Home suddenly without hot water? You’re not alone; in Hamilton we see spikes after cold snaps, power flickers, and during heavy household use. This guide shows you safe 60-second checks for both tank and tankless units, when to call a pro, and how to decide repair vs replace using our free calculator.
If you already know you need a pro, head straight to Water Heater Repairs or request a same-day visit via Book Online. Planning ahead or considering an upgrade? See our Hot Water Tank Installation page.
Key Takeaways
- Do the 60-second checks: breaker or GFCI, gas valve open, temp at ~49 °C, cold-water inlet fully open, run 1 hot tap for 60–90s. If you smell gas or see active leaking, use Emergency Plumbing.
- Tank basics: pilot out or breaker tripped = common fixes. Tanks 10–12+ yrs are often near end-of-life — repairs may only delay a leak.
- Tankless codes: ignition/flow/scale are the usual suspects. One safe power cycle is fine; if the code returns, descale/service.
- Repair vs replace: use the Water Heater Repair-or-Replace Calculator to weigh age, parts cost, and risk.
- Typical Hamilton pricing: repairs often $220–$880 installed; replacements typically $1,450–$7,900 installed depending on system and scope.
- Need hot water back today? 905-928-6831 or Book Online. For upgrades, see Hot Water Tank Installation or Water Heater Repairs.
What to check in 60 seconds (tank & tankless)
These are safe, no-tools checks to rule out common, easy fixes. If you smell gas, see continuous leaking, or the tank is hissing/steaming, stop and call 905-928-6831 or use Emergency Plumbing.
Step-by-step (quick scan)
1) Power / gas supply
Electric tanks & tankless: Look for a tripped breaker. If tripped, reset once. If it trips again, don’t force it — book service: Water Heater Repairs.
Gas tanks & tankless: Confirm the gas valve to the water heater is parallel (open) with the pipe. If you smell gas, evacuate and call a pro.
2) Appliance switch & display (tankless)
Make sure the power switch is on and the display is lit. If the screen shows an error, snap a photo — it helps us arrive with the right part.
3) Temperature setting
Tanks and tankless should typically be set around 49 °C (120 °F) for home safety and comfort. Accidentally bumped dials are common after storage access.
4) Cold water line & shut-off valve
Confirm the cold-water inlet valve above the unit is fully open. A half-closed valve can mimic “no hot water” by starving flow.
5) Tap test: one fixture only
Run a single hot tap for 60–90 seconds. If it’s warm then goes cold, you may have mixing valve or capacity issues (we’ll diagnose). If it stays cold everywhere, continue below.
6) Tank pilot (gas tanks only)
Peek at the sight glass near the bottom. No blue flame? The pilot may be out. Many modern heaters use electronic ignition — avoid manual lighting unless the manufacturer instructions are present and you’re comfortable.
7) Drips at the TPR valve
A slow drip from the temperature & pressure relief (TPR) valve suggests overheating or pressure issues. Put a bucket under it and book service.
8) Check other hot-water appliances
If dishwasher or washing machine is also cold, the issue is likely at the heater, not a single faucet.
Fast triage table
| Symptom you see in 60s | Likely cause | Safe next step |
|---|---|---|
| Breaker tripped (electric) | Heating element short / thermostat fault | Reset once. If it trips again, book repairs. |
| No display on tankless | Power off / GFCI tripped | Check switch and nearby GFCI outlet; press RESET. |
| Display on, but no hot water (tankless) | Error code (ignition/flow/scale) | Note the code; see “Tankless codes” below; book if persistent. |
| Pilot not lit (gas tank) | Thermocouple/thermopile or gas supply | Do not repeatedly relight; Book Online. |
| Warm then cold quickly | Capacity issue, failed element, mixing valve | Reduce simultaneous use; we’ll test elements & valves. |
| TPR valve dripping | Overheat/over-pressure | Bucket underneath; turn down temp; call if continuous. |
💡Tip: Snapping photos of the rating plate (brand, model, serial) and any error code helps us bring the right OEM parts — fewer trips, faster hot water.
