Custom Air Conditioning Retrofit

[rubicon327]

Originally Posted by Centex

Just very wild guessing here, I wonder if the greater length of corrugated flex-line has anything to do with the 'noise'? Given the relatively short lengths of all of these installations (compared to allowable total lineset lengths) I doubt it's a 'fluid/gas friction' issue but wonder about some odd turbulence in the corrugated line?

Again, just wild guessing and trying to ID installation detail differences.

Not sure. All I can add is that my installation does not have the flex lines and the install I did for Jake (viator36) has 3' flex lines and we both do not have any whining noise.

[rubicon327]

Originally Posted by rubicon327

Wanted to update everyone on the status of QUIET A/C on battery. Tested my upgrade today with 400AH Bestgo LiFePO battery, 2000W Xantrex Freedom XC running the 9,000 BTUH Fujitsu mini-split. Battery started at 95% SOC. During the hottest part of the day with outside temperatures from 86-93F and trailer in full sun the mini-split ran for 5 hours before the battery got to 30% SOC. Inside set point of 74F. Highest amp draw was around 104A DC for the first 20 minutes then it cycled between 5A (fan only) and 50-75A (when inverter compressor ramped back up). The system ran perfectly and 5 hours under these conditions exceeded my expectations! Would do even better with a more modest set point, shaded trailer with portable solar panel out in the sun or overnight as ambient temperatures are lower.

Another update with mini-split operating on 400AH lithium battery and 2000W Xantrex Freedom XC inverter/charger. Camped for two nights this past weekend where the trailer was hot and humid around bedtime even with the MaxxFan on. Closed everything up and turned on the inverter and mini-split A/C which brought the trailer from around 82 to set point of 74. The mini-split ran all night (inverter compressor only ramping up as needed) and because the outside temp was reasonable it only used about 25% or 100AH in about 9 hours based on my Victron battery monitor. The outdoor unit is so quiet it did not bother our tent campers on the same site about 15' away. The katydids were louder. This exceeded my expectations and it was amazing to be able to have whisper quiet cooling (inside and out) overnight powered from a battery! I think I deserved it as I had five 13 year old boys out there camping with me.

[LtDan]

Joel, that’s next on my list, some serious juice storage!
Back to this whining noise Tford and I have, it has to be in the installation, the two you have done make no noise, Tford’s and ours does?
To summarize, I had a tech pressure test, vacuum, and check pressures, Tford didn’t, so that’s probably not it.
I use 3’ flex lines, he used 6’, one of Joel’s install used 3’ I believe, and didn’t make noise?
Manual states 10’ of line minimum, mine including the flex lines are about 13’. And I think I remember reading they have a bit higher capacity than the solid copper?
I was worried pulling the lines that it would be really easy to kink one of them, maybe this is it, but wouldn’t that affect performance?
I’m going to pull the corner trim, stick a piece of tubing in my ear and see if I can isolate it.

[rubicon327]

Originally Posted by LtDan

Joel, that’s next on my list, some serious juice storage!

I think you are mistaking me with Joel. I’m Dave.

[LtDan]

Sorry bout that Dave, who’s Joel?

[rubicon327]

Originally Posted by LtDan

Sorry bout that Dave, who’s Joel?

Joel is jphil23462 who did a 5.0 mini-split install supplemented with copious solar and lithium. Highlights start on page 24 of this thread.

[hugh]

Originally Posted by rubicon327

Another update with mini-split operating on 400AH lithium battery and 2000W Xantrex Freedom XC inverter/charger. Camped for two nights this past weekend where the trailer was hot and humid around bedtime even with the MaxxFan on. Closed everything up and turned on the inverter and mini-split A/C which brought the trailer from around 82 to set point of 74. The mini-split ran all night (inverter compressor only ramping up as needed) and because the outside temp was reasonable it only used about 25% or 100AH in about 9 hours based on my Victron battery monitor. The outdoor unit is so quiet it did not bother our tent campers on the same site about 15' away. The katydids were louder. This exceeded my expectations and it was amazing to be able to have whisper quiet cooling (inside and out) overnight powered from a battery! I think I deserved it as I had five 13 year old boys out there camping with me.

