Tankless Water Heater Repair & Maintenance
Tankless Water Heater Repair and Maintenance in Ontario
Hot Water Back, Any Brand
Error code and a cold shower? EHI handles tankless water heater repair and maintenance across Ontario for every brand, with Rinnai as our specialty.
- Same-day tankless water heater service across the GTA and Ontario
- Rinnai specialists, every brand serviced
- Written quote before any repair starts
- Annual descaling flush that keeps your warranty valid
Voted Best Company 2019 to 2021 · Authorized Midea, Lennox, Kepler & Rinnai dealer, plus Goodman · 20+ years
Our Brand Partners
Tankless water heater problems we fix
Here's what's usually behind the symptom, and what we do about it.
No hot water at all
Usually one of three things: the unit isn't getting gas (closed valve, low pressure, a frozen regulator), it isn't igniting, or a sensor has locked it out. We check gas supply and pressure, the flame rod and ignitor, and the error history before replacing anything.
Error code on the display
Every brand has its own list, and the common ones point to ignition failure, flame loss, overheating, a blocked vent or a fan fault. We read the code, test the part it points to, and confirm the cause rather than guessing from the number.
Cold water sandwich
Hot, then a slug of cold, then hot again mid-shower. It's the gap between the unit shutting off and refiring when a tap closes and reopens. A recirculation option or a small buffer tank fixes it; sometimes a clogged inlet filter is making it worse.
Low flow or pressure at the taps
Scale on the heat exchanger and a plugged inlet screen choke the flow. A descaling flush and filter clean usually restores it within an hour.
Scale build-up and a unit that's lost its punch
Hard water leaves limescale inside the heat exchanger. The burner works harder, the water comes out cooler, and eventually the exchanger fails. An annual tankless water heater flush prevents the whole chain.
Ignition failure
Clicking and no flame, or a flame that drops out after a few seconds. A dirty flame rod, failed ignitor, blocked intake or exhaust, or low gas pressure in a cold snap. Our TSSA-certified techs test each one in order.
Water leaks under the unit
Could be a weeping relief valve, a failed heat exchanger gasket, a cracked exchanger from a freeze, or just the condensate line. We find where the water's coming from before we quote.
Loud, rumbling or whistling
Rumbling usually means scale; whistling or a high-pitched fan noise points to the combustion fan or a restricted vent. Both are worth a service call before they become a breakdown.
Sound familiar?
Describe the problem and we'll tell you what it usually is, what it costs to fix, and whether it's worth fixing.
What our annual tankless water heater maintenance includes
Rinnai and most other makers call for an annual flush, and in hard water areas that's not optional. Here's the full visit.
- Descaling flush: 45 to 60 minutes of white vinegar or a commercial descaler circulated through the heat exchanger via the isolation valves
- Cold water inlet filter removed and cleaned, screen checked for grit and scale
- Air intake filter and combustion fan cleaned where fitted
- Burner, flame rod and ignitor inspected and cleaned
- Venting checked for blockage, sag and proper termination; condensate line and neutralizer media checked and replaced when spent
- Gas pressure and combustion checked by a TSSA-certified technician
- Error code history reviewed, temperature settings confirmed, relief valve tested
- Dated service record for your warranty file
Why hard water in parts of Ontario matters for your tankless
Much of Southern Ontario sits on limestone, and the groundwater that comes with it is hard. Kitchener-Waterloo, Barrie, Newmarket and well-water homes across York, Durham and Simcoe all see it. Even Lake Ontario municipal water carries enough minerals to matter over time.
Inside a tankless unit, that water passes through a narrow heat exchanger at high temperature, which is exactly where scale likes to form. A layer of limescale insulates the exchanger, so the burner runs longer, the outlet temperature drops, flow slows, and the unit throws codes. Left long enough it cracks the exchanger, the most expensive part in the unit. Manufacturers know this, which is why the warranty expects an annual flush. On well water we also talk about a softener or a scale inhibitor ahead of the heater.
How tankless water heater service works with EHI
- 1
Call with the symptom or the error code
Tell us the brand and what the display says. Same-day service across most of the GTA, and evenings and weekends through our emergency line when the house has no hot water.
- 2
Diagnose and quote in writing
A TSSA-certified gas technician tests gas, ignition, sensors and flow, reads the error history and gives you a written quote before any repair starts.
- 3
Repair with the right parts
Common Rinnai parts ride on the truck. For other brands we source OEM parts fast. Any brand, any age.
- 4
Flush, test and hand over
Where scale is part of the problem we flush before we leave, then run the unit through its cycle and show you the readings.
Tankless water heater repair cost in Ontario
Every job starts with a diagnosis and a written quote. Here's what the common repairs involve.
| Service | Typical cause | Price |
|---|---|---|
| Diagnostic visit | Any symptom or error code | Quote |
| Annual descaling flush and maintenance | Preventive, or low flow and rumbling | Quote |
| Flame rod or ignitor | Ignition failure, flame drop-out | Quote |
| Inlet filter and flow sensor | Low flow, cold water sandwich | Quote |
| Combustion fan or vent repair | Fan noise, vent-related codes | Quote |
| Heat exchanger replacement | Leak or scale damage; often the repair-or-replace conversation | Quote |
Repair pricing depends on the part and the brand. When a repair isn't worth it, a new Rinnai tankless is from $3,300 installed, and financing is available.