Tankless: common error codes and what they mean (ignition, flow sensor, scale)
Tankless units protect themselves with error codes. The wording varies by brand (Navien, Rinnai, Noritz, Rheem), but the root causes are similar. If your screen shows a code, snap a photo and Book Online so we arrive with the right kit (descale pump, filters, ignition parts).
Most common code families
Ignition / flame failure
- What you experience: Cold water, code appears shortly after opening a tap.
- Typical causes: Low gas pressure, dirty flame rod, restricted air/vent, failed igniter, condensate backing up.
- What we do: Combustion analysis, clean sensor/rod, verify gas supply & orifice, clear condensate, test igniter and control.
Flow sensor / minimum flow not met
- What you experience: Unit doesn’t “wake up” unless you open multiple taps; temperature swings.
- Typical causes: Clogged inlet screen, scaled heat exchanger, sticky flow sensor, underset minimum flow, restrictive fixtures.
- What we do: Clean inlet filter, test/replace flow sensor, descale heat exchanger, confirm programming and fixture flow rates.
Over-temperature / scale detected
- What you experience: Short bursts of heat, then shutdown; repeated high-limit trips.
- Typical causes: Lime scale on the heat exchanger (very common in Hamilton’s mineral-rich water), failing thermistor, low flow.
- What we do: Pump descale with manufacturer-safe solution, flush lines, test sensors, recommend a pre-filter and maintenance plan.
Exhaust/air & condensate
- What you experience: Unit tries to start, then faults; may run fine on warm days, fails on windy/cold nights.
- Typical causes: Vent pitch or icing, birds/wasps at termination, blocked intake screen, condensate trap full.
- What we do: Inspect/clear terminations, correct pitch, thaw/clean, service condensate trap and neutralizer.
Quick homeowner table (tankless)
| On-screen clue | Plain meaning | Your quick step | Our fix on site |
|---|---|---|---|
| “Flame fail / ignition” | Burner didn’t light or hold | Try one power cycle; note if gas stove/dryer work | Clean flame rod, test igniter, verify gas pressure & venting |
| “Low flow / no demand” | Unit not sensing enough water | Clean faucet aerators, fully open one hot tap | Clean inlet screen, service flow sensor, descale |
| “Overheat / scale” | Too hot at heat exchanger | Shut off, wait 10 min, try 1 tap only | Full descale, sensor check, setpoint verification |
| “Exhaust/air” | Intake or vent issue | Look for snow/debris at vent (from the ground, no ladders) | Clear terminations, fix pitch, service condensate |
Pro tip to avoid repeat codes in Hamilton
- Add an inlet filter and schedule a descale every 12–24 months (more often if you see white crust on fixtures).
- Keep setpoint near 49 °C and use a tempering valve for safe fixtures.
- If your tankless is 10–15 years old with frequent codes, check parts availability and compare total repair cost with upgrade options on Hot Water Tank Installation (we also install high-efficiency replacements).
If you’re staring at a stubborn code or the shower’s gone cold, we can help today. Book a licensed tech: 905-928-6831 or Book Online.
Repair vs replace in Ontario (age thresholds, parts availability)
When your water heater quits in Hamilton or nearby (Ancaster, Dundas, Stoney Creek, Burlington), the decision usually comes down to age + repair cost + parts availability + risk of future leaks.
Simple rule of thumb
- Tank (gas or electric)
- 0–6 years: Repair is usually sensible if the tank body is sound.
- 7–9 years: Repair small items; start planning for replacement.
- 10–12+ years: Replacement is usually the better investment due to leak risk and limited ROI on parts.
- Tankless
- 0–8 years: Repair and descale; ensure annual maintenance.
- 9–12 years: Compare repair cost vs total lifespan left; many models still worth fixing if parts are available.
- 13–15+ years: Consider replacement, especially if codes repeat and the heat exchanger is scaled or sensors are obsolete.
