Ice machine DC100/60A, (Brema CB 955)

[Rossco90]

I have several of these machines that do not produce ice when running.

These are self contained spray systems which use an air cooled condenser and run on R404a

My guess is that either the charge is low or i have a restriction somewhere along the lines of the filter/drier or capillary tube.
To access the system, i have a schrader valve on the compressor service port. Ideally i would like to attach manifold to both the high and low sides. So have some questions regarding servicing.

1. Can i work out system pressures using the single service valve?

2. When recovering, vac and purging... can i solely use the single service valve?

3. When charging as a liquid, my understanding is to avoid liquid in compressor, so charging R404a into compressor service valve is wrong?

4. For attaching manifold to both high and low sides (should this be the preferred method of servicing a system like this), which points should i be using and what method preferably? (i have a bullet piercing valve or piercing pliers)

Any help with the above questions would greatly be appreciated!

[knighty]

do you know the original refrigerant charge of the system?

then (as long as everything else looks good)

you can recover the system and re-charge with the current weight of refrigerant.

[Rossco90]

Original is 390g, i would like to recover and see if that matches up as i went around with leak detection and couldn't find anything.

[Brian_UK]

When liquid charging the priority is to get liquid out of the refrigerant cylinder.

With liquid at your manifold gauge set you can regulate via the low pressure valve which will act as an expansion device thereby only letting mostly vapour through to the compressor and suction side of the system. If you also let the system stand for a while then the system will equalise as normal.

However, if you are charging with the compressor running then just be careful, watch the low pressure gauge, if it starts climbing quickly then reduce the flow of refrigerant from the bottle. If done with care then you should be okay.

[Rossco90]

can this be done using a manifold without a sight glass?

[Brian_UK]

Yes, let in a small amount to bring the pressure up from the vacuum and then start the compressor, you will see the low pressure gauge pulse a higher pressure whenever you let a slug of liquid in.

The gauge pressure shown needs to be held as a positive pressure. If you shut the valve the pressure shown will drop to a "working" type figure, open the valve and it will rise again.

You can actually buy a liquid charger device to screw into your charging line but to be honest I've found it easier to judge it myself.

[skarrs71]

Filter drier should be fairly easy to check, if there is a temperature drop across it indicates restriction. As has been stated above though, charging can be done by carefully bleeding into suction, slowly in small doses.