Triangle Tube Problems: No Heat to Leak
The Short Answer: Triangle Tube “water heaters” are almost never a 40-gallon atmospheric tank. A Smart is a stainless indirect. Prestige / Instinct Excellence is a condensing boiler with a DHW plate. Maxi-Flo is an external coil. Cold showers with a hot boiler are a sensor, pump, 3-way, or priority. A lockout is condensate or ignition. A wet jacket is a tank. Photograph the control. Stop at the gas train.
Licensed local technicians
Triangle Tube cold, locked out, or leaking?
Connect with a licensed 24/7 technician in your zip code right now.
Search Intent & The Real Problem
The badge says Triangle Tube. Showers died, the Prestige is in lockout, or the pan is wet. Forums paste ICON flash codes and Rinnai 11 onto a Smart tank that has no burner. The Smart (SMART30 through SMART120 class) stores potable water and steals heat through a corrugated stainless coil. Prestige, Instinct, and Challenger are wall-hung condensing boilers; Excellence / combi versions make DHW in a brazed plate. Maxi-Flo is a strap-on exchanger — tankless-coil physics, different iron.
Cousins, not twins: SuperStor, Buderus Logalux, Amtrol BoilerMate, Weil-McLain AquaPlus, HTP Phoenix if you actually have a gas-fired storage tank. Combi DHW: Baxi.
What other guides get wrong
They tell you to relight a pilot on a Smart. There is no pilot. They vinegar-flush the domestic side of a corrugated coil and call the boiler “descaled.” Acid through that coil is a licensed isolation job. They treat Prestige Excellence like a Rinnai wall tankless and descale the house cold. And they Flex Seal a stainless jacket.
Step-by-Step Troubleshooting
Step 1: Name the machine, then split no-heat vs lockout vs leak
| What you have | Path |
|---|---|
| Floor tank, Triangle Tube / SMART plate, coil unions | Indirect — this page, steps 2–3 |
| Wall-hung Prestige / Instinct / Challenger, PVC vent, display | Boiler / combi — steps 2 and 4 |
| Excellence / combi: heat works, showers dead | 3-way, flow sensor, plate scale |
| Two domestic lines into an external HX, no tank | Maxi-Flo / coil |
| Jacket wet, rust at the base, fittings dry | Replacement |
| T&P discharge wet, tank dry | Pressure / temperature — never cap |
- What to look for: Rating plate. Sensor well on a Smart. Circulator or zone valve on the boiler loop. Mixing valve on the domestic hot. Photograph the piping before anyone “straightens it out.”
- Required tools: Phone camera, flashlight.
Step 2: Is heat actually being requested?
- What to look for (Smart): Tank sensor in the well, not shoved under insulation. Boiler display showing a DHW call. Pump spinning or zone valve open. Supply pipe hot, return cooler if the tank is taking heat. Both pipes hot and the tank cold = air or a closed coil. Both pipes cold during a call = pump, relay, or control output. DHW priority disabled after a thermostat swap is how a “dead” Smart appears every heating season.
- What to look for (Prestige / Instinct combi): DHW flow sensor actually seeing a tap. 3-way valve moving off CH. Remote or control setpoint not sitting on a summer-off or CH-only profile.
- Required tools: Contact thermometer on both coil pipes. Eyes on pump LEDs. The sticker on that control.
Wrong well = the control thinks the tank is always hot or always cold. I pull probes out of the foam at least once a month. Purging the hydronic side is a boiler procedure. Do not open domestic faucets to “bleed the coil.” Do not purge a gas line.
Step 3: Mixing valve, recirc, T&P, and a Smart that is “not enough”
- What to look for: 160–180°F at the tank, 105°F at the shower = mixer or crossover, not a dead coil. Recirc returning into the cold inlet and stripping the tank. Mixing valve failed closed on the hot port. House static over ~80 psi dumping the T&P on every heat cycle — T&P on a new heater, expansion tank full. Typical relief 150 psi / 210°F. Never cap it. Stainless Smart tanks do not get the magnesium-anode funeral that AquaPlus does; do not yank a plug that is not an anode.
