What is a good superheat for 410a

Just like with Superheat, Subcool is a calculated value by taking the difference between two temperatures. First you must find the actual temperature of the refrigerant vapor and then you need the saturation or boiling point of that same refrigerant. ... (R-410A, R-404A, & R-134A are excluded from this.) This helps us keep compliant and ...

Superheat is a measurement of how much gas is inside of your evaporator coil, Low to no superheat means we are flooding our evaporator coil with liquid refrigerant, this can happen because of a failed open TXV, refrigerant overcharge, or failed evaporator fans. High superheat means we have a large amount of vapor refrigerant in our evaporator ...For R-410A, a working pressure capability of at least 400 psi is recommended (this includes recovery cylinders). Standard DOT recovery cylinders rated for 350 psi should not be used. Besides, what is suction and discharge pressure of r410a?Normally R-22 operating system typically have a high-side (discharge) pressure of 260 psig and low-side (suction) …Evaporator superheat: 40°F: Compressor superheat: 70°F: ... A sight glass after the filter drier is a good method to tell if the drier is starting to plug because of the refrigerant flash from the added pressure drop in the restricted drier. Filter driers can be purchased with Schrader valves (pressure taps) on their inlets and outlets. ...Superheat is a measured value. It is the difference between two temperatures. Superheat is measured as the difference between the actual temperature of the refrigerant vapor and the saturation temperature of the refrigerant at that same point. Superheat on the system's low side can be divided into two types: evaporator superheat and total (or ...Example 2: Target Superheat Calculation (This calculation will get you close to manufacturer superheat chart results) WB is 64° F, DB is 96° F. Target Superheat Formula = [ (3 x WB) – 80 – DB] /2. [ (3 x 64) – 80 – 96] /2 = Target Superheat. 3 x 64=192, 192-80=112, 112-96=16 16/2=8° F of Target Superheat. 8° F of Target Superheat.

At a high level, superheat occurs when you heat vapor above its boiling point. Subcooling occurs when you cool a vapor below the temperature at which it turns into a liquid. But let’s dive in deeper, starting with superheat. Boiling is when a liquid gains heat and transforms into a vapor. Remember, superheat occurs when you heat vapor above ...The Maldives are the pièce de résistance of the miles and points crowd but you will never see a trip report to the Maldives from me. I share my reasons why. Increased Offer! Hilton...Subcooling is easier to understand. The refrigerant transfers latent heat to the air in the condenser meaning that its BTUs drop at a constant temperature, that is, the temperature you see on your gauge, say 110F. As a liquid, it tends to fall to the bottom of the condenser looking for the liquid line.Remember that the target superheat will change as the building lowers in WB and while charging refrigerant. The outdoor DB will general stay the same while checking the charge but it may fluctuate some. Set the Actual Superheat as close to the Target Superheat as possible to have an accurate refrigerant charge.R-410A, or Puron, is one of the most popular refrigerants in today’s modern world. However, if you rewind just fifteen or twenty years you would find that very little people even knew about it. Most contractors and technicians worked with R-22 systems for home and commercial air conditioning. R-22 had been the standard bearer refrigerant for ...Using a 410a subcooling calculator can help optimize your system’s performance and troubleshoot issues. And remember, 410a refrigerant is the more eco-friendly and efficient choice compared to 404a. Don’t forget to practice regular maintenance and keep your system in tip-top shape. Happy cooling!There seems to be some confusion here. I calculated the target superheat to be 24F using this online calculator.That means theoretically, it should be 24F.. The actual measured superheat was initially very low, just a few degrees F so I recovered some refrigerant from the system and it's now currently around 10 degrees, so theoretically I need to recover more refrigerant out of the system.

