Furnace and Water Heater spacing

[NMatts]

How far should the furnace be from the water heater. I was reading the manual on the furnace and it says there should be 24 inches of space in the front to work on. That space is infact 30 inches. But on the side I see that water heater is barely 18 inches at 45 degree angle from the furnace front. Do I need to have water heater moved.

Btw, little more than a year ago, I had water heater stop working so energy guys from the supplier company came and changed the thermocouple to make it work again. They did not mention anything about the spacing and did not put any tags. Infact they came twice for the repair project. Does that mean I am fine regarding the space matters.

[Garry Blankenship]

I am not your Huckleberry for this, but will try. A water heater must by code be accessible for service, inspection and removal. It is reasonable to assume that any side or elevation that requires access / maintenence would require the minimum 24" of clear space. My Code Check source does not stipulate what dimensions constitute "accessible", but common sense is a good start. There are no references to side or rear access, so I am assuming they are not a "code" concern. Ditto for furnaces on service, inspection and removal. Mimimum 6" from walls, minimum 12" from a door swing, 18" minimum on the control side.

[Markus Keller]

If the units meet basic clearance requirements and both are readily accessible, I wouldn't sweat the clearances too much. I find its more important to assess air flow, combustion air and types of units. Especially, how return air is set-up and if poor return ducting can / is causing negative draft in the space.
Obviously if its a wide open basement or something it probably isn't a big concern. In a confined space though it tends to be an issue.