york y cal

[thebigcheese]

looking at a york and its been a while

system 1 is alarming sensor failure

system 2 runs for about a minute ,shuts down then goes on to ar timer

is there a problem on sysem two or is that normal?

is the sensor failure a sensor fault or could it be because system has problems with refrigerant? (suspect short as there is oil around sightglass but still liquid in liquid line)

[yorkman_gr]

1) on the status display which sensor says is failing? the unit having electronic TXV?
2) After the system is shouting down what the status message says? look at the history for the last alarms
3) What is the LWT and RWT ?

[thebigcheese]

yes the unit has eevs,
when you go through the data for chiller one the saturated suction temp is reading -36, i have checked all probes that i can see with a meter and cant see a large difference in range,
which probe does it take this reading from?

[yorkman_gr]

if i remember well lets say every system having two suction sensors, one is measuring the suction temperature and the other the expansion temperature and combine that with the low pressure transducer regulating the EEV i will say that the defect sensor is the one that is monitoring the expansion temperature and you find this sensor just after your EEV under the insulation, if this sensor is out of range the microprocessor it will shut down the system because your expansion temperature have going to the freeing points, also lack of ***** in the system will cause the same effect

[yorkman_gr]

look at the AMB J5 14/9 and 14/10 just take some readings is suction sensors

[thebigcheese]

ok thanks york man, thinking i might weigh out the charge and see how short we our, will keep you updated,

out of instrest would this be your next step?

[goshen]

Hi
you could always swap sensors from one circuit to another,
weighing out your charge would be a smart thing to do!
this way you can also elimenate refrigerant shortage and low suction temp,if all else is working ok.
good luck

[yorkman_gr]

that it will be a good move but also you can take readings when the system is running like suction temperature, superheat, sub cooling, suction pressure, etc so before you going to all this recovering process you can take some readings first, and if you give the type of the chiller i will try to find the charge from each system

[al]

TBC

Scroll through oper data and note down all readings, look for any obvious wrong ones. Check the leaving water sensor first, confirm its reading with a stab in thermometer, could be the reason why system 2 is short cycling with no fault showing. Also check the water pressure drop while you're at it, many faults can be traced to poor water flow.

If you're badly stuck on site pm me for my number and i can talk to you in real time! i owe you for that lift to the airport all those years ago!!

alec

[Grizzly]

Hi Bigcheese.
You may like to change the system 1 liquid temperature sensor.
- 31 seems excessive especially as the chiller did not trip on low suction?
That is the smaller of the 2 pipes going into the evap. (Follow the liquid line back from the EEV)
It's the btm one, right hand as you look at them is system 1 and obviously the l/h is the no2 system.
I am assuming you have checked the water flow through the evaporator ?
Grizzly

[thebigcheese]

Water flow was first thing i checked as well as all the other normal things to look for check etc, should have mentioned this is on a looped system with another y cal so kinda have a bit of grace as one chiller copes with load

[Grizzly]

You seem to know what you are doing, fair enough!
Still have a hunch for the liquid temp sensor ( Read refrigerant inlet temp!)
Grizzly

[thebigcheese]

thanks for all the replys guys will keep use updated when i get back to site and fix it (being very positive here lol)

[thebigcheese]

still havnt been back 2 site, but been doing to much thinking while on other jobs

if i was to swap sensors do i need to do anything to reset reading etc. i ask this becasue when i was last on site i swapped some sensors, held some sensors etc and temperatures did not change

also is there a delay in lp switches making ie dosent read for first minute etc

[al]

Swapping sensors normally doesn't need a reset, BTW is it a plate or shell heat exchanger? There is a time delay on Lp switch but if it faults it alarms as such.

Plate heat exchangers have 3 sensors, 2 of which average so replacing one sensor may not solve the problem, on the shell exchanger there is only leaving water sensor.


alec

[thebigcheese]

Its a tube and shell, hopfully get a look at it tomorrow so will get a good poke around the system, as i only had a quick look last week

[thebigcheese]

well reclaimed the charge, 30kg short. happy days i thought,
pressures tested repaired 4 leaks all mechcanical

changed filter cores

pressure tested again over night, pulled deep vac

weighed in 55kg of the 60kg needed

switched on and bang straight into a vacuum and out on low suction, ar timer, then runs and goes
out on sensor fault

[Grizzly]

Sorry for asking stupid questions, just trying to understand your dilemma in order to help.
The 55kg was that in one system or across the 2?

Your sensor issue may be either a suction temp or pressure sensor out of range.
Use the History function to observe individual readings.
Grizzly

[thebigcheese]

55 was in one circuit, 60kg per circuit is full charge.

Dont think i have an issue with sensors as i have swapped and tested them, suspect its throwing this fault up due to low suction pressure straight away before the lp reads,

Suspect there has to be a problem with the valve not opening