Adjusting subcooling levels in R410a systems involves: Increasing or decreasing the refrigerant charge; Fine-tuning the system for optimal performance; Always keeping safety precautions in mind; Comparing R410a Subcooling with Superheat Understanding Superheat. Superheat is the process of heating refrigerant vapor above its boiling point. It ...What is a good superheat and subcooling on 410a? Most heating and cooling systems should operate at a superheat of 10F at the evaporator and between 20F to 25F at the compressor. If your HVAC system has a thermostatic expansion valve (TXV), the subcooling should be between 10F and 18F. My calculations: Superheat Line Temp - Guage = SH 70-40=30 ...Teredo tunneling is a protocol that is part of the next generation TCP/IP protocol called "IPv6." Teredo tunneling enables devices using the IPv6 protocol to communicate through a...R-410A is an HFC refrigerant that is a blend of the HFC R-32 and the HFC R-125. This refrigerant was designed to be a safe, non-toxic, non-flammable, and reliable alternative to the HCFC R-22. It was invented in 1991 but did not begin to see real popularity until the 2000’s.An R-22 Replacement for New ACs and Heat Pumps. Freon™ 410A (R-410A) refrigerant offers higher cooling capacity and significantly higher pressure than R-22 for use in systems specifically designed for R-410A. This hydrofluorocarbon (HFC) refrigerant is compatible with polyolefin (POE) oils and replaces R-22 in positive displacement air ...

Petco park premier club.

You have 35 feet total, 35-15=20, 20x.6=12, 12 oz to a pound should do it for ya. and with the r410A, being low 12 oz will make a real difference in cooling capacity, try to get the charge as close as possible. Make sure you weigh it as you are putting it in, so take a scale, digital, with you. good luck. Reply.22.4 80.8 190.2 372.5 23.2 82.4 193 377.1 20.9 77.6 184.6 363.5 21.7 79.2 187.4 368 19.4 74.5 179.1 354.6 20.1 76.1 181.8 359 17.9 71.5 173.7 345.9R-410A is an azeotropic mixture of HFC-32 and HFC-125. It has been developed as a long-term replacement for R-22 in a variety of new air condi-tioning and cooling equipment. R-22 is an HCFC, or hydrochlorofluorocarbon, which means that it con-tains chlorine, an element that is damaging to the ozone layer. Because R-410A contains no chlorine at ...Conditions: 43.3 °C (110 °F) condenser/7.2 °C (45 °F) evaporator/2.8 °C (5 °F) of subcooling/8.3 °C (15 °F) of superheat Table 2b. Theoretical Cycle Performance Medium Temperature Low Temperature R-404A R-407A R-404A R-407A Relative Capacity (R-404A = 1.00) 1.00 0.89 1.00 0.86Superheat in HVAC refers to the temperature of refrigerant vapor above its saturation point in the evaporator. Ideal superheat is typically 10-15°F. Subcooling involves refrigerant liquid temperature below its saturation point at the condenser outlet. Normal subcooling is often 10-15°F. Both metrics help assess system efficiency and refrigerant state, but acceptable values can vary by ...

Zaleplon: learn about side effects, dosage, special precautions, and more on MedlinePlus Zaleplon may cause serious or possibly life-threatening sleep behaviors. Some people who to...Feb 6, 2020 · Now the typical rule of thumb is between two to four pounds of refrigerant per ton of your air conditioner. (You should always check the exact specifications of your machine, but most of the time the two to four pound guideline will be sufficient.) Most home air conditioners are between one ton and five tons. Superheat and Subcooling Explained!There seems to be some confusion here. I calculated the target superheat to be 24F using this online calculator.That means theoretically, it should be 24F.. The actual measured superheat was initially very low, just a few degrees F so I recovered some refrigerant from the system and it's now currently around 10 degrees, so theoretically I need to recover more refrigerant out of the system.The following charging methods are therefore prescribed for systems with indoor EEV/TXVs. 1. Subcooling (in the cooling mode) is the only recommended method of charging above 55°F ambient temperatures. 2. For best results - the indoor temperature should be kept between 70°F to 80°F. Add system heat if needed. 3.What is a good superheat for 410a? With short line lengths (less than 30 ft.), the superheat should be between 10F and 15F. With longer suction line lengths (between 30 and 50 ft.) superheats of 15F to 20F are normal.Physical Properties Of R22. In parallel to using the R22 PT chart, professionals will usually need to know some of the following R22 physical properties: R22 liquid density at -69°C: 1.49 g/cm 3. R22 gas density at 15°C: 3.66 kg/m 3. Triple point temperature: -115.76K. Critical pressure: 49.36 bar. Heat capacity ratio at 86°F: 1.178253.In this HVAC Training Video, I Show How to Check the Refrigerant Charge on an R-410A Air Conditioner using the Total Superheat Method. I First Show How to Fi...If we eventually want to calculate what the line temperatures should be on a system, we will need to use target superheat and subcooling. Superheat is measured on the suction line. Subcooling is measured on the liquid line. A simple way to help you remember whether you need to use bubble point or dew point is to think: Bubcooling and Dewperheat.Think 42-48 degrees, R22 or R410. Bryant/Carrier 410a systems with a TXV have a subcooling of 8 to 16. Check the data plate or the table inside the cover for the subcooling for the specific model/tonnage. Make sure airflow is right, charge fixed orifice by superheat, TXV by subcooling.Find step-by-step Engineering solutions and your answer to the following textbook question: A low-temperature power plant operates with R-410a maintaining-20$^{\circ} \mathrm{C}$ in the condenser, a high pressure of 3 MPa with superheat to 80$^{\circ} \mathrm{C}$. There is one open FWH operating at 800 kPa with an exit as saturated liquid at 0$^{\circ} \mathrm{C}$.Which would suggest 26 is high for the superheat and 61 is way high for the subcooling. The suction pressure and SST is normal, but 350 could be high for the head depending on the unit SEER. Residential 13 SEER equipment would be closer to 300 for an 80 degree ambient. It's about right for 10 SEER.

