High discharge temperatures can indicate minimal movement of refrigerant. Because the refrigerant isn't being pumped at design rates it stays in the condenser for a longer period of time and is cooled more, hence lower head pressures, and in turn, if the compressor is not pumping well, you will see elevated suction pressures. Reply.Lennox Learning Solutions teaches you what causes high head pressure on a heat pump in the heating mode.There is several factors that can cause hight pressur...Hydraulics. Pratima Bajpai, in Biermann's Handbook of Pulp and Paper (Third Edition), 2018. NPSH, NPSHA, NPSHR. NPSH is the absolute suction head minus the vapor pressure of the liquid being pumped. NPSHA is the net positive suction head available and must be greater than NPSHR, the net positive suction head required. NPSH increases as the …NPSH margins of 2 m, 2.5 m or 3 m have widely been accepted for small/medium pumps or low-/medium-energy pumps. For high-energy pumps, higher factors and margins should be used. For example, for some high-pressure and high-energy pumps NPSHa = 1.5 × NPSHr + 3 m might be used. Difficulties & Challenges …Suction Head. Based on the Energy Equation - the suction head in the fluid close to the impeller *) can be expressed as the sum of the static and velocity head: h s = p s / γ liquid + v s 2 / 2 g (1) where. h s = suction head close to the impeller (m, in) p s = static pressure in the fluid close to the impeller (Pa (N/m 2), psi (lb/in 2))This will cause the following symptoms: Low evaporator (suction) pressure; High evaporator and compressor superheats; Low compressor amp draw; Short …Suction Head. Based on the Energy Equation - the suction head in the fluid close to the impeller *) can be expressed as the sum of the static and velocity head: h s = p s / γ liquid + v s 2 / 2 g (1) where. h s = suction head close to the impeller (m, in) p s = static pressure in the fluid close to the impeller (Pa (N/m 2), psi (lb/in 2))Head pressure: 118F 83 + 35 = 118F more or less shows on the high side gauge if I understand this correctly. Low side pressure: 125 psi = 42 saturation temp. 66.2 low side line temp. High side pressure: 335psi = 104 saturation temp. 83.1 high side line temp. Temp at the vent in rooms: 56.1F + or minus. Temp from supply side: 55.2F.management system. Unless the suction pressure requires readjustment, the ONLY reduction in compression ratio (ratio of absolute discharge pressure/absolute suction pressure) will come from lowering the head pressure. In this case, lowering the condensing temperature to 80ºF (175 psig) will yield a significantly lower compression ratio (10.35 ...Causes of high head pressure low suction pressure. For any HVAC system, The two pressures are to be maintained. Excessive refrigerant, higher outdoor temperature, improper cleaning of coils are the main reason for both pressures. Suppose the evaporator is not getting sufficient refrigerant from the compressor. It will not be able …Other signs to look for include high head pressure, low suction pressure, and a high temperature difference between the suction and discharge lines. These symptoms may indicate a problem with the system’s balance and should be addressed promptly to avoid further issues. ... Low suction pressure high head pressure is a …Scale results in a low head pressure in the cooling mode and high suction pressure in the heating mode. False. A domestic hot water loop is loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor. True.Keeping your shower head clean is essential for maintaining good hygiene and ensuring a steady water flow. Over time, mineral deposits and bacteria can build up, causing clogs and ...Causes of high head pressure low suction pressure. For any HVAC system, The two pressures are to be maintained. Excessive refrigerant, higher outdoor temperature, improper cleaning of coils are the main reason for both pressures. Suppose the evaporator is not getting sufficient refrigerant from the compressor. It will not be able …One of the leading causes of low suction pressure is refrigerant leakage. When refrigerant leaks occur, the system’s refrigerant charge decreases, resulting in reduced pressure levels. Leaks can occur at various points, including connections, joints, valves, or even within the coils themselves. 