My question is, can you have 4 water heaters in series. I did an apartment building the other day and its the first time I have seen this. I see there are no TP lines, and they are missing their pans. Anything else I am missing? Thanks for your help.
The ‘breeching’ (the vent connector the four vents are running into) looks wrong in the pic. It should be sized for the combined BTU as per the gas code tables, and typically breeching gets larger as each appliance is added in. Maybe it is the picture, but it looks as if the breeching is the same diameter as each vent connector, about 4".
Refer to qualified gas fitter for evaluation.