Textbook question - piercing valves

[myngos211]

Hello all,

I've been looking through my HVAC textbook between semesters and read that piercing valves should be removed once system access is no longer needed. This of course goes for the non-permanent type but my question is, how on earth do you remove a piercing valve and not lose your refrigerant? What am I missing here that the textbook does not cover?

[maintenanceguy]

My only guess is that it's talking about the plier-type piercing valves that lock onto a refrigerant line like a pair of vice grips.

These are used to evacuate small equipment like window units or refrigerators when you're going to dispose of them.

I agree, every type of piercing valve will leave a hole and can't just be removed (unless the refrigerant already was)

[ryan1088]

Here's the best answer I can think of...Don't work on anything that requires any of that stuff!!! Window units suck.

[myngos211]

I'm now thinking that what they failed to mention is that a tech can use a piercing valve to access the system in order to evacuate, install permanent service valves and make any necessary repairs before charging.

[myngos211]

Lol...true. I was given a 2 ton window unit that the previous ho put a screw through the coil. BRand new otherwise but I would like to attempt a fix and install in my shed.
Here's the best answer I can think of...Don't work on anything that requires any of that stuff!!! Window units suck.

[fearlessfurnace]

well it already has big blue sky recovery so braze in real service valves.

[ryan1088]

Lol...true. I was given a 2 ton window unit that the previous ho put a screw through the coil. BRand new otherwise but I would like to attempt a fix and install in my shed.

Ok I can see your point there. I would get the taps that you braze in, pierce, then do what you need to do and leave it in there. All the other ones are prone to leak. If you really want an adventure then try doing all your work from the process tube off of the compressor!

[Fabrk8r]

They are intended for small appliances such as refrigerators or window units.

Place the piercing valve near the end of the process stub on the appliance. After service is complete pinch off process stub, remove piercing valve and re-seal stub with soft solder.

No refrigerant will be lost.

[karsthuntr]

Use this, no need to remove.

http://www.cdvalve.com/components/com_virtuemart/shop_image/product/CD3092_4b4c909abfd31.jpg

This one needs to be removed, it will leak.

http://www.zenitram-inc.com/Files/1218.jpg

[ryan1088]

Use this, no need to remove.

http://www.cdvalve.com/components/com_virtuemart/shop_image/product/CD3092_4b4c909abfd31.jpg

This one needs to be removed, it will leak.

http://www.zenitram-inc.com/Files/1218.jpg

That's just what I was talking about!

[karsthuntr]

That's just what I was talking about!
Pictures make it more better. :)

[fridg]

Manitowoc requires you to use one of these so as to not interfere with the charge , they do work.

http://t1.gstatic.com/images?q=tbn:ANd9GcSH8Go3XP9KAZlxVfgijOIbYz0MwdORs a7UNJcHL3Qiqvvxf8zo2P2P1OCK

[myngos211]

Thanks for all the replies. Great pics too.

[Pion]

When necessary, I usually will only use piercing valves to recover refrigerant and install permanent access fittings.

[karsthuntr]

When necessary, I usually will only use piercing valves to recover refrigerant and install permanent access fittings.
That's why you use the top picture I posted. You braze it in (with it full of gas) and leave it there. Its a single step instead of using the bolt on one and then removing it and brazing in something else.

[nashuahvac]

You are supposed to use the piercing fitting to pull out the refrigerant. Then you braze on a new process tube and use one of these http://www.sjdiscounttools.com/rob12458.html to attach your hose to the end of the process tube (its like a rubber compression fitting) and charge by weight. Then you pinch off the tube, remove the fitting and braze over the end of the process tube. This way everything is still hermetic when you are done. It's not that hard as long as you make sure the process tube is long enough to work with.

Really though, just braze on a regular access fitting and be done with it.

[hceptj]

That's why you use the top picture I posted. You braze it in (with it full of gas) and leave it there. Its a single step instead of using the bolt on one and then removing it and brazing in something else.

Same here...had a 20+ year old 10 ton Lennox with a defective high pressure switch a couple weeks ago, no core under the bad switch so I just brazed in the new service valve and wired in a new high pressure switch...took longer to go to the parts house than it did to do the work...:)

[karsthuntr]

Same here...had a 20+ year old 10 ton Lennox with a defective high pressure switch a couple weeks ago, no core under the bad switch so I just brazed in the new service valve and wired in a new high pressure switch...took longer to go to the parts house than it did to do the work...:)
Lennox is where I found out about the brazed saddle valves. I had a pressure switch go bad on a lennox unit. Lennox sent me the saddle valve and a screw on pressure switch and said to leave the old one in since it was brazed in.