10 year anniversary 4 ton split sys maintenance?

[CWO4GUNNER]

Before you know it fall will be here and Arizona will be in its 2nd spring season in reverse. At that time when temps get down in the low 80's I really want to do more for my home and rental units 10/11 year old 4 ton split systems other then just the yearly preventative and cleaning maintenance. Id really like to replace or filter the existing R22 refrigerant and then weigh it back in IAW manufacturers recommended amount. Do you think its enough to just use a filter-drier on my evac machine or spend the money and install virgin R22. Since these simple systems don't have an inline filter-drier in the system, I'm imagining after 10 years all wear/tear contamination floating around in those systems that if removed might save me a premature compressor or TXV failure. What do you think and any other 10 year major maintenance recommendations? Also do you think that its unnecessary to vacuum the system or should I vacuum to pull out and dry any possible water contamination, which I highly doubt?

PS...Even though Im classroom/EPA certified, I have never done these procedures but have been brushing up and just not sure about the necessity, but think maybe its a good Idea and excuse to do it.

 

[softailgarage]

Replace the R22 with virgin. I'm no expert, but I have a feeling doing anything else will cost you time and money, more money than if you just did it right the first time.

 

[bazar01]

Well, if it's me, if the unit has lasted 10 years, then it was installed right.
If it is not broke, don't fix it.
You can do an acid test, visually inspect evaporator coil for build up and clean with a fin comb. You can check refrigerant charge best during the summer season.
If tenant has not been changing filters, then expect the evap coils to be plugged up which would require pulling and cleaning it out. No sense in wasting R22.

 

[rlitman]

If the system has not leaked in 10 years, why do you think that moisture or dirt would have gotten in, in a way that a filter/dryer would help?
I would strongly suggest you not evacuate a system working well for "preventative" measures. You are asking for trouble.

Now, IF you have cause to evacuate the system, installing a filter/dryer is a good idea, but don't go breaking something running well just to do that.

 

[rlitman]

Well, if it's me, if the unit has lasted 10 years, then it was installed right.
If it is not broke, don't fix it.
You can do an acid test, visually inspect evaporator coil for build up and clean with a fin comb. You can check refrigerant charge best during the summer season.
If tenant has not been changing filters, then expect the evap coils to be plugged up which would require pulling and cleaning it out. No sense in wasting R22.

What he said! Coil cleaning is a good idea. You can use the self rinsing stuff on the evaporator, and gently hose off the condensor after spraying with the foaming cleaner.

 

[sourdough]

if the system has not leaked in 10 years, why do you think that moisture or dirt would have gotten in, in a way that a filter/dryer would help?
I would strongly suggest you not evacuate a system working well for "preventative" measures. You are asking for trouble.

Now, if you have cause to evacuate the system, installing a filter/dryer is a good idea, but don't go breaking something running well just to do that.

^^^^^^

+1!

 

[CWO4GUNNER]

*In class we never discussed refrigerant test kits or testing so that's not an option.

* If it were just my home unit I had to worry about the burden and probability of the "BIG-ONE" failure would be remote. But with tenant units the probability is much higher. The real 10 year concern here is a low charge from refrigerant loss over time which is very very common, like 15% a year. A low charge equals noticed poor performance if Im lucky or premature compressor failure if im not lucky. So after 10 years how do I check on if the refrigerant charge is absolutely peace of mind correct? Not by guessing, maybe by doing super-heat /sub-cooling calculations which is really a ****-shoot. Only way to be sure is to evacuate and weigh in the charge IAW manufacturers specs. Hence the opportunity to use the portable filter-drier attached to the evacuation machine to rid compressor metalic particles which can cause motor windings to short, hence might as well vacuum the system to remove any traces of moisture/ test for leaks, hence opportunity to get get rid of the 10 year old R22 and use the 30 lbs bottle in storage or not. It all comes down to either risking a low charge failure by just waiting or acting to prevent it. What do you think?

 

[CWO4GUNNER]

This article sheds allot of light on contaminated refrigerant generated within a sealed system especially when you do not have an installed filter common in most low end residential split systems. In fact in doing my research in mini-split ductless systems for my future install, I haven't come across one ductless system schematic that shows the installation of a filter-drier. http://www.achrnews.com/articles/the-importance-of-filter-driers

 

[rlitman]

Yep, and you have an R-22 system, not R410a. You should re-read it again, in that light.
The chemical issues that occur with PAG and POE oil are not going to affect the mineral oil in your system.

 

[Rockhead261]

Clean everything.
Replace the contractor and run capacitors.
Check all electrical connections and clean/tighten/repair/ replace as needed.
Pull blower motor, clean, lube.
DO NOT replace refrigerant.

 

[sourdough]

*In class we never discussed refrigerant test kits or testing so that's not an option.

* If it were just my home unit I had to worry about the burden and probability of the "BIG-ONE" failure would be remote. But with tenant units the probability is much higher. The real 10 year concern here is a low charge from refrigerant loss over time which is very very common, like 15% a year. A low charge equals noticed poor performance if Im lucky or premature compressor failure if im not lucky. So after 10 years how do I check on if the refrigerant charge is absolutely peace of mind correct? Not by guessing, maybe by doing super-heat /sub-cooling calculations which is really a ****-shoot. Only way to be sure is to evacuate and weigh in the charge IAW manufacturers specs. Hence the opportunity to use the portable filter-drier attached to the evacuation machine to rid compressor metalic particles which can cause motor windings to short, hence might as well vacuum the system to remove any traces of moisture/ test for leaks, hence opportunity to get get rid of the 10 year old R22 and use the 30 lbs bottle in storage or not. It all comes down to either risking a low charge failure by just waiting or acting to prevent it. What do you think?

