At 21:20 hours while at staging area for an MVA W/ Rescue on WB Route 422, MCEDS advised Chief 34 of a 2nd incident in the 200 block of Militia Court, in the Borough of Collegeville for a CO Detector with no symptoms. R34 and SD34 responded. Upon investigations units found a malfunctioning heating unit. Heater was secured and Resident was advised to have units service immediately.