Liquid line driers on all split systems??

[absolutefrigid]

Just a quick question and I probably know the answer to it but I'm going to ask all you pro's out there that have been in the business for a while. Shouldn't there be liquid line driers on all split systems?? And if not why? Thanks!!

[woody19]

Most definetly. The filter/drier is there to collect any debri/moisture left in the system. It should always be replaced anytime the system is opened for any repairs also. Carrier/Bryant condensing units are shipped from the factory with one and I'm sure other manufactures do likewise. Some may dispute installing them on a new system but they are probably the same ones not using a micron gauge when evacuating.

[chandleraz_guy]

I think all the new Trane split systems have filter driers on the inside of the units.

Seem to recall issues on here about not running with both factory and contractor installed driers.

[subcooled_]

Every split system should have a liquid line filter drier period. Anytime the system reaches 0 PSIG or less, the filter drier needs to be replaced...as in that new lineset you just installed and let the nitrogen out of or a leak repair.

And as previously stated, many manufacturers do include them in the condenser to ensure they're being used.

[firecontrol]

I suppose I'm going to open up the proverbial can of worms here BUT been here long enough and figured it was my turn.

So I'm reading that every new unit should have a filter dryer installed.

Probably hundreds of thousands of units out there running just fine since they were installed without them.

The filter dryer is designed to trap any moisture that might be in the system and stop foreign material from traveling around the refrigeration circuit and causing trouble.
SO...... my question is why would a brand new properly installed air conditioning system have any moisture in it? Facts are, if the system was properly installed by a trained and qualified technician there will be no moisture at all. This eliminates the first reason to have the filter dryer.
SO...... my next questioin is why would a brand new properly installed air conditioning system have foreign material in the refrigeration circuit? Facts are, if the system was properly installed by a trained and qualified technician there will be no foreign material in the refrigeration system to cause a problem.

Having made these two points I would make an observation here to possibly widen this thread.

Why don't we install low and high pressure switches in all condensing units that don't come from the factory with them installed? I mean if we're all about protecting the equipment from all unforseen trouble, wouldn't the potential for a loss of charge or a condesner fan failing be a perfect reason for installing pressure switches in every unit to protect them?

Why don't we install low ambient controls or low temperature cutoff switches on all units incase an owner accidently turns the air conditioning on when the outside temperatures are such that possible damage could be done to the compressor?

I personally used to install delay-on make timers on all condensers I installed. This was to eliminate those pesky calls to go out to a customer's home and reset a circuit breaker or replace a couple of fuses. I found the small cost much easier to add into the bid price of the unit than say seventy-five dollars on the chance that I'd need to explain why a reset of a circuit breaker is not covered under warranty and is going to cost them a service call.


Just had one of them days.

[subcooled_]

By your filter drier logic, you would never need one. Assuming all leak repairs are done properly (and installs), there would not be any moisture or foreign contaminants. I consider the filter drier cheap insurance against said things.

I would like to see low and high pressure safeties on all A/C units, again cheap insurance. Installing delay on make timers hasn't resulted in any service calls? I'm surprised no one has panicked when it didn't come on right away.

[mark beiser]

I personally used to install delay-on make timers on all condensers I installed.

Why would you install a delay on make timer? Should be a "delay on break".

A "delay on make" timer will hold the unit off every time there is a call for cooling, regardless of how long it has been off.
A "delay on break" timer keeps the unit from turning back on in the for a set period after it has been on, but will allow the unit to come on immediately with a call for cooling if it has been off long enough.

[wconell]

I suppose I'm going to open up the proverbial can of worms here BUT been here long enough and figured it was my turn.

So I'm reading that every new unit should have a filter dryer installed.

Probably hundreds of thousands of units out there running just fine since they were installed without them.

The filter dryer is designed to trap any moisture that might be in the system and stop foreign material from traveling around the refrigeration circuit and causing trouble.
SO...... my question is why would a brand new properly installed air conditioning system have any moisture in it? Facts are, if the system was properly installed by a trained and qualified technician there will be no moisture at all. This eliminates the first reason to have the filter dryer.
SO...... my next questioin is why would a brand new properly installed air conditioning system have foreign material in the refrigeration circuit? Facts are, if the system was properly installed by a trained and qualified technician there will be no foreign material in the refrigeration system to cause a problem.