2. Dirty Evaporator or Condenser Coils.In the cooling mode this will result in low suction pressure and low discharge pressure. Sub cooling would be extra high. However, heatpumps can't always be charged accurately using sub cooling alone. Usually "a stuck check valve" can be freed-up by using a strong magnet.Low suction/High head. I have a carrier 38QRF024300 with a 40QNQ024 unit I be been having issues with. Originally my readings were 157# suction (410A) and 275# head reading 7,5.2, and 4.1 amps when RLA is 12.8; with 5 degrees of subcooling. Ambient is 80 in parking garage.If you don't mind getting your hands a little dirty, some petroleum jelly can increase the suction power of your plunger to help with particularly stubborn clogs. If you don't mind...Fig. 3.55 illustrates this by plotting the pump discharge head vs. flow for high- and low-suction tank conditions. The control valve, however, tries to maintain a steady pressure. As a result, the flow rate varies as the suction pressure varies. In some cases, the flow rate may drop to below the recommended minimum at very low head conditions.The net positive suction head (NPSH) of a pump refers to the difference between the suction pressure at the pump's inlet and the fluid's vapor pressure at the system …We will first examine the low-pressure side of the system, otherwise known as the vapor or suction line. During air conditioning mode, the pressure on the vapor line of an R-410A system will be somewhere between 102 to 145 PSIG. If the system had R-22, the vapor pressure would be between 58 to 85 PSIG but these pressures will be …If the motor turns the wrong way, the impeller could potentially back off the shaft, causing serious damage to the internals. 2. Clogged Suction. Make sure the suction pipe is free and clear of debris. Less flow into the pump, will obviously yield less flow out of the pump. 3. Worn impeller, wear ring, wear plate.High suction pressure is a phenomenon in which the refrigerant-carrying suction line of an AC system exceeds the pounds per square (PSI) for which it’s …The net positive suction head (NPSH) of a pump refers to the difference between the suction pressure at the pump's inlet and the fluid's vapor pressure at the system …Yahoo announced today that it was repurchasing 40 million of its shares from activist investor Third Point, bringing the hedge fund’s Yahoo stake to below 2%. That means that Third...My suction is running at 45psi and head is at 110psi. I checked evap coil and filter and both were clean, so I figured it was low on R22. I added 7 lbs. (factory charge is 7.25 lbs) and pressures did not change. The suction line is frosting up to the compressor. I'm starting to think I have a bad reversing valve.When a refrigeration system that produces low or no cooling has high suction pressure and high head pressure , it probably A. has an inefficient compressor B. has a low-side restriction C. is overcharged D. is undercharged. Refrigeration and Air Conditioning Technology (MindTap Course List) 8th Edition. ISBN: 9781305578296.Number 2 is incorrect, metering device part depends on system to system. High load is correct. Look at your liquid line temps, subcooling and approach temps. They will help diagnose high head issues. There is another cause of high head pressure, mismatched (higher btu) compressor. Different refrigerant in the system.33 posts · Joined 2011. #7 · Jul 4, 2011. " high head, low suction". 310 isn't high, unless the outdoor temp is 70F which probably isn't the case. Typical condensing temps for 13 SEER cooling equipment is 15-20 degrees above outdoor temp. The saturated temp for 310psi is right at 99F.Fig. 3.55 illustrates this by plotting the pump discharge head vs. flow for high- and low-suction tank conditions. The control valve, however, tries to maintain a steady pressure. As a result, the flow rate varies as the suction pressure varies. In some cases, the flow rate may drop to below the recommended minimum at very low head conditions.My suction is running at 45psi and head is at 110psi. I checked evap coil and filter and both were clean, so I figured it was low on R22. I added 7 lbs. (factory charge is 7.25 lbs) and pressures did not change. The suction line is frosting up to the compressor. I'm starting to think I have a bad reversing valve.And, just as common, is suction pressure and/or head pressure being involved in the cause. Often, the refrigeration system will still run, but it’ll run inefficiently because the suction pressure is too high while the head pressure is simultaneously too low. ... Compressor amperes: low. Low side pressure: 11.6 psig/10° High side …In search of more space and pressured by low inventory, home shoppers are flocking to new construction. By clicking "TRY IT", I agree to receive newsletters and promotions from Mon...Low Load. While we often think of the combo of low suction, superheat, and head pressure as being caused by low airflow, it actually falls under a larger heading of low evaporator load. That simply means that the quantity of heat being picked up in the evaporator is lower than the refrigerant mass flow rate requires for the desired operation.The margin of pressure over vapor pressure, at the pump suction nozzle, is Net Positive Suction Head (NPSH). NPSH is the difference between suction pressure (stagnation) and vapor pressure. In equation form: NPSH = Ps ‑ Pvap. Where: NPSH = NPSH available from the system, at the pump inlet, with the pump running.Bombogenesis happens when the atmospheric pressure in a low-pressure system drops rapidly, intensifying a storm and creating a bomb cyclone. Advertisement This planet