trane chiller question

[cool jag]

hi i am working on a trane chiller the alarm is chiller water flow (ent wtr temp) we have changed sensor in evap barrel (inlet & outlet) & added water to system chill water side. it still going out same alarm .any more ideas?

[BKS60]

Yep!!!!

[Tassajara]

Whats the entering and leaving water temp?

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[cool jag]

ent 62, lvg 64 why is ent lower then lvg then look out on alarm we hve read the trane manual page 5-29

[Tassajara]

This might seem like a crazy question are you sure those sensors are not reversed?

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[cool jag]

well we did that and it started to work but not sure if that was the right thing to do. i'm a new guy working on chillers but not new to hvac work just trying to stay float

[zw17]

I can tell you are very unsure about what you are doing so please, call someone who is sure about it. Do not change the sensors around.

[jayguy]

I can tell you are very unsure about what you are doing so please, call someone who is sure about it. Do not change the sensors around.

double down on that advice.

there are several things that could be happening. the sensors could be reversed although it is unlikely. you could have a bunch of crud in the bottom of the evaporator where the entering water temperature is located. you could have pushed the new entering water temperature sensor in too far. you could have very low flow. you could be missing your internal water baffles. you could have a poor system design where an existing chiller that is running and making cold water 'shocks' this chiller at start up.

get someone in there that can teach you what to look for. pick the 'wrong' solution and you could be buying a new chiller...i don't think that would keep you a float much.

[zw17]

I just was thinking about it and if you switched around the EEWT and ELWT sensors in the right way and under the right conditions (which I believe you are) you run a very real risk of freezing the barrel.

Stop what you are doing, put things back the way they were, and call for some help.

[cool jag]

this chiller has been there for five years with no problems .this chiller has no bypass on cooling tower. it seems do this on cold mornings 18 degree f

[FixItRight]

what is the model#?

[cool jag]

do not have it will get it

[servicetrane]

reviewed and water filters, or diffusers water pumps

[cool jag]

sorry but i don't follow please tell me more i'm willing to learn if your willing to teach

[always looking]

That diagnostic is usually caused by no flow through the barrel. Throttle the leaving water butterfly valve, if so equiped to see if you hear water flow. If it doesn't get really turbulant sounding, you don't have flow. Put gauges on to check for pressure drop to see if you have flow.

[cool jag]

thanks will do

[Gear-Drive Guru]

A lot of Trane screw machines have a built in freeze protection where if the entering water temperature of the evaporator is cooler than the leaving and the chiller is enabled it will fail.
In my country, if this occurs it is because the chiller, controls the pumps and the enable signal is given to the chiller. When the pumps are started the protection is enabled and if there is a cool pocket of evaporator water in the circuit and the reversed temperatures occur the unit faults. To prevent this from occurring, start the chilled water pump at least 5 minutes before the chiller is enabled. Circulating the water evens out the temperatures in the circuit and since the chiller is not enabled, the protection is not active and the fault will not occur.

[Bklyntek]

Take time to think through the problem at hand, don't rush.
Similar issue just the other day. Except w/a hi ent water temp
Fault. Techn. Is new to chiller work, chiller started w/a hot loop.
Piping not well insul. Sun baked, water at 88.7' intake, so it shut
Off. So I told him call BAS to open valve and try in 20m.
Stable at 64',go ahead &start chiller & log readings. This was
After him starting & resetting sev. Times. Explained to him what
Occurred and advised for him to repeat where necessary.

[Bklyntek]

Completely Agree with gear drive guru. Same principle :
Differing applications.

[milkyway]

This might seem like a crazy question are you sure those sensors are not reversed?

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ent and leave water sensors reversed?
they are the same sensors, dont think this would be a problem

I just was thinking about it and if you switched around the EEWT and ELWT sensors in the right way and under the right conditions (which I believe you are) you run a very real risk of freezing the barrel.

Stop what you are doing, put things back the way they were, and call for some help.

i was taught if someone ever replaces a sensor that it is best to run the wire all the way back to the board,
i am under the understanding if one cuts a sensor that it changes the resistance,
now, i ran across something the other day.,.,

was working on a RTAA1404 , going off on water temp, i changed the temp sensors in the ent and leave wells in the water lines at the machine., theses sensors tied in to the 695, come to find out i replaced the wrong one., i was supposed to change the water temp sensors on the barrol,.
question, why sensors on the cooler barrol,.(because factory mount safetys i would think) and external water temp sensors, in the water lines, more safetys?