Parker LL-S level control help

[Mojjee]

Hello again, I believe the level control on my evap is sticking and not cutting out at high level. Flooded evap twice now. Is there any fix for these things or will I have to buy new?

Thanks, Mojjee

[josef]

Hi, you must completely remove the oil

[RANGER1]

Agree with josef , its usually oil every time causing sluggish operation . Need to drain control column .
Also float switch can also cause irratic operation if contacts are corroded etc

[RANGER1]

And yes you can buy the switch by itself .

[Mojjee]

You are saying that I could have excess oil in the float assy itself ?

[josef]

I assume that the level control using the older equipment (Frick 9x9), will be found for many years a little oil and it will cause failure.
Another thing is how to write RANGER 1, oxidized contacts.
Parker level have no many other faults-reliable regulation

[josef]

http://www.herl.de/herl/english/start_e.htm

[RANGER1]

Not necessarily float itself but lower part of control column .
The oil can accumulate at lowest point or pocket if not drained .
This can cause float level to have delay to open and close . You may have this problem or faulty switch assy .

[josef]

Yes, I agree RANGER 1

[US Iceman]

Oil draining of flooded evaporators should occur on a regular basis. If the oil level increases in the surge drum, the oil is also accumulating in the float column.

Have you personally ever drained oil before? If not, there should be a written procedure on how to do this or have a more experienced person show you how to do this.

More ammonia leaks take place when someone new drains the oil!

[Mojjee]

There is an oil pot under the evap that is double valved, the last one being spring loaded. I have drained oil from it several times. There is a mark for where the frost line should be-roughly half the height of the pot. I was told to drain the oil from the sightglass peridocally . This valve is spring loaded also. I am not aware of any other places on the vessel to drain from. I totally agree with the leak philosophy. Its obvious that i'm the new guy tending to this equipment and I will accept any and all advice. Most of the equipment is about 40+ years old ,9x9,7x7, the receiver and evap. The Mycom was the newest addition about 10 yrs ago. I am replacing a guy who left rather unexpectedly so I am on a search for wisdom. I really appreciate the help.

[josef]

40 years? and works :eek:

[RANGER1]

Mojje ,
You can also check hhigh level switch assy operation .
There is a screw to undo ( if not already undone ) at base of switch itself , so you can remove switch .
see josef's parker drawing about item 3 area for screw position
Currently it should be sitting all the way down so screw would line up with groove on float assy .
If not sometimes switch will not activate at all .
Lift float switch assy off and high level should activate straight away if no time delay. If has time delay would think it should be 10 seconds or less .
Also if it reaches high level is it this float causing problem or another leaking part like solonoid valve or orifice ?
You may have a few things to look at .

[josef]

Good comment Ranger1.:)
Mojjee, please watch your step on the pressure

[US Iceman]

If the float switch is as old as the rest of the equipment the float could have a hole in it. This would allow it to fill up with liquid and sink, which would never let the switch trip on high level.

If this happens more than once I might start to get suspicious of the float itself.

Mojjee, I did not mean to criticize you. Some of the things you mentioned seem to be from a new kid on the block. That's not bad and was not intended that way.

I don't want to see anyone get hurt.;)

[Mojjee]

Thanks, Iceman. I didn't take it offensively . I know what you mean about folks getting hurt. The level control is not the origional it was replaced about 5-6 yrs ago. Initially I thought the problem may have been caused from the float not being insulated so I had it insulated. That really didn't seem to make it any better. I will get the oil drained and check the switch on the level control. Thanks,Mojjee

[Sandro Baptista]

Hello again, I believe the level control on my evap is sticking and not cutting out at high level. Flooded evap twice now. Is there any fix for these things or will I have to buy new?

Thanks, Mojjee

Hi Mojjee,

This is an R717 plant, right?

Has the working float control with frost formation at outside. If not so the high float shouldn't have oil, and so we can blame the oil.

Do you know if the the surge drum/liquid separator accumulator has been flooded in periods where there less cooling demands. If is this the situation it's very probably the bad tight of the solenoid which is letting a low flow of refrigerant escaping for the surge drum from the HP and so if there isn't sufficient consumption of R717 and then it be flooded.

If this happens during the periods where the plant doesn't need to work try to close stop valve that feed the surge drum.

Give us a feed back when all be okay.

Regards.

[Mojjee]

The working float had frost around the body. I removed the ice and had it insulated. Thanks

[US Iceman]

The working float had frost around the body.


If the float had frost on it this indicates two things:


The liquid level was up to the float switch which tells you,
The oil level was sufficiently below the float switch.

[Sandro Baptista]

Hi Mojjee,

If not so the high float shouldn't have oil, and so we can blame the oil.

Regards.

