Filter drier

[AC5096]

Bryant recommends installing them at the evaporator coil.

The instructions state "Installation of filter drier in liquid line is required"

[hvacrmedic]

On a new installation I don't even use a filter drier. But I purge with nitrogen while soldering, ream all connections, and keep tubing clean. This along with a good vacuum, why is it necessary? Just some added pressure drop in my opinion.

A small pressure drop in the LL doesn't affect performance. Systems using POE oil REQUIRE a filter drier.

[Tech it out]

A small pressure drop in the LL doesn't affect performance. Systems using POE oil REQUIRE a filter drier.

As I said, I am accustomed to R22 units, havnt had much dealings with 410a so a lot of times I read something here and my mind is thinking in terms of R22. I do realize the importance of a drier in a 410a unit.

[hvac17011]

what is the difference between 410a and 22 as far as the filter drier goes I forget. i guess the poe oil absorbs the moisture.

[smokin68]

By the metering device is best....period. Yes I've replaced many on the LL by the condenser, not my installs. This is why a nitrogen flow while brazing is important....prevents the copper from forming the black carbon while combined with oxygen, and blocking the txv's screen or orifice. On the new systems with it already installed, a nitrogen flow while brazing works great I've found. No issues.

[smokin68]

what is the difference between 410a and 22 as far as the filter drier goes I forget. i guess the poe oil absorbs the moisture.

410a creates acid alot quicker the R-22 when moisture is in the system, because of the oil used. But a monkey can install a system and it will last a year usually, out of warranty. Not what my company believes in.

[smokin68]

heatingman said it correctly IMO, at least how I was taught.

[gravity]

install them at the indoor metering device. if it is a heatpump system i also install at indoor unit and start the unit in COOLING mode for 10 minutes to allow the filter drier to catch any left over debris. the reasons why i install them inside are; prevents rust and leaks on drier, catches the junk before it enters TXV screen. also a sight glass after the filter drier is a good idea. i also purge with nitrogen while brazing. if you have been in the trade long enough, you will hear of the service calls that "the txv is bad its only a year old" these jobs usually have the drier at the outdoor unit and no nitrogen was purged when brazing. 9 times out of 10 the txv is clogged and/or the filter drier is clogged but the diagnosis is still a bad TXV

[superd77]

Driers have been installed outside for many, many years. Why change now??? Yeah, it seems logical to install it at the MD, but you are creating extra work of climbing in an attic when it's 105+ outside. (140 plus in attic)

If you guys change a compressor, do you climb in a scalding hot attic to see if there's a drier?? I don't.

TXV's go bad when trash gets in them, true! But 90% or so go bad cause of mass production and cheap manufacturing.

Do us all a favor and put the driers outside... After all, what can break loose in the LL to stop up a drier anyway?

[Tech it out]

Driers have been installed outside for many, many years. Why change now??? Yeah, it seems logical to install it at the MD, but you are creating extra work of climbing in an attic when it's 105+ outside. (140 plus in attic)

If you guys change a compressor, do you climb in a scalding hot attic to see if there's a drier?? I don't.

TXV's go bad when trash gets in them, true! But 90% or so go bad cause of mass production and cheap manufacturing.

Do us all a favor and put the driers outside... After all, what can break loose in the LL to stop up a drier anyway?

I am inclined to agree with this position especially if the AH is in the attic. The temps will be far greater up there than outside. Plus what percentage of techs will go in the attic to check if there has been a drier installed up there when they have to open a system for some reason? I don't think that number would be high. So do you then end up with 2 driers for the same system? I have seen it happen.

There are usually only 2 joints between the cu and the ah downstream from the drier if speaking in terms of resi units, one at the drier, one at the ah. I understand the need for close to the ah but I think some logic should be used depending on the application. JMHO

[Kevin Weaver]

Back in the early 80's, the drier came loose like a lot of units do now. But installers wouldn't put them on, would "save them for my side jobs", so manufactures started putting them inside the outdoor unit. Is this the best place for it, probably not but its better than not having one at all. I like them outside for serviceability. I know in Florida they rust out from the salty air, but here they don't rust out. Well I have seen some partially on the ground and 25 years old rust through. If the compressor goes bad and needs replaced and the drier is inside, a lot, not all, techs put one outside, now the unit has 2.

[AC5096]

The Bryant R-22 cond. units used to come with a copper molecular sieve drier. Never used them, but would use a 083S or an 163S instead.

[grizzzlle]

Not to jack the thread but are there differences in quality of dryers between manufactures? Is it something a homeowner needs to be concerned with if having a dryer replaced?