi. It does not contain Freon, it contains Ra refrigerant. Put it in using the low pressure connection. Freon is probably the most misused term out there right now. When you say freon, you are referring to refrigerant. There are many different types of refrigerant. Each different refrigerant has different pressures at different temperatures and such.

Asked in Air Conditioning and Coolant How do you know when you need freon? The only way to know if Freon refrigerant is needed in an air conditioner is to use tools and gauges to measure the performance of the system.

The amount of refrigerant needed is based on the design of the entire system including the size of the unit, length and size of the refrigerant lines, temperatures, and type of refrigerant. Refrigerant is not consumed. If refrigerant is needed then the system was either not charged correctly when installed or there is a leak. There could be many reasons a system is not cooling. The correct answer to the question is: A skilled service technician will determined that the system was low on refrigerant by using pressure gauges, thermometers and other tools.

There not function a home owner can perform to see if refrigerant is needed. To calculate the refrigerant charge in a car, you must check its AC service valves under the hood in a car that is turned off using manifold gauges. Attach its red hose to the high-pressure gauge and the blue hose to the low-pressure gauge. Open the pressure valve on both sides. The normal low should be 25 to 45 psi.

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The normal high should be to psi. Asked in Air Conditioning and Coolant How much the lower pressure side in the ac unit must be? The Freon is added through the low side ac port.Listed below are field service terms or trade jargon often used to describe these pressures. Condensing pressure: High-side pressure, head pressure, discharge pressure. Evaporating pressure: Low-side pressure, suction pressure, back pressure. Figure 1. A basic refrigeration system showing refrigerant pressures, states, and conditions.

Condensing Pressure The condensing pressure is the pressure at which the refrigerant is phase changing from a vapor to a liquid.

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This phase change is referred to as condensation. Thus the term condensing pressure. This pressure can be read directly from a pressure gauge connected anywhere between the compressor's discharge valve and the entrance to the metering device, assuming that there is negligible pressure drop. In reality, line and valve friction and the weight of the liquid itself cause pressure drops from the discharge of the compressor to the metering device.

If a true condensing pressure is needed, the technician must measure the pressure as close to the condenser as possible to avoid these pressure drops. This pressure is usually measured on smaller systems near the compressor's valves.

On these small systems, it is not critical where a technician places the pressure gauge as long as it is on the high side of the system because pressure drops are negligible. The pressure gauge will read the same no matter where it is on the high side of the system if line and valve losses are negligible.

Evaporating Pressure The evaporating pressure is the pressure at which the refrigerant is phase changing from a liquid to a vapor. This phase change is referred to as evaporation or vaporizing, thus the term evaporating pressure. A pressure gauge placed anywhere between the metering device outlet and the compressor will read the evaporating pressure. Again, negligible pressure drops are assumed.

In reality, there will be line and valve pressure drops as the refrigerant travels through the evaporator and suction line. So, the technician must measure the pressure as close to the evaporator as possible to get a true evaporating pressure.

On small systems where pressure drops are negligible, this pressure is usually measured near the compressor. Again, on small systems, gauge placement is not critical as long as it is placed on the low side of the refrigeration system.

This is because the refrigerant vapor pressure acts in all directions equally. However, line and valve pressure drops are assumed to be negligible in this simple system. If line and valve pressure becomes substantial, gauge placement becomes critical. The larger and more sophisticated the system, the more critical gauge placement becomes because of associated line and valve pressure losses. If the system has significant line and valve pressure losses, the technician must place the gauge as close as possible to the component that he wishes to read the pressure from.

R-404A Refrigerant Pressure Temperature Chart

Refrigerant States Modern refrigerants exist in either the vapor or liquid states. Refrigerants have such a low freezing point that they are rarely in the frozen or solid state. Refrigerants can coexist as a vapor and liquid as long as conditions are right. Both the evaporator and condenser house liquid and vapor refrigerant simultaneously if the system is operating properly. So, refrigerant liquid and vapor can exist in either high- or low-pressure sides on the refrigeration system.

Refrigerant Conditions Along with refrigerant pressures and states, there are refrigerant conditions. Refrigerant conditions can be saturated, superheated, or subcooled.

