# 410a low suction pressure freezing up



## Sutton89

Hey guys, need some help from the more experienced ones here. New 5ton coil and condenser no txv. Low suction pressure about 90 psi fluctuates but never above 105psi. High side is good. Super heat is like 2 and subcooling is around 1. Unit keeps freezing up. I'm thinking it's an air flow issue. 

Where would you guys be looking/start to solve this?


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## smsprestige

when you say high side is good what exactly does that mean?


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## ACGUY

2 things: when I find the pressure fluctuates I it is normally non condensables in the system. As for freezing up there is a airflow issue. Check the indoor coil for dirt or loose filters get sucked up.


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## heatingrepairchicago

if the proper duct size is there with the new coil recover all the 410, put a vacuum pump on the system for a good 45 minutes to a hour. then recharge the system and try it then.


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## crmotoxr

Always check static pressure first when the coil is not frozen. Make sure filter is clean and all vents/dampers are open.


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## heatingrepairchicago

make sure your line set sizes are proper 3/8 X 7/8


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## pintofstout

A superheat of two, unless it's a centrifugal, is probably a superheat of zero. A subcooling of one is probably a subcooling of zero. 

Sounds like it's got the wrong oriface, I'm guessing head is actually low


Sent from my iPhone using Tapatalk


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## ShepherdEHC

What type of system is it, thats the first thing and u said no tvx so cap tube ?? goto give up more information, can't help if everything is so vague. superheat and subool are looking real bad, also to me looks like u have a restriction somewhere or you are overcharged. Start with that in mind n see what you can do


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## HVACPhilly

You have one of two issues, or maybe both. Start with air flow ( air filter, duct size and Blower speed) if all good, do a system recovery, replace filter drier, a good hour of vacuum pump.


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## Atlair

Enter our website https://www.atlairhvac.com to provide information


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## sprsun

A R-410A evaporator running below 100 psig will freeze-up just like its R-22 cousin. One of the most common causes of low suction pressure is loss of critical refrigerant charge caused by small leaks over time.


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