Having made these two points I would make an observation here to possibly widen this thread.

Why don't we install low and high pressure switches in all condensing units that don't come from the factory with them installed? I mean if we're all about protecting the equipment from all unforseen trouble, wouldn't the potential for a loss of charge or a condesner fan failing be a perfect reason for installing pressure switches in every unit to protect them?

Why don't we install low ambient controls or low temperature cutoff switches on all units incase an owner accidently turns the air conditioning on when the outside temperatures are such that possible damage could be done to the compressor?

I personally used to install delay-on make timers on all condensers I installed. This was to eliminate those pesky calls to go out to a customer's home and reset a circuit breaker or replace a couple of fuses. I found the small cost much easier to add into the bid price of the unit than say seventy-five dollars on the chance that I'd need to explain why a reset of a circuit breaker is not covered under warranty and is going to cost them a service call.


Just had one of them days.

You beat me to it. If there is any thought wether a contaminant is present that may not be removed from a system,THEN a liquid drier does no harm, however it is not needed in a properly installed system. I personally believe a small amount of efficiency can be lost by installing one when not needed and some filter/drier brands are not very good at doing there job anyway. It's important to use a quality filter/dryer.
Refrigerant pressure controls have always been the shortfall of the manufacturers. How many compressors would have survived a bad motor or a freon leak if they were in the equipment? Systems made many many years ago all had these controls. It seems the fight for keeping the prices down has also let the consumer down.

[kuryakin]

Well, I look at it this way: It's cheap insurance, and adding a filter/dryer means moisture and contamination levels will decrease over time, whereas without one, they may increase, especially contaminants. With the newer PAG/POE/PVE oils, moisture is doubly critical. So, it's like chicken soup, it couldn't hurt!! <G>

I suppose I'm going to open up the proverbial can of worms here BUT been here long enough and figured it was my turn.

So I'm reading that every new unit should have a filter dryer installed.

Probably hundreds of thousands of units out there running just fine since they were installed without them.

The filter dryer is designed to trap any moisture that might be in the system and stop foreign material from traveling around the refrigeration circuit and causing trouble.
SO...... my question is why would a brand new properly installed air conditioning system have any moisture in it? Facts are, if the system was properly installed by a trained and qualified technician there will be no moisture at all. This eliminates the first reason to have the filter dryer.
SO...... my next questioin is why would a brand new properly installed air conditioning system have foreign material in the refrigeration circuit? Facts are, if the system was properly installed by a trained and qualified technician there will be no foreign material in the refrigeration system to cause a problem.

Having made these two points I would make an observation here to possibly widen this thread.

Why don't we install low and high pressure switches in all condensing units that don't come from the factory with them installed? I mean if we're all about protecting the equipment from all unforseen trouble, wouldn't the potential for a loss of charge or a condesner fan failing be a perfect reason for installing pressure switches in every unit to protect them?

Why don't we install low ambient controls or low temperature cutoff switches on all units incase an owner accidently turns the air conditioning on when the outside temperatures are such that possible damage could be done to the compressor?

I personally used to install delay-on make timers on all condensers I installed. This was to eliminate those pesky calls to go out to a customer's home and reset a circuit breaker or replace a couple of fuses. I found the small cost much easier to add into the bid price of the unit than say seventy-five dollars on the chance that I'd need to explain why a reset of a circuit breaker is not covered under warranty and is going to cost them a service call.


Just had one of them days.

[wconell]

Well, I look at it this way: It's cheap insurance, and adding a filter/dryer means moisture and contamination levels will decrease over time, whereas without one, they may increase, especially contaminants. With the newer PAG/POE/PVE oils, moisture is doubly critical. So, it's like chicken soup, it couldn't hurt!! <G>

How would moisture in a hermetically sealed system increase? (Perhaps the service tech who doesn't bleed the hoses before adding refrigerant?) Moisture from oils used with r410a won't be removed. The liquid dryers job is to mainly protect the liquid circuit and the componants in the evaporator. If moisture and contaminants are a real concern, a suction dryer should be used as well.