IMO, if you are losing 15%/yr. refrigerant loss on a 10-year-old unit, even over the last 5 yrs., you are not cooling now. If you are cooling adequately with a 20* delta T across the evap, not much can be wrong, including any significant refrigerant leaks, insofar as the charge. If the D/T is low, after checking condenser/evaporator cleanliness/airflow, look at the discharge/suction pressures for your ambient: if after 10 years it is slightly low, add some of your precious R-22 stash and check the difference. A 4-ton unit can't have a huge original charge weight (unless you have really long line sets).Monitor and check.

ANYTIME you open the system you are allowing moisture, air, and maybe contaminents into the system.

Methinks you should save the money you spend on an EPA spec recovery machine (and the money for disposing of used refrigerant) and put it in a dedicated savings account for a replacement A/C unit if you are that concerned. One can only prolong the life of old machines just so long before you kick yourself in the **** and wonder why you didn't replace it/them in the first place (when things start to go south). You will have saved many $, and then the new machines will (hopefully) have a 10-20 year life.

I am no refer expert, but having seen what my previous institutional employer (hospital) did to save money ended up costing much more in the long run by refusing to replace badly malfunctioning units past their normally expected lifespan in lieu of their SOP: keep replacing parts/refer/labor.

Just my $.02 worth.

 

[CWO4GUNNER]

Well the only other reasoning I have on my side of this argument is my past career experience in a similar but different technical field. Its only after I retired I got schooled and certified in HVAC. What I lack is proficiency with my equipment gained from field experience, that's where some of you guys have come in with your comments and filled in the gap, I depreciate that. So OK you've all pushed back my mined on the Idea of hacking into my rental unit AC's for now. But I still need to exercise what Iv learned and become proficient with the gear and skills the GI bill paid for. So for now Iv decided Ill limit all of those procedures I mentioned above to my own back yard AC unit and maybe add a few like installing a TXV. I mean come on guys besides saving money what fun is it when your a natural born DIYer, to watch some poor guy working for some corporation rush through a job cutting corners so he can get at least 10 service calls in before the end of the day, Id rather have it cost me more in a few mistakes and learn something, fix my mistakes and then sit back admiring my work as it shimmies and shakes lol.

 

[joel63]

Clean everything.
Replace the contractor and run capacitors.
Check all electrical connections and clean/tighten/repair/ replace as needed.
Pull blower motor, clean, lube.
DO NOT replace refrigerant.

^^^^^
Excellent and straight to the point.

In addition make sure there's some type of "delay on break" feature to protect the compressor for short cycling.
Most of the new thermostats have this feature built in.

 

[CWO4GUNNER]

^^^^^
Excellent and straight to the point.

In addition make sure there's some type of "delay on break" feature to protect the compressor for short cycling.
Most of the new thermostats have this feature built in.

Yeah I remember when I changed out my 1st set of contacts at home, thought I messed something up cause the unit took 5 minutes to start after setting to cool. Turns out I had shut the unit down mid cycle causing the delay. Now I wait for the unit to cycle off before turning to off and de-energizing to do work, restarts much quicker.

Lastly providing I get proficient at everything else, Id like to make use of my nitrogen and Oxy-acedilene caddy to match a used clean oversize outside R22 goodman outside unit to get rid of that inefficient 9 seer outside condenser unit I currently have. Maybe I could match up at least a used 13 seer outside condenser unit. But ill probubly wait until the compressor dies, since Ill be installing a ductless 6 zone mini-split first. Then who cares and it will make a great low cost DIY backup AC project.
Got to use up that 2 year old 30 lb bottle of R22 somehow.

 

[LS6 Tommy]

Refrigerant doesn't wear out or degrade IF your system is tight and was installed properly. Sounds like yours was. Do an oil sample test before you go into the refrigerant circuit...

Tommy

 

[dclassical]

So after 10 years how do I check on if the refrigerant charge is absolutely peace of mind correct? Not by guessing, maybe by doing super-heat /sub-cooling calculations which is really a ****-shoot

What makes you say that? Even when installing a brand new unit, I don't know of installers who will precisely measure the length of the lineset. I have always seen them estimate the length, know that the unit had refrigerant for 25' and then use sub-cool/super-heat.

Say your target is a sub-cool of 14 deg, measure it and take action if needed.

 

[CWO4GUNNER]

Yeah..well our 50yr industry instructor never taught refrigerant testing, said will never use it, ddon't need it in residential applications. Only in comertial and samples are sent out for analysis regularly. So its Greek to me. Normally I'd agree with you on that logic but my situation is unique. You see I'm not just a client/customer, I'm the technition as well and I need the drill experience to support my small group of rental unit customers. In other words, the risks are all part of the learning curve here.

 

[theoldwizard1]

There are chemical "condenser" cleaners (mild acid ?) but I have always heard an annual rinsing with a garden hose (NOT a pressure washer) is a good idea.

If you want to go crazy, disassemble the furnace output plenum and CAREFULLY vacuum both sides of the evaporator coil.

 

[CWO4GUNNER]

There are chemical "condenser" cleaners (mild acid ?) but I have always heard an annual rinsing with a garden hose (NOT a pressure washer) is a good idea.

If you want to go crazy, disassemble the furnace output plenum and CAREFULLY vacuum both sides of the evaporator coil.

Easy stuff, already did that. But rather than disassembling I simply made my own access covers. When I inspected the coil after 8 years, it was clean enough to eat off of. :