Re: CIAT Chiller d6.1 alarm
Quote:
Originally Posted by
GAJ87
Hi Guys
I have a ciat chiller 'aquaciat ILZHE 130 400/3/50Hz' it is using 407c and it cools/heats a coil inside an air handler located right next to it
Being the time of year it is the chiller is now used for heating mode. Every morning the chiller is out on d6.1 alarm which is 5 HP cuts in 24hrs when in heating/building frost free mode.
Once this alarm is reser it runs fine for the day until it alarms during the night again and we reset it the following morning.
Would anyone familiar with ciat equipment have an idea of what may be causing this?
Is the fan in the AHU running during the night?
With 5 High pressure cut outs during the night but no issues during the day I would be looking if there was an interlock between the airflow being proven before the heat pump was allowed to be enabled, such as a DPS.
Re: CIAT Chiller d6.1 alarm
Hi.
Thanks for your reply. The fan does stay on all through the night in the AHU. Also the actuator controling the water flow is set with a minimum opening grade of 40%.
Today i noticed that parameter p13 defrost cycle temp was set to 143 and p14 maximum defrost temp set to 145. I know these are the default values but i thought they were a bit tight so i lowered p13 to 130.
The water outlet pipe sensor and inlet sensor has also been replaced. Also in the last few weeks this unit was pressure tested and charged with correct amount of refrigerant as a leak was found
This is a problem that happened also last winter when the ambient temp dropped
Re: CIAT Chiller d6.1 alarm
Do you have the correct water flow through the heat exchanger?
Re: CIAT Chiller d6.1 alarm
Hi. I don't know the flow rates but i know that this has been checked to be ok.
If it was to do with the flow would it not send the chiller into alarm during the day also?
It only has to be reset once in the morning and then it runs fine for the rest of the day.
Re: CIAT Chiller d6.1 alarm
Thinking logically, the high pressure fault means that at some point (during the night), it cannot reject the heat of compression.
With a water cooled condenser, the flowrate is critical. Is there some sort of 'night set back' on the machine or AHU?
As the heatpump runs without fault during the day, there must be something happening during the night that alters the heat rejection leading to high pressure and shut down.
Without knowing or seeing the site, it is difficult to pinpoint the cause from here.
Re: CIAT Chiller d6.1 alarm
Yeah i know what you're saying.
The AHU is looked after by another company and controlled by a cylon control system. We have had these guys out to verify that there is not night set back during the night but maybe something was missed when they checked.
I suppose best thing to do is to verify the flow rates again and to check that there is no night set back setting causing a problem.
I do not work with many ciat chillers so i thought maybe there is something on the chiller controls that i did not know about that i should check
Thanks for your help
Re: CIAT Chiller d6.1 alarm
Just wondering about the frost free mode on these chillers. Do you know about ciats strategy for them. Because this fault only happens when the ambient is slightly above or slightly below 0oC i am thinking it could be related to something to do with the frost mode
Re: CIAT Chiller d6.1 alarm
Does the unit have a desuperheater circuit?
http://www.ciat.uk.com/wp-content/up...ion-manual.pdf
Have a look on page 36 to see if your high pressure control is set up correctly http://www.ciat.uk.com/wp-content/up...-2-control.pdf
Re: CIAT Chiller d6.1 alarm
Have you checked it through a defrost cycle , what are the pressures,does the outdoor fan come on,what are your water temperatures.