Zeotrope. If you have a white disposable refrigerant cylinder with a red band around it, you would know that it contained? HFO-123yf. Refer to figure RQ01. On a HFC-410A system, assume the suction pressure is 132 psig and the measured suction line temperature is 50F. The amount of superheat is. 2F.

Temp. Temp. Temp. Temp. Temp. Temp. Temp. Temp. ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C) ( F) Liquid Vapor ( C)-49 5.5 5.4 -45.0 1 49.7 49.5 -17.2 51 145.8 145.2 10.6 101 323.1 322.1 38.3-48 6.0 5.9 -44.4 2 51.1 50.8 -16.7 52 148.4 147.9 11.1 102 327.7 326.7 38.9We would like to show you a description here but the site won't allow us.To determine the Target Superheat for an air conditioning system with a fixed orifice (such as a piston or capillary tube) measure the indoor WB (wet bulb) temperature with a digital psychrometer and the outdoor DB (dry bulb) temperature with a standard digital temperature reader. Input these temperatures in a superheat chart, calculation, app, or digital manifold set in order to determine the ...Residential 410a system as follows: Liquid line: ~400psi. ~ 30 subcool. Vapor line: 105psi. ~30 superheat. The LLFD does not feel cold. The TXV is backed all the way out.Conversely, turning the adjusting screw counterclockwise will decrease the superheat. What is a good superheat for 410A? Most heating and cooling systems should operate at a superheat of 10F at the evaporator and between 20F to 25F at the compressor. if your HVAC system has a thermostatic expansion valve (TXV), the subcooling should be …What is the target superheat for R-410A in this situation? Let’s use the target superheat formula and calculate this manually: Target Superheat (R-410A) = (3 × 69°F – 80°F – …Whats a good superheat for 410a. What is a good superheat for 410a. What should superheat be for 410a. In theory, air conditioning systems are designed to never lose refrigerant, which means they must never be loaded. Of course, we all know that is not the case and there are times that a system loses the refrigerant due to losses or bad ...FoundersCard: Alaska Airlines Benefit Returns. Members can now receive an extra 5% off Alaska Airlines flights booked directly with the airline. Discount applies to First as well a...

713 252 2215.

1968 chevelle for sale craigslist.

