Film-Tech Forum ARCHIVE: Pressurized cooling system in Barco Series 1 projectors

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Posted by Mattias Mattsson (Member # 4308) on 01-10-2015, 07:34 PM:

As I understand the reason for the pressurized cooling circuit in Barco series 1 projectors is to allow them to be mounted upside down?

In my experience the pressure falls to zero (or near zero) over a couple of months even if the circuit is not leaking.

If the projector is not mounted upside down, is there a reason to re-pressurize the system?

Posted by Steve Guttag (Member # 268) on 01-11-2015, 11:18 AM:

Not really other than to ensure no air is in the system. It will definitely function without the pressurization. I repressurize the systems I service as part of our regular maintenance. However, I don't stop what I'm doing because I see the pressure gauge has fallen (even to zero).

Posted by Buck Wilson (Member # 5885) on 01-11-2015, 05:49 PM:

Our 3 DP2000s ran at 0psi for years. Even now, only one of the 3 is charged, but I wouldn't be surprised if it's lost some or all of its pressure since we charged it a few months ago.

Still doesn't keep them from leaking [Cool]

Hahaha

Posted by Mattias Mattsson (Member # 4308) on 01-11-2015, 07:10 PM:

Steve, Buck, Thanks for your answers!

Posted by Steve Kraus (Member # 476) on 01-11-2015, 08:02 PM:

How does the pressure fall if it's not leaking?

Posted by Buck Wilson (Member # 5885) on 01-11-2015, 09:45 PM:

Something something It has an air-charged accumulator something something.

IE the accumulator pressure could bleed off without loosing coolant.

Steve could tell you more.

Posted by Dave Macaulay (Member # 813) on 01-12-2015, 03:29 PM:

I find they just leak down. No trace of liquid anywhere visible. The accumulator air volume is unchanged. This is, of course, impossible as the coolant didn't teleport out - but I have spent plenty of time trying to find a leak, and failed. Sometimes the pump leaks (it should be replaced at 4 or 5 years, can't recall for sure) and there's signs of fluid under it. But even after pump replacement the pressure goes from normal to zero in six months.

Posted by Buck Wilson (Member # 5885) on 01-13-2015, 03:40 PM:

In my experience, it seeps at the light engine connections but doesn't go anywhere because it immediately burns off. You can typically see a dried trail an inch or so long. YMMV

Posted by Steve Kraus (Member # 476) on 01-13-2015, 04:21 PM:

Is this strictly a BARCO issue?

Posted by Dave Macaulay (Member # 813) on 01-13-2015, 06:07 PM:

Other projectors do lose coolant, but I think the old Barcos are the only ones with a sealed and pressurized liquid cooling system. There's a pressurizer, it takes about 100cc of coolant added to go from zero to 0.5 Bar (spec pressure). They all lose some pressure over time but 100cc of fluid should be very visible.

Posted by Pete Naples (Member # 761) on 01-14-2015, 05:42 AM:

I've seen a number of Christies suffer air ingress due to the couplers failing after a number of years.
I gleaned from the OEM manufacturer that those couplers used in Series 1 cooling circuitsn on Christie and Barco are not rated for use in high UV environments... Draw your own conclusions on that.

Christie won't supply the couplers, only the complete cooling system which is an expensive way of replacing couplers. However if you know where to go you can purchase the couplers stand alone. At least you can in the UK.

Posted by Steve Guttag (Member # 268) on 01-14-2015, 06:42 AM:

The couplers are available easily in the USA too. You can get them in all of the sizes and orientations (straight, 90-degree) too. Note, you can also get the newer style which are MUCH better too. I've been debating to change them over since the newer ones that are used in series 2 projector don't "piss" when disconnected like the older style.

Same with the hoses. I think some of the problem with the series 1 are those whitish hoses. The black ones in the series 2 seem like a notable improvement that should have been retrofitted into the series 1 systems.

Barco Info-T 1143 discusses checking the female connector on series 1 projectors for signs of cracking (impending disaster). My guess is that the UV is breaking it down. I note in their first picture, the connector looks like it is on a black hose but in subsequent pictures the hosing looks correct of the period (white and discolored to brown/yellow).

Posted by Dave Macaulay (Member # 813) on 01-14-2015, 08:19 AM:

I've had the most trouble with the big Christie CP2000S type projectors, specifically the coolant connectors in the bottom of the light engine chassis (down into the lower cabinet). On disconnection when replacing coolant, the guts of the things shoot out towards the ethernet switch and bounce to who knows where. They won't seal on disconnect any more - no big deal - the problem is that the guts are needed to open the sealing valve on the mating hose connector. So... the spring and spindle have to be found and poked back in or you have no coolant flow. I don't know how/why they fail, the spindle pulls the sealing o-ring right out through its orifice.
This has occurred on many of the old monster Christies I have the pleasure of servicing. The projectors themselves are troopers, they just keep on going.

Posted by Steve Guttag (Member # 268) on 01-14-2015, 11:46 AM:

For those looking for the fittings. They are made by CPC (both the older white ones and the newer grey ones). The white ones are part of their "PLC" family. You'll want the PLCD for the kind that have the shut off built into them.

Posted by Mark Gulbrandsen (Member # 72) on 01-15-2015, 06:37 PM:

Haven't had a single issue with any of the NEC's cooling loops. They also keep the quick couplers well away from any UV.

Mark