Can I replace this head without draining the hydronic system

) air pressure switch designed for negative pressure sensing applications in high-efficiency venting systems

enabling the linear modulation of M/MR valves

handling differential pressures up to 75 psi on 1/2" valves to prevent bypass and ghost flow

Modine 5H0730570008 Switch 321702-401 Can I replace this headThe Modine 5H0730570008 Blocked Vent Switch is a critical safety component engineered to monitor exhaust integrity in Modine gravity vent heaters, including PA, PAE, and PD series units manufactured after 1986. Functioning as a high limit spill switch, this manual reset device detects flue gas spillage caused by downstream obstructions or inadequate draft. By monitoring temperatures within the draft diverter, it interrupts the 24V control circuit to