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- Jan 1, 2018
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- 1,163
About 10 years ago I installed a Fujitsu mini-split heat pump and have been extremely happy with it. Last year during heating season it threw a code. Power cycling the breaker cleared the code. This winter it has thrown a code twice already. Tons of research came up with "10 blinks = low on refrigerant". The HVAC guys around here are hacks and from what I can tell they have had no formal HVAC training. So off I go to buy some R410a without a proper certificate.
Guess what... R410a is being phased out! R-32 and R-454B refrigerants are the purposed replacements. My understanding is that both are supposed to operate at lower pressures like good ole R22. And they are both said to be more efficient than R410a.
Anyway the best price I could find on R410a online is $150 for 2lbs or $200 for 5lbs. A quick CL/facebook search shows a dealer retiring and going out of business selling 25lb factory sealed tanks for $250 or 10 for $200 each. It was a 5 hour round trip and my favorite building supply outlet that I planned on visiting on the way is out of business. I also picked up an old but working refrigerant scale for $40.
From what I can find online the proper procedure is to recover all the refrigerant from the system, weigh it, then refill the system with the original 410a plus extra new 410a to bring it up to the proper calculated needed refrigerant weight. Evidently the only HVAC techs that actually do this are the ones charging by the hour. For the most part the standard procedure is to add a little 410a and bring the pressure up to 117 - 120psi on the low pressure line then see if the error code stops recurring. ...a job for tomorrow. I am thinking I will have to heat the great room then change to cool mode so I can measure the pressure in cool mode? Or do I?
I installed my Fujitsu with 15' of copper tubing which was the max length of copper tubing that can be used with the initial pre-charge of the compressor unit without having to add any additional refrigerant. So I am thinking I have been on the edge since the initial install. Maybe another .2 lbs will improve the efficiency of my Fujitsu which is supposed to be 29 seer? Everything I have read says it is better to have too little refrigerant than too much so I am thinking 1/5 lb is a good start.
What am I going to do with all the extra R410a? Well, I have a second 3 head Mitsubishi mini split to maintain AND I have seen current model Mitsubishi mini-splits that have been uninstalled for very cheap on CL/FB... which I hope to put in my shop some day. So far I have installed my 2 mini-splits and 2 more for 2 different friends. I am feeling pretty confident with the process.
Interesting: The single 1 ton Dalkin minisplit model I found that uses the new (more efficient R-32) has an eer of 10.6 while my 12 year old Fujitsu has am eer of 15.2... hmmm....
R-410A is a member of the hydrofluorocarbon (HFC) class of refrigerants and is composed of equal parts R-32 and R-125. Its chemical formula is CH₂F₂ + CHF₂CF₃.
If the "new" R32 is more efficient (at moving heat I assume) than R410a why didn't they just use R32 instead of 50% R32 + 50% R125 = R410a?
Guess what... R410a is being phased out! R-32 and R-454B refrigerants are the purposed replacements. My understanding is that both are supposed to operate at lower pressures like good ole R22. And they are both said to be more efficient than R410a.
Anyway the best price I could find on R410a online is $150 for 2lbs or $200 for 5lbs. A quick CL/facebook search shows a dealer retiring and going out of business selling 25lb factory sealed tanks for $250 or 10 for $200 each. It was a 5 hour round trip and my favorite building supply outlet that I planned on visiting on the way is out of business. I also picked up an old but working refrigerant scale for $40.
From what I can find online the proper procedure is to recover all the refrigerant from the system, weigh it, then refill the system with the original 410a plus extra new 410a to bring it up to the proper calculated needed refrigerant weight. Evidently the only HVAC techs that actually do this are the ones charging by the hour. For the most part the standard procedure is to add a little 410a and bring the pressure up to 117 - 120psi on the low pressure line then see if the error code stops recurring. ...a job for tomorrow. I am thinking I will have to heat the great room then change to cool mode so I can measure the pressure in cool mode? Or do I?
I installed my Fujitsu with 15' of copper tubing which was the max length of copper tubing that can be used with the initial pre-charge of the compressor unit without having to add any additional refrigerant. So I am thinking I have been on the edge since the initial install. Maybe another .2 lbs will improve the efficiency of my Fujitsu which is supposed to be 29 seer? Everything I have read says it is better to have too little refrigerant than too much so I am thinking 1/5 lb is a good start.
What am I going to do with all the extra R410a? Well, I have a second 3 head Mitsubishi mini split to maintain AND I have seen current model Mitsubishi mini-splits that have been uninstalled for very cheap on CL/FB... which I hope to put in my shop some day. So far I have installed my 2 mini-splits and 2 more for 2 different friends. I am feeling pretty confident with the process.
Interesting: The single 1 ton Dalkin minisplit model I found that uses the new (more efficient R-32) has an eer of 10.6 while my 12 year old Fujitsu has am eer of 15.2... hmmm....
R-410A is a member of the hydrofluorocarbon (HFC) class of refrigerants and is composed of equal parts R-32 and R-125. Its chemical formula is CH₂F₂ + CHF₂CF₃.
If the "new" R32 is more efficient (at moving heat I assume) than R410a why didn't they just use R32 instead of 50% R32 + 50% R125 = R410a?
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