Reply to Thread

Okan after getting the conversion to psi and degree F thanks to screwit there are a few procedures that u need to do when trouble shooting and start with.

Step 1 u need the design sheet
Step2. Need to check if u have the proper water temps ,and GPM at the inlet of the evap and cond,if u do not have the proper temps or GPM that needs to be the first thing to correct ,if u start with anything else u will be chasing after ur tail (that is why the trane tech told to start with good water temps at the cond)
with the water temps u supplied there seems to be a indication that either u have to much GPM on the cond or not enough GPM on the evap
The reason I say that is because rule of thumb u should always have about the same water td on evap and cond

The high side pressure should be around 90 to 100 degree F cond saturation, the way I understood ur valve is controlled by only freon differential it really does not care how much the high side pressure is at,like mentioned by others u need a valve and control the proper water temps at the inlet of the cond

The other thing of what u have described this chiller never seems to run at 100 percent is it over sized does it do lots of stops and starts this does not help for the oil return and the fact that there could be times that entering water at cond could actual be colder then entering water at evaporated is also not good and does the pump for the cond come on right before the chiller comes on cond pump should only come on when the chiller has a demand and off when no demand

There could be a chance something else is wrong with the chiller like the gas pump but need to start with good water temp and GPM at cond and evap

I can't tell you how thrilled I am to see free technical info for a guest member and engineering bulletins to boot.

Use your head people.

How about one of you drive over and fix his chiller for free?

I've got a system like yours with three RTHDs running on direct well water so entering temp is around 52 -55 all the time. Condenser reg valve needs to be set up properly through Techview and system should run fine. Minimum and max voltages to the valve will need to be set and you will want some condenser pre-run time of a minute or so. Trane should know how to set this up and should do it for you.

Originally Posted by Healey Nut

I sure hope not !!!!
This chiller is two months old , it cost a lot of money to buy and install . You need to call Trane and be sure that the tech that you get is familiar with the RTHD and how to check and set up the condenser water control properly
The tech must also know how to perform oil recovery and get the chiller going WITHOUT ADDING OIL !!!!!!! Adding oil will make only the situation worse .
There is also a specific test to check if the gas pump is working correctly , has this test been performed , just because the solenoids are sequencing doesnt mean its working .

It sounds to me like your trying to be cheap and not involve the services of a qualified service tech ..if this is the case then you better place the order now for a new compressor now ..

I ran into a similar situation where the chiller tripped on loss of oil and the tech added oil to get it back online.....which made it worse....which caused the tech to add more oil.....which made even more worse....and so on.....until the chiller wouldn't run at all. the customer finally called Trane. When I got there, I removed 5 gallons of oil to get the level where it was supposed to be. Which took a while cause I could only remove a gallon at a time, and run it again to return the oil to the sump. And so on. The nameplate oil charge was 5 gallons, so they had double the charge..

That's why I asked if anybody added oil.

If there isn't any oil on the floor don't add any to the chiller! If you do add it make sure you take it back out.

I assume the river water stays at a fairly constant temperature. If the chiller had tripped off for any length of time due to cold condenser water, the chilled water will have probably gotten warmer than condenser water. If this is the case the only way you're going to get this thing running is by jumping out the condenser water flow switch, and closing the condenser water valve until you get a good system differential pressure.

53.6 F(12 C) condenser water is way way way too cold for this machine. Hell it's too cold for a centrifugal. Even with a condenser water modulating valve I think it's too cold. But if you set up the modulating valve properly it may work, as long as the chilled water temp doesn't get higher than your condenser water temp.

Ideally you would want a condenser water bypass to recirculate the leaving condenser water back into the inlet side. This gets the water nice and toasty, the way screw chillers like it.

And what % of glycol are you running and what type,, ethylene or ....please dont say propylene !!!!!!!!

