Low Suction Pressure:What,Types,Causes,Several Facts

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The low suction pressure is an avoidable phenomenon for the efficient working of the system.

The low suction pressure was due to a decrease in the local pressure of the refrigerant. The liquid refrigerant droplet will get converted into vapors sometime.

There are a few most relevant causes of the low suction pressure in the HVAC system. Some of the most probable causes are as below,

In low suction pressure, The refrigerant will get partially converted into vapor due to the conversion of sensible heat into latent heat.

What is low suction pressure?

Refrigeration and air conditioning is widely used home appliances nowadays.

It is occurred due to less refrigerant flow through the system. The low suction pressure was due to a decrease in the local pressure of the refrigerant.

The low refrigerant flow is occurred due to restrictions in the flow due to dirty filters. The heat transfer is minimum due to the insufficient refrigerant flowing through the system. It will ultimately reduce the operational performance of the HVAC system.

Low suction pressure causes

low suction pressure is developed in the refrigeration system. Some of the most probable causes are as below,

  • The coil is covered with dust or frost
  • Restriction in the refrigerant line
  • Filters and strainers are dirty
  • Faulty fan motor
  • Low room temperature
  • Faulty compressor
  • Dampers are closed
  • Undersize of duct

The above list is the leading cause of the low suction pressure. Some small reasons can also cause the low pressure in the system. The minor causes are restriction in a piston, physical neck formed on the coil, insufficient space, etc.

The low suction pressure can be avoidable by following a few simple steps and cares,

  • Clean the strainers and filters periodically
  • clean dust and frosts from the coils,
  • Provide sufficient space to the outside unit of refrigeration
  • Monitor the system’s performance
  • Clean the fan and its blades
  • Keep the complete system dust-free

The low refrigerant flow is occurred due to restrictions in the flow due to dirty filters. The heat transfer is minimum due to the insufficient refrigerant flowing through the system. It will ultimately affect the performance of the system.

Low suction pressure in chiller

There are some different problems associated with low suction pressure in a chiller.

  • Insufficient refrigerant in the system
  • The metering device is clogged
  • The problem of the brine flow through the system
  • The gauge is not working properly
  • The level of oil is more than the limit in the chiller
  • Clogging of filters
  • Dilution of oil
  • Working condition is not as per requirement

These are the most relevant facts for the low suction pressure in the chiller. The dilution of oil can cause the failure of the bearing.

Low suction pressure in refrigeration system

The low suction pressure in the refrigeration system is caused due to following,

  • Insufficient charging of the refrigerant -It increases the running time of the compressor
  • Disturbance in the refrigerant flow – due to choking of filters or restriction in the system
  • Choked filter – The filter is blocked due to impurities in the system
  • Clogging of the TEV – Thermostatic expansion valve is stopped due to ice or dust particles
  • Restriction in the expansion device
  • The coil is covered with dust and frost, which decreases the coil’s heat transfer capacity.

It is recommended that the cleaning of coils should be carried out periodically. It can be carried out with a brush.

Low suction pressure in a compressor

The compressor is the part that can be found in almost all refrigeration systems.

  • Set the indoor temperature high if it is low
  • Clean or replace the filter, if it is chocked
  • Set the thermostatic valve at optimum superheat degree to avoid the low suction pressure
  • Clean the air duct. If there is a restriction from the air duct. keep external pressure moderate
  • Measure the condensing pressure, Clean it if the condensing pressure is not at the desired level
  • If the shape is not proper, the air duct should be appropriately designed. It is recommended to redesign it.
low suction pressure
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Low suction pressure in pumps

The pump is the essential component for most hydraulic systems

The low suction pressure in the pump reduces the flow and the head delivered by the pump.

There are so many causes for the low suction pressure in the pump. Some of the common causes are described as below,

The primming of the pump is an essential process to avoid low suction pressure. The water flow is less than the requirement if the primming is insufficient. Ideally, the pump should be installed near to the resources of water. The pump’s flow rate is reduced if the pump is far from the source of the water. If the suction requires more power, the discharge is reduced. It would help if you kept the pump distance as per the specification of the pump.

The suction line diameter should be kept sufficient so that the flow can quickly reach the pump’s inlet. If the suction line area is reduced, it can cause a problem with the suction. Make sure that the suction line should not leak from anywhere.

The pump is operating with the impeller rotation in it. The direction of rotation is unique. Suppose it rotated in the reverse direction. The fluid will not get pressurized. This can happen because of faulty electric connections.