- Required tools: Thermometer at tank-out vs mixed-out. Hose-bib gauge if the T&P is wet.
Lukewarm with a hot tank is not “buy a SMART120.” Measure.
Step 4: Prestige / Instinct lockout and the DHW plate
Condensing Triangle Tube boilers make acidic condensate on purpose. A clogged trap, a dead condensate pump, or a frozen outdoor drain will lock the burner out. That is the same family as a Phoenix condensate fault, different cabinet.
| Display (confirm your sticker) | Meaning | First move |
|---|---|---|
| Ignition / no-flame class | Trial failed | Gas cock parallel, other appliances light, then licensed |
| Flame lost after light | Combustion / rod / wind | One look, then licensed — do not keep cycling |
| Blocked flue / condensate | Trap, vent, pump | External drain first |
| DHW or CH sensor | Probe out or failed | Reseat in the well, then licensed |
| Blank | No 120 V or fuse | Switch and outlet, then licensed |
- What to look for: Appliance shutoff handle parallel to the pipe. Trap full of sludge. Pump reservoir overflowing onto the gas train. PVC vent with a belly of water. Intake screened shut. Excellence plate that used to hit setpoint and now dies at 108°F with the boiler roaring — scale in the DHW plate, not a new Smart tank. Inlet/manifold pressure is licensed (NG often ~3.5–7 in. w.c. / LP ~10–11 in. w.c. — confirm the rating plate).
- Required tools: Phone photo of the code before you power-cycle. Wet/dry vac on the external condensate line only.
Clearing an external trap and emptying a pump is fair DIY. Opening the sealed combustion box, jumping a float, or acid-flushing the plate without isolation valves is licensed. A silent blower: leave it off.
Step 5: Coil leak, vessel leak, and when it is scrap
- What to look for: Boiler losing pressure while the domestic side gains pressure or discolors — pinholed coil mixing hydronic water into potable. Shut domestic and the boiler; that is a health issue. Foam jacket wet at the base with every fitting dry = inner vessel. Do not epoxy, Flex Seal, or dump stop-leak into an indirect. Cool condensate at a Prestige drain while it fires is normal; hot water from inside the jacket is not. Generic floor puddles: bottom of the tank.
- Required tools: Paper towel. No gauges on a guess.
A pinholed coil is a tank, not a flush. Isolate — apartment shutoff if you need the house water off. No floor drain? This drain procedure.
When DIY Ends: Calling a Licensed Pro
Stop at boiler programming, hydronic purging, gas combustion, a repeating lockout, Er-style sensor faults, and any leak from the vessel or coil. You may verify valves are open, reseat a probe that is obviously out of the well, unkink a condensate hose, and photograph the display. Combustion analysis, 3-way replacement, plate descaling, and Smart replacement are licensed boiler work. Triangle Tube / ACV warranties are allergic to jumpered safeties and a condensate line someone pinched “so it would stop dripping.”
Frequently Asked Questions
Q: Why is my Triangle Tube water heater not making hot water? A: On a Smart, the boiler is not getting a DHW call (sensor, pump, or priority) or the coil is air-bound. On Prestige Excellence, look at the 3-way, the DHW flow sensor, and plate scale. House heat working does not prove the tank circuit.
Q: Why is my Triangle Tube Prestige locked out? A: Blocked condensate, blocked vent, failed ignition, or a sensor. Photograph the code, clear the external drain path, confirm the gas cock is open, then hire a licensed tech if it repeats. Do not keep resetting a silent blower.
Q: Can I repair a leaking Triangle Tube Smart tank? A: Unions, valves, and T&P yes. A wet jacket or a coil leaking boiler water into potable is replacement. Do not epoxy the shell.