And check your flows as by the Delta T values heat in (Evap 80% of Design Delta) does not balance with heat out (Cond 20% of Design Delta), I suspect you are are way down on evap flow rate which could also be the cause of your oil loss. If you post your discharge s/heat in the log readings this may help determine.

Originally Posted by R123

Did anybody add oil to the system as a result of a loss of oil trip????

I sure hope not !!!!
This chiller is two months old , it cost a lot of money to buy and install . You need to call Trane and be sure that the tech that you get is familiar with the RTHD and how to check and set up the condenser water control properly
The tech must also know how to perform oil recovery and get the chiller going WITHOUT ADDING OIL !!!!!!! Adding oil will make only the situation worse .
There is also a specific test to check if the gas pump is working correctly , has this test been performed , just because the solenoids are sequencing doesnt mean its working .

It sounds to me like your trying to be cheap and not involve the services of a qualified service tech ..if this is the case then you better place the order now for a new compressor now ..

Did anybody add oil to the system as a result of a loss of oil trip????

Dear Healey Nut, I dont say our filtretion is the best,my first problem is to learn whether I should warm the condenser water or not and to learn if the main reason of oill los is another thing.If you think the problem is filtration then OK.

I thought the regulating valve is OK when the head pressure is lower than limits.Do you think that it should reduce the water flow continiusly?

Originally Posted by R123

Why don't you convert all the temps to F and pressures to PSI for the metrically challenged.

Just google for a kpa to psi converter .

That is for a stock unit with copper tubes and steel shells. I would hope that the chiller was ordered for marine conditions CuNi or titanium. This is what usually tips off the sales guy that this is a special chiller. Just because you are using raw water, the manufacturer cannot wash his hands of the chiller unless the customer did not specify thier intentions. Raw water does not cause oil loss; poor operation and maintenance cause oil loss and breakdowns.
Ships don't have cooling towers, I promise you that; and somehow they still work, from the equator to the poles.

Define filtration , A screen with 6" holes in it to remove large fish , dead bodies , skunks, beavers and large fish is a filter and could be described as good filtration....why ...because it works to remove those objects that are too big to pass through it .
When I said water treatment I was meaning chemical treatment to reduce the corrosive qualities and biological nasties , if present in the water being used .

Your condenser water is to cold and just because the "Trane tech" installed the card doesnt mean he set the parameters up properly ??
I have also posted the warning right out of the IOM about untreated water .
This is the page that no one ever reads ...


CAUTION
Proper Water Treatment!
The use of untreated or improperly treated water in a RTHD may
result in scaling, erosion, corrosion, algae or slime. It is
recommended that the services of a qualified water treatment
specialist be engaged to determine what water treatment, if any,
is required. The Trane Company assumes no responsibility for
equipment failures which result from untreated or improperly
treated water, or saline or brackish water.
Using untreated or improperly treated water in these units may result in inefficient
operation and possible tube damage. Consult a qualified water treatment
specialist to determine whether treatment is needed.

And converted for the metrically challenged......

We have Trane RTHD in our plant which is installed 2 months ago. We are having oil loss at compressor problem. We are using directly river water in condenser and we have a variable cooling need conditions. The river water temperature is 11-13 C (52-55.4 F) in this winter. Although head pressure,oil pressure,refrigerant luquid level is OK we sometimes face oil loss problem

Evap entering water 1.2C (34.2 F)
Evap leaving temp -2.8C (27 F)
Condenser entering water 12C (53.6 F)
Condenser leaving water 13C (55.4 F)

Evap refrigerant pressure 136 (20 psig)
Condenser ref. pressure 400 (58 psig)

Evap app. temp : 3-4 C (3.2 to 7.2 F)
Condenser app. temp: 1-2C (1.8 to 3.6 F)
Load: %42

Chiller works in above conditions about 75-80 minutes.Then as we dont have cooling need so much it goes to;
Evap entering water -1.7C (29 F)
Evap leaving temp -3C (26.6 F)
Condenser entering water 12C (53.6 F)
Condenser leaving water 12.5C (54.5 F)

