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Pigeonkicker
10-10-2014, 11:08 AM
Hello first time post.

Can any body tell me the best practice for testing the high pressure trip on above chiller. It's for the insurance.

Many thanks in advance.

piewie
10-10-2014, 03:45 PM
I was going to say shut the discharge valve, but then I remembered that the switch is possibly mounted off valve on the oil coalescer. I have not been near a YCIV in 6 months now but the Chinese YVAA s have now started to come with the HP switch (which is one of those little resin sealed items with the copper tube protruding) mounted before the discharge shut off valve. I will have a look for next week as I have a service call on a YCIV.

Questions: What is the complete model number?

Why do the insurers want to test the switch?
Do they actually want to test the functionality of the switch or do they simply want to check that if it opens it actually kills the compressor?
Are they providing mechanical insurance on the chiller?

Sometimes insurers don't really know what they want and one needs to tell them what they want?


How old is it?

Gibbo
10-10-2014, 09:08 PM
It is a normal insurance inspection procedure for any pressure vessel they want to check the HP safety trip point in relation to the high side PRV setting they will also look at the age of all of the PRV's if they are over 5 years old they will tell the customer to replace them before he will ok there insurance policy.

Brian_UK
10-10-2014, 09:16 PM
Blank off the condenser and/or switch off fans and monitor the head pressure.

I don't know this model but the above may work unless other controls shut the thing down.

Grizzly
10-10-2014, 11:09 PM
Whenever I do HP Cut-outs with Zurich, I lower either the software setting to near the normal running and the turn off 1 or more condenser fans.
Or lower the mechanical HP switch till it trips. This trip value is then logged by the Zurich Assessor, prior to the switch being put back to its original position or setting.

Rarely will a insurance assessor force a full blown HP trip.

Surely with a YCIV you can just lower the hp cutout setpoint within the software.

From memory there are 2 HP physical cutouts on a YCIV .
25/27bar? These are of the sealed chocolate block type . so they cannot be adjusted.

Talk to the assessor as to what is acceptable to him?

So best practice is to prove one of the cut-outs work and given that the software setting if the first to trip as it is set lower than the mechanical. Proving it functions is usually acceptable.

Also not all chillers have prv's nor require them, but that's another story altogether!
Cheers Grizzly
Grizzly

Pigeonkicker
13-10-2014, 10:59 AM
YCIV0590VA59VABBXTXXXXXCXXXX44GXXXXXHXXXSEXLBXXXNXXTX1XXMXXX R

Manufacture date: aug 17 2010

The HP switches are on the head of the comp so I could shut the valve and run it up, but is that safe for the VSD compressors??

Glenn Moore
15-10-2014, 10:27 PM
Its safe for the VSD but not for the compressor or you. When setting HP switches or testing them, always reduce the condensing medium ie Water if water cooled condenser or Air if an air cooled condenser. The YCIV has many condenser fans which means you can switch some off via their isolators and then slowly cover the rest of the condenser surface to block the air flow, which allows you to keep an eye on the Head pressure at all times and manually shut the plant down if the safetys fail to operate at the design setting. Raising the head pressure slowly and using a calibrated pressure guage allows you to carry out the task in a controlled safe manner. Normally the VSD incorporates the safety circuit in its control set up.
You may find that the compressor starts to ramp down as the head guage starts to get close to its trip setting, as this type of control via the VSD allows the unit to still work but preventing the unit tripping on its Hi safety simply by slowing the compressor and reducing its capacity . VSDs can have many useful functions which are a little odd until you understand what they can do. Hope it helps

piewie
20-10-2014, 02:12 AM
Glenn has offered a really good method here and the most I can add is that because this is a CE Spec chiller that there are in fact two HPCOs per each circuit. I have not come across this before but is something to bear in mind when checking the operation of the HPCOs.