Example 2: Target Superheat Calculation (This calculation will get you close to manufacturer superheat chart results) WB is 64° F, DB is 96° F. Target Superheat Formula = [ (3 x WB) – 80 – DB] /2. [ (3 x 64) – 80 – 96] /2 = Target Superheat. 3 x 64=192, 192-80=112, 112-96=16 16/2=8° F of Target Superheat. 8° F of Target Superheat.Native American activist groups are criticizing President Trump’s planned fireworks display at Mount Rushmore for the July 4 holiday. Few monuments seem more patriotic than South D...Imiquimod Topical (Aldara) received an overall rating of 7 out of 10 stars from 11 reviews. See what others have said about Imiquimod Topical (Aldara), including the effectiveness,...I rarely look at pressures, mostly saturation temp. Anything above 35 degrees on low side, and under 120 degrees on high side, is my general rule of thumb. It is all dependent on the metering device, airflow (indoor/outdoor), outdoor ambient temp, inside wetbulb, superheat, subcool. Guessing is not a very good way to do it.Feb 6, 2020 · Now the typical rule of thumb is between two to four pounds of refrigerant per ton of your air conditioner. (You should always check the exact specifications of your machine, but most of the time the two to four pound guideline will be sufficient.) Most home air conditioners are between one ton and five tons. Superheat and Subcooling Explained!R-407A - often sold under tradenames like Freon® (Chemours), Genetron® (Honeywell), and others - is the first "replacement replacement" that we've covered in the Refrigerant Focus series. It was designed to replace R-404A (Pentafluoroethane, 1,1,1-Tetrafluoroethane, 1,1,1,2-Tetrafluoroethane), which was developed as a replacement ...But are they learning the money management and fundraising skills that will allow them to run their own companies? By clicking "TRY IT", I agree to receive newsletters and promotio...Digital Fieldpiece Gauges: https://amzn.to/2LFjNnKR410A Equipment: https://amzn.to/2xv6AG5My Favorite Tool: https://amzn.to/3NIFJuOTools We Recommend: https:... ….

