Gas hot water heater placement?

Greetings. I just found this site through a suggestion by someone and need your help.
Background: Our old gas water heater died and we are replacing it. It was on the main floor in our laundry room. We have decided to relocate the new one to under the house.

We bought a direct vent gas heater and when we went to buy the vent system the guys at HD told us that you could not vent a direct vent heater to the wall instead it had to go up through the ceiling.
If we wanted to wall vent we could either get one of those or one with a power fan. These are an additional $300.00

The install manual shows what we are wanting to do and states that for every foot a pitch of 1/4 inch is needed.

The tank would be 5 feet from the wall and the rise is 12 inches so would this work? Were they correct? Should we use an electric one instead? my wife is concerned with gas build up and the HD guys said the pilot light would go out often. Truth?

Thanks for your help.

I'm not as familiar with gas as I spec and design primarily around electric but I've got 2 comments for you.

1. MFR recommendations for installation are usually spot on, if they show you what you want to do and you could do it you are usually ok. Make sure if you are side venting to have clearances as indicated in their instructions.

2. 95%+ of HD (and other Big Box Stores) workers are incapable of giving good advice, especially where plumbing, electric and HVAC are concerned. Most of their employees only know what someone else told them, they have no direct knowledge or experience.

At the HD, at least around here, they do not carry any direct vent models in stock. The odds that anyone in plumbing dept. has the slightest idea about how to install one are very low.

The whole idea of a direct vent is that they go horizontal. BUT, there are specs....covering type of material, slope, and maximum length. Get the manufacturer's install manual, which for most brands you can look at online.

tank

IF the specifications say you can side wall vent it, then you can. The pilot MAY go out more often because of where it is located, but that is not necessarily the case.

Water heater placement ! ! !

You are about a decade or two too late to put your heater under the house
unless you use a seal combustion power vent that draws it's air from outside the house ! ! !

The reason is because in July 2003 all gas water heaters sold in the U.S. Must
meet the " FVIR" specifications this means they have a much tighter need for clean air
to prevent their burner vents from clogging up
see the posts on Whirlpool Flame Guard water heaters
even though you might not use one of these check out what they say about the vents clogging up even inside the house
under floor you are going to pick up a ton of dust and dirt,
what most people don't know is any gas appliance has a need for a "large" amount of fresh air to support combustion ! ! !
They act like a vacuum cleaner sucking lots of air and anything thats carried by
the air

dust

Unless someone is crawling around in the area, there is no reason why there should be a "lot of dirt and dust" in the air.