That's amazing! My Mach 10 would chew through 100ah just running the evaporator fan!

[Thisismyusername]

I'm sorry. I know it's buried in this thread somewhere but I've dug through and can't find it this time.

1. Why the flex tubing? I think it was to go from the condenser to the main run of tubing to reduce breakage risk?
2. What flex tubing were you all using?
3. How did you connect your flex tubing to your main run of line?

Bonus question: how do you know how many feet of refrigerant line the prefill on the unit is good for?

I'm going to try and set up a mini split on a non-escape TT. Bumper mounting the condenser and mounting the inside unit in a space cut out of the cabinets up front.

On this diagram the blue line is the refrigerant and comm lines, green indoor unit, orange power line, red is the condenser unit.

[John in Santa Cruz]

Originally Posted by Thisismyusername

I'm sorry. I know it's buried in this thread somewhere but I've dug through and can't find it this time.

1. Why the flex tubing? I think it was to go from the condenser to the main run of tubing to reduce breakage risk?
2. What flex tubing were you all using?
3. How did you connect your flex tubing to your main run of line?

Bonus question: how do you know how many feet of refrigerant line the prefill on the unit is good for?

I'm going to try and set up a mini split on a non-escape TT. Bumper mounting the condenser and mounting the inside unit in a space cut out of the cabinets up front.

On this diagram the blue line is the refrigerant and comm lines, green indoor unit, orange power line, red is the condenser unit.

you want to keep those lines as short as practical, put the condensor at the same end of the trailer as the evaporator.

[rubicon327]

Originally Posted by Thisismyusername

I'm sorry. I know it's buried in this thread somewhere but I've dug through and can't find it this time.

1. Why the flex tubing? I think it was to go from the condenser to the main run of tubing to reduce breakage risk?
2. What flex tubing were you all using?
3. How did you connect your flex tubing to your main run of line?

Bonus question: how do you know how many feet of refrigerant line the prefill on the unit is good for?

I'm going to try and set up a mini split on a non-escape TT. Bumper mounting the condenser and mounting the inside unit in a space cut out of the cabinets up front.

On this diagram the blue line is the refrigerant and comm lines, green indoor unit, orange power line, red is the condenser unit.

Jas: I used the flex lines on an installation I did for a fellow Escape owner and he has not had any leaks. Without them I have had to add refrigerant twice in 6 years. I may add them in the future but I have been trouble-free for awhile now. I used 3’ Rectorseal NoKink flex lines.
https://rectorseal.com/nokink-group/ You flare each end with a flare tool. One goes directly on the condenser fitting and the other goes to a flared union to join to the main copper tubing. You need to insulate these sections on your own. You do want to keep the lines as short as possible but most manufacturers have some pretty good latitude. My Fujitsu 9RL2 for example is designed for pre-charge max lineset length of 49’, a minimum of 10’ and a maximum of 66’ (add’l refrigerant required). You can see it under lineset requirements on the submittal sheet: https://www.ecomfort.com/manuals/fuj...c38c81331f.pdf

I prefer condensers on the tongue myself but understand there can be limitations in mounting location. Good luck with your project and let me know if you have any other questions. It’s a challenging DIY project but whisper quiet heating and cooling is worth it!

[Centex]

Originally Posted by Thisismyusername

1. Why the flex tubing? I think it was to go from the condenser to the main run of tubing to reduce breakage risk?

The flex line accommodates slight movement of the compressor unit relative to the trailer, perhaps beneficial for the long term, especially if the compressor unit is installed on resilient mounts (recommended for this mobile application). The goal is reduction of stresses inducing fatigue failure, especially at the rigid connection to the compressor fittings.

Originally Posted by Thisismyusername

2. What flex tubing were you all using?

Google: Rectorseal NoKink for information.

Originally Posted by Thisismyusername

3. How did you connect your flex tubing to your main run of line?

The Rectorseal NoKink flexible lines are furnished with a short length of standard rigid copper refrigerant line at each end - that is flared for standard flare-fittings as appropriate.

