Low side stuck

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andrew vanis
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Re: Low side stuck

Post by andrew vanis »

Thanks for the responses. Learned a bit about couplers. Mine are working well since on other systems they work as well expected including holding pressure and vacuum. Even on this specific car they worked as expected before the low stuck situation described in first post.

With this specific car when I was evacuating after posting this issue the low side also came down so decided to try a recharge and the compressor was making unexpected noises and the pressures seemed out of line based on my experience with this car model (like hitting 250psi on the first can whereas usually it gets to those pressures on the 4th can). My friend has an extra new compressor and new TXV so I'll be putting those in today and will update.
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andrew vanis
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Re: Low side stuck

Post by andrew vanis »

Put in new TXV and Compressor,

Held excellent vacuum for hours so charged it and on a 100deg day got a 30deg drop evap air in/out at 2k RPM and 20deg idle.

...should have also pressure tested just in case because next morning it was underperforming and H and L pressures were low.

Pressured up the high side and found a bad crimp on an existing H side hose.

Will re-sleeve/crimp and post update.

Question - when pressure testing should sides equalize? I expected the sides to equalize like what happens when a car is sitting overnight. I pressurized the H side to like 250 and the L side came up only to 80.

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tbirdtbird
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Re: Low side stuck

Post by tbirdtbird »

Andrew you know better than to charge to the hi side.
You have been here long enough. In fact it is downright dangerous to do so, the can will explode in your face.
In any event at this point i am not sure what is going on.
I almost think your forum ID has been hijacked because you are no longer using typical MVAC terms.

Please clarify
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andrew vanis
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Re: Low side stuck

Post by andrew vanis »

andrew vanis wrote: Fri Jun 14, 2024 11:37 am
Question - when pressure testing should sides equalize? I expected the sides to equalize like what happens when a car is sitting overnight. I pressurized the H side to like 250 and the L side came up only to 80.
I'm not charging

I'm pressure testing by putting nitrogen into the high side

engine/compressor is off
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andrew vanis
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Re: Low side stuck

Post by andrew vanis »

andrew vanis wrote: Fri Jun 14, 2024 11:37 am
Will re-sleeve/crimp and post update.
So this was a 2-piece connector piece (MIO/FOR w. o-ring) connecting 2 hoses. First the O ring was crushed (likely trying to fix a leak in the vicinity , but it was probably not the o-ring), replaced and tested, then one side/fitting leaked at the crimp at 210psi, That is what I wrote the above. Cut off the hose and sleeve/furl and crimped on a new sleeve. Then testing to 450psi, the other fitting on the other side leaked a bit at the original crimp. I was out of #8 sleeves so for kicks I just re-primped the existing. It held solidly at 450psi.
tbirdtbird
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Re: Low side stuck

Post by tbirdtbird »

Ok thanks for clarifying.
I’d be using the nitrogen on both sides, and if leak testing, I’d avoid the term ‘charging’
In this shop we prefer puffing up system with about 20 psi of refrigerant to both sides and then using a sniffer to check for leaks. Car and comp off. Put sniffer probe into evap drain under the car. To us this is the easiest way to leak test
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