Parts availability in Ontario
- Common wear parts (thermocouples, thermostats, heating elements, mixing valves, TPR valves) are widely available.
- Control boards, specialised gas valves, older tankless sensors may be manufacturer-specific and harder to source after ~10 years.
- If your model is discontinued, we’ll check current Ontario distributor stock during your visit and advise fastest options (repair vs swap).
Use the calculator (smart, fast decision)
Not sure which way to go? Try our free tool: Water Heater Repair-or-Replace Calculator — it weighs age, quoted repair, efficiency, and risk for a clear recommendation.
Need eyes on it today? Book a licensed tech: Water Heater Repairs.
Quick decision table
Situation | Lean Repair | Lean Replace |
|---|---|---|
Tank ≤ 6 yrs, minor part (element/thermostat/thermocouple) | ✔ | |
Tank 10–12 yrs, any leak at body or persistent TPR drip | ✔ | |
Electric tank hot for 5 min then cold (likely lower element) | ✔ | |
Gas tank with repeated pilot dropout, rust at base | ✔ | |
Tankless 0–8 yrs, first-time ignition or flow code | ✔ (with descale) | |
Tankless 12–15 yrs, frequent codes and heavy scale | ✔ | |
Parts back-ordered, no hot water for family | ✔ (speed matters) |
Why this matters for leads & safety:
Replacing at the right time avoids catastrophic leaks and repeat service calls. We’ll always present a written scope for both options so you stay in control of cost and downtime.
Typical installed ranges in Hamilton
Every home is different (venting, gas line size, condensate routing, drain pan, permits), but most Hamilton jobs fall within these typical installed ranges. We price the installed scope, not hourly, so you know the number before we start.
For a firm quote, tap Book Online or call 905-928-6831. Same-day diagnostics available across Hamilton, Binbrook, Caledonia, Grimsby, and Niagara.
Common repairs (installed)
| Repair (typical) | What’s included | Typical range (installed) |
|---|---|---|
| Electric tank heating element + thermostat | Element, thermostat, gasket, testing | $280–$520 |
| Gas thermocouple/thermopile | Part, testing, safe relight | $220–$420 |
| Gas control valve | OEM valve, setup, combustion check | $480–$820 |
| Mixing/tempering valve | Valve, fittings, balancing to 49 °C | $320–$620 |
| TPR valve & discharge | Valve, piping to code, test | $220–$420 |
| Tankless full descale | Pump, solution, flush, inlet screen | $260–$460 |
| Tankless flow sensor or igniter | OEM part, labour, calibration | $380–$880 |
Ranges reflect typical residential work in Hamilton; complex access, code upgrades, or parts scarcity can vary totals. We’ll confirm onsite before work begins.
Replacements (installed, standard scopes)
| System | Typical Hamilton scope | Typical installed range |
|---|---|---|
| 40-gal atmospheric gas tank | Like-for-like swap, new flex connectors, vent check, TPR/discharge | $1,650–$2,450 |
| 50-gal atmospheric gas tank | As above, popular family size | $1,850–$2,650 |
| Direct-vent / power-vent tank | Venting review, new connectors, programming | $2,350–$3,350 |
| Electric tank (40–60 gal) | Like-for-like, breaker check, connectors | $1,450–$2,350 |
| Tankless condensing (replacement) | Mounting, vent/air, gas sizing check, condensate kit, commissioning | $3,800–$6,200 |
| Conversion: tank → tankless | New vent/air, gas upsize if needed, condensate & neutralizer, commissioning | $4,900–$7,900 |
Notes that protect you:
- We verify gas sizing & venting to code, and include a combustion check on gas systems.
- Where sump or drain is nearby, we recommend a drain pan & leak alarm (simple insurance for finished basements).
- Considering efficiency or space savings? See Hot Water Tank Installation and our Hamilton HVAC services for whole-home comfort planning.
Ready for clear pricing in writing? Start here → Water Heater Repairs or Book Online.
