In a large pot heat olive oil, add onions, celery and potatoes. Saute for 5 minutes, then add mushrooms, zucchini, corn, yellow and orange bell peppers; saute for additional 5 minutes. Season with salt and pepper.
Add low sodium vegetable broth and water. Add enough water to cover the vegetables. Bring to a boil. Reduce heat to medium and simmer for about 15 minutes.
Add vermicelli and broccoli, simmer for additional 10-15 minutes until vegetables are tender. Serve hot.