Tankless Water Heater Installation in North Mountain, Phoenix
Conversions, Replacements & Repairs | Old Vents Checked | Google 5.0 Rated
If you are trading a gas tank for a tankless unit, your furnace sits in the same closet and seems to share the heater's flue pipe, or you've wondered what becomes of the metal cap on the roof once the tank is gone, you're on the right page. The new heater gets its own vent, and the one the tank used is left serving whatever is still connected to it.
We are a family business with Christian owners, and on a North Mountain conversion, the old vent is its own item on the quote, beside the new unit. Before you ring anyone, go and count the pipes leaving the top of your heater closet.
Navien Installer, All Brands Serviced
AZ ROC #150707
Licensed, Bonded & Insured
Tank-to-Tankless Conversions
Old Flue Checked
Tankless Repairs & Descaling
10% Off Water Heater Installs
Service Window
Booked from 7 a.m., with the last work wrapping up by 7 p.m.No Card Terminal
Pay by check, cash, or Zelle.Vets, 55+, Seniors & More
Vets and anyone 55 or older: 15% off. Seniors, first responders and military members: 10%.No Answer on Our End
We ring back, usually within 10 to 15 minutes.Scale Removal
Plan on roughly $250 for an average tankless descale.Holiday Calendar
Holiday bookings are taken at a 25% premium.Navien Installer, All Brands Serviced
AZ ROC #150707
Licensed, Bonded & Insured
Tank-to-Tankless Conversions
Old Flue Checked
Tankless Repairs & Descaling
10% Off Water Heater Installs
Service Window
Booked from 7 a.m., with the last work wrapping up by 7 p.m.No Card Terminal
Pay by check, cash, or Zelle.Vets, 55+, Seniors & More
Vets and anyone 55 or older: 15% off. Seniors, first responders and military members: 10%.No Answer on Our End
We ring back, usually within 10 to 15 minutes.Scale Removal
Plan on roughly $250 for an average tankless descale.Holiday Calendar
Holiday bookings are taken at a 25% premium.Five Things a North Mountain Conversion Quote Shows
When the Tank Leaves a Vent It Shared With the Furnace
Half the homes in the 85051 ZIP code date from 1973 or earlier, and in 85029 from 1975 or earlier (census medians). In gas-heated houses of that era, the furnace and the water heater can sit close together and send their exhaust up through one shared vent. Take the tank out of that arrangement, and the vent is left sized for two appliances with only one on it.
What the code says about a vent left behind
The City's current fuel gas code, the 2024 International edition, keeps the model code's venting rules without local changes. Section 501.15 covers the case “where an appliance is permanently disconnected from an existing chimney or vent,” and requires that “the chimney or vent shall be resized as necessary to control flue gas condensation in the interior of the chimney or vent and to provide the appliance or appliances served with the required draft.” For a natural-draft (Category I) furnace, the resizing follows the code's vent-sizing section.
The vent's condition counts too
The same section looks at the inside of the vent that stays. Its flue passageway has to be “free of obstructions,” and its liner or inner wall “shall be continuous and shall be free of cracks, gaps, perforations or other damage or deterioration that would allow the escape of combustion products.” A vent that has carried a furnace's and a tank's exhaust for decades is looked at for that, as well as for size.
The name the federal rules give it
The U.S. Department of Energy calls the reverse case an “orphaned water heater”: a furnace and water heater that “share a common vent,” until the furnace is replaced by a condensing model and “they can no longer share that same venting.” A tank-to-tankless conversion is the mirror image of that case: the furnace is the appliance left on the old vent.
How the conversion is planned around it
Beyond Conversions: Tankless Service in North Mountain
Conversions from a gas tank are where the old-vent question comes up. We also replace tired tankless units, repair them, and descale them against Phoenix's hard water, and every major brand is serviced. Sizing the unit and the gas line that feeds it is covered on our main tankless page.
In homes built before 1978, we only take on work that leaves painted surfaces undisturbed. If a vent, gas or water route would need a painted wall or ceiling opened, that part goes to a lead-safe certified contractor you hire directly; we do not perform or arrange it.
Closet, Old Vent, New Unit, Old Vent Closed
Tell us what sits beside the tank
Say whether a furnace shares the closet, and count how many pipes leave the top of it. Two answers, and between them they decide whether this job has a vent problem in it.
The old vent, sorted out
On site, the connectors and the vent's path are traced. The quote then lists the tankless unit.
The unit in place, on a vent of its own
The tank leaves, and the unit goes up with its own vent route, which is where the old flue stops carrying two appliances and starts carrying whatever is left. That changeover is the part of the day the quote was written around.
The old vent closed
Where the tank was alone, its connector is removed, and the old vent is taken out of use as the quote describes; where the furnace stays on it, the vent work on the quote is done by the heating contractor it was referred to or by us.
Serving North Mountain From Our Phoenix Base
American Discount Plumbing is based in Phoenix and serves all of North Mountain.
Closets and Roofs We See Before a Conversion
“The furnace and the water heater are in one hallway closet, and a single pipe goes up through the ceiling.”
Probably a shared vent.
Two connectors that meet above the appliances and continue as one pipe are the usual sign. Once the tank leaves, that pipe serves the furnace alone, and it is the part of the job the quote has to deal with.
“A new furnace went in a few years ago with white plastic pipes, and the tank stayed on the old metal flue.”
The tank has been on its own for a while.
A high-efficiency furnace vents through its own plastic pipe, which leaves the tank alone on a vent once sized for two. A conversion now leaves the old flue with nothing on it.
“There's a metal vent cap on the roof above the heater closet, and we're planning to replace the furnace next year as well.”
Those two belong in the same conversation, because between them they decide whether anything is left on that vent at all.
If nothing else uses the vent once the tank goes, the quote says how it and its roof opening are taken out of use, and by whom. If the furnace is still on it now but a replacement next year would vent on its own, then the vent ends up empty in stages, and the quote can show it handled either way so the order of the two jobs is yours to choose rather than something you discover afterwards.
Old-Vent Questions From Tankless Conversions
Still have a question? Call Pavel (Paul) directly and get a straight answer, no phone tree.
Then the tank was the only gas appliance on that vent, and the resizing question doesn't come up.
The conversion doesn't change the furnace; what the code asks about is its vent, which may need a different size once it carries only the furnace's exhaust.
It depends on the vent's height, its connectors, and the furnace's rating. The answer can be a smaller vent pipe or a listed liner inside the existing one, and the code's sizing tables decide which.
The code worries about two things: flue gas can condense inside an oversized vent, and the appliance may not get the draft it needs to carry its exhaust out.
Yes. The same section covers an appliance connected to an existing vent during a new installation, so the vent is checked again for the new furnace.
The code treats a masonry chimney on its own terms. It has to be lined in accordance with NFPA 211, and where an existing chimney is found unsafe for its use, it is repaired, relined or replaced with a vent suited to the appliances it serves.
Every Service in North Mountain
More for North Mountain, followed by our general tankless and appliance pages:
Google Stars for American Discount Plumbing
A vent job is hard to judge from the outside, so a customer's account of how the visit went is worth reading on Google.
Going Tankless in North Mountain? Call American Discount Plumbing
If you also plan to replace the furnace, call (602) 883-2787 before either job is booked; the order of the two decides whether the old vent is resized or retired.
A written account of the flue the tank leaves behind, what is still connected to it, and who closes it.
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