Smardt chiller help

[Righttemp]

Just installed our first air cooled Smardt chiller and need some help. We installed
it but a factory trained contractor started it up. On start up compressor runs
for a minute and then trips, their saying exv problems. Factory is sending new evx. Has anyone have any problems with these chillers or have any manuals.
Building has been down since friday. Any help will do thanks

[hands]

We just installed one for one of my customers about a month ago, other than a leak in the condenser, there have been no problems.

[chiller rob]

first need to ohm the windings and see if the exv is actually bad... i think it 38 w/w

yes there have been some control problems... some times it is the level sensor that drives the exv...

what we have been seeing is the valve can get out of time... the only time it has a chance to calibrate is when the unit shuts down... this can really be a problem when the machine is on process and does not shut down at all...

having a dc bipolar stepper motor driver (sporlan sma-12) can be a big help...

if the kiltech wont control, you may try moving the exv to your lead compressor and let it control off the one of the drivers on the compressor i/o...

set the super heat at 0 and let it go... you may need to adjust the alarm and fault limits to help stay on line...

you always have the option of setting the min positon on the valve and working it a little to match your base load...

with any adjustments look at the compressor map and make sure you are not riding the surge or the choke line...

good luck...

[Righttemp]

Thanks Rob for your reply. I tried suggesting the EXV be controlled by the turbocore since there is only one compressor. The startup guys said you can't do that. A new EVX was installed. When they started up the chiller the IGV was not opening and found that there was a loose connection. Now the chiller runs but trips on low pressure. The 90 ton chiller was charged to 550lbs. Any other suggestions.

[Airmechanical]

Thanks Rob for your reply. I tried suggesting the EXV be controlled by the turbocore since there is only one compressor. The startup guys said you can't do that. A new EVX was installed. When they started up the chiller the IGV was not opening and found that there was a loose connection. Now the chiller runs but trips on low pressure. The 90 ton chiller was charged to 550lbs. Any other suggestions.

just thinking out loud here!

depending on how quick it goes out on low pressure

sounds to me like the delay for the low pressure safety is not giving the stepper enough time to open!



.

[chiller rob]

you may want to look at the temp control set up on the kiltech... start with a prop band at 20 untill you get things calmed down...

you may be to aggressive and the modbus demand is increasing but the compressor may not load due to it being on the surge/ choke line that i mentioned before... once the compressor comes off the line it may be racing to get to setpoint and tripping on suction...

when going thru commishioning always really look at the alarm and fault settings on the kiltech and the compresssor...

most times i set up the controls so the compressor runs inside the kiltech control envelope for example 134a

kiltech Hp fault set 250 (for example air cooled application)
kiltech Hp alarm set 200 (kiltech will hold demand if 5% of alarm value is reached)
t-cor hp fault set 250
t-cor Hp alarm set 190

what this does is let the alarm limit the compressor before you get to your trip point and keeps the unit on line... use these alarms settings to your advantage...

t-cor Lp alarm set 31 psig
kiltech Lp alarm set 30 psig
t-cor Lp fault set 28
Kiltech Lp fault set 28

this is for 44 deg chilled water application

Personnally i dont have any aircooled equipment but alot of water cooled...

and yes the driver on the kiltech is the same as the driver on the compressor i/o

you should be able to run sporlan, danfoss, powerpax exv's...

550 lbs of refrigerant sounds like alot for 90 tons...

listen to the compressor, during a low pressure condition it will speed up to stay on line... further causing low pressure...

lastly leak test the unit on a regular basis... not having oil in the system makes leaks hard to spot and we as techs are not used to that...

the liquid float assys, compressor press/ temp transducer o-rings have had some issues...

good luck...

[JacksonBall]

Hi gents,

I work for Smardt as Dir for Business Development. I handle the reps and contractor network and know about most installations. If you are having an issue, you can contact patrick@smardt.com or michelle@smardt.com.

Here is your missing IOM:

Smardt Air Cooled IOM Manual - Rev 3
http://interactions.smardt.com/Docs/...ooled_Rev3.pdf

Let us know how we can help.

Jackson