Printable View
Is there any screening device inside a discharge muffler?
http://i28.tinypic.com/2z8xfyp.jpg
I know these are frequently used to reduce noise and vibration on reciprocating compressors and the reduction in vibration can save piping connections from fracture. On a scroll compressor, are there significant benefits to having a discharge muffler?
No!Quote:
Originally Posted by Larry2
Just to reduce noise and vibration. If you have short pipes in split systems or in packaged units then it could be unavoidable.Quote:
I know these are frequently used to reduce noise and vibration on reciprocating compressors and the reduction in vibration can save piping connections from fracture. On a scroll compressor, are there significant benefits to having a discharge muffler?
Some splits have strainers in this type of device - is it a muffler or a filter ?
Has the left hand pipe been cut off larry?
Filter (strainer) is few times smaller than muffler.Quote:
Originally Posted by Brian_UK
That left pipe that looks like it was cut off is a manifold to split gas two ways. The top has a plug brazed in. That is as it came from the factory.
http://i27.tinypic.com/dlrplu.jpg
According to the pamphlet I found online for this unit, that spun copper piece in the discharge line is a muffler. The part number, Spinco 52C5501 doesn't turn up information on google.
This will be the third scroll compressor I've lost out of three systems the recent year for a 100% failure rate at 14 years old. The one I replaced last year simply lost efficiency.
I believe this one has fragmented the scroll internals. It was spinning but not consuming much power and not pumping. The next time is started, the rotor was locked solid.
I was wondering if the muffler has any screen that would capture bits that would come out of the compressor during failure.
Couldn't find the part numbers on the Spinco site only pictures but I was having trouble viewing the site, it may be me or their site having troubles.
http://www.spincometal.com/Products/SpunProducts/
It looks like the filter drier in this system is plugged up.
http://i27.tinypic.com/28aqgzl.jpg
I started recovery. Regardless of the disposition of the unit, this has to be done first. I know everyone will chime in "bin the unit". I can't afford to spend on this if I can rescue it.
This frosty drier with check valve is in the circuit during cooling and defrost. The right side of the drier is 5 degrees colder than the left. Flow left to right should be unrestricted. The arrow shows filltered flow would be left to right. This frosting showed during pull recovery from both sides of the system. I guess the drier is clogged.
If the frosting only occurs during reclaim of the gas, then it simply means that it's full of liquid boiling of. It may or may not be blocked, but that it happens during reclaiming doesn't tell us one way or another.
But saying that, it is always good practice to replace the driers every time you reclaim (or recharge) a system.
Quote:
Originally Posted by Brian_UK
You got further than I did Brian. I only found a site that talked about making specialty brass parts. I suspect this part has a manufactures number and not an industry number. It may have been constructed to specs unique to my unit. I read elsewhere that manufactures get complaints about noise from pipework, so maybe this part is only needed to avoid complaints.
If one is not concerned about transmission of noise through the pipework, how important is the muffler to reliablity? I'm considering taking it out to inspect it for debris and installing a length of pipe in place.
I read something a year or two ago about filter/driers coming apart and dumping their contents into the system. I can't recall if that related to installation in the discharge line. Is it safe to place a filter/drier in the discharge line ahead of the reversing valve to protect it? Or would the stress of starting up, dumping out liquid after sitting, etc cause a filter to upset it's contents?
Filter/driers can become 'full', in other words they can no longer absorb any more moisture. When they become heated or overheated then they can release the moisture back into the system and occasionally some of the filling can follow.
I wouldn't suggest putting a filter/drier directly on the compressor discharge, the temperature changes and extremes would not be good for it.
Larry,Quote:
Originally Posted by Larry2
Here is Copeland's statement concerning mufflers.
"Flow through Compliant Scroll Compressors is semicontinuous and has relatively low pulsations. External mufflers, where they are normally applied to piston compressors today, may not be required for Compliant Scroll. Because of variability between systems, however, individual system tests should be performed to verify acceptability of sound performance, especially heat pumps. When no testing is performed, mufflers are recommended in heat pumps."
Here's the link if you desire to read more.;)
Section 4
4-1300
http://www.hvacrinfo.com/ae_index.htm
I read that last night :) . That didn't convince me that a length of pipe would be a poor replacement for my purposes. I don't care about sound transmitted through the pipework. I am concerned about early failure of the compressor or piping though. I certainly wouldn't want a failure that cause gas release.
It seems like a muffler could reduced pressure impulses from being reflected back to the scroll unit and their pipes. I didn't find much supporting the need for scroll units though reciprocating units seem to be supported for muffler use. I can't find anything saying that is important for a scroll. I'm wondering if noise is the only concern that set the design choice. Consumers complain about noise and a sale can go one way or the other based on noise level from the unit.
I did read in the archives that adding a muffler solved fracturing pipe joints. I think that was a larger system and with a reciprocating compressor. I read elsewhere of these mufflers being added on under warranty when consumers escallate noise complaints through the manufacturer.
Thinking 30 years back, we soldered most fridge connections with Stay-brite. We never soldered the compressor connection because of vibration fatigue would cause failure.
I've not found any expanded views of the internal construction for a muffler. My question is if this component needs to be replaced following a compressor failure, ie will this part collect debris from a mechanical compressor failure. The very next item is the reversing valve.
If the discharge muffler is of no consequence other than noise, A short length of pipe would probably suit me well until I am really ready to bin these units in favor of ground source gear in five years.
