Chilled water flow Fault (Trane Chiller)

Hello everyone,
i'm new here and this is my first post.
i have a Trane Chiller (RTAD 085-180 (50Hz)), which gives a fault of : " Chilled water flow (Ent Wtr Temp) "
" Latched Fault - Manual Reset Required"

at the diagnostic manual, it says that the description of this fault is one of these:
1- Entering Water Temperature < leaving WT
2- No water flow
3- Defective EVP sensor

it also shows that the temperature of inlet Water in lower that the exit water!
i tried to check the evaporator temperature sensors; the exiting water temperature sensor gives the right reading, but the entering water temperature sensor gives a reading of 2.4 C more (which should not be the cause that the entering water temperature is lower than the exiting water temperature).

so,, any help, suggestions or diagnosis..

forgive my weak experience and language

your help is much appreciated

You need to check the resistance of the temperature sensor against the manufacturers temp/resistance chart to see if it is faulty.

proove water flow, check flow switch makes and breaks- maybe check paddle isnt snapped- and as frank says check the sensors inlet an outlet at different temperatures to ensure it reads the correct resistance at different temps to see if the sensor is breaking down

Welcome to the forum Suhaib.

Please read the following...
The RTAD UCM-CLD Internal Water Flow Loss protection works on the principle that in the absence of chilled water flow the entering chilled water sensor (located in the tube bundle) will sense a drop in temperature in reference to the leaving chilled water sensor.
This machine manual reset diagnostic is only present when a chiller circuit is energised – chiller is enabled and to trigger the entering water must fall below the leaving chilled water temperature by 1.1 C for 56 degree Seconds.We have encountered previously a small number of installations a site-specific phenomenon where system thermal layering or pockets of colder water can cause nuisance faults on this diagnostic. After the chiller has been off for a period of time and is enabled the pump start-up will circulate the water prior to a compressor start. During this pre-start time if sufficient temperature difference is present the chiller can fault on this diagnostic.The field solution is to install an adjustable 0-5 minute 115v timer with an instantaneous & timed contact. When the chiller is enabled remotely the instantaneous timer contact closes allowing the chilled water pump to start circulating the trapped pockets of colder water. After the 5-minute period (this time may be adjusted lower to meet site specifics providing sufficient water mixing has occurred) the timed contact closes completing the remote enable circuit and starting the chiller.
Basically you need to move some water through your chiller.
Try manually running the water pump.
Then observe your Entering and Leaving water temps.
They may change for the better.
Also consider what IM and Frank have told you as their comments are just as relevant.
Grizzly

Quote:

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Originally Posted by Grizzly

Welcome to the forum Suhaib.

Please read the following...
The RTAD UCM-CLD Internal Water Flow Loss protection works on the principle that in the absence of chilled water flow the entering chilled water sensor (located in the tube bundle) will sense a drop in temperature in reference to the leaving chilled water sensor.
This machine manual reset diagnostic is only present when a chiller circuit is energised – chiller is enabled and to trigger the entering water must fall below the leaving chilled water temperature by 1.1 C for 56 degree Seconds.We have encountered previously a small number of installations a site-specific phenomenon where system thermal layering or pockets of colder water can cause nuisance faults on this diagnostic. After the chiller has been off for a period of time and is enabled the pump start-up will circulate the water prior to a compressor start. During this pre-start time if sufficient temperature difference is present the chiller can fault on this diagnostic.The field solution is to install an adjustable 0-5 minute 115v timer with an instantaneous & timed contact. When the chiller is enabled remotely the instantaneous timer contact closes allowing the chilled water pump to start circulating the trapped pockets of colder water. After the 5-minute period (this time may be adjusted lower to meet site specifics providing sufficient water mixing has occurred) the timed contact closes completing the remote enable circuit and starting the chiller.
Basically you need to move some water through your chiller.
Try manually running the water pump.
Then observe your Entering and Leaving water temps.
They may change for the better.
Also consider what IM and Frank have told you as their comments are just as relevant.
Grizzly

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Dear all,
i really appreciate your kindness,
we shut down the chiller for about 30 minutes and manually operated the circulating pump, then when we run the chiller it worked well.

for entering water temperature sensor it still gives a reading of 2.4 C more than the real temperature, what is the effect?
knowing the problem root cause is very important to make sure that it would not repeat,,, any suggestions?
i need to know also if it is working properly, what signs i can read to evaluate?

Hello Suhaib.
Good to know you are getting somewhere.
Check out the attached.
As the Voltage read goes down the Temperature goes up!
Therefore cleaning the sensor contacts / connections may help the error to reduce.
Good luck Grizzly.

Quote:

---

Originally Posted by Suhaib

Dear all,
i really appreciate your kindness,
we shut down the chiller for about 30 minutes and manually operated the circulating pump, then when we run the chiller it worked well.

for entering water temperature sensor it still gives a reading of 2.4 C more than the real temperature, what is the effect?
knowing the problem root cause is very important to make sure that it would not repeat,,, any suggestions?
i need to know also if it is working properly, what signs i can read to evaluate?

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Hello Grizzly,

the problem was repeated again after my last reply, we replaced the sensors on the evaporator, it looks like that both are giving wrong reading, and the readings of the sensors differ from water to water& Glycol mixture.

i would like to thank you, Frank and install monkey for helping in this problem ;)