has a lot of ...The high head leads to poor heat rejection and the higher pressures can force more of the available refrigerant into the evaporator and show up as normal or high suction pressure with normal or low superheat. Also make sure the outdoor fan motor is running in the proper direction. Reply.Both fans working fine. Good air flow through evaporator and condenser. There are no leaks, and no icing. I have tried adjusting the charge to raise the low side pressure, but in doing so would also raise the high side exponentially. (i.e. Increase the suction pressure by 20 psi, and the head pressure would jump as much as 150 psi)Significance of Monitoring Head Pressure. Regularly monitoring head pressure is crucial for various reasons: Energy efficiency considerations: A well-regulated system consumes less power. System longevity: Systems with proper head pressure often have longer lifespans. Maintaining comfort levels: Stable head pressure ensures consistent …Your blood pressure readings are useful indicators of your cardiovascular system’s overall health. Low, high and normal blood pressure readings help your doctor make the right deci...Pressure gauges provide readings of the condensing and suction pressures, allowing technicians to monitor and adjust the head pressure as needed. B. Measuring Head Pressure in Refrigeration Systems To measure head pressure in refrigeration systems, technicians connect pressure gauges to the service ports on the high and …Repeatedly tripping sentronic+. 35 psi net oil press. No press difference between crank and suction. Crankcase heater working. R-22 40 psig suction 160 psig head, 8* sh at comp. sorry no sc data. 40* outdoor ambient. Sh measurements taken at each evap outlet right around 4*. No one evap showing major flooding.1. Reduced Cooling Capacity. 2. Reduced Airflow From the Vents. 3. Increased Energy Consumption. 4. Poor Indoor Air Quality. How to Diagnose and Fix …The most common liquid line restrictions are clogged filter-driers, metering device inlet screens, a kinked liquid line, or a TXV with an empty bulb. These very rarely cause high head for more than a short period of time. The most common causes of high head pressure include high load, overcharge, and poor heat rejection (such as from …units are pressure units, not head units. For simplicity, I’ll stick with NPSH, regardless of the units used. Suction Pressure: The First Half of the NPSH Equation Suction pressure must be determined at the pump suction nozzle when the pump is running. If suction pressure is measured with a gauge, the atmospheric pressure (at the pump location)Cause #1 Return Duct Leakage:. The suction pressure can be high if the room temp is high, or the return duct has leaks. Cause #2 TXV Improperly feeding: Cause#3 Outdoor/Indoor coil dirty: low airflow situations can cause refrigerant to not completely condense into a liquid, or turn into a gas Cause #4 Unit is Overcharged: One …Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. If the system is continuing to cool it may be doing so at reduced capacity, observed as a loss of up to ten degrees of temperature drop across the coil.The normal operating pressure for R-404A in a freezer at a temperature of 70 degrees Fahrenheit and a suction temperature of 30 degrees Fahrenheit would be around 9.6 psi. The low pressure should be 18-20 psi while the high pressure should be around 200 psi. However, this can vary depending on the specific conditions of the freezer and …I have a suction pressure of 70, converted temp of 41, suction line temp of 51, head pressure of 250, converted temp of 117, head line temp of 96. Air entering condenser is 82 and exit is 100. Air entering evaporator is 76 and exiting is 52.Greetings, I am working on a R22 Lennox Split Heat Pump 3 ½ ton. The unit will trip on the compressor relief valve in heating. I was unable to test the unit S/C and S/H accurately, due to the High Side pressure building up so fast with in a minuet will be hitting 400psi and blow the low side would sit at about 50psi. I tested the RVR from cooling to …Scroll Troubleshooting Solution Chart - Copeland A/C Specific. Deep Vacuum Conditions. Deep vacuum can cause arcing damage to the Fusite pins. Models built after September 1991 have an internal vacuum protection and stop pumping when the pressure exceeds approximate. 