Just bought a house and this is my first winter in it. Noticed that all the plumbing vents (two bathrooms and kitchen )are tied into one 2" vent. So my first question is:is that ok to have all in one vent out the roof?
The real issue I notice right now is that I have I big backdraft out of my one bathroom fan-the only one connected to the multi vent 2" pipe. This makes the master bath ice cold. The other is a plain 4" flex connected to a dryer type exhaust into the attic which has no draft issue (I know , I'll fix that after all the other major issues get fixed). The drafty fan is piped with 2" PVC starting at the fan and very hard to get to. Is the draft due to the undersized 2" pipe? Any suggestions on how to stop it? Should I add roof vents for both baths?