how much freon

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donn

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Full is when the gages read correctly. On MHs you cannot get a good answer. Too many variables. A good AC shop will hook it up, check for leaks and recharge to the correct pressure
 

Utclmjmpr

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Cedar City, UT
Donn is correct,, Motorhomes have an infinite number of FEET of line due to the length of the coach,, can be 40 or 50 feet of line in some coaches.. The correct pressure will put it where it needs to be..>>>Dan ( As an example,, my 39 foot coach has the compressor mounted on the rear diesel engine with a condenser just behind the front axel and a dryer and receiver in front of the dash,, that's a lot of line to fill,, up and back.)
 
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Gary RV_Wizard

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At our Silver Springs FL home
Yeap, go with the gauges and fill until the pressure is right.

Typically the quantity varies depending on the installation and how empty the system is. Rarely is it totally empty once it has been filled, though I suppose it would be if the entire system was evacuated with a pump or all the major components were removed & replaced.
 

headshaker

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Mar 13, 2021
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pearland tx
And of course R-134A is "Refrigerant" R-12 is "Freon". also a refrigerant. R-134 is Tetrafluoroethane

Say Tetra Fluoro Ethane
Yes you are correct
And of course R-134A is "Refrigerant" R-12 is "Freon". also a refrigerant. R-134 is Tetrafluoroethane

Say Tetra Fluoro Ethane
Yes you are correct in terminology. I'm old school I call all sodas Coke.
 

TonyL

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Gauge reading is only part of the equation. You need to match them to both ambient temperature and indoor temperature. Most systems should have had a sticker advising what the correct weight of charge is, to use gauges alone will require a competent engineer, adding small amounts at a time and watching for system changes.
 

Ex-Calif

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If the system has been opened I would highly recommend getting the right tools for the job. I avoided A/C work for years but the tools are relatively cheap now.

If the system has been opened you need to dry, then purge, then fill the system. I got a dryer and vacuum unit that runs off my air compressor for little money on amazon.
 

TonyL

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Gary, in the UK only registered engineers can buy refrigerant. I was unaware that anyone in the US could pick up refrigerant in an auto store. Service Refrigerant gauges have different temperature scales on them depending on what refrigerant is being used. It is a basic comparator for saturated refrigerant temperature. I do not know what is fitted to DIY kits.
My point is, unless you know what you are doing, too much refrigerant can be very dangerous. I have seen first hand on commercial systems, 1 1/2" tubing blown apart because an engineer kept charging a system and didn't know that the high pressure switch was faulty. I bet he/she needed clean underwear when the tube ruptured.
 

crawford 111

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dandridge,TN
mine has a receiver dryer on top has a sight glass I just use it till most of bubble's are gone and it's done. Well that's if and when I fine I need to add to system.
 

Henry J Fate

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Since the OP is asking how much refrigerant to add, I assume his system pressure is below the low pressure switch or the system has been evacuated.

I would first turn on the roof AC and get the temperature in the RV to 75f on a day that the outside temp is no more than 80f.

Start the engine and place the dash air conditioning to ON with the lowest possible temp setting.

Begin adding refrigerant while listening for the compressor to start. Continue adding until the system is operating at normal pressure. I will generally add refrigerant close to the high end of specification.

A reasonable expectation would be to add a couple of pounds then continue to top it off watching gauges, listening for compressor operation and some touchy Feely on the piping for signs of cooling and heat removal.
 

TonyL

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H makes a valid point. But before you add any refrigerant you should find out where the original refrigerant went.
 

Ray-IN

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mine has a receiver dryer on top has a sight glass I just use it till most of bubble's are gone and it's done. Well that's if and when I fine I need to add to system.
Open and read that air conditioning service manual link I posted and you'll find that watching the sight glass when using R 134 is not reliable.
 

crawford 111

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dandridge,TN
Open and read that air conditioning service manual link I posted and you'll find that watching the sight glass when using R 134 is not reliable.
I was referring it was better then just guessing on how much you are adding. many people just grab a can and a hose and go at it. to the other person yes pag oil but you need to know how much to add.
 
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