10:1. Scroll compressors should never be used to evacuate a system, …Number 2 is incorrect, metering device part depends on system to system. High load is correct. Look at your liquid line temps, subcooling and approach temps. They will help diagnose high head issues. There is another cause of high head pressure, mismatched (higher btu) compressor. Different refrigerant in the system.Lower suction pressures generally result in a higher DTD, and higher suction pressures usually result in a lower DTD. When we look at head pressure, we’re actually learning …R410a suction pressure may be around 120psi, and R410a head pressure may be anywhere from 225psi to 350psi. Many conditions could apply here, there’s absolutely ‘no’ set point pressure for 410a, r22, or anything else. Educate yourself on whats going on in the heat transfer process.Liposuction is the removal of excess body fat by suction using special surgical equipment. A plastic surgeon typically does the surgery. Liposuction is the removal of excess body f...NPSH Required (NPSHR): The minimum pressure required at the suction port of the pump to keep the pump from cavitating. NPSH or Net Positive Suction Head is a very important part of a pumping system. The systems NPSH A must be higher than the pump’s NPSH R in order for proper pump performance and to eliminate the risk of cavitation, which can ...Very high suctuion and head pressure on heating mode. Hello, I have a Rheem (2015) heat pump 2ton 410A, on cooling mode the system runs great; suction and liquid pressure are ok 185/360, super heat 10 F, with 90F outdoor temperature, now the winter is coming and the system on heating mode the gages read high pressure on …problems. Fluid flows from areas of high pressure to areas of low pressure. Pumps operate by creating low pressure at the inlet which allows the liquid to be pushed into the pump by atmospheric or head pressure (pressure due to the liquid’s surface being above the centerline of the pump). Consider placing a pump at the top of the mercuryso i just installed a brand new ac unit and its been kicking my butt.. but anways i put a 410a 1.5 ton 16 seer payne condenser with a 2 ton payne N coil with a txv already installed.. 155 suction pressure 280 discharge pressure 4 amps 10 degree sub cooling which condenser calls for only 3 degree superheat havent ran into a problem like this …problems. Fluid flows from areas of high pressure to areas of low pressure. Pumps operate by creating low pressure at the inlet which allows the liquid to be pushed into the pump by atmospheric or head pressure (pressure due to the liquid’s surface being above the centerline of the pump). Consider placing a pump at the top of the mercuryHigh discharge temperatures can indicate minimal movement of refrigerant. Because the refrigerant isn't being pumped at design rates it stays in the condenser for a longer period of time and is cooled more, hence lower head pressures, and in turn, if the compressor is not pumping well, you will see elevated suction pressures. Reply.Head pressure 190 Suction Pressure 90 Suction line temp 54 inside temp 75 wetbulb 69 So ive been thru this problem b4 with the low head high suction so i assume piston or a-coil . I open up the duct and the other hvac guy has put in a 3ton acoil . I told the neighbor that he should replace the acoil with a 2 1/2 ton .Gauge Pressure + Atmospheric Pressure = Absolute Pressure. 74 PSIG + 13.91 PSI = 87.91 PSIA. Now that the team has the pump’s suction pressure in PSIA, they can easily calculate NPSHa: NPSHa = Suction Pressure – Vapor Pressure. NPSHa = 87.91 PSIA – 72 PSIA = 15.91 PSIA. NPSHa is always expressed in head units.Second, the pump curve for the 14.125-inch impeller shows that the pump's shutoff head is 212 feet, a 16-foot head increase over the normal pump head of 192 feet at 1,000 gpm. A fluid density of 62 pounds per cubic foot (lb/ft 3 ) would result in a pressure increase of 8.6 pounds per square inch (psi), which is less than the observed 16 psi ...HIGH SUCTION PRESSURE / LOW HEAD PRESSURE ISSUE. Hey guys, need some help i am working on a carrier unit with a Scroll Compressor. I am getting 80 PSIG low side and 165 PSIG high side. Liquid Line is also very hot to the touch. I know this is not normal readings and since it's a scroll compressor, I am thinking about replacing the TXV.• High suction pressure/Up-thrust: Patent pending dual bearing arrangement that handles rotor up-thrust and to keep the shaft ... High-Head/Low Flow Services • Capacities 20 GPM (6.8m3/hr) to 2,800 GPM (636 m3/hr) • Heads to 4500 feet (1372 meter)*Low blood pressure, or hypotension, is generally not a concern and requires no treatment in healthy people, according to WebMD. Treatment of hypotension may require treatment of an...We would like to show you a description here but the site won’t allow us.In addition to a malfunctioning TXV, other factors that can cause high subcooling include a dirty condenser coil or restricted airflow over the condenser. Low Suction pressure/ low head pressure. A bad TXV can also cause low suction pressure and low head pressure in an HVAC system by restricting the flow of refrigerant into the evaporator coil.Scale results in a low head pressure in the cooling mode and high suction pressure in the heating mode. False. A domestic hot water loop is loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor. True.Step 1. Scale in a geothermal heat pump's fluid system results in an overall increase in fluid temperature high head pressure in the cooling mode and low suction pressure in the heating mode an overall decrease