Bosch tankless

Jeff_78

I'm going to be installing a Bosch 425hn this week. My question is in regards to mounting and venting. First are there any issues or long term problems with venting the unit into a preexisting unlined chimney, where the old water heater was? and second is it possible to mount it on the chimney itself, If yes do you have any suggestions on the best way to do so? thanks for any input

Ed_26

bosch

As per mfg. specs,... as per gas code for your area!!!

jeff_51

I wouldn't ever vent into and unlined chimney

nuff said

S Ebels

Read the manual

I don't think they are recommended for chimney venting at all or at the very least without a Stainless Steel liner extending to the top.

Stan W_2

Tankless Bosch.

If you don"t have your ticket, ( and if you don't use a proffessional ) the warrenty will be voided,
including your house insurance,( claim )if the Bosch tankless is at fault.
You may ( as a Home owner ) pull a permit, and get it checked by the Permit company inspector for insurance documentation, As in our local area up here in Alberta, Canada. As for your area, I would not know the local code and insurance policey.
Proper sizing of the vent and gas lines: Using Manufacture"s specs presides local code.

Stan W_2

Tankless Bosch.

If you don"t have your ticket, ( and if you don't use a proffessional ) the warrenty will be voided,
including your house insurance,( claim )if the Bosch tankless is at fault.
You may ( as a Home owner ) pull a permit, and get it checked by the Permit company inspector for insurance documentation, As in our local area up here in Alberta, Canada. As for your area, I would not know the local code and insurance policey.
Proper sizing of the vent and gas lines: Using Manufacture"s specs presides local code.

SVDW

Owners manual will address not only venting but gas line sizing. If your existing gas piping is sized for a conventional tank style 40,000 btu burner you may have to have a new line run from the meter. Not an uncommon problem with these big BTU instant burners.

Scott Gregg

Don't do it

I'm with Jeff. Venting a tankless into an unlined chimney is a bad idea. You are asking for trouble. Venting is the most important thing on a tankless heater. If anything else is done wrong it might not work. If venting is done wrong you might wake up dead.

Personally I am not a big Bosch fan anyway. If it's not too late, get a Noritz or Rinnai (Much better units all around) and sidewall vent them.

See the tutorial under the tankless link on this site:

www.profitableplumbing.com

S Ebels

Jeff

I'll say it again, Read the manual! I just looked up the installation instructions online and there are too many variables detailed there to be able to give you any credible advice here. Looks to me like the best way to go would be a separate B-Vent chimney. The flue size is very fussy on these and most masonry chimneys are going to be way oversized unles you line it.

Jerry_15

Mega dittos (at least Rush contributed something to civilization}. I don't know of any bldg code that will accept any gas appliance vented through an unlined chimney. With forced draft forget about it. I only carry 2 mil in insurance, and like to sleep at night (and wake up too). How about you?
PS mount it anywhere you want. I might throw up a piece of 3/4 ply first rather than fasten right to the brick, but vent it according to spec.

CHARLES_4

Tankless water heater

Get back to us when you get out of the hospital...

Jeff_78

new on the topic

The bosch unit in question is not the forced draft unit its the natural draft atmosheric model. the unit is running at 80% efficincy. Whats the difference between this unit and the 40 gallon gas water heater that has been in the same chimney for the last 10 years? thanks for input

Mad Dog_2

You're terrible Jerry......................................

I think you may be a closet conservative after all.....you're obsessed. Its ok...you can come out now. BUt of course you guys are correct. Is this guy a pro? don't sound like it. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Scott Gregg

a couple of things.

Here are a few both related and not related to the original question. The first two are why I only care for the professional grade tankless heaters. (They don’t suffer from these problems.)

1. The 40-gallon tank heater can give a constant temperature when flows fluctuate.
2. The 40-gallon is not limited to 2.5GPM flow rate.
3. The 40-gallon tank fires less BTU’s.
4. The flue gasses from the tankless are going to want to expand once they hit that cool chimney and there will be more of them from the higher firing rate. At the very least you MUST size the chimney and line it if it is not the correct size for the application.

There really is a difference.

Jerry_15

That Bosch your talking about sounds like the old standing pilot T-2 model with the rubber diaphragm. Why bother? The sudden pressure drop with two fixtures on will guarantee loud moans from your better half; but only coming from the bathroom. The bedroom will become a cold and barren place. Snap out of it. In case you didn't get it the first time, NO GAS APPLIANCE CAN BE VENTED LEGALLY INTO AN UNLINED BRICK CHIMNEY - EVER!!! JEEZE LOUISE!!!

Jerry_15

Yo Mad Dog - I've been called worse, by better. At least I take my pain killers in plain view, and leave a good tip, and don't drop a dime on the guy on the next stool. What a jerk. When I want comedy I turn on Al Franken. Smarter, way funnier, and he even checks his facts. Even that gets tiring. One sided tirades always do.