Repair or replace your tankless?
A tankless unit under ten years old with a sensor, ignitor, fan or filter problem is worth repairing. Past twelve to fifteen years, or with a cracked heat exchanger, the repair can run close to the cost of a new unit that's more efficient and carries a fresh warranty. We give you both numbers and let you choose. See tankless water heater installation for what a new Rinnai costs.
What it costs, and how we keep it lower
Written quote first
Diagnosis, then a written quote, then the repair. The number on the quote is the number on the invoice.
Financing on larger repairs
0% for 3, 6 or 9 months, or open loans from 2.99% on approved credit.
Warranty protected
An annual flush with a dated service record keeps most manufacturer warranties valid. Warranty details.
Rinnai specialists
Authorized Rinnai dealer with common parts on the truck, and every other brand serviced too.
Want the real number for your home?
A guaranteed quote takes one visit. Rebate and financing options come with it.
Why Ontario homes and businesses choose EHI Heating And Cooling
20+ years in Ontario homes
We've installed through more January cold snaps and July heat waves than we can count. That experience shows up in the sizing, the ductwork and the little details.
Voted Best Company 2019 to 2021
HomeStars Verified. Our reviews come from real Ontario homeowners and business owners.
Authorized Midea, Lennox, Kepler and Rinnai dealer, plus Goodman
Factory-backed equipment, factory-backed warranties, and techs trained on the gear we install. We install and service Goodman too.
Guaranteed final pricing
The number on your quote is the number on your invoice. We may also beat comparable reputable quotes by up to 10%.
Rebate paperwork handled
Pre-approval, heat-loss calculation and documentation for the Home Renovation Savings Program. You just sign.
Licensed, certified crews
TSSA-certified gas technicians, licensed refrigeration techs and ESA-licensed electrical work on every job.
Ready when you are
Call us or send the form. Quotes are free, guaranteed and come with your rebate estimate.
HVAC service across Ontario
We're a service-area business. Our crews come to your home or business, from the GTA to Northern Ontario. Don't see your town? Call, we probably cover it.
Toronto and York Region
Simcoe, Muskoka and cottage country
Hamilton and Niagara
Southwestern Ontario
Eastern Ontario
Serving Ontario from our Stouffville office
Find us on Google, get directions, or check our hours. Our crews travel to your home or business across the province.
EHI Heating And Cooling (Efficient Home Improvements)
- Phone
1-647-694-5845 - Email
efficienthomecomfort@gmail.com - Service area
All of Ontario. See the cities we serve
Hours
- Monday8:00 am to 8:00 pm
- Tuesday8:00 am to 8:00 pm
- Wednesday8:00 am to 8:00 pm
- Thursday8:00 am to 8:00 pm
- Friday8:00 am to 8:00 pm
- Saturday8:00 am to 8:00 pm
- Sunday10:00 am to 5:00 pm
Emergency service available outside these hours.
- Office
4261 Bloomington Road, Whitchurch-Stouffville, ON L4A 3Y6
Frequently asked questions
How often should a tankless water heater be flushed?
A tankless water heater should be flushed once a year in most of Ontario, and every six months on very hard well water. The flush circulates vinegar or a descaler through the heat exchanger for about an hour to remove limescale, and most manufacturers require it to keep the warranty valid.
Why is my tankless water heater showing an error code?
An error code means the unit has detected a fault and locked out to protect itself. The most common causes are ignition failure, flame loss, overheating from scale, a blocked vent or intake, or a fan fault. Note the code, try one reset, and if it returns, book a service call.
What is a cold water sandwich?
A cold water sandwich is the burst of cold water you feel mid-shower after a tap elsewhere closes and reopens. The tankless unit shuts off when flow stops and takes a few seconds to refire, so the water already sitting in the pipe arrives cold. A recirculation option or a small buffer tank fixes it.
Can I flush a tankless water heater myself?
You can, if the unit has isolation valves and you own a pump and hoses, but the full maintenance visit also includes cleaning the inlet filter, inspecting the burner, flame rod, fan and venting, and checking gas pressure, which needs a TSSA-certified technician. Most homeowners book the whole visit once a year.
Do you repair tankless water heaters from brands other than Rinnai?
Yes. We repair and maintain tankless water heaters of any brand across Ontario. Rinnai is our specialty as an authorized dealer and we stock common Rinnai parts, but our technicians service other makes too and source OEM parts for them.
How much does tankless water heater repair cost in Ontario?
Tankless water heater repair cost depends on the part and the brand, so we diagnose first and give a written quote before any work. Filters, flame rods and ignitors sit at the low end; combustion fans and heat exchangers cost more, and that's where we talk about repair versus a new unit from $3,300 installed.