RV HVAC

[J-thetechwizard]

Hello,
Does anyone have any extensive RV HVAC experience???
I'm working on this RV with a typical package unit on top...I pulled off the shroud to find a system similar to a window unit, no service valves.

I'm fine with breaking it open and brazing in a new suction valve but is that the norm?? I can't imagine buting a whole new package just to recharge the unit or top off charge...doesn't make sense, of course RV's keep you paying and paying until your broke so I wouldn't be surprised!!!!

I also melted down the RV's neutral isolated bus while trying to operate the A/C...30A RV main trying to pull from a 15A house breaker...didn't really think that would cause a meltdown, of course the RV owner didn't say anything either way so I didn't check.

let me know what you think,

J-thetechwizard

[Southern Mech]

Put piercing valves on the lines

[mark beiser]

Usually there will be process tubes you can seal off with a pinchoff tool to braze access fittings on.

[Cmstech]

Treat your customer right, get brazable service valve stems, not the piercing style they leak over time. Change the breaker out for safety

[catmanacman]

They are a glorified window unit and if you have to do very much to them best to replace it as they are not that expensive

[ar_hvac_man]

We have alot of rv campgrounds around here so I get quite a few calls on them. The main culprit is usually a clogged condenser. If it needs juice i use 3/8 braze on piercing valves. Many will balk at brazing on a system with reefer in it but..they are wrong.

[Southern Mech]

Treat your customer right, get brazable service valve stems, not the piercing style they leak over time. Change the breaker out for safety

The braze on valves still pierce

[AYservicetech]

Give the customer the option of bullet piercing valves with potential for future leaks or higher cost option of evacuating system and brazing in service valves... Let him decide.... I'd go with the bullet valves as the other route is more work and money than the unit is worth and I am yet to see a bullet valve that was the cause of a leak....( doesn't mean that it doesn't happen)

[Southern Mech]

No need for evac and recharge. There is a piercing valve that is brazed on, not bolted with oring and gasket. I used them when I did refrigeration, they do not leak.

Sorry for my last post, I really didnt catch on to what was being said till just now

[AYservicetech]

Didnt even know they had those ! I will definitely be looking for them now though... Go with that one!! 😜

[Gunslinger]

We have alot of rv campgrounds around here so I get quite a few calls on them. The main culprit is usually a clogged condenser. If it needs juice i use 3/8 braze on piercing valves. Many will balk at brazing on a system with reefer in it but..they are wrong.

X2 on the clogged condensers. Amps increase and trip breakers.

[Cmstech]

The braze on valves still pierce


I was just thinking about those cheap one that pierce as you screw them down. I've seen those on window units and refrigerators.

[Southern Mech]

I was just thinking about those cheap one that pierce as you screw them down. I've seen those on window units and refrigerators.


Those peticular style should vanish from the trade.

[J-thetechwizard]

well luckily the RV is my girlfriend's moms so cost is not a matter. However, this thing has seen better days and work is work! I suspect the chasis ground to the breaker panel is bad since the neutral bus heated up during operation....the package ac is very clean and there is no sign of any wear that would cause extreme FLA.

I also have to check the house ground since that is part of the problem in question.

The weird part was that the 30A main in the RV never tripped! the 20A breaker for ac would trip once in a while or the 15A house breaker would trip, but there is no indication why the netral bus melted down except possibly a bad chasis ground to the breaker panel or a bad house ground.

[J-thetechwizard]

oh...BTW where do I get those braze in piercing valves, those sound cool???

[doc havoc]

We get ours at Johnstone Supply. C&D Valve makes them. There are 2 styles. One is self piercing (M-series)and the other requires a piercing tool that screws onto your valve stem removal tool (V-series). The part number for the 3/8" valve is CD3098. 304551
This is the V series that requires the piercing tool. You can braze it on to a system with refrigerant in it. Just be careful you don't burn through the tubing.

[Snapperhead]

i've heard of brazing while charged , but never attempted it ... is there anything different about doing it ? No pump down or nothing ?

[AStudent]

well luckily the RV is my girlfriend's moms so cost is not a matter. However, this thing has seen better days and work is work! I suspect the chasis ground to the breaker panel is bad since the neutral bus heated up during operation....the package ac is very clean and there is no sign of any wear that would cause extreme FLA.

I also have to check the house ground since that is part of the problem in question.