Originally Posted by Thisismyusername

Bonus question: how do you know how many feet of refrigerant line the prefill on the unit is good for?

There's excellent technical literature available for download on the Fujitsu website. Referring to the Design & Technical Manual for the 9RL2 and 12RL2 units (sorry, PDF is too large to attach on this forum and I don't have the URL handy) we find tables relating to "Additional Charge Calculation" which state that for line lengths of 49ft (15m) or less, no additional refrigerant charge is required.

The maximum line length is 66ft (20m), with an additional charge of 0.22oz/ft (20g/m) required for lengths above 49ft (15m).

Aside, it's very common in static residential applications to have lineset lengths longer than those contemplated in any RV application being discussed here, with no adverse impact on system performance. IMO you should feel free to arrange the components in the manner that work best for your RV-based objectives without obsessing over achieving short lineset length. In fact too short (<10ft) can introduce risk of vibration transmission that is undesirable (though a section of flex-line may mitigate that).

Hope that helps, Have Fun!

EDIT - I see Dave posted first - he is of course the expert on this mod

[rubicon327]

Originally Posted by Centex

I see Dave posted first - he is of course the expert on this mod

Thanks but based on your answers it looks like you are right there with me. Where are you with your system?

[Centex]

Originally Posted by rubicon327

..... Where are you with your system?

I've had significant delays due to family matters (elder care) totally unrelated to trailering - all trailer and personal projects (and travel) have been a catch-as-catch-can proposition through the summer, just brief (but welcome) respites when I can grab an opportunity. Still focused on the electrical / solar mods, I've not yet even ordered the minisplit components.

So, no forecast for completion but no change in any of the plans either (it's Fujitsu 12RL2 for me with the 5.0 in Texas).

Life happens, we do what we gotta do, and just try to maintain optimism, ya know.

[Thisismyusername]

You all are so very helpful, thank you!

1. Is this the union for joining between the semi rigid refrigerant line and the rector deal no kink?

https://www.amazon.com/Conditioning-...2810114&sr=8-3

2. When manufacturers quote the length of the line set that comes with their mini splits are they including the length of refrigerant line that comes out of the back of the inside unit? Or just the line set that goes from the condenser to the lines on the inside unit?

3. In the grand scheme of things the cost difference between a 36-in and 72 in length of rector seal seems negligible if I need extra length in my system anyway is there any reason not to go with a longer run of flex line and a shorter run of semi-rigid line versus going with a shorter run of flex line and a longer run of semi-rigid line?

4. A lot of places I have read through mention that the flare nuts included by many split manufacturers seem to be poor quality or insufficient. Is that an accurate portrayal? And if so how do you purchase replacement ones that are of sufficient quality?

[Centex]

Originally Posted by Thisismyusername

....
2. When manufacturers quote the length of the line set that comes with their mini splits are they including the length of refrigerant line that comes out of the back of the inside unit? Or just the line set that goes from the condenser to the lines on the inside unit?....

I'm suddenly reminded that you may not be using the Fujitsu 9/12RL2 unit. The Fujitsu 9/12RL2 has no lines at all on either the indoor or outdoor unit as delivered - the lineset or combination of lines used must reach from fitting-to-fitting on each component.

Some units are designed for use with 'pre-charged' linesets (the Fujitsu 9/12RL2 is NOT) which would be a whole different ballgame and I can't help you with that. Those are filled with refrigerant or evacuated to vacuum with special single-use 'punctured when installed' end fittings, I've no experience with that type, but it's my understanding that unlike standard 'open' linesets these cannot be cut to custom length.

With all of that in mind, please note that the refrigerant line length and charge data provided by Rubicon (Dave) and I above is specific to the Fujitsu 9/12RL2 units and may differ for whatever you choose - you'll need to find similar data for your specific unit regarding line-length and 'precharge'.

