A/C problem again, low pressure port leaking
07-08-2008, 12:08 AM
#1
Registered User
Thread Starter
A/C problem again, low pressure port leaking
Anyone know what to do about a leaking low pressure port? Filled my system on Saturday and it all leaked out. So I refilled with some dye and when I disconnected the gauges I noticed the low pressure port was leaking. The truck never had the plastic protective caps on it when I bought it so I stole one off my other vehicle. I don't know if it will stop the leak or not.
Can the port of valve be repaired or does the whole line need replacing?
Can the port of valve be repaired or does the whole line need replacing?
07-08-2008, 02:49 PM
#3
1st Generation Admin
Actually, that missing cap IS the seal for the service port. The schrader valve simply keeps the refrigerant from gushing out while one connects gauges.
There are two types commonly used.
- The plastic or metal ones that use an O-ring for sealing, and
- The metal (brass or aluminum) ones that depend on one snugging the cap down so as to have a new metal-to-metal seal with each tightening.
Those with the O-ring are tightened "Hand Tight". Those depending on a metal-to-metal seal need tightening with a wrench. Be sure to use a Back-Up wrench so as not to wring the fitting off the pipe.
I wouldn't worry about the schrader valve core itself leaking. Again, they are not intended to provide a gas tight seal.
There are two types commonly used.
- The plastic or metal ones that use an O-ring for sealing, and
- The metal (brass or aluminum) ones that depend on one snugging the cap down so as to have a new metal-to-metal seal with each tightening.
Those with the O-ring are tightened "Hand Tight". Those depending on a metal-to-metal seal need tightening with a wrench. Be sure to use a Back-Up wrench so as not to wring the fitting off the pipe.
I wouldn't worry about the schrader valve core itself leaking. Again, they are not intended to provide a gas tight seal.
07-08-2008, 10:25 PM
#5
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Actually, that missing cap IS the seal for the service port. The schrader valve simply keeps the refrigerant from gushing out while one connects gauges.
There are two types commonly used.
- The plastic or metal ones that use an O-ring for sealing, and
- The metal (brass or aluminum) ones that depend on one snugging the cap down so as to have a new metal-to-metal seal with each tightening.
Those with the O-ring are tightened "Hand Tight". Those depending on a metal-to-metal seal need tightening with a wrench. Be sure to use a Back-Up wrench so as not to wring the fitting off the pipe.
I wouldn't worry about the schrader valve core itself leaking. Again, they are not intended to provide a gas tight seal.
There are two types commonly used.
- The plastic or metal ones that use an O-ring for sealing, and
- The metal (brass or aluminum) ones that depend on one snugging the cap down so as to have a new metal-to-metal seal with each tightening.
Those with the O-ring are tightened "Hand Tight". Those depending on a metal-to-metal seal need tightening with a wrench. Be sure to use a Back-Up wrench so as not to wring the fitting off the pipe.
I wouldn't worry about the schrader valve core itself leaking. Again, they are not intended to provide a gas tight seal.
that's 100% incorrect. the caps keep out the grime just like the caps on your tire valves. if the valve leaks it needs to be repaired.
07-09-2008, 07:49 AM
#6
1st Generation Admin
Crap!
Does that mean I have to go back over 17 years worth of HVAC and refrigeration systems where another so called technician left the caps on the floor/roof and replace the cores? I replaced the caps and the systems held a >500 micron vacuum as well as a 250psig dry nitrogen gas pressure test.
The boss is gonna be mad.
I think we're talking about two different style schrader valves (the "Old-School" and the newer).
That new and improved valve now being used on automotive systems is beginning to show up on newer commercial packaged systems in combination with the more common 1/4" valves. The benefit is the overall larger passage afforded. This in turn allows a much quicker evacuation/dehydration.
Oddly, commercial and domestic HVAC & refrigeration tool suppliers are very slow in introducing/marketing the new hoses and fittings/adapters for them.
They too have to O-ring in the cap for ultimate sealing.
Does that mean I have to go back over 17 years worth of HVAC and refrigeration systems where another so called technician left the caps on the floor/roof and replace the cores? I replaced the caps and the systems held a >500 micron vacuum as well as a 250psig dry nitrogen gas pressure test.
The boss is gonna be mad.
I think we're talking about two different style schrader valves (the "Old-School" and the newer).
That new and improved valve now being used on automotive systems is beginning to show up on newer commercial packaged systems in combination with the more common 1/4" valves. The benefit is the overall larger passage afforded. This in turn allows a much quicker evacuation/dehydration.
Oddly, commercial and domestic HVAC & refrigeration tool suppliers are very slow in introducing/marketing the new hoses and fittings/adapters for them.
They too have to O-ring in the cap for ultimate sealing.
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07-10-2008, 11:16 AM
#8
1st Generation Admin
If you want, the schrader core can be considered the Primary seal where as the cap is the Secondary seal.
Interestingly, I've got a poll going in an HVAC&R forum asking what does what. . . .. . it's 50/50.
In the end, fix the leakage of refrigerant overall.
Interestingly, I've got a poll going in an HVAC&R forum asking what does what. . . .. . it's 50/50.
In the end, fix the leakage of refrigerant overall.
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