Tankless water heater installation

[DKAudio]

I don't need one but found a Bosch Aquastar (4.6 GPM) for $300, it has been mounted but is pretty much new. I was wondering how hard these are to install? My vent for the water heater is connected to the same one as my furnace. It is in the middle of my basement going straight up through the roof. I want to mount the tankless heater on the wall to get it out of the way. What are my options for venting this thing? Anything I should know about them? Your replies will determin if I am going to buy it or not. Thanks

[HayZee518]

is your furnace and the water heater both natural gas or propane? if one or the other then exhausting the burnt gases into the same flue is ok. you can't mix two different exhaust gases like a wood or coal stove into the same chimney flue as nat gas or propane.

[DKAudio]

They are both NG but the flue is about 6' away from the wall where I would mount the water heater, I can't vent horizontal then to a 90 and up, can I?

[HayZee518]

so go up at a 45 degree angle and a ninety into the flue. just remember heat rises.

[DKAudio]

That may be a problem. My basement ceilings are already pretty low (7' maybe).

No big deal, the guy isn't getting back to me like he said he would. I assume she is sold and gone.

[596]

Tankless water heater REQUIRE stainless steel flue pipe. If you download the installation manual from Bosch, it may also specify that it may not share a flue with any other appliance. Get that installation manual first. Are you also aware of the gas requirement? It requires a larger gas supply pipe than is typically found on a tank type heater.

[DKAudio]

Thanks, I believe my flue is galvanized. The guy must have sold it anyways, he never replied to me. Looks like I will be going with standard 40 gal again when mine dies. My whole basement is under ground level so I couldn't do a horizontal kit even if I wanted to. Oh well, new tanked water heaters have to be way more effecient than my 1980 40 gal (still going strong though, looks like new too).

Thanks

[pushkins]

I love the opening line to the original post " I don't need one, BUT, I found one" !!!

Ha ha ha .....sounds like me!

[DKAudio]

Why not eh? I am counting the days until my 1980 water heater goes...

[DKAudio]

Now I am looking at getting a Bosch Aquastar AQ125XNG. I can't find any info on it. Boschs website has the 125 Aquastar series but just BO and FX...

AquaStar 125B, 125HX, 125FX, 125BS Tankless Water Heater Models by Bosch

Does anyone know anything about this model? I would need to do a side vent for it and use my existing galvanized one just for my furnace. The problem is I built a deck that pretty much blocking where I would vent. I may be able to go past it but IIRC they say to go only 15' w/ a max of 2 90s; may not be an issue. I can't vent under my deck, can I (my deck is only 2' off the ground).

Do you need a power vent kit to do horizontal or is that just to increase length?



596 said that most tankless water heaters require a larger gas supply line than tanked ones, any idea what it is? I believe mine right now is 3/4" reduced to half.