Not knowing the specifics of the particular unit you are using I think it best that I 'go silent' on your questions, hopefully others can offer good guidance. It might be helpful for you to include a link to whatever unit you are using with your question posts.

[rubicon327]

Originally Posted by Thisismyusername

You all are so very helpful, thank you!

1. Is this the union for joining between the semi rigid refrigerant line and the rector deal no kink?

https://www.amazon.com/Conditioning-...2810114&sr=8-3

2. When manufacturers quote the length of the line set that comes with their mini splits are they including the length of refrigerant line that comes out of the back of the inside unit? Or just the line set that goes from the condenser to the lines on the inside unit?

3. In the grand scheme of things the cost difference between a 36-in and 72 in length of rector seal seems negligible if I need extra length in my system anyway is there any reason not to go with a longer run of flex line and a shorter run of semi-rigid line versus going with a shorter run of flex line and a longer run of semi-rigid line?

4. A lot of places I have read through mention that the flare nuts included by many split manufacturers seem to be poor quality or insufficient. Is that an accurate portrayal? And if so how do you purchase replacement ones that are of sufficient quality?

#1. That union looks fine. Obviously will need to order one for each line size.

#2. I think it is moot. There is only a short pigtail of refrigerant line that comes off an indoor unit.

#3. The flex lines do impart more resistance to refrigerant flow than the semi-rigid but if you aren't near the limits in length per the manufacturer you should be fine. Really depends on where you want the joints to land and how much you want to insulate on your own.

#4. I used a Fujitsu which is a very high quality unit and had no issues with their flare nuts. I cannot speak for others. One thing to note is you should be prepared to cut off and flare new ends on any pre-insulated line set you buy. Not sure if it was just the brand I got with my mini-split but I can't even call them flares...they looked like they were enlargements in the end of the pipe just to hold the nuts on.

[Tford]

An update on my whistling line situation, techs have come out and evacuated, pressure tested now TWO outside units (Pioneer determined it was a warranty issue and sent a new outside unit). I have informed Pioneer of the same noise and asked if they want to send another air handler, the HVAC techs still think it is the original air handler with either a blockage or a bad solder joint causing the whistle/whine. I’ll report in again when this is all said and done…..the units cool well!

After doing all this, the flex lines are nice but in my opinion they mostly alleviate trying to bend and fit 2 longer lines (that’re insulated) through a couple holes in your trailer. It’s hard enuff making the lines go out air handler, over to the side and down the side covers and then across the back seating area and out the bottom to the outside unit without a kink. If my problem eventually turns out to be the flex lines, I’ll just make up two hard lines about 6’ long and pass them into the trailer to the same unions I have now…..

[Tford]

So now the flex 1/4” line has been replaced with a solid line. Unit cooled quietly on startup and our troubles are behind us…..but they’re not….upon running for about 15-20 minutes, the compressor had kicked off and when it cycled back up the whistle started up again. So NOW I’ll put in the second new air handler unit that was sent as a warranty AND I’ll replace the 3/8” flex line…..wish me luck…this will be all new equipment with the exception of the original 10’ twin lines…and they’ve sent new ones of those too, just not crazy about running them up the back sides again…

[LtDan]

Curious as to how this turns out? We camped four nights last week using the heat and there was no whistle at all.
Is one line under pressure during cooling and the other during heating? If so that makes me think I may have kinked a line during install, it sure seems like the noise is coming from where the lines run up the back corner.

[rubicon327]

Originally Posted by LtDan

Curious as to how this turns out? We camped four nights last week using the heat and there was no whistle at all.
Is one line under pressure during cooling and the other during heating? If so that makes me think I may have kinked a line during install, it sure seems like the noise is coming from where the lines run up the back corner.

In a heat pump the refrigerant flow direction reverses depending on the mode. In the cooling mode you have a cold, low pressure liquid going to the indoor unit and a warmer, low pressure gas leaving the indoor unit. In heating mode you have a hot, high pressure gas going to the indoor unit and a warm, high pressure liquid leaving the indoor unit. The phase of the refrigerant is the same in each pipe but the direction of flow and the pressures and temperatures are different.