The weird part was that the 30A main in the RV never tripped! the 20A breaker for ac would trip once in a while or the 15A house breaker would trip, but there is no indication why the netral bus melted down except possibly a bad chasis ground to the breaker panel or a bad house ground.

15A breaker attempting to power a 15A compressor in record breaking heat. I might be wrong but I doubt you need to check the refrigerant charge.

[jim147]

15A breaker attempting to power a 15A compressor in record breaking heat. I might be wrong but I doubt you need to check the refrigerant charge.

I'll agree with this if they are really trying to run the whole RV off a 15 amp house circuit.

I have two units, the shop beer fridge and my house freezer with bullet piercing valves on them for over ten years now. When should I expect them to leak? (They were condemned as unrepairable when I got them or I would have sealed up the process stub when I worked on them.)

jim

[koolkahuna]

I'll agree with this if they are really trying to run the whole RV off a 15 amp house circuit.

I have two units, the shop beer fridge and my house freezer with bullet piercing valves on them for over ten years now. When should I expect them to leak? (They were condemned as unrepairable when I got them or I would have sealed up the process stub when I worked on them.)
jim

Are the "bullet" piercing valves the pot metal/silver color ones that clamp on with allen bolts with different size saddle inserts depending on pipe size?
Those ones are hit and miss. I'd like to HIT the guy who installs them as anything other than a temporary means for system access for recovery and proper access valve installation, and I won't MISS them if they disappear!
Seriously though, I have seen some that haven't leaked for over ten years, and a large number that have. Likely due to improper installation. If I HAD no other option, I would oil the O-ring before installation on a "cleaned" pipe.
I would feel guilty until I could return for a proper repair.
I believe the braze on piercing valves to be the best solution and will only use the clamp on style when I can't find my Imperial Eastman recovery pliers with the piercing access fitting.

I just repaired an RV AC last month. Clamp on piercing valve had been installed previously, to my surprise it wasn't leaking but the cracked condenser elbow was.

The braze on style work great. Just clean the pipe and valve well, wrap the copper tabs tight to the pipe, don't overheat the pipe when brazing and of course wear eye protection.

[hydra]

I've used the bullet piercing valves successfully for years. The key is to clean your copper well, pick a straight spot on the process stub and tighten down the Allen screws completely in even turns in a clockwise or counter clockwise pattern. Just like you were tightening down head bolts. When I remove them years later, the copper is slightly compressed and the saddle has to be forced off due to tight seal.

[hvaclu420]

Thanks for posting about the brazed in piercing valves. Never saw them before nor heard of them

[ICanHas]

Search posts by user Hungrytech. He's got a YouTube video of installing the said type of valve.
But then, if it's a package unit, why not just recover the charge first? You're going to have to do it anyways to fix the leak.

[ar_hvac_man]

Search posts by user Hungrytech. He's got a YouTube video of installing the said type of valve.
But then, if it's a package unit, why not just recover the charge first? You're going to have to do it anyways to fix the leak.

Its basically a window unit and the leak is almost always in the evap. Its not cost effective to replace an evap in this type of unit.

[J-thetechwizard]

WOW! This has been a very informative thread!
RV Update:
I found so many problems while troubleshooting this RV ac issue...
1. The garage 110v recepticle was wired backwards, sending all hot voltage and amperage straight to the RV neutral bus.
the thing I can't figure out is how that plug worked all these years, including running this same rv???
it always seems like when I start getting into things, things that used to be ok suddenly become an issue! go figure!

2. after I put a 30A breaker on a plug, I was able to run the a/c without any problems, however I feel it is low on charge because it barely gets cool. A package unit is designed to pump constant cold air (55 degrees or so) all day long.

3. the ac pump itself only draws 9A during normal operation so at least its not failing and over drawing.

when it comes down to it....we have to be decent electricians with a strong understanding of grounding and basics.

it's not just about super heats and sub cools!

[hydra]

That's a fact J!

[doc havoc]

i've heard of brazing while charged , but never attempted it ... is there anything different about doing it ? No pump down or nothing ?

No pump down or anything. They work pretty slick. I like to use a minimum 15% silver rod for brazing. The beauty of it is, because you don't have the system open to the air, you don't get the oxidation inside the pipe when you braze.
305551
This is the piercing tool you attach to your valve core removal tool to pierce the line for system access after you've brazed on the fitting and leak checked it.

[J-thetechwizard]

thats is slick! I'm sold!!

[Snapperhead]

well aint that sumpthin