Evap refrigerant pressure 128 (18.5 psig)
Condenser ref. pressure 360 (52 psig)

Evap app. temp : 2 C (3.6 F)
Condenser app. temp: 0.8C (1.4 F)
Load: %26

We have a condenser regulating valve in the outlet of condenser and works when the head pressure is under limits(1,7 bar 24 psid)).The data sheet says;

Evap. entering temp 2 C (35.6 F)
Evap leaving temp -3 C (26.6 F)

Condenser ent. temp 25 C (77 F)
Condenser leaving temp 30 C (86 F)

But it also says you can use cold water minimum 12.5C (54.5 F) and as far as I know cold water means lower power suction.

Your entering condenser water is below minimum (refer to the bulletin on CW control posted in the previous post) but you also have an issue with your flows as you have 4K delta on youe evap (design 5K) and only 1K delta on your condenser (design 5 K). I suspect you are way down on evap flow by your percentage RLA of 42% and no that ain't equipment waranty.

Actual
Evap entering water 1.2C
Evap leaving temp -2.8C
Condenser entering water 12C
Condenser leaving water 13C

Design
Evap. entering temp 2 C
Evap leaving temp -3 C
Condenser ent. temp 25 C
Condenser leaving temp 30 C

I would like to thank everyone for help.A trane tech started up the unit and told the limits.He just adviced to warm the water but said there should be no problem with this condenser water.They installad an electronic card which controls the regulating valve but it only works when system differantial pressure is under the limits otherwise it is full open.We have been using direct river water since years fot the oher chillers and also heat exchanger and had no problem so far as we have a good filtration.

I already called the Trane tech.When start up he did not say you should warm the water but now says you should warm the water.When I ask him that all the conditions are ok,gas pump working-system differantial pressure is not under limits-the check valve is ok(We hope so because the machine is new) what the reason is for oil loss problem I could not receive a good answer he just said warm the water and if you still have this problem we will come again and check the other things.But I dont want to spend money for it before I am sure that the problem is cold condenser water.

Thanks to everyone who wants to help and also special thanks to PAT A/C friend.I will convert the units tomorrow and write here

Originally Posted by spinning wheel

I am sure that a Trane service person started the chiller and performed a commisioning report....This is a Trane problem as the sales guy sold them this chiller and they knew where it was going...."

not necessarily. i have run into many jobs where i spoke with the salesman and he did not know where it was going or what it is going to do. often times (when they are lucky) they get a decent set of conditions. when they aren't, they get a set of conditions like: 75 tons of cooling, no heat, economizer...need it in 4 weeks.

that is the truth...it may be wrong to do it that way...but this is how it is done many times. as for a Trane service tech doing the start up...doesn't always happen and it is not required by trane for this model in order to get the warranty.

I am sure that a Trane service person started the chiller and performed a commisioning report. During this time the start up tech should have explained the unit's limitations if any and configured the condenser water flow valve, if it was supplied by the Trane branch. Anyone who works on ships or chemical plants by a water source will have experienced this before. Not the end of the world, just some problems to contend with. This is a Trane problem as the sales guy sold them this chiller and they knew where it was going. The only problem is who pays for it "Trane warranty department or the sale department."

Is the chiller controlling the cond water reg valve or is this external control, the chiller does not need to be controlled to have 25 Deg C ECWT provided the refrigerant differential pressure is being made. The chiller can control this directly by throttling the CLWT. I also agree with Graham, Healay Nut - if your running direct river water for the condenser you are going to run into serious issues sooner than later with the heat exchanger. Not sure why this is a product warranty issue, sounds like installation issues to me on information available

This is the problem with us in America. The entire word uses metric units, we even signed an agreement to start converting to it. However, we are cowboys and refuse to learn new ways. So to the rest of the world, if you want an Americans help, convert to imperial units please. We are to lazy to learn it!
Thank You, for understanding our limitations.