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airconadam
19-04-2007, 10:26 PM
hi any york chiller engineers on here please all it is ihave a millenium recip chiller on r22 15kg a circuit and circuit 2 keeps goin off on high pressure when i have put my gauges on the discharge the pressure is 12bar standing and the suction is 13bar standing when i start that circuit up the discharge shoots upto 24bar and trips out basically rite away and the suction when running goes down to 4 bar but the circuit will only run for aprox 20 secs if that and trip out ireclaimed the refrigerant today due to finding a leak at the back of the compressor on the condensor and got 8kg of gas out any chance that low gas could cause this to trip it of on high pressure thanks alot adam

Brian_UK
19-04-2007, 10:48 PM
Leak found, well done. Possible that air got into the system and your high pressure was due to non-condensibles.

20 seconds running isn't really enough time to reach any sensible conclusions on a chiller.

Have you recharged it yet and got it running or is that tomorrows project?

airconadam
19-04-2007, 10:57 PM
iam guna put it under pressure just to make sure there are no more and that is tomorrows project so do you reakon that that could of been the problem iahve just never know a system to go off on high pressure due to low gas thanks brian you got any more suggestions thanks alot adam

Brian_UK
19-04-2007, 11:01 PM
The high pressure is a 'result' of low gas not 'due' to low gas.

Check the low pressure switch settings and any pump down sequence settings, you don't need to pump down to vacuum just below normal operating conditionisn.

Also you don't know what anybody else has done on the system before you arrived. Did they try a top up but with the wrong gas? anything can happen;)

WARNING:- Be careful with your pressure test, there should be a high side and a low side test pressure. If you put the high side test pressure into the low side you could blow the compressor terminals.

airconadam
19-04-2007, 11:10 PM
hi brian thanks i didnt know that with the high side and the low side this is a really simple system and with the basic components tev filter drier comp heat exchanger thats it as you know iwas working on another chiller exactly the same as this one and pressure tested it to 23bar into the high side but had my low side gauge on the low side of the system just to check it if u like that might sound confusing sometimes hard to put things into writing so thats a definate then that low gas can make it go of on high pressure and low pressure thanks again adam

airconadam
19-04-2007, 11:14 PM
sorry aswel brian but when you said non-condensibles what did you mean by this thanks

Brian_UK
19-04-2007, 11:25 PM
sorry aswel brian but when you said non-condensibles what did you mean by this thanks
Air in the system, having entered through a leak, or your gauges, takes up space in the pipework but does 'not condense' as per the refrigerant.

It also compresses at a different rate hence the very quick rise in pressure.

Basically, anything that isn't the correct refrigerant is a non-condensible as far as we are all concerned.

So routine tomorrow should be, find the leak, fix the leak, pressure test, change the filter drier, pressure test if needed, evacuate, have lunch, recharge, get running, phone boss and say "I've done it and I'm off home now."

airconadam
19-04-2007, 11:32 PM
haha thanks alot brian i understand you now everyday is a school day. this system also has a strainer on it now correct me if iam wrong but are these basically a filter or not thanks alot the filter drier is on the discharge rite from the compressor and brazed in should be fun also brian how do you copy and paste a quote as you done then thanks

Brian_UK
19-04-2007, 11:44 PM
Nooooo,, filter/drier may NOT be the thing on the compressor discharge, they are normally after the condenser in the liquid line or you may have a suction drier.

The compressor discharge pipe may contain a muffler to cut down on pulse noise.

al
19-04-2007, 11:47 PM
Adam

it's also possible you have a tripped condenser fan, what model chiller is it? fans are normally set to come on at 18B depending on unit program.

Al

airconadam
20-04-2007, 12:08 AM
ah rite brian iknow wot u mean with the muffler hehe sorry so what about the strainer then the fans come on rite away as soon as one of the circuits start up and all the fans run fine thanks

airconadam
20-04-2007, 12:11 AM
the strainer is in the liquid line brian so does this act like i sed before as a filter thanks

lana
20-04-2007, 07:19 AM
Hi airconadam,

I think you have to do as Brian said. Check the system for non-condensible.

If the system is empty then do a good vacuum and then charge it.

Cheers

airconadam
20-04-2007, 07:53 PM
thanks fellas i went to the system today to fix the leak etc and when i got there the comp was on a fault which was thermal overload now this compressor had been of for 24hours and not been running any suggestions but i got it under pressure today and thats it due to another job so hopefully monday i wil give it most of the day to vac out and then add the refrigerant thanks guys

Brian_UK
20-04-2007, 11:04 PM
Anything is possible with a fault code, whether it is the correct fault code is for us to establish :)

al
21-04-2007, 01:31 PM
Adam

If this chiller has a millenium display panel then the fault will HP/MP trip, the high pressure switch is also in line with the motor protection device.

Al