I have a ZR36 compressor to install in place of the broken ZR34. I think that is close enough. I laid in that spare from eBay last year for $120 delivered. My goal is to get five more years out of the gear while technology advances on to more efficent stuff. I would like to do a decent repair without swapping out the entire system.
I don't have an account to buy equipment, so when folks say "bin the unit" you are looking $4000 to $8000 to replace everything compared with a day or two of my time and $300-$400 on parts. The payback on that, even at SEER 13 is favorable on taking the gamble. If the system fails early on, I don't need to stand behind my work. :p
I'm back out to attend to the recovery gear. That goes really slowly in this chilly weather.
That muffler on picture is practically only widening at pipe and replacing it with pipe could not make any difference, except more noise from compressor discharge pulsations. Positioned like that, it cannot collect in itself any debris.Quote:
I've not found any expanded views of the internal construction for a muffler. My question is if this component needs to be replaced following a compressor failure, ie will this part collect debris from a mechanical compressor failure. The very next item is the reversing valve.
More likely that debris (if any) will be collected at bottom of U tube between muffler and 4-way valve.
I guess you're right, the drier collected some liquid. I always replace this part when I open the system to install a fresh compressor. It's an expensive part because of the check valve, but I think it's cheap insurance. I also put a 3/8" solder in biflow filter at the air handler.Quote:
Originally Posted by The Viking
I plan to cut open this compressor to see just how much it broke apart inside. I'm expecting to see evidence of electrodeposited copper and fragments of the scroll. My hunch is the installer didn't bother with a vacuum pump during comissioning.
I have a question about conducting the acid test. On a hermetic system which has no oil reservoir, how do you obtain the oil sample? One kit says get 90 dropplets of oil from the system. That will be easy to collect with the compressor removed, but it may be necessary to test for acid after the new installation several times while changing out filters.
I will keep that in mind. It may pay to take the U tube and muffler off as an assembly for inspection and blow some OFN through it.Quote:
That muffler on picture is practically only widening at pipe and replacing it with pipe could not make any difference, except more noise from compressor discharge pulsations. Positioned like that, it cannot collect in itself any debris.
More likely that debris (if any) will be collected at bottom of U tube between muffler and 4-way valve.
if your worried why not cut out, blow through with OFN then rebraze on?
I removed the compressor and cut it open for inspection. There weren't any broken fragments, so the muffler should be okay. There was copper plating everywhere.
http://i29.tinypic.com/2qkjmfm.jpgI
http://i31.tinypic.com/25jfvgo.jpg
http://i27.tinypic.com/2inhd.jpg
http://i28.tinypic.com/ru63dk.jpg
http://i26.tinypic.com/o9jspd.jpg
Quote:
Originally Posted by Larry2
Can you test the oil for acid.
Copper plateing like that is normaly caused by contaminated oil.
Cheers taz.
Ps nice pictures.:)
Yes, that's my plan. I'll test the oil to see how bad the acid is. Since acid disolves the copper pipes and it deposits onto the steel where oil lubricates parts, we know there was acid in the system.
When these were put in, the contractors used an orifice refrigerant control. The paperwork certified SEER13 preformance only if the systems was configured with a txv kit. So I had the contractor come back to install the missing items. Becaue our contract stated SEER13 gear, he had to bring it up to factory snuff. I didn't snoopervise since I was working that day. I suspect he didn't draw a a vacuum after he swapped the refrigerant control for a txv on each of my systems.
I bought some chemicals meant to neutralize acid in the oil that remains behind in the pipe work. It's part no HS18004 made by Highside. I'll replace the filter/drier in the outdoor section. That one functions in heating cycle only. I will add a bi-directional 163S filter/drier just a head of the indoor expansion valve.
I'm trying to decide if I should clean the condensor with superflush or leave it be.
Ouch, you got newbed bad!
You can use Isopropyle alchol and OFN, to flush the coil out, nice and cheap, vac pump will get the rest out.
Clean the fan blades and coils, both indoor and outdoor, on all three systems. Then check the temperatures of the air entering and leaving both coils on the running systems. Compressor failures (especially after long term use) are most commonly caused by insufficient airflow through the coils and copper plating is a sign of overheating (cooking the oil which forms acids) again caused by insufficient airflow.
Let us know what you find and what those temperatures are.
If I understand you correctly, you have three 14 year old systems, each of which has experienced one compressor failure in the past year. What these systems have in common is maintenance or lack thereof. Airflow, airflow, airflow.Quote:
Originally Posted by Larry2
I'm confused. Are you saying these TXV's were installed 14 years ago?Quote:
Originally Posted by Larry2
And why do you suspect that the systems were not evacuated? Is there some reasoning behind this or is this just wild speculation?
Gary, all three systems were opened shortly after they were first installed to install expansion valves in place of fixed orifice metering devices. Expansion valves were an acessory kit that was part of the manufacturer specification to obtain the SEER 13 rating.
The largest of the three systems has a sight glass/moisture indicator. That indicator showed a slight yellow cast to the green color when I pulled the cover from that system last year. After I replaced that compressor and evacuated the system, the indictor turned brilliant green. The other two systems didn't have any indicator. I may be leaping to conclusions.
Everyone's advice about cleaning the coils is appreciated and accepted. And if you look at the photo earlier, there is overheated oil sticking to the highest pressure spot of the scroll. When I replaced the compressor in the largest system last year, I thoroughly washed the coils. The outdoor coils are two layers thick. They don't come thoroughly clean without separating the two layers to hinge the outer coil away from the inner one. I'll repeat that cleaning as I service these units.