2. No GN pans in the tunnel machine
A tunnel machine is a good choice when serving a high number of portions and washing larger volumes of tableware, but there is definitely one thing the tunnel machine is not optimized for and doesn't handle well: washing pots and pans.
First of all, you have to use precious water and often chemicals to soak, scrub, and pre-wash the items before they go into the tunnel – no good for your sustainability initiatives, nor your margins.
Unnecessary use of water and chemicals.
What is also an issue is that GN pans have a large surface and don't fit well in the dishwashing baskets. In turn, the tunnel machine is optimized for washing items that fit in the wash baskets - so what happens is that the GN pans, not possible to be positioned straight, push water forward or backward in the tunnel machine (depending on where in the basket the highest part of the pan is positioned). If pushed forward, the water from the dishwashing zone will end up in the rinse-zone, and then further into the drying zone. In severe cases, the water could end up outside the machine and create a wet, slippery floor.
One thing is sure, however: either scenario will result in the machine detecting low water levels in the wash tank, causing it to start filling and heating new water to make up for the loss, and dose more chemicals to create the right balance.
Conclusion: Use the tunnel machine for what it is optimized for: washing a high amount of items that don't need pre-washing, and fits well within a dishwashing basket - and invest in a proper ware washing machine that is optimized for washing and sanitizing pots and pans.