Any contractors or people who know stuff about home repair on tonight?

[acemcmac]

Text

This is a cutaway view of my house... not 100% to scale (at least my kitchen dosensent feel like 9x9x9

My back chimney really does go from my basement to eye level on the third floor. It's in really bad shape. It's also a shared chimney. My neigbhoring owner is a contractor and wants me to let him take it out at "zero cost to me." (clearly this is a get-it-in-writing kind of deal.)

The only thing that exhausts out of this chimney is my 15 year old, natural gas hot water heater. He suggested that I either get a new hot water heater and install PVC direct exhaust out the back of my basement. Alternativley, I think I could either run exhaust over to my main chimney.... (40 foot run?) or I could simply locate a new hot water heater near my main chimney. The first option is clearly the most preferable due to cost, but I have no idea if that's "code."

What do you guys think is the best approach for this?

The green lines represent the runs that would go along with each of the proposals... the green box represents the relocated hot water heater in option 3

 

[acemcmac]

Not ONE armchair contractor in the whole house ?!?

 

[Rubycon]

DHWG flues cannot be PVC and IIRC condensing DHWG boiler units don't exist in residential settings - even winter/summer setups.

Long horizontal runs are bad - a GOOD fan is needed and even then expect lots of internal condensation problems.

Keep in mind I'm a lot more familiar with shipboard systems but the principles are similar.

EDIT: DHWG = Domestic Hot Water Generator

 

[Greenman]

I'm a contractor in CA, and I've never heard of a water heater that will vent through PVC, that doesn't mean they dont make them, it just means they aren't in this market. You will need to do some homework on that. Around here, we use "B" vent, it's double walled steel. Also we can't run a water heater vent into a chimney flue. And that 40' horizontal run wouldn't be allowed here either, I'd need to check my code book to find the limit, but it's a lot less than that.
Is there some reason you can't reuse the hole where the old chimney is? Just run it up in B vent and put a china cap on it and you're all done. Note that the outlet has to be ten feet from any windows.
If I were you, I'd take that drawing down to the local building dept. and ask them what your options are. Always best to know how you're going to finish a job before you start it.