What to expect when we arrive (diagnose → written installed scope → same-day fix)
We keep it simple and fast so you’re back to hot showers ASAP.
Our 6-step visit in Hamilton homes
- Arrival window + access
- We text on the way. Clear ~1.5 m around the heater if you can. If it’s urgent or leaking, use Emergency Plumbing.
- Safety & code checks (5–10 min)
- Gas leak/CO scan, venting and combustion air, electrical/breaker, TPR drain path. If anything is unsafe, we make it safe first.
- Root-cause diagnostics (15–30 min)
- Tanks: test elements/thermostats (electric), pilot/thermopile & controls (gas), measure recovery and temperature rise.
- Tankless: read error history, test flow sensor, inlet screen, run combustion analysis, check condensate and vent.
- Written installed scope (before work)
- You get a clear installed price for repair(s) or replacement — no hourly surprises. We’ll also run your numbers through the Repair-or-Replace Calculator on request.
- Same-day fix or swap
- Common parts are on the truck (elements, thermostats, thermopiles, TPRs, mixing valves). If replacing, we review capacity, recovery, and venting options (see Hot Water Tank Installation).
- Commissioning + cleanup
- We purge air, verify setpoint (49 °C), test TPR, check for leaks, and show you exactly what we did. You’ll get a digital invoice & photos, and a simple maintenance plan.
Typical timeline (same-day scenario)
| Step | Tanks | Tankless |
|---|---|---|
| Diagnose & quote | 20–30 min | 25–40 min |
| Common repair | 30–60 min | 45–90 min |
| Full replacement | 2–3.5 hrs | 3.5–6 hrs |
Want to see what neighbours say? Browse Testimonials, then Book Online or call 905-928-6831.
FAQs: No Hot Water ?
Why won’t my gas pilot stay lit?
A weak thermocouple/thermopile, a failing gas control valve, or poor combustion air are common causes. Re-lighting repeatedly isn’t a fix and can be unsafe. We test millivolts, confirm draft, and replace the faulty part same-day. Start here: Water Heater Repairs.
My tank is noisy (pops/rumbling). Is it dangerous?
That’s usually sediment superheating on the bottom. It reduces efficiency and can overheat elements/controls. A flush and anode check typically solves it; badly scaled tanks near end-of-life may be better to replace. See Hot Water Tank Installation.
We get hot then suddenly cold — what gives?
Common culprits are a failed lower element (electric), undersized tank, or a mixing (tempering) valve that’s sticking. We measure recovery and balance the tempering valve to 49 °C for safe, steady output.
My tankless keeps throwing an ignition or flow code. Can I reset it?
You can power-cycle once and clean faucet aerators. If the code returns, the issue is real (gas pressure, flame rod, scale, flow sensor). Repeated resets can hide a safety fault. Book a tankless diagnostic & descale: Water Heater Repairs.
The TPR valve is dripping — should I worry?
Intermittent drips during heat-up can be normal. Constant dripping means over-temperature/pressure or a failed valve. Put a bucket under the discharge, turn the setpoint down, and book service. If it’s pouring or steaming, use Emergency Plumbing.
What temperature should I set?
Most Ontario homes should target ~49 °C (120 °F) with a working tempering valve for fixture safety. Higher setpoints can increase scald risk and scale formation.
How often should I flush or descale in Hamilton?
For tanks, annual check/flush helps in our mineral-rich water. For tankless, 12–24 months for descaling depending on usage and visible scale on fixtures. We can set a reminder at your visit.
Will a repair void my warranty?
No — we use OEM-equivalent parts and document the work. If a tank body leaks within manufacturer warranty, a replacement claim may apply; we’ll advise the fastest path.
How quickly can you get us hot water again?
Same-day diagnostics and common repairs are typical. If the model is discontinued or parts are back-ordered, we’ll quote a like-for-like replacement so you can choose speed vs. wait.
Still stuck with cold water? We can be there today. 905-928-6831 or Book Online. If you’re weighing costs, run the Repair-or-Replace Calculator, then we’ll confirm on site.