Saturated condition: Saturation is usually talked about in reference to a temperature. The saturation temperature is the temperature that a fluid will phase change from liquid to vapor or vapor to liquid. Both the liquid and vapor at their saturation temperatures are called saturated liquid and saturated vapor respectively.After a visual inspection the very next step for the most seasoned technicians is pulling out their gauges and checking the pressure and temperature.

It just becomes second nature after enough calls. It will never fail that one of the first questions the pros ask the rookie is what is your subcool and what is your superheat? This article aims at providing you with just that information. There had to be a replacement for the Ozone damaging refrigerants of the past and the successor was the HFC RA that we all know of today.

RA has one of the highest Global Warming Potential numbers of any modern day refrigerant and is known as a super pollutant. Because of this we are seeing various countries and manufacturers no longer using RA in new machinery. Instead, companies and countries are opting for more climate friendly refrigerants such as natural refrigerants, hydrocarbons, and newer less GWP heavy HFO refrigerants.

There you have it folks. I hope this article was helpful and if you find that something is inaccurate here in my chart please do not hesitate to reach out to me. I have sourced this the best I could but there is always going to be conflicting data. The aim with this article is to give you accurate information so again, if you see anything incorrect please let me know by contacting me here.

RefrigerantHQ's Pressure Charts. You may also like. We do not directly sell any products or refrigerants, but rather provide information, knowledge, and explanations to the consumer. This content is provided 'As is' and is subject to change or removal at any time.

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Page 1 of 5 1 2 3 4 5 Last Jump to page: Results 1 to 13 of Thread: RA Freezer. First time using and installing a freezer split system with A. Can some one tell me LP,HP settings. Box is using a LL Soleniod for pump down operation with stat. System is air cooled walk in box. What would be normal operating pressure and super heat??

Hp safety out. Look for B. VTP99 liked this post. Pressures similar tohead may be a little higher under load or in hot weather. Normal head would be depending on outside temp and load conditions. Suction depending on inside temp. LP-cut out around 5 psi, don't pull into a vacuum. Make sure the condenser can breath. Good luck. Note concerning the difference in my and Mo's reccomended HP setting.

Depends in part where you are. Here in the hot south you'll nusience trip unless you set it high.

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Up north you can get by with a lower setting. Not fast enough there K! And I'll be ripping out some Beacon goodies not my choice for sure. Head Pressure Rec mmending psig for high pressure cutout is pushing! This is kind of pushing into the danger zone is it not!? That thing seems to be moving a lot better! Regards, mckim. Re: Head Pressure. N2fords liked this post. Walk in box is in kitchen and condensor is mounted on the side of the box.

No head master,air cooled with condensor fan.At DrywallTalk.

r404a refrigerant suction pressure

Knowing that many homeowners and DIYers are looking for a community to call home, we've created www. Remember Me? Lost Password? Trade Talk. Make a Forum Post. Add a Blog Entry. Brighten Pools Custom Made Air Start a Project. Submit a Product to Review. Normal Range of Operating Pressures for A? Send Message. Have not worked with A before and I'd like to know what the normal range of operating pressures would be for a cooler at 34 degrees with an ambient outdoor temp of 80 degrees? Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death.

Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

What pressure would you expect for RA, R22, or R12 at those same conditions. Convert the pressure for those gasses to saturation temp, and use the same saturation temps on RA systems. You concure? I just punch up the refrigerant I'm working with and it automatically shows the saturation temps.

Normal Range of Operating Pressures for 404A?

More than that I can attach the included temperature clamps to the lines and get Superheat and Sub-cooling in real time. I also picked up the wireless remote temp probes and the HG3 so I can get a full system analysis and target Superheat.

No more guesswork. I couldn't be more pleased with this setup and customers are impressed with the level of efficiency I can squeeze out of their systems.

Im just making sure Im doing this right so that I don't get confused. Originally Posted by Rooster. Good investment!!! Love that unit too! Have used a friends a few times and getting ready to buy my own. While the "old timers" may frown on using it I say BB code is On. Smilies are On. Trackbacks are Off. Pingbacks are Off. Refbacks are Off. Forum Rules. Our Pro Network: ContractorTalk. Go to Page Join NowView Full Version : a high pressure?

It isn't about pressures, it is about temperatures. This is excessive and tells us that the condenser cannot handle the load. We need to find out why. Measure the temperature of the air entering the condenser and the temperature of the air leaving the condenser, then subtract entering air temp from leaving air temp.