Just a correction I hope you have understand that I
meant to say
"If not so the high float shouldn't have oil, and so we can't blame the oil."

[Mojjee]

I have ordered a new switch minus the float mechanism. Spent some time today draining oil from the evap sightglass. I have a small cylinder attached to the vessel that has a small round sightglass on it would this be the surge tank ? Looking in the glass I can't really see anything due to brown crud on the inside. Would this have any bearing on my level control issue? Thanks, Mojjee

[US Iceman]

I have a small cylinder attached to the vessel that has a small round sightglass on it would this be the surge tank ?


Is it an oil pot underneath the surge drum, or are you talking about the float column the float switch is attached to?

[Mojjee]

It is a small tank with a round sightglass that is centered on the evaporator. As if the sightglass would show you the center of the level in the evap. Its not the oil pot. The oil pot is below the lowest point of the evap.

[US Iceman]

Does it look like this:
http://www.haphillips.com/products.html?pc=70&pid=4

If so, it's part of an old Phillips low side float valve that was probably installed a long time ago and left in the system.

[Mojjee]

2845

2846I'll send a pic or two.

[Mojjee]

One more
2847

[RANGER1]

Mojjee ,
I guess you are waiting for new float switch for high level switch ?
Do you know what controls or operates operating level control on this vessel ?eg . float switch + solonoid valve
phillips float valve
It appears by your photos that you have a high level float , which is meant to stop compressors to protect them .
You said high level switch ices up so you insulated it . Normally should not ice up unless liquid level is that high .
If liquid level is that high level control is not working properly as well as high level cut out switch .
Level problem would first appear when plant under low load situation .

[Sandro Baptista]

Mojjee,

When the high level is all iced up (which indicates that the surge drum if almost full of liquid) the compressors stop? the solenoid valve receive the signal comand to stop? Does the high level switch closes? Do you see the "arm" touching the rod (you can see it by the head glass of the parker? If all these is performed, then the problem is the lack of tight of the solenoid valve. As I have told you in a previous post this could be notorious when you have low or no cooling demand.

Regards

[samlee12]

Had a problem last week at a seafood plant with a Parker level float. Surge drum had filled completly with liquid. Suspected problem with float as liquid feed solenoid and strainer were new. Isolated float and removed from system liquid level was above float but switch was still energizing solenoid. Removed bottom connection and stuck long skinny screw driver in hole to push up float ball. Float ball would only rise an inch then jam up, found dent on steel rod were level switch is mounted on, causing float not to rise.Looks like somebody hit it with something.Changed out float, system now operating properly.

[sterl]

I'm not sure, I can't see all of it: but the chamber with the sight glass on it looks a whole lot like a float valve, as US Iceman indicates; and its at something like 50% vessel height. Its equalizing piping indicates that it is a Low Side Float Valve. If that the case: the circuit should have a high pressure receiver, or some other reservoir upstream....
A lot of these rinks were critically charged : which would tend to make the device a different manufacturer's High Side Float. In which case: Its level compared to that of the chiller is not consequential...but


Many rink chillers had no tubes in the top 25% of the chiller shell, which space acted as the separator...The float valve would appear to be around the 50% level whereas the High Level float switch appears to be at 75% plus of the shell height. If ithe switch's float chanber was prone to drawing frost, it obviously had some liquid refrigerant in the chamber; If its now trying to control liquid level at that height, its not surprising the Mycom pulls a little liquid over....

The LL switch shown is connected via its two side connections; this is not usually overly bothersome on a high level float switch because if everything else is working, liquid never goes there; but on an operating float switch, side connected, the lower portion of the chamber is NOT drained by the plumbing...so once oil gets there, the bottom most portion of it simply stays there. This can intermittently capture the ball itself in the puddle of cold oil....

Is the solenoid valve (S8?) in the foreground of your photos interrupting liquid delivery to the float valve? Is the float valve still functional? If the upper equalizer of the float chamber is open but the liquid level is higher than the float, the flash gas from makeup liquid is going to tend to lift liquid to the upper connection of the float switch chamber, so every time the solenoid opens, the float switch gets "flooded" from its upper connection....It that solenoid valve is the active liquid makeup, it very likely short-cycles.

Does the circuit have a high pressure liquid reservoir? Is the Float Valve active and controlling? If so, its pretty critical that you get a new glass and possibly a new frost shield for it.

[Mojjee]

There is a receiver upstream. I thought that that container with the sightglass was possibly a float. It doesn't seem to be functional nor does it have any wire going to it. Can't see thru the glass due to sludge/age. It seem that the only metering occurs thru the solenoid valve which is open when the machine is running and closed only when its not. I took some good advice and started the machine unloaded (33%) and stepped it up gradually. Evap level seemed to behave itself.