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funnyguy
13-05-2022, 11:54 AM
Hi all

I have a chilled water heat exchanger using CO2. On 1 side there is liquid solenoid ICF. Other side is ICS 3 with pilot CVPH and S1 solenoid and S2 CVPH.

Chilled water is setpoint 5 degrees.

How would one go about setting the pilots?

RANGER1
13-05-2022, 10:00 PM
funnyguy,
Hoping this is a serious request, as sounds unusual to cool water with Co2
Few ways of doing it, obviously pretty critical on Co2.
From chart on link below CVP-H range 25 to 52 bar, each turn clockwise is equivalent to 4.1 bar, so starting point could be minimum 5 turns in for 10 deg C.
25 bar minimum setting on CVP-H, add 5 (turns) x 4,1 bar = 20.1 bar. 25 + 20.1 = 45.1 bar (4510 kpa 10.8 deg C).

Ensure lots of water flow.
Accurate gauge
Relief valve for equipment protection (check setting & equipment maximum pressures).

Set S2 CVP-H first, EVM solenoid off say 10 deg C or more
S1 with EVM set second at lower pressure than S2 CVP-H 5 deg C

0 deg C = 3383 kpa
5 deg C =3868 kpa
10 deg C = 4400 kpa


instrukciya_po_ustanovke_i_nastroike_pilotov_cvp_cvpp_cvc_cve_evm_i_cvh.pdf (danfoss.ru) (https://open.danfoss.ru/file/54790bd2-1fb3-489b-9427-381ef6de3536/instrukciya_po_ustanovke_i_nastroike_pilotov_cvp_cvpp_cvc_cve_evm_i_cvh.pdf)

funnyguy
15-05-2022, 11:42 AM
Set S2 CVP-H first, EVM solenoid off say 10 deg C or more
S1 with EVM set second at lower pressure than S2 CVP-H 5 deg C
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Thanks Ranger. I just feel that when I was doing it my gauge needle didn't want to reach 5 deg C (3868 kpa) nor did it want to reach 10 deg C (4400 kpa).

The ICS module would only want to open at a lower pressure say -5 deg C which I had to leave it at to keep the chilled water system running.

RANGER1
15-05-2022, 12:09 PM
So really it probably should be set to just 1deg C to prevent freezing.
maybe water flow need to be adjusted to design flow to achieve.

You can set lower, but risk freezing.
Do you have design umbers, I would ask if you can.

funnyguy
15-05-2022, 12:19 PM
Do you have design umbers, I would ask if you can.

I dont have those. Pity.

I have had to adjust the chilled water low temperature alarm to prevent system shutdown until reset.

RANGER1
16-05-2022, 01:17 AM
What controls superheat on Co2 side of PHE?
Is water getting down to temperature?

applecache
16-05-2022, 03:47 AM
Nothing controls superheat on the shell and tube. It does get down to 5 degree.

RANGER1
16-05-2022, 09:44 PM
So pressure will not increase above water temperature.
How accurate is gauge, has to be very accurate!
Adjust S2 as per table of turns if you cannot increase pressure to required opening pressure.
If there is a power failure & S1 set to low, you may get a freeze up if flooded Co2.
Is Co2 on shell side