Soda dispenser - backflow problems

I know this is a beer forum, but the equipment for soda can be similar, so I'm hoping someone can help me out. Please forgive me if I've posted in the wrong forum.

So I bought a full size post mix soda dispenser like you see in restaurants, and have been working on getting it installed in my home. The first step I've been working on is getting the carbonator hooked up. It is a McCann's carbonator, model #E200092.

Unfortunately, when I hooked the carbonator up and ran it, I got major backflow problems. I called up McCann's technical support, and they said the check valve was bad and needed to be replaced. I found a supplier for the check valve, and it was $150!! I bought the entire 8 head system for $300, so dropping $150 on a valve for the carbonator seems absolutely ridiculous.

In my research, it seems some municipalities require an additional backflow prevention device. I've also seen some stuff about "ASSE 1022" type backflow prevention devices associated with soda dispensers.

So I'm wondering if I can install a separate backflow prevention device on the supply line to the carbonator, rather than replace the $150 valve between the pump and the holding tank.

I've attached some pictures of my setup and the check valve here:
http://akinc5000.imgur.com/beverage_dispenser

Anyone have any knowledge of soda systems and can help me out?

For the record, I'm aware of the dangers of carbonated water backflowing into my plumbing. After the backflow "incident", I ran every plumbing fixture in my house for 10 minutes to flush out the system.

that link is dead for me...

but from the sound of it, any check valve or back flow prevention device should work as well as the next (without knowing any more about the actual setup).

you can use as many additional inline check valves as you want to, provided they contain no brass or copper which creates toxic compounds in the presence of carbonic acid. if the pump on your carbonator is brass and the bad check valve is between the pump and the carbonator tank you'll have to find a stainless check valve with the correct fittings that is rated for 130psi or better.

I don't know much about those soda carbonators, but you might want to look at www.chicompany.net or give them a call. I see they sell used as well as new soda system parts.
http://www.chicompany.net/index.php?main_page=product_info&cPath=361_75&products_id=844
http://www.chicompany.net/index.php?main_page=product_info&cPath=361_75&products_id=845