surging or thumping noises in liquid r22 line

[afn6353]

12 year old r-22 Trane system with #65 orifice at evaporator makes thumping sounds that seem to come from the liquid line near the orifice as soon as the compressor starts and continues (with less forceful thumps) as long as the compressor is running. The sounds aren't new, but the pressures are running a little high (80 on the low side, 350 on the high side) for my tastes. If I let out enough coolant to drop pressures down to a more normal range (50 low and 250 hi), then the evap only gets cool on the bottom half and wants to ice up there, so I increase the charge until the unit cools the entire core and sweats properly. Anyone else out there run into this, and what did you do, if anything, to get rid of the thumping?

[sedgy]

killing the ozone layer with r22 will not solve the problem, why not employ a skilled fridge tec to do the job?

[coolhibby1875]

the noise you are hearing is more likely to be coming from the discharge, you can install baffles to the discharge to reduce the thumping noise

[hyperion]

The fact that you originally had a higher suction and discharge pressure suggests that you may have either a high evaporator load or a high discharge load due to ambient conditions or a dirty condensing unit or both.
Once you have corrected these temperature related problems, you could, as has been suggested, install a discharge muffler to take out some of the compresor pulsations. This will need to be installed as close to the discharge port on the compressor as possible.
Hopefully your adjustment of the refrigerant gas charge was carried out in a sensible and controlled manner, ie that you reclaimed the gas rather than vented it to the sky!

[afn6353]

sedgy, thanks for your assumptions. the last time we "employed" a "skilled" highly trained and trusted "tech" such as yourself (there's my assumption) from a local ac company, they charged my wife for the "repair" over $200 for adding about 2 lbs of r22 without even trying to find out where the ozone "killer" had been released. Soon after, we had the same symptoms again, so I bought a Robinaire system for reclamation and have repaired the hole inside the core myself. I just came here for a little advice from someone more experienced, which, thanks to a couple of other members, I've gotten. The test which the government makes you take to become "licensed" is a joke and doesn't give you the knowledge gained by the members who post here. Many thanks to those that take the time to help others here and on other sites.

hyperion and coolhibby, thanks for the advice. The noise I'm hearing isn't a regular beat. It almost sounds like there are pockets of gas in the liquid line popping when they go through the orifice, thus causing the irregular thumping, which is not rhythmic, like the pulsing which might come from the compressor. I can't feel any of the pulsing or thumping at the condenser end of the system, either. I cleaned the A-frame when I had it out to fix the hole, and cleaned the condenser core at the same time while I had it apart. It's always pretty hot and humid here in florida, so I know the system has it's work cut out for it. It only runs for a few minutes at a time and the air coming across the condenser is pretty hot, so it's doing a great job cooling the place efficiently and taking out tons of moisture, too because the drain line is flowing constantly. Is it possible the oil became contaminated with the charge put in by the repair guy and is causing this? (Or maybe he added too much oil) I hadn't lost any oil before my repair, so I didn't add any when I charged it myself.

[sedgy]

hi afn6353, < my assumptions< was an answer to your question < if I let
enough coolent out< and its not my fault that in the us, they dont educate and test your engineers, as they do in the uk, I gave you a true answer to your question its up to you to adapt that to your own situation

[monkey spanners]

Are there any non condensables in the system? What are the air on and air off temps?
Is the filter drier good? I hope the previous company didn't put any sealant in the system :confused:

I think if that is a fixed orifice system you need to charge by suction superheat, if its a txv system you charge by liquid line subcooling, is there a chart on the outdoor unit anywhere, or maybe you could phone their technical department. That will get your charge correct.

We don't have those types of systems here in the uk, i've learnt what little i know of them from DrZarkloff on youtube :D

Theres no need to get arsey with sedgy, letting out refrigerant is and has been very illeagal here for many years, i'm surprise its not in the USA as you tend to set the standard in many things.

Jon :)

[tbirdtbird]

He said he recovered. Venting is not legal in US
350 hi side is kinda high. ? restriction? Liquid line cooler or frost just after filter drier?
I doubt oil is contam and I doubt tech added oil
Sounds like it is short cycling too
As has been stated often you need these numbers to properly evaluate; maybe get a diff. tech and be there yourself when he arrives:

Evap air/water in temp
Evap air/water out temp
Low side pressure or saturation temp
Suction line temp at evap outlet
Suction line temp at compressor inlet

Cond air/water in temp
Cond air/water out temp
High side pressure or saturation temp
Liquid line temp at receiver or condenser outlet
Liquid line temp at TXV/ inlet

[tbirdtbird]

Hmmm, rethinking this
"I cleaned the A-frame when I had it out to fix the hole,"
so you recovered, removed the coil, repaired, reinstalled, vacuumed, recharged? Else we could be dealing with noncondensables (air) at the least

[FEISTY]

OK Guys. Deep breath. Now that the " who's is bigger " contest is over, let's just try to help where we can. The world is full of customers who got the short end of a service call. Doesn't make us all bad. If he " properly repaired " the leak and pressure tested for " hidden " leaks with nitrogen, it's possible there is air in the system and/or moisture, depending on the method used to " clean " the coil. How many of us have seen the homeowner's garden hose or...God forbid...the power washer they got as a gift..cleaning system. I had 1 where the work was done pretty well but dryer not changed and moisture throttled thru orifice. Just my 2 cents worth but any calm help...helps. Good luck and let us know what ends up working. That info helps all of us. Have a good day !!

[hyperion]

Good point tbirdtbird, it could be air or non condensibles in the system, but normally that would tend to prevent much cooling from happening. How recently were the repairs done and did the thumping noise just occur with the higher ambients or has it been there since the repair?

[afn6353]

Hello all, and Happy New Year! May it be a prosperous one for everyone.
Thanks for the posts since I last logged on. My repair from the spring of 2010 is holding and unit is cooling fine despite the irregular muffled popcorn popping sound coming from the orifice. System seems economical and is providing dry air, so no complaints there. It's been making the sound long before I repaired it, so I might not have caused it, but I didn't get rid of it either. I was just hoping to come across someone who had experienced the sound before and could help me identify the cause to keep me from wasting time guessing. When it warms up a little (here in Florida:cool:!) , I'll let you know how it goes.
thanks again