in fluid temperature low head pressure in the cooling mode and high suction pressure in the heating mode.R-22 Low Side Pressure 2: R-22 High Side Pressure 3 °F 1 °C: psig: kpa: Bar-50° ... Typical low pressure or suction side, may vary by equipment and metering controls - these are "gauge pressure readings" or "psig" Typical high …The most common liquid line restrictions are clogged filter-driers, metering device inlet screens, a kinked liquid line, or a TXV with an empty bulb. These very rarely cause high head for more than a short period of time. The most common causes of high head pressure include high load, overcharge, and poor heat rejection (such as from …404a pressures in low. I have a r-404a roof-top condensing serving a walk in freezer. pressures are 235 psi head pressure and a 28psi suction pressure. Outdoor ambient is 30degress and indoor box temperature is about 20degrees. System has a head pressure control on roof for hot gas. Wondering if pressures sound right.R410a suction pressure may be around 120psi, and R410a head pressure may be anywhere from 225psi to 350psi. Many conditions could apply here, there’s absolutely ‘no’ set point pressure for 410a, r22, or anything else. Educate yourself on whats going on in the heat transfer process.When all else seems to function properly, a system with a high suction pressure and a low head pressure suggests _____. the compressor has leaky valves and/or worn piston rings A running burn is indicated by _____.A cold suction line (low superheat) with low suction pressure is a symptom of low evaporator air. A liquid restriction would result high superheat (warm suction line). The high head probably due to the other guys overcharging, trying to get the suction pressure up. But the low air problem would result in high head pressure in the heat cycle.Lennox Learning Solutions teaches you what causes high head pressure on a heat pump in the heating mode.There is several factors that can cause hight pressur...Head pressure consists of two main components: the condensing pressure and the suction pressure. The condensing pressure occurs in the condenser, where the …Our diagnostic sheet shows that liquid line restrictions cause low suction pressure and normal to low head pressure, not high head pressure. That’s because the compressor requires refrigerant of a specific density to pump refrigerant into the high side of the system; when the suction pressure is low, the compressor can’t move as much ...Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. If the system …High Suction Pressure! I have a 3Ton Carrier Heat Pump unit using 410A that has extremely high suction pressure around 250PSI. I also have a low liquid line pressure around 300PSI and my sub-cooling is around 40-50 Degrees. I have checked for a stuck liquid line solenoid but this system does not have one, and I checked the reversing valve and ...So, when pressure in the pump causes more load on the motor, it slows down. When the motor slows down, the flow rate drops at the same percentage. A motor that operates at about 2000 RPM at low pressures will typically slow down to about 1750 RPM when the pump is pressurized to the maximum rating. It stands to reason, then, …
One of the leading causes of low suction pressure is refrigerant leakage. When refrigerant leaks occur, the system’s refrigerant charge decreases, resulting in reduced pressure levels. Leaks can occur at various points, including connections, joints, valves, or even within the coils themselves. 2. Dirty Evaporator or Condenser Coils.. Papa john's corydon indiana
At room temperature, it will boil if the absolute pressure is less than about 0.4-psia. Water has low vapor pressure; other substances may have high values and, while numerically different, work similarly. Consider three examples of a tank providing different suction heads as a function of the tank pressure: Figure 3a. Tank open to atmosphereBoth fans working fine. Good air flow through evaporator and condenser. There are no leaks, and no icing. I have tried adjusting the charge to raise the low side pressure, but in doing so would also raise the high side exponentially. (i.e. Increase the suction pressure by 20 psi, and the head pressure would jump as much as 150 psi)what causes a high suction pressure and a normal head presssure on an r22 system besides low air across the evaporator coil? Can air in the system cause this situation? TD is 17f. otd is 91degrees liquid line pressure is 230psi; suction pressure is 90psi.By contacting an HVAC technician, you can get your AC system’s suction pressure back to normal levels. If you are experiencing a problem with your air conditioning or heating call us at 512-336-1431 to schedule an appointment. We’ll be glad to come out and take a look at the issue. 