Giant · Residential gas storage tanks · Gas storage tank
Giant UG40
The Giant UG40 is a 40 US gallon (151 L) atmospheric-vent natural gas or propane storage water heater with a 40,000 BTU/h input, a glass-lined tank, FVIR technology and a 6-year tank and parts warranty, made in Canada by Giant.
Key figures
- Nominal capacity
- 40 US gal (151 L)
- First-hour delivery
- —
- Input
- —
- Efficiency
- —
Nominal volume, rated volume and first-hour delivery are different figures; size by first-hour delivery.
Giant UG40 in practice
The Giant UG40 is the 40-gallon member of Giant's Canadian atmospheric-vent residential gas storage line, at 40 US gallons (151 L) with a 40,000 BTU/h input on both natural gas and propane. It vents by natural draft into a chimney, drawing combustion air from inside the home, so it is the natural replacement where an existing atmospheric tank sits under a working flue. Giant lists FVIR technology, a glass-lined inner tank, a heavy-duty magnesium anode rod, a turbulator dip tube to reduce sediment build-up, a thermopile pilot design and a front-positioned gas valve with a piezoelectric (push-button) igniter.
Giant's page gives storage capacity and input but does not publish a first-hour rating, recovery rate, energy factor or dimensions for this model, so WaterHeating.ca does not state those figures. The published warranty is 6 years against inner tank leakage and 6 years on component parts from the date of installation, with conditions in the owner's manual. Giant publishes CSA and EnerGuide references on the same Canadian page.
Atmospheric units need a suitable chimney or B-vent in good condition and combustion air from the room; they cannot be side-wall vented. Where the flue is gone or a sealed mechanical room is planned, a power-vent or power-direct-vent model is the appropriate family. Whether CANRO supplies this model for a given job is confirmed at consultation.
Best suited to
- Households of two to four people with moderate simultaneous demand
- Like-for-like replacement of an existing 40 US gal atmospheric gas tank under a working chimney or B-vent
- Homes that want hot water to continue during power outages (push-button pilot ignition)
Limitations to know
- Needs a suitable chimney or B-vent and room combustion air; cannot be side-wall vented
- Giant does not publish a first-hour rating or energy factor for this model, so sizing is confirmed in a demand assessment
- A 40-gallon tank may run short for five-plus people or a large soaker tub
- Warranty excludes labour and anode consumption; anode inspection is required
Applicability and support
- Model number
- UG40
- Variants on this page
- UG40 (LP) (Propane)
- Canadian availability
- available
- Production status
- current
- CANRO supplies
- Confirmed at consultation
- CANRO services
- Confirmed at consultation
- Recirculation
- Not published
- Warranty
- Series terms
Storage tanks can serve a recirculation loop with an external pump and return connection; Giant does not publish recirculation guidance for this model, so any loop is designed at consultation.
Where CANRO provides on-site service
On-site service is currently offered across Metro Vancouver: Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Delta, Langley, Port Moody, Port Coquitlam, Maple Ridge, Pitt Meadows, White Rock, Tsawwassen; plus Anmore, Belcarra, Lions Bay, Bowen Island, Abbotsford with travel or ferry arrangements confirmed by phone. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Giant. Manufacturer gallon and BTU/h figures are preserved with metric alongside; notes flag conflicting documents and missing figures. Groups expand for detail.
Storage capacity 1
| Specification | Value | Note |
|---|---|---|
| Storage capacity | 40 US gal (151 L) | Giant lists US gallons on the Canadian product page; the figure is the nominal tank volume, not a first-hour rating. |
Input 1
| Specification | Value | Note |
|---|---|---|
| Input, natural gas | 40,000 BTU/h | 11.7 kW. Giant lists the same input for the propane version. |
Venting and air 1
| Specification | Value | Note |
|---|---|---|
| Venting | Atmospheric; air is drawn from inside the home and exhaust vents into a chimney | Atmospheric models need a suitable chimney or B-vent and room combustion air. The installation manual governs the vent system. |
Operating limits 1
| Specification | Value | Note |
|---|---|---|
| Certification | CSA reference published by Giant; EnerGuide referenced on the same page | Reproduced from Giant's Canadian page; the rating plate governs the installed unit. |
Other 2
| Specification | Value | Note |
|---|---|---|
| Type of gas | Natural gas (N) or propane (LP) | Giant lists both fuels for the UG40. |
| Warranty (Giant published) | 6 years against inner tank leakage; 6 years on component parts, from the date of installation | Giant states certain conditions apply and the owner's manual carries the exceptions. |
Manuals
Maintenance the manufacturer specifies
- