PDA

View Full Version : vilter 450xl



Joshieboy
16-12-2007, 09:29 PM
I am having problems with my 150hp 8 cyl 450xl, its shutting down on high discharge temp, have replaced four of the eight safety heads due to cracking in the discharge valves, we are using the 440 style safety heads, the suction temp runs about 95F yet the house suction temp is around 33, we have two other comps, both are fes 300hp screws and they don't show the high suction temp, is it possible that the unloaders are not working on the vilter?

NH3LVR
16-12-2007, 09:57 PM
This is one we can really get into.
When you say the suction temp is 33F, I assume you mean the suction pressure, converted to temperature.
The FES screws not seeing the high suction temp is hard to understand. Do you mean that the suction lines temperatures at the machines are that different?
I have seen this occur only when a machine was running but not pumping. If there is no gas flow through the suction to this machine it will run very hot. Vilter puts a limit of 20 minutes or so for a machine to run fully unloaded in some applications.
Please tell us a bit more about your system and compressor.
Is this a new condition, or has it always been a problem? There can be a problem if the cylinder covers are not the right ones. Oil and Gas unloading cylinder covers are different when you look at them closely (do not ask how I found this out!)
I believe you have some Vilter Mechanics around there. This should not be a major issue to resolve.

Joshieboy
16-12-2007, 10:07 PM
not sure about if this has been a problem in the past, company just purchased the complex, did find several old safety heads lying around so im assumming they have had this problem in the past. the complex is only about 6 years old, and yes the suction temps are that different at the machines. do not know if the cylinder covers are right, what is the difference?

NH3LVR
16-12-2007, 10:26 PM
The cylinder cover for gas unloading has a small hole drilled through it to the underside of the head. It is easy to miss, or ignore the lack of. If it has been replaced with a oil unloading head the compressor will not load.
Please keep in mind my expertise is with the 440, not the 450. Some parts are different.
Do you have the manual for the 450?

Joshieboy
16-12-2007, 10:46 PM
I will check out the heads, thanks. yes i do have he manual for it

NH3LVR
16-12-2007, 10:53 PM
If the machine is not apart now I can suggest some other checks to determine if the loaders are working properly.

Joshieboy
16-12-2007, 10:58 PM
the machine is apart, but we are putting it back together next week with the rest of the safety heads changed, but i will definently love some suggestions on how to check the loaders

NH3LVR
16-12-2007, 11:32 PM
It is not very complicated.
I will assume that at least two of the cylinders are loaded at all times. A few machines were made that would unload them all.
After you start the machine, put an clamp on Ampmeter on one of the motor leads.
Operate the unloader controls and watch for a change in curret draw. You can also listen to the change in sound if the engine room is not too loud.
If you had bad valves it is possible that the machine could not pump enough to draw gas through the machine. Bad valves would also raise the discharge temp.
I am assuming that you have the diaphragm type valves. In any case you need to lap (or surface grind) the bottom of the safety head and the top of the cylinder if there is any question of its condition.
The suction valve surface of the cylinder can be lapped as well, but requires a little trickery. It is not as critical as the discharge side.

Joshieboy
16-12-2007, 11:39 PM
thanks i will try that and let you know what i find out

PaulZ
17-12-2007, 02:36 PM
Another thing to check is the free length of the head springs. If they are below tolerance (over compressed) the entire valve assembly could be lifting allowing bypass between the liner and the valve plate. If this compressor has been running hot for a long time the springs may need replacing. Paul

NH3LVR
17-12-2007, 03:44 PM
Another thing to check is the free length of the head springs. If they are below tolerance (over compressed) the entire valve assembly could be lifting allowing bypass between the liner and the valve plate. If this compressor has been running hot for a long time the springs may need replacing. Paul

Excellent point Paul.
I think we need to find the cause of the cracking. this cannot go on forever. Vilters are not in the habit of breaking parts for no reason.

L1GHTYR
20-12-2007, 03:27 PM
Vilters also have internal relief valves that vent from the discharge side back to the crankcase. It may be loose, blown, etc. Check that since you have it apart.

NH3LVR
21-12-2007, 04:17 AM
Vilters also have internal relief valves that vent from the discharge side back to the crankcase. It may be loose, blown, etc. Check that since you have it apart.

Damm! I thought about that but forgot to mention it.
Thanks for correcting my oversight L1GHTYR.
If it has ever opened and failed to reseat it will cause overheating. I used to replace them at every overhaul. It was our companys policy.

RANGER1
21-12-2007, 01:41 PM
A 450XL would probably have disk or valve plates same as suction valves (but smaller in diameter).Another check could also be good water flow through heads.should be able to hold your hand on each head.Good oil pressure to load heads,say 40psi.Proper head gasket on each head,as if cylinder has no unloaders or unload piston discharge gas will recirculate back into suction through unload piston open hole . Does compressor have bypass solonoid between suction+discharge?. If so is it recirculating gas back into suction?.Maybe after assy if you dont find anything obvious with anyones suggestions a valve test could be carried out .A simple test before you put side cover on sump is pump up discharge side of comp with air / nitrogen to see if it does"nt blast or leak into sump area to quickly, if it does obviously see where from.

L1GHTYR
21-12-2007, 06:45 PM
It's interesting that you are using 440 heads on the 450, I thought about doing the same on our 4516XL. I had a few of the springs in a safety yoke start spinning and drill their way into the yoke. Three of them next to each other, net result was a broken discharge valve plate which led to spinning a rod bearing and destroying the crank. I know this is off the topic, but since the company just purchased the building, you don't really know what was done in the past or why. Maybe the former owner had safety yoke problems that caused similar damage like ours. This may be the reason why the safety heads are not 450's. We had to replace many parts on ours because it got really hot before the oil temp cut out shut it down.

Joshieboy
04-01-2008, 04:10 AM
well we seemed to fix the problem, only now we are getting high discharge temps, whats your thoughts?

US Iceman
04-01-2008, 04:39 AM
This from your first post...


I am having problems with my 150hp 8 cyl 450xl, its shutting down on high discharge temp,...


and you have this...


well we seemed to fix the problem, only now we are getting high discharge temps, whats your thoughts?


It doesn't sound like you are making any progress?

High discharge temperatures are usually the result of broken discharge valves, leaking internal relief valves, abnormally high suction superheat, or too high of a compression ratio.

The maximum compression ratio for a Vilter recip. is 8:1 (on ammonia). If you are operating higher than this your suction pressure is too low or your discharge pressure is too high.

Check the easy stuff first before you begin to replace parts.;)

Grizzly
04-01-2008, 07:02 PM
This from your first post...


and you have this...


It doesn't sound like you are making any progress?

High discharge temperatures are usually the result of broken discharge valves, leaking internal relief valves, abnormally high suction superheat, or too high of a compression ratio.

The maximum compression ratio for a Vilter recip. is 8:1 (on ammonia). If you are operating higher than this your suction pressure is too low or your discharge pressure is too high.

Check the easy stuff first before you begin to replace parts.;)
Iceman.
Unlikely I know especially as the others are running ok, but what about Air that can cause High Discharge Temp?
Grizzlyhttp://www.refrigeration-engineer.com/forums/images/icons/icon14.gif

US Iceman
04-01-2008, 09:28 PM
Hi Grizzly,

Sure, air will increase the discharge pressure, which in turn raises the compression ratio and at the same time causes the discharge temperature to increase.

The increase in temperature due to the air would require a LOT of air to be present.

Abnormally high discharge temperature usually result from broken discharge valves, high suction superheat, or leaky internal relief valves.

Joshieboy
04-01-2008, 11:58 PM
well before we were having high suction temps, but thats better now, what we are getting is about 33psi on the suction side, 35-36 degrees, suction side. at 80psi discharge the temp stays about 220, if we try to get it up to the 110 were we like to run it, the temp shoots up to 260 or higher and the oil temp runs about 140-142. I hope that clears things up

US Iceman
05-01-2008, 12:48 AM
33 psig is about 20°F, so that would mean you have about 15-16°F of suction superheat If I am reading you data correctly. That's not too bad.

80 psig discharge isn't too bad either as long as you have sufficient pressure to push liquid to the expansion devices. However, if you are trying to run full cooling loads you might find the TXV's (or whatever you are using) may not be capable of providing sufficient liquid to the evaporators.

220-260°F is not too high under normal conditions, but 260°F seems high with only 110 psig discharge pressure.

Are the compressors fully loaded? At part load the discharge temperature may creep up a bit.

For the oil temperature of 140-142°F, this is high for the operating conditions you are running. Either the oil cooler is not getting enough water or the oil cooler may be partially plugged up with dirt.

Joshieboy
09-01-2008, 10:31 PM
the system used to run at 110 psi discharge at 180-190 F, but it has always seemed to have high oil temps, we have cleaned out the oil heat-exchanger and were pushing plenty of water through it, i'm just wondering could the water flow be to fast and not absorbing that heat?

US Iceman
09-01-2008, 11:56 PM
It could be the water-cooled jackets have a lot of scale which causes the water flow to slow down. That would increase the oil temperature if the water supply is in series with the oil cooler and jackets. The water flow is typically though the oil cooler first and then the heads. If the heads scale up, the water flow could be reduced.

Core4 Guy
17-02-2008, 07:26 PM
I've read this whole post and something seams wrong, which you know. The facility has multiple compressors on a common suction. All the conditions would then dictate to be some what the same. Yet, the compressor is either over compressing or the dischage gas is bypassing into the suction and recompressing.

I ran this system on a Ph chart to see what the discharge temp range thearetically would be. I came up with no less than 170f at 50 psia and 124 psia.

I dont think there's much difference between the 440 and 450XL machines (except that they took off all the sharp edges inside, my fingers thank them). Everyone else came up with great suggestions. I would look at two things. Compression and Inefficiency creates high dischage temps. I would look for a true Crank Case suction presure vs Discharge Preasure and make sure the gauges calibrated and are not before (suction) and after (discharge) of any valves. I think these machines are suction unloading so this really would only increase the cyclinder temp not the dischage temp. I would also shut down the machine and isolate the suction to see if the d valves hold.

Also another trick I would do is get a IR temp meter, turn off the water to the heads (temporally) and check the top and sides of the cyclinders any cyclinder that is loaded will be doing work thus warmer head, any cyclinder with bad discharge valves will be really hot, any suction valves bad will be warmer on the casing wall, any unloaded cyclinder will be the same as the bad suction valve. Play with the unloaders and watch them work with temperature. Get to know your machines, love your machines.:eek:

The reason I would check the pressures is because I once had a lunch bag located before the isolation valve on the suction side of a machine causing a pressure drop into the crankcase. I failed to notice the issue on start up and had high dischage temp issues. What a pain to repair. Say thanks to the welders...

Rick

Josip
17-02-2008, 09:37 PM
Hi, Core4 Guy :)


...................The reason I would check the pressures is because I once had a lunch bag located before the isolation valve on the suction side of a machine causing a pressure drop into the crankcase. I failed to notice the issue on start up and had high dischage temp issues. What a pain to repair. Say thanks to the welders...
Rick

...seems a perfect design:eek:, unbelievable but possible.....or maybe something went wrong during pipe installation;)

Best regards, Josip :)

Core4 Guy
17-02-2008, 09:54 PM
Did my IR temp probe pass you by Josip? Really, check the head temps with the water cooling off. You can see what cyclinder is loaded and what one isn't. Mark your heads with the cyclinder number and compare it to a simular machine on your common suction. You can't get around physics. The heat of compression is very constant on machines check each head. You will see two pistons per head with an IR temp meter. Also check you seal temps often the will tell you alot. Trending temps on a by- annual basis will help with rebuild times.

Josip
17-02-2008, 10:41 PM
Hi, Core4 Guy :)


Did my IR temp probe pass you by Josip? Really, check the head temps with the water cooling off. You can see what cyclinder is loaded and what one isn't. Mark your heads with the cyclinder number and compare it to a simular machine on your common suction. You can't get around physics. The heat of compression is very constant on machines check each head. You will see two pistons per head with an IR temp meter. Also check you seal temps often the will tell you alot. Trending temps on a by- annual basis will help with rebuild times.

.... :confused: no, I us IR instruments too.....but, for broken discharge valves no need to have IR temperature meter...you can feel that by hand even with cooling water running....it is sometimes a problem to check suction valves when cylinders are within case (not extended out) but then we have some other marks showing problems with suction valves...compressor works continuously....to low compressor capacity...excessive suction pressure...abnormal noise from compressor...

....also we can check the state (of two in parallel working compressors) sometimes only by comparing power consumption...

....my comment was regarding good installation of start up suction filter bag...

...generally I agree with your troubleshooting methods;)


Best regards, Josip :)

Core4 Guy
17-02-2008, 11:12 PM
Josip, I would say this to my boys. Then why do you have what seems to be an answerable problem? High discharge superheat.

I am new to this and please don't think I am being anything but inquisitive. I love what I do and don't mind in the least, being wrong.

Somethings have answers, but they must be broken down to the simplist form. Is one cyclinder creating a higher compression ration than another. Does one cyclinder have a higher incoming superheat than another. Do they all? You don't have to have a bad discharge valve to have a higher discharge temperatures. But, you do have to have a higher compression ratio (system problem or a compressor problem) or an inefficient cyclinder (recompression or suction leakage).

We are alot alike, we are the same age, we have the same duties, and we care enough to learn and ask questions.

I don't have the answer with the exception that if there is a difference between the original 450 suction and discharge valve volumns as compared to the 440 valve volumns. If the 440 Valve plate can't accomadate the higher volumns of the 450 stroke it will create a higher discharge temp... Thus a higher internal compression ratio, thus higher DSH.

Would you like me to call Wayne Weber who used to head of engineering at Vilter. I can guarentee there is a solution to the problem.

NH3LVR
17-02-2008, 11:32 PM
Second day on the forum, already smarter than the Mods.

US Iceman
17-02-2008, 11:40 PM
Would you like me to call Wayne Weber who used to head of engineering at Vilter. I can guarentee there is a solution to the problem.


I don't think that will do any good as we are having trouble getting good data with which to troubleshoot this problem.

Josip was not the one who started this thread, he is only trying to help the original poster. Who, unfortunately has not been visiting his thread he started.:(

If we had better information and a line of communication with the original poster we can get through this, no problem.

BTW, I used to work for Wayne and I'm sure he has better things to do than troubleshoot fickle compressors.;)

US Iceman
17-02-2008, 11:41 PM
Second day on the forum, already smarter than the Mods.


:D:D

Now play nice!

Core4 Guy
17-02-2008, 11:51 PM
Second day on the forum, already smarter than the Mods.

NH3LVR,

As I said I am new to the site, I am young, and I love what I do and do what I love. I just thought I'd offer a different view.

I really came to this site to see what other people think about energy usage. I hope you know I'm not as smart as what you call the Mods. I'm from CA and I'm young as you can tell. Some times I think before I type. I just get excited by people that care... (I can see that I'm a short timer here!)

US Iceman,

Do you also know Fred Heidrick?

US Iceman
18-02-2008, 12:00 AM
Yep, he and I worked on the Vilter software programs for many years. We are suposed to get together for dinner in the next few days.

How did you come to know Fred?

Core4 Guy
18-02-2008, 12:14 AM
Tell John & Fred I said hi... We are partners together forever in enGEN Systems (know matter how long it takes). An organic rankin cycle system. A heat driven refrigeration system... Waste heat can solve processors energy problems.

Tell Fred to get off the phone and is he still "drinking" Spiced Rum?

You will find out all about me from Fred. I really love the "stinky" stuff and have grown up in it.

I also have r-22 systems running far more efficiently than NH3 system. I look for cooling industries that need energy efficiency and right now it's data centers...Have you ever seen a suction pressures higher than discharge pressures, in a running system? Ammonia or Halocarbons, Thermosyphon is the answer.

US Iceman
18-02-2008, 12:23 AM
Have you ever seen a suction pressures higher than discharge pressures, in a running system?


Yeah, it's an expander.



Thermosyphon is the answer.


You're preaching to the choir.:D I have used these in some weird applications. They either work or don't work. Piping and installation is everything!;)

NH3LVR
18-02-2008, 12:26 AM
:D:D

Now play nice!
I am allways nice. (That could have been taken as a jab at the Mods):D

US Iceman
18-02-2008, 12:37 AM
No problem. I hope I have better luck with that comment than the one I made about giving away secrets.:rolleyes:

Core4 Guy
18-02-2008, 12:45 AM
Yeah, it's an expander.



You're preaching to the choir.:D I have used these in some weird applications. They either work or don't work. Piping and installation is everything!;)


Who do you think started the expander talk 10 years ago with Vilter...

Core4 Guy
18-02-2008, 12:55 AM
No problem. I hope I have better luck with that comment than the one I made about giving away secrets.:rolleyes:


Secrets, Lets go back to the original post 450XL.. I don't care what the systems doing as long as the two compressors are doing different things. Discharge superheat is physics and inefficiency. There must be a difference between the two. If I have to say, "period". One machine can't produce a massively different discharge than another unless there is a problem in that machine. The only way to figure it out is to "figure it OUT."

As far as secrets go I really don't like giving them away, "ones we can sell" but be serious.

Josip
18-02-2008, 01:10 AM
Hi, Core4 Guy :)


........Then why do you have what seems to be an answerable problem? High discharge superheat.

I must admit I do not know Vilter piston compressors at all...but, compressor is compressor and pistons are pistons 4, 6, 8, 12 or 16 within one case...and refrigeration process is the same.....speaking about high discharge temp....could be a lot of reasons....some of them are here...

-compressor safety valve leaky-or open bypass valve
-discharge valve/s leaky or defective
-filter in liquid line is clogged
-excessive load on plant
-expansion valve produces high SH
-expansion valve sensor misplaced
-condenser needs cleaning
-refrigerant vapour in liquid line
-refrigerant charge insufficient
-insufficient coolant/air to condenser
-temp of coolant/air to high
-expansion valve lost charge
-restricted supply of refrigerant
-external pressure equalization on expansion valve closed
-water valve closed
-expansion valve partially clogged-wax, ice, dirty..
-non condensable gases in condenser

--maybe I forget something....




I am new to this and please don't think I am being anything but inquisitive. I love what I do and don't mind in the least, being wrong.

I love also what I do and I can be wrong either;), especially when trying to give a good answer within insufficient info....but, that is not a problem...we are here trying to help each other and maybe to learn something what is good and new:)


Best regards, Josip :)

Josip
18-02-2008, 01:13 AM
Hi, NH3LVR :)


I am allways nice. (That could have been taken as a jab at the Mods):D

Yes, you are always nice.:) (A real gentleman)

Best regards, Josip :)

Core4 Guy
18-02-2008, 01:28 AM
Josip,

First off, if you say you have two machine operating the same load suction and discharge (basically next two each other and water cooled), eliminate the system problems and concentrait on the machine issues... this is getting good. The water cooling is not designed to change discharge temp it's only designed to change head (for oil breakdown) and oil temp. The discharge temp issue of a individual machine is not a function of anything but the machine on a common system. If you trend everything (yes the walls of the compressor exterior cyclinder) you will see something.

This all got way out of line and I'm sorry of ego's were bruised. I love this "Forumn" after one day but I can see that I might have to watch what I say and how I say it. I really only wanted to learn how much money places Croatia were paying for energy, water, and sewer... Your guy's can really ball, go Warriors!

Rick

Rick

NH3LVR
18-02-2008, 02:12 AM
I can think of a bunch of people on this forum that could troubleshoot this problem in short order. It is a shame that the original poster seems absent.
I used to love working on these sort of problems. In and out. If it was not for these kind of problems the boss would have sent the younger (and cheaper) guy.
But now I drive a desk. But it is interesting dealing with the refrigeration contractor who services our plant. When they throw out terms like "Superheat" and "Pressure Drop" I fail to fall to the floor and worship at their altar.

US Iceman
18-02-2008, 02:37 AM
The only way to figure it out is to "figure it OUT."


It might be worthwhile noting that some of the members on this forum have more experience than you are years old. Now don't get excited about this. This thread has been around for awhile and the original poster lost interest I guess. Some threads tend to go dormant.

It's OK to renew the thread with new comments, but it's not really necessary to address the moderators or other RE members as uninformed.

After you are here for a while you will begin to see how difficult it can be for others to understand an American sense of humor versus someone else's.

Most of the members here are patient enough to translate the posts into their native language and sometimes the "full effect" does not come across. Likewise enthusiasm is hard to present in a written post.

This is not about bruised egos, it's about getting along with others who may interpret the messages in different ways.



As far as secrets go I really don't like giving them away, "ones we can sell" but be serious.


This comment was in reference to another thread where I made a slightly sarcastic comment about telling secrets on troubleshooting liquid overfeed systems. Both times this was meant in jest. We all try to help one another here and sometimes the humor gets taken literally or in some other context.

In Josips reply he touched on an area we frequently have problems with. People want answers with very little data for us to analyze.

Here's an example: My discharge pressure is too high, what can be the problem?:confused:

We see this a lot. Then when members or moderators (mods for short) try asking for information and data the poster sometimes stop replying or loose interest.

This thread is an excellent example. You can't analyze anything with only several pieces of information. More input is always nice to have though and opinions are welcome.

US Iceman
18-02-2008, 02:43 AM
But it is interesting dealing with the refrigeration contractor who services our plant. When they throw out terms like "Superheat" and "Pressure Drop" I fail to fall to the floor and worship at their altar.


:D:D:D... that's just too funny!

Oh I bet they love you! People like to throw around technical terms like a bull passes **** (you know;))

It's more fun waiting for them to overload their backsides and then ask them a subtle question. It does not take too long to sort out the good ones from the less desirable ones.

Core4 Guy
18-02-2008, 02:50 AM
Good luck guys....

chilldis
29-12-2008, 03:14 AM
I have read this entire epic of a disfunctional 458XL. try this USE PARTS FOR A 458XL ON A 458XL. replace the valve plates and springs, check the safety springs for wear or deformation, and replace the safety relief valve, clean the suction strainers and confirm proper water flow through the oil cooler and the heads. make sure all the parts are clean and assemble the unit by the book. after startup make sure all banks are loaded. also replace the discharge thermometer and pressure gauges. your issue should be resolved if factory rebuild procedures are followed step by step.

Me2Mike
17-01-2009, 12:19 AM
I can remember coming into the engine room one morning anf finding my Vilter 350L (R-22) looking like a flame thrower was parked in front of it. The blue paint was more like a dark brown. The unit ran unloaded after a low press cut out failure. We added a hi temp manual reset cut out and placed the bulb on the discharge line. and gave the unit a freash coat of Vilter Blue.........

Joshieboy
09-06-2009, 12:54 AM
Hi people, sorry I haven't been checking my thread but I had to throw my hands in the air and call in the pro's to fix it as I am new to this. It turns out the problem was a improper head gasket allowing discharge gas into the crankcase. Once again sorry for not checking back waaay sooner all your help was appreciated.

Joshieboy

US Iceman
09-06-2009, 01:28 AM
How did you get an improper head gasket?

Any hot gas recirculation will cause high discharge temperatures. It is almost the same problem as bad discharge valves. The gas gets compressed once, leaks back into the cylinder, gets compressed again and the temperature goes way up.

Joshieboy
09-06-2009, 01:36 AM
they put on a waterjacket gasket instead of a gasket to block off the unloader passage, which this was the bank with no unloader so right back in the crankcase it went! I guess thats what I get for trusting the previous tech that worked on it.

US Iceman
09-06-2009, 02:43 AM
they put on a waterjacket gasket instead of a gasket to block off the unloader passage, which this was the bank with no unloader so right back in the crankcase it went! I guess thats what I get for trusting the previous tech that worked on it.

Well that would do it. Same thing as the internal relief valve leaking (although maybe not that bad!).