I've mainly been an installer for 10 years and I am wanting to get into service or trouble shooting end of the business. The one one thing that I have trouble with is the whole aspect of superheat and subcooling. Any helpful info would be greatly appreciated.
Hi welcome, simply do a search on this forum, both these topics are very popular and there has been multiple threads on both with good, accurate detail.
A good link from Sporlan, shows how to use the PT Cards,
The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.
superheated, only gas present, subcooled, only liquid present, saturated, both gas and liquid present.
subcooling let you know how much refrigerant is in a system and superheat tells you whats wrong.
lets assume you have a low charge, subcooling would drop and superheat will rise.
now you have a restriction, subcooling may be slightly high or if someone overcharges it to overcome the restriction subcooling goes up superheat would be high but it ccould come down depending on how much overcharge there is and the amount of restriction.
lets say evap is dirty, subcooling normal but superheat is low.
so subcooling is the amount of condensed subcooled liquid in the condenser and superheat is the amount of superheated vapor leaving the evaporator or how much liquid is in the evap.
my advise is to sit down and ponder whats really going on in a refrigeration circuit.
I have a pretty general idea of how refidgerant works in within a system. What I was really wanting to know where to take these temps.,pressures,etc. readings,and with what recommended instruments (mainly to messure temps.)
I'm sure you already have an idea but I'll through my 2 c in here.
Superheat is used to see how how full an evaporator is on a cap tube or a fixed orifice.
Subcooling is used to see how full a condenser is on a TXV system.
Superheat- compare saturation temp. to temp at outlet of evaporator. difference depends on equip. ac or ref.
Subcooling- compare condensing temp. to condenser outlet temp. again depends.
not much but I hope it helps.
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