[woody19]

I agree that if a system were properly installed by a qualified technician using nitrogen to purge while brazing, doing a proper evacuation,etc. there would not necessarily be a need for a filter/drier. Now let's talk about the REAL world.I have seen too many trucks with driers sitting on shelves that were supplied by the manufacturers and not installed. Comp. manufactures will tell you about 85% of all comps. returned for warranty failed due to: moisture in the system, over or under charge. If you're one of the "qualified technicians" then, as a matter of added insurance, why not install a drier anyway especially if it's provided to you at no charge?

[kuryakin]

Contamination can increase. And one of the breakdown products of PAG oils can be water, if you cook it enough.
A filter/dryer will catch both of these. And yes, it will actually dehydrate PAG/POE/PVE oils. The problem is, if it's a lot of water, the ability of the molecular sieve bed in a filter dryer to absorb become compromised, since absorption is an equlibrium thing. The wetter the filter/dryer, the wetter the system.
The issue with these oils is vacuum cannot dry them. Dessicants can, but it's limited.
Of course, if you did all of these PROPERLY, moisture intrusion is minimal anyway, unless there was a major breech in the lines somewhere...

How would moisture in a hermetically sealed system increase? (Perhaps the service tech who doesn't bleed the hoses before adding refrigerant?) Moisture from oils used with r410a won't be removed. The liquid dryers job is to mainly protect the liquid circuit and the componants in the evaporator. If moisture and contaminants are a real concern, a suction dryer should be used as well.

[absolutefrigid]

Just noticing all the different responses, Does the manufactures respond in the same way?? I know this opens a can of worms but don't you think we should all be doing it the same way? Just like anything else though we have our on opinions......and our on way of working on these systems.

[kuryakin]

I think you'll find nearly all new units actually have a filter/dryer inside. IMHO, I think they are usually undersized, but that's just me... <G>

Just noticing all the different responses, Does the manufactures respond in the same way?? I know this opens a can of worms but don't you think we should all be doing it the same way? Just like anything else though we have our on opinions......and our on way of working on these systems.

[RoBoTeq]

Filter/driers are cheap insurance. Even if everything went perfectly during an installation, an operational system is eventually going to put debris from wearing components into the system.

Goodman Manufacturing was the first to have every outdoor unit with a factory installed filter/drier. While, as has been noted, the earlier versions of these units had smaller then typical filter/driers in them, the amount of warranty claims for compressor failure within the first year dropped dramatically. This is why so many other manufacturers are now putting filter/driers in their units.

[dawgtchrr]

Contamination can increase. And one of the breakdown products of PAG oils can be water, if you cook it enough. ...

Hope this is a mis-speak. I've always be told and teach my students that PAG's are never used in any system but the motor-vehicle AC or motor-vehicle like systems. Have you really seen AC systems with PAG's????

[kuryakin]

Seen? No. But I believe I read somewhere, (and I may have misremembered this, that some of the early R410a systems used PAGs. No reason why they shouldn't work, though, in central systems. The best one, which I've only seen in minisplits and the IQDrive is PVE oil.

Hope this is a mis-speak. I've always be told and teach my students that PAG's are never used in any system but the motor-vehicle AC or motor-vehicle like systems. Have you really seen AC systems with PAG's????

[dash]

For those that believe a "properly " installed system needs no drier;

1.)How many microns would you evacuate to and how long should it hold there ,to say NO moisture is present in the system???

2.) How would you know there are no comtaminents ,in the coil or lineset?

[munanee]

Always install a liquid line drier after breaking the lines. I have a problem with those driers installed internally by the manufacturer. You can't change them simply by stacking the refrigerant in the condenser, you have to recover it first.

Now, in the real world, too many technicians do not use nitrogen when brazing lines. This causes oxydizing inside the copper which breaks away and clogs TXVs. ALLWAYS USE A LIQUID LINE DRIER!!