Confused alittle

[Ryry3691]

I have a direct vent on the bottom of my water heater, I want to by a new but direct vent water heater are expensive. I've seen a cheaper one for a mobile home sealed closet with vent to the roof and vent coming from the floor, can I use an Atmospheric water heater if it lifted off the floor so air can come in, or suck it up and replace it with what's there

 

[frodo]

I have no idea what the first picture is
the second picture looks like a plumbing vent flashing was use on the ceiling
that is wrong as hell. looks like ****. all that is needed is a collar
https://www.supplyhouse.com/Hart-Cooley-16119-4-Gas-B-Vent-Storm-Collarall it does it hide the 1'' separation between vent and combustible ceiling material
the 3rd picture. WTH is that? a fire place vent termination?

 

[CT18]

I did a water heater for my bro in law in his mobile home and he put a louvered access on it. He was able to use a standard draft heater

 

[Ryry3691]

I have no idea what the first picture is
the second picture looks like a plumbing vent flashing was use on the ceiling
that is wrong as hell. looks like ****. all that is needed is a collar
https://www.supplyhouse.com/Hart-Cooley-16119-4-Gas-B-Vent-Storm-Collarall it does it hide the 1'' separation between vent and combustible ceiling material
the 3rd picture. WTH is that? a fire place vent termination?

The first is vent coming up from the floor, (tank is leaking), and the last pic is a close up of the water heater vent!

 

[frodo]

One square inch per 1000 input BTU’s, but not less than 100 total square inches. ***** *** Combustion air from outside the dwelling 1) Direct opening to outside requires one square inch per 4000 BTU’s (no duct). 2) Opening via horizontal duct requires one square inch per 2000 BTU’s. 3) Opening via vertical duct requires one square inch per 4000 BTU’s.

 

[Ryry3691]

Ok cool ty