NEED HELP! Gas Buderus boiler

Hello folks,

I have a buderus boiler that's in great shape but been having issues with it all Winter.

For some reason.. randomly the heat stops working at my house. The only way to get it going again, is to reset the Emergency Switch.

Even though this method is an easy fix, it's not very convenient when i'm out of town and start worrying about the pipes bursting.

We at first thought it was the Nest Thermostat (which replacing it made it work for a week flawlessly) but not it since we're apparently back at the issue.

I've had another pair of plumbers try and figure out the issue(GEM), and they suggested next time it goes to press the relay(which was replaced a year ago). Not sure how well this method works because it's essentially just resetting the boiler similar to the emergency switch method.

It's a 2 Zone setup, Would hate to start replacing parts left and right because it could really add up fairly quickly.

I have GEM coming for the 3rd time tomorrow. My original plumber couldn't figure it out, GEM can't pinpoint the issue... any help would be great.

Thank you,