The result is the condenser delta-T aka dT. If the dT is more than 30F, then the airflow through the condenser is insufficient. If the airflow is sufficient, subtract the liquid line temp near the condensing unit from the SCT. The result is the condenser outlet subcooling. If the subcooling is more than 15F, there is too much refrigerant in the high side of the system, backing liquid up into the condenser, reducing its ability to reject heat. This is far from excessive, but we should always check dT and correct any airflow problems before checking subcooling.

Airflow can and will effect subcooling. Let us know what you find, each step of the way. If you have charge the system till it clears. With heavy load comes high superheat, as we saw in your other thread. Similar air in and air out measurements on the evaporator would give us the evap dT, indicating evap airflow, although the heavy evap load says that the airflow is probably sufficient. That brings us to the condenser outlet subcooling SCT minus liquid line temp and the evaporator outlet superheat suction line temp minus SST.

If the condenser outlet subcooling is above 15F, you have added too much refrigerant. Note: The difference between liquid line temperature and air out temperature is the condenser approach. Given sufficient airflow and normal subcooling, high condenser approach would indicate a thin insulative coating on the condenser tubes, generally resulting from carbon deposits in high automotive traffic areas accumulating over long periods of time.

But this being a new system, we can safely ignore the condenser approach temp. Similarly, evaporator approach can indicate coating of the evaporator tubes, such as oil coating the inside of the tubes caused by oil logging.

r404a refrigerant suction pressure

By definition, if the superheat is right at design room tempyou have enough refrigerant in the system to do the job. However, solid liquid entering the TXV will help to prolong its life.

Therefore, when everything else is right, it is a good idea to slowly add a small surplus of refrigerant until the sight glass clears or the subcooling is 15F, whichever comes first.

This is the optimum charge. The manufacturer's recommended charge gives us a quick easy way to charge the system close to optimum, which is an important consideration when you are charging the customer for your time. It is "close to optimum" because just as identical twins have subtle differences, no two systems are truly identical, much less hundreds of identical systems coming off an assembly line.

Liquid line seems a bit hot and the head pressure seems a high for ambient, as gary said above you need to use the pt chart to determine what the no normal pressures are, I have always used a simple formula that calculates normal or close to normal high side pressure.In this post we are going to take an in-depth look at RA.

Knowing the pressure and the temperatures associated to the machine you are working on is essential to being able to diagnose any possible issues.

Without knowing the temperatures you are more or less walking blind. These pressure checks give you the facts so that you can move onto the next step of your diagnosis. Instead of pasting a large table of information here I will instead direct you to our specific RA refrigerant temperature page. This can be found by clicking here. Regardless of what refrigerant you are looking at they all have their own pros and cons.

There is no perfect refrigerant. There may never be. R was used for the refrigerators and R was used for freezers. At the time the world switched over to RA there was little other choice and most business owners and contractors consolidated their refrigerators and freezers over to one refrigerant to simplify things. That is why you see A nearly everywhere in these types of applications. No folks, this time we are going to go about it smarter. This is me being optimistic. Things are always changing and evolving.


It was then that the CFC refrigerant R was invented. It was comprised of of R This new refrigerant R offered a lower discharge temperature and improved capacity when compared to R For thirty-five years R reigned supreme, but like all good things it had to come to an end. In and R was phased out for all new machines. These refrigerants were phased out due to the chlorine that they contained.

When the refrigerant was vented or leaked it would move into the atmosphere where the chlorine would damage the Ozone Layer. The Ozone layer protects us from radiation and a thinning of said layer can result in a whole host of problems including various cancers.

r404a refrigerant suction pressure

Once the seriousness of the problem was revealed world leaders got together in Montreal and signed a treaty that most all of us know by now, The Montreal Protocol.

This treaty aimed at phasing down and eventually completely out Ozone damaging chemicals. This included insulation, pesticides, refrigerants, and many other applications. At this time the world turned towards HFC refrigerants. One of the very first phase outs was R for automotive applications. Today, as I write this article inRA is being phased down and in some cases completely out across the world. The European Union has import and production limits set on RA and have plans to completely phase it out over the next few years.

This time though folks the phase out has nothing to do with the Ozone Layer. GWP is a measurement of how much heat a greenhouse gas traps within the atmosphere. The higher the number the worse the product is for the environment. Like with every scale there has to be a zeroing measurement.

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