1431-183 A/C & Heating proudly serves Round Rock ...Terms in this set (54) In order for a system to operate correctly, the high side of the system must have enough _____. Vapor pumped, heat removed from condenser, vapor space. If there is a lack of refrigerant in a system, each pounds of refrigerant will not completely __________. Condense on the high side. When a system is undercharged, the ...High Discharge Pressure on heat pump. I was working on a customers heat pump today, A lennox HPXA19-060-230-02 with A cbx32mv-060-230-6-02. It kept short cycling but was giving off 100 f supply. I put my guages on at heat mode and it would trip discharge line temp at 650 PSI (154.7 F) on discharge with a 200 f discharge line temp.Low blood pressure, or hypotension, is generally not a concern and requires no treatment in healthy people, according to WebMD. Treatment of hypotension may require treatment of an...Table 1: R134a Saturation Properties pressure table (Reference: www.chemours.com) Back to the problem at hand. For any refrigeration cycle/AC unit there are two operating pressures: suction pressure and discharging pressure, high and low settings for each pressure line determined by the manufacturer will stop the unit.Study with Quizlet and memorize flashcards containing terms like In a 2-ton capillary tube system, the unit does not develop full capacity. Heat pressure is low and suction pressure is high. What is the problem?, In a 2-ton capillary tube system, the unit does not develop full capacity. Head pressure is high, suction pressure is high, and there is no superheat. What is the problem?, Will the ...Low suction/High head. I have a carrier 38QRF024300 with a 40QNQ024 unit I be been having issues with. Originally my readings were 157# suction (410A) and 275# head reading 7,5.2, and 4.1 amps when RLA is 12.8; with 5 degrees of subcooling. Ambient is 80 in parking garage.When both the suction pressure and head pressure are low, how might a technician determine that the problem is low evaporator airflow and not a low refrigerant charge ... When all else seems to function properly, a system with a high suction pressure and a low head pressure suggests _____. the compressor has leaky valves and/or worn piston ...Low suction pressure and high head pressure occur when there’s a drop in refrigerant pressure in the AC system, coupled with elevated output pressure in the compressor. The primary culprit behind this condition is a faulty or malfunctioning TXV valve .Low head pressure may occur simulataneously with high pressure on the suction side of an air conditioner, heat pump or refrigeration system compressor system. If the system is continuing to cool it may be doing so at reduced capacity, observed as a loss of up to ten degrees of temperature drop across the coil.This means the pump takes suction pressure, adds more pressure (the design pressure), and generates discharge pressure. So, the discharge pressure is equal to the suction pressure plus the pump’s design pressure. The discharge pressure of the pump should be approximately equivalent to the total dynamic head (TDH) required by …higher head pressure and higher subcooling. When any refrigeration system is low on refrigerant it will usually have: low suction and low head pressure. What can cause high superheat in a TEV metered evaporator? ... What combination of symptoms only occurs on a unit with an inefficient compressor? Low head pressure and high suction pressure ...One of the leading causes of low suction pressure is refrigerant leakage. When refrigerant leaks occur, the system’s refrigerant charge decreases, resulting in reduced pressure levels. Leaks can occur at various points, including connections, joints, valves, or even within the coils themselves. 2. Dirty Evaporator or Condenser Coils.So, when pressure in the pump causes more load on the motor, it slows down. When the motor slows down, the flow rate drops at the same percentage. A motor that operates at about 2000 RPM at low pressures will typically slow down to about 1750 RPM when the pump is pressurized to the maximum rating. It stands to reason, then, …When a refrigeration system that produces low or no cooling has high suction pressure and high head pressure , it probably A. has an inefficient compressor B. has a low-side restriction C. is overcharged D. is undercharged. Refrigeration and Air Conditioning Technology (MindTap Course List) 8th Edition. ISBN: 9781305578296.Subaru engines have a radiator and water channel design that uses pumped and pressurized coolant to stabilize its internal temperature. Unlike most internal combustion engines, ins...Hi, sorry you're having trouble. Low suction and high head is usually due to a restriction in the liquid line. Basically, you're starving the evaporator. If the unit has an expansion valve on the inlet to the evaporator, it may be defective. Some are adjustable, most residential ones, not. I would look there first.Scale results in a low head pressure in the cooling mode and high suction pressure in the heating mode. False. A domestic hot water loop is loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor. True..