Freon™ 410A is intended for use in new air conditioning applications that have traditionally been serviced by HCFC-22. ... condenser/7.2 °C (45 °F) evaporator/2.8 °C (5 °F) of subcooling/8.3 °C (15 °F) of superheat. Freon™ 407C and 410A Refrigerants 4 Table 3. General Property Information: Freon™ 407C, Freon™ 410A, and HCFC-22 ...Superheat can run as high as 25 and still have sufficient cooling to the compressor motor. On some old relics that I have worked on (semi hermetics 06d's, 5h40, 5f20's) I concentrate on a 15 degree superheat, that ensures no flood back and sufficient cooling to compressor motor (motor cooling not applicable to 5f and 5h series, open drives). Reply.Superheat is a measure of heat added after the boiling point. Sub-cooling is heat rejected after the boiling point. For example, the saturation temp ( boiling point ) of water at sea level is 212 degrees. If you cool it, it will change stats and condense. If you continue to heat it it will evaporate.Superheat and Sub-cooling - In HVAC refrigeration coils and fans are used for air conditioners and heat pumps to transfer heat in one direction or another. A good HVAC technician is well versed in refrigeration. ... One is a capacity issue and the other is old residual oil from R-22 to R-410A are different and the old oil will cause your new ...Superheat is a way to ensure that the system is boiling off all of the liquid before it exits the evaporator. Refrigeration and air-conditioning systems may produce different ...4. When ambient air temp (Outside air temp) is 75-85 degrees the superheat should be 12-15 degrees, if the ambient temperature is 85 degrees or over the superheat should be 8-12 degrees. 5. If superheat is low then flooding the evaporator. Note: Do not adjust charge yet. 6. If superheat is high then starving the evaporator. Note: Do not adjust ...INSTALL FILTER DRIER(S) AND MOISTURE. INDICATOR(S) — Every unit MUST have a bi−directional filter drier in the liquid line. Locate the filter drier at the indoor unit, close to the evaporator coil thermal expansion valve (TXV) inlets. CHS units include one R−410A−duty filter drier, shipped in cartons attached to the unit base pan.When connecting gauges, connect to the always-suction port on the low side. On quite a few systems, you can get your head pressure on the liquid line, but some systems may require you to connect to the discharge line to check the head pressure. A common rule of thumb is the 100-degrees over ambient rule; the temperature of the discharge line on ...Apr 16, 2020 · Actual Line Temp – Sat Temp = Total Superheat. 55°F - 37°F = 18°F. 18°F of Total Superheat > 9°F Target Superheat = Undercharged. Since the actual total superheat measured is higher than the target superheat, we would need to add refrigerant a little at a time until the superheat is the same as the target superheat.Step 3. Subtract the evaporator saturation temperature from the thermocouple temperature. This difference is the system superheat. This shows the temperature rise above the bubble point temperature of the system. Review the operating specifications for your system to determine the proper superheat. Inadequate superheat can cause liquid ... What is a good superheat for 410a, We use gauges and a temperature probe to measure subcooling, just like when measuring superheat. 2. We check the temperature of the liquid line near the condenser coil. 3. We'll check the head pressure at the condenser, comparing the readings to the manufacturer's standard. 4. Then we subtract the two numbers to calculate subcooling., Superheat is a measure of heat added after the boiling point. Sub-cooling is heat rejected after the boiling point. For example, the saturation temp ( boiling point ) of water at sea level is 212 degrees. If you cool it, it will change stats and condense. If …, The refrigerant is a HFC blend consisting of five components. They include 8.5% of R32, 45% of R125, 44.2% of R134A, 1.7% of Butane (R600A), and 0.6% of iPentane (R601A). HVAC technicians usually use R438A as a retrofit replacement for R22. Retrofit replacements require the technician to change the system’s components, …, Superheat is calculated as the difference between the saturation temperature of a substance and the actual temperature of the gas. 3 When it comes to HVAC, refrigerants often boil at much lower temperatures than water. For example, if a liquid refrigerant boils at -10 degrees and is then heated up to -5 degrees, it has been superheated by 5 ..., R-410A Pressure-temperature chart Click anywhere on this document to return to Refrigerant Gas Properties information at InspectApedia.com This chart was provided by the Bonneville Power Authority,, Process: The low discharge superheat can be obtaind by the following, At first we need to run the refrigeration system minimum for 10 min. When the system running for a while we have to attach the pipe clamp thermocouple in one side of the refrigerant line which actually separate the thermal expansion valve and the condenser discharge valve.; Connect with the refrigerant manifold gauges with ..., Superheat is a measure of heat added after the boiling point. Sub-cooling is heat rejected after the boiling point. For example, the saturation temp ( boiling point ) of water at sea level is 212 degrees. If you cool it, it will change stats and condense. If you continue to heat it it will evaporate., R-410A, sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A, is a zeotropic but near-azeotropic mixture of difluoromethane (CH 2 F 2, called R-32) and pentafluoroethane (CHF 2 CF 3, called R-125) that is used as a refrigerant in air conditioning and heat pump applications. R-410A cylinders were colored rose but are no longer specially color ..., Evaporator outlet temperature. 56°F. Condenser outlet temperature. 74°F. When dealing with refrigerant blends that have temperature glide, when the liquid refrigerant boils in the evaporator, the composition of the liquid and vapor phases are different. The liquid phase becomes richer in the higher boiling point component as the low boiling ..., The difference between the saturated suction temperature and the measured suction line temperature is the suction superheat. 