no superheat, no subcooling

[02powerstroke]

Here is the situation... Design pressures are 150/300psi with 12 degree subcooling...

Actual conditions are 92Psi liquid at a temperature of 69F. High pressure side is at around 220Psi and about 12F BELOW saturation temperature. Cooling isn't really doing much indoors and runs constantly.

Is the compressor on the way out or is there a charge issue here. Forgive me as I am fairly new to the service industry.

Thanks in advance guys

[ChaseAir]

you have 14 deg superheat on r22 at that pressure and temp. The 92 is the suction not the liquid. The liquid (or high pressure or head pressure) temp should read below the saturation temp (it does SUBCOOL the refrigerant after all).

Your suction pressure is kinda high. This could be caused by hot temperature inside or high airflow. Is this a txv system?

[02powerstroke]

R22 is the refrigerant

[zw17]

Here is the situation... Design pressures are 150/300psi with 12 degree subcooling...

Actual conditions are 92Psi liquid at a temperature of 69F. High pressure side is at around 220Psi and about 12F BELOW saturation temperature. Cooling isn't really doing much indoors and runs constantly.

Is the compressor on the way out or is there a charge issue here. Forgive me as I am fairly new to the service industry.

Thanks in advance guys

I am kind of lost in your post...

Fill this out for me:

Refrigerant type (22,410,134)?
Type of system (split, package, chiller)?
Metering device (TXV, orifice, cap tube)?
Suction pressure?
Suction line temp?
Liquid line pressure?
Liquid line temp?
Return air temp?
Temp drop across the evap coil?

This will help us get started.

[02powerstroke]

I'll get to a laptop quick and fill that out..

[ChaseAir]

What is your coil temp difference? Do you have duct leakage to have high suction like that?

[02powerstroke]

I am kind of lost in your post...

Fill this out for me:

Refrigerant type (22,410,134)? R22
Type of system (split, package, chiller)? Split
Metering device (TXV, orifice, cap tube)? TXV
Suction pressure? 92 psi
Suction line temp? 69F
Liquid line pressure? ~220 psi
Liquid line temp? 108F
Return air temp? Didn't measure this, however the thermostat is set to 79F.
Temp drop across the evap coil? Supply air temperature is 67F.
This will help us get started.

I edited the quote to include the requested information

Also, if my suction line pressure is 92psi and my saturation temp is about 57F. If my suction line temperature is 69F, doesn't that mean I have no subcooling?

[Southern Mech]

I edited the quote to include the requested information

Also, if my suction line pressure is 92psi and my saturation temp is about 57F. If my suction line temperature is 69F, doesn't that mean I have no subcooling?

no that means you have 12* superheat. Line temp - Sat temp = superheat for suction and subcool for liquid.

I really reccomend you learn what this is, the superheat / subcool as you can not diagnose a refrigeration issue w/o this. It's kinda like your blood pressure

[zw17]

You have 14*F superheat
You have 0*F subcooling

That 0*F subcooling tells me you are way undercharged.

[knave]

if my suction line pressure is 92psi and my saturation temp is about 57F. If my suction line temperature is 69F, doesn't that mean I have no subcooling?

The suction line is superheated gas returning to the comp from the indoor coil. If sat. temp is 57 and the gas is 69, you have 12F of superheat.

[gregp]

is not adding up here. How can you have 12-14 degree superheat and no subcooling? The TXV will be wide open with no liquid to it, only vapor. S/H should be much higher.

[knave]

is not adding up here. How can you have 12-14 degree superheat and no subcooling? The TXV will be wide open with no liquid to it, only vapor. S/H should be much higher.

Saturated refrigerant can be any combination of liquid and vapor, as long as both are present.

[zw17]

02, have you tried adding gas? I would start by adding until you see you liquid line temp start to drop a bit. No more than 2-3lbs though.

If you don't have the manufactures recommendation on target subcooling I would shoot for 10*F to start. Check your temp drop and superheat and report back to us.

[jpsmith1cm]

Yep..

Add some gas and you will settle down.

Probably even bring your suction pressure down, too.

Bonus points for the OP if he can explain why suction will drop...

[jpsmith1cm]

I really reccomend you learn what this is, the superheat / subcool as you can not diagnose a refrigeration issue w/o this. It's kinda like your blood pressure

I could not agree with this post more.

You NEED to understand subcooling and superheat before you can consider yourself competent in this field.

[02powerstroke]

sorry for the confusion.. yes that is correct, I have about 12F of superheat and a couple degrees of subcooling, at best.. I had to run to grab some parts for another job, but will re-measure in a little while... as for now, I didn't want to add gas just yet.. wanted to be sure

[02powerstroke]

I keep mixing my lines up, and it came out in the form of subcooling/superheat confusion... yes, I have about 12F of superheat coming into the compressor via the suction line... the liquid line has nearly no subcooling to it.. I am going to re-attach the gauges in a bit, when I return to the site, to be sure of my numbers I quoted above.

[waltervan]

Here is the situation... Design pressures are 150/300psi with 12 degree subcooling...

Actual conditions are 92Psi liquid at a temperature of 69F. High pressure side is at around 220Psi and about 12F BELOW saturation temperature. Cooling isn't really doing much indoors and runs constantly.

Is the compressor on the way out or is there a charge issue here. Forgive me as I am fairly new to the service industry.

Thanks in advance guys

Why is the design pressures so high 150PSI suction on R22. Where did you get the design pressures are you sure thats not the testing pressure?

[02powerstroke]

Why is the design pressures so high 150PSI suction on R22. Where did you get the design pressures are you sure thats not the testing pressure?

this was from the manufacturer's information... suction pressure will drop on the suction side when you add refrigerant since you have more refrigerant to absorb heat... since there is more refrigerant you will have more refrigerant to absorb the energy and will result in less liquid refrigerant turning into a gas, or vaporizing

what do I get?

[jpsmith1cm]

this was from the manufacturer's information... suction pressure will drop on the suction side when you add refrigerant since you have more refrigerant to absorb heat... since there is more refrigerant you will have more refrigerant to absorb the energy and will result in less liquid refrigerant turning into a gas, or vaporizing

what do I get?

You get to try again......