Water Heater / dryer venting

Inspected an 80 year old recently remodeled home today. There was a small brick chimney from the crawlspace up through the roof that I suspect used to exhaust whatever system originally heated the home. It was no longer used for any kind of furnace. A typical attic installed forced air funace was present in the attic with its vent through the roof as is typical.

The remodeler had run the dryer vent through a transition box in the new laundry room up aluminum flex duct then into the small chimney.

Then above in the attic they had installed a new natural gas water heater (new to the attic I suspect) and run the exhaust vent for the water heater into this same small chimney.

I do not see this type of stuff around here much. Several questions.

Is this permissible in general? Using the old chimney in this manner at all? If so, is it okay to use it for these two appliances together?

The small chimney had no cap of any kind. I have some concerns that water could enter the vents of the two appliances. Also that wind could cause the appliances to either not vent well or even back draft on themselves, or back draft the water heater vent into the dryer.

I did not like the setup. But not sure how to call it out or if I should.

A gas appliance should not be vented into an unlined chimney. It will deteriorate the mortar.

I don’t think mixing lint in a water heater flue is a good idea ever.

The small chimney was unlined.

So who would I recommend to repair / review this situation. I suspect that most plumbers don’t see this situation around here much either. I can’t say I have ever seen this set up before, though it is probably common in some areas.

My comment on the unlined chimney is:
The chimney has a gas appliances venting into an unlined chimney. Gas combustion gases can deteriorate the mortar and drafting is typically poor. Use of a metal chimney/liner is recommended. Remediate as required.

I would recommend providing a dedicated vent for the dryer.

This is TOTALLY wrong! Two different “animals” to begin with… Clothes dryers require there own vent and NOT share a vent with a masonry chimney PERIOD! Clothes dryers with respect to vent material, length of vent and lint!! See Mfg’s installation instruction and or AHJ requirements or even the local gas provider ( if natural gas). That setup could be a house fire waiting…:shock:

Lint is a leading cause of house fires. Most clothes dryer appliance installation guides require smooth metal venting as short as possible for best performance and to reduce fire hazards… You see this flex foil and nylon crap and you write it UP as a fire hazard… You may see some semi-rigid piping and that maybe acceptable BUT the MFG has the final say.

A unlined masonry chimney with “natural” or propone gas burning appliances attached/ venting will be subject to moisture “etching” of masonry / mortar. When you burn natural gas properly you get: Carbon Dioxide and moisture at a lower temp then let say wood burning fire places (higher temps) and less moisture. If that chimney is unlined, at some point the inside will deteriorate and possible result in a collapse of the chimney…

Note: Any natural gas appliance attached to the chimney better be the same Category! By that I mean negative pressure. You don’t mix the categories like positive (3-4)pressure and negative pressure (1-2).

Hope this helps.

Thanks. I knew it was wrong, but it is really unusual for around here. I will call it out as described and recommend review/repair of installation and permits associated with the remodel. There were several things in the “flip” that seemed this way, though they were more subtle than a lot that I have seen.