4. Add refrigerant to lower the suction superheat. Recover refrigerant to increase the suction superheat. Note that you should never add refrigerant if the superheat is already 5F or less, even if the charging chart shows ..., For superheat measurement, we are only using a low side gauge (blue gauge). The suction line is the bigger vapor line; locate the suction line service port, and screw the blue line from the gauge on there. Here we will measure the lower saturated temperature (40°F in the example above). Attach the clamp-on thermometer to the suction line., Indices Commodities Currencies Stocks, Supervision is needed by a licensed HVAC Tech before doing this as Experience and Apprenticeship garners Wisdom and Safety.These Videos are all part of our T..., What is the target superheat for R-410A in this situation? Let’s use the target superheat formula and calculate this manually: Target Superheat (R-410A) = (3 × 69°F – 80°F – …, Remember a txv is a constant superheat valve. It will maintain its set superheat. When it has a proper liquid seal/ enough subcooling. 3degrees of subcooling is not enough. If a sightglass was installed you would see the sightglass flashing a lot at 3f. Add some gas get to 10-12f you will see that txv react properly, Tecumseh Refrigerant Matrix (EN) Service Guidelines HCFC R22 to HFC Blends (EN) Guidelines for Utilization of R134a and R513a (EN) Guidelines for Utilization of R407A, R448A, R449A Rev2 (EN) Guidelines for Utilization of R410A (EN) Guidelines for Utilization of R404A and R452A (EN) Guidelines for Utilization of R407C (EN), Superheat refers to the temperature of the refrigerant gas leaving the evaporator coil above its boiling point. When the superheat is too high, it indicates that there is not enough refrigerant being evaporated in the coil. This can lead to a decrease in cooling capacity, which can cause the system to run inefficiently. Low Superheat, What is a good superheat for 410A? Superheat for most systems is about 10F measured at the evaporator; 20°F to 25°F close to the compressor. if the suction pressure is 45 PSi and the suction temperature is 32 F system still comes with 10°F of superheat., Superheat Item is a non-combat Magic spell that smelts ore into bars without a furnace.. It is cast on an ore in the inventory, requiring the Smithing level to smelt that ore into a bar. It cannot be cast on noted ore. This also requires the same amount of coal as standard smelting. Each cast yields 53 Magic experience along with Smithing experience from the …, Continue the process until the system has been determined to be leak-free. Connect the vapor-line and liquid-line pressure taps to a vacuum pump and micron meter. This step is also almost always omitted. Evacuate the refrigerant lines and indoor coil to at least 350 microns. Close off the valve to the vacuum pump and observe the micron meter., Which would suggest 26 is high for the superheat and 61 is way high for the subcooling. The suction pressure and SST is normal, but 350 could be high for the head depending on the unit SEER. Residential 13 SEER equipment would be closer to 300 for an 80 degree ambient. It's about right for 10 SEER., An essential tool for charging 410A by subcooling is a set of HVAC gauges. These gauges allow you to measure the pressure in your system, helping you determine the correct refrigerant charge. Make sure to use gauges specifically designed for …, What should my superheat be on a 410a system. What should superheat be for 410a. What is a good superheat for 410a. What a low overheating indicates? How do you increase subcooling? When overheating is too low, what happens to the compressor? What is subcooling in the condenser? Why is overheating important? What does overheating and subcooling ..., We can now refer to a pressure-temperature (PT) chart to determine the corresponding pressure at 108°F. The Danfoss Ref Tools (previously Refrigerant Slider) app is perfect for this. The liquid line pressure at 108°F saturation temperature is 356.5 PSIG. This screenshot of the Ref Tools app shows the liquid line pressure of R410A at ..., Jul 19, 2022 · Now you look at your digital thermometer and see the suction line temperature is 53°F. These readings would indicate you have 10°F of superheat (53-43 = 10). Calculate subcooling. Once you know superheat, you can determine subcooling to see what is happening to refrigerant on the system’s high-side., FreonTM 410A is a non-ozone depleting blend of two HFC refrigerants. It exhibits higher pressures and refrigeration capacity than R-22. The compositions of FreonTM 407C and …, Evaporator outlet temperature. 56°F. Condenser outlet temperature. 74°F. When dealing with refrigerant blends that have temperature glide, when the liquid refrigerant boils in the evaporator, the composition of the liquid and vapor phases are different. The liquid phase becomes richer in the higher boiling point component as the low boiling ..., 410A System with high head. I went to do a maintenance on a 410A Trane system today, when I came up on the trane I noticed it was running like a 450 pound head pressure, the first thing i thought was why in the world would it be so high, so I cleaned the cool, checked filters, checked txv bulb position, everything checked out although there ..., If the system's pressure is 250 PSI, using the Superheat Calculator 410A, we can calculate the superheat as follows: See also Parshall Flume Calculator Online. Superheat = 45°F - 65°F = -20°F. Therefore, the superheat value in this scenario would be -20°F (-28.89°C)., Nov 2, 2003 · Superheat and subcooling calculations can be calculated the same way we have always done with R-22 refrigerant. The only difference will be the higher pressure-temperature relationship when reading the temperature-pressure chart. The temperature glide for R-410A is only 0.3 degrees F and can be ignored, and fractionation is not a concern., Superheat and subcooling are two important concepts in HVAC. Superheat is the number of degrees a vapor is above its boiling point at a specific pressure. Subcooling, on the other hand, is the number of degrees a liquid is below its freezing point at a specific pressure. By keeping track of both superheat and subcooling, technicians can more ..., What is a good superheat for 410a? Do you add refrigerant to lower superheat? Add refrigerant to lower the suction superheat. Note that you should never add refrigerant if the superheat is already 5F or less, even if the charging chart shows 0°F. You don't want to overcharge the system if your thermometer or gages are not perfectly accurate., Negative Superheat. Superheat is the temperature gained in the refrigerant once it has completely boiled into a vapor. When it is still boiling, it will be in a mixed state and will be at saturation temperature for that given pressure. Zero superheat is something you will often see when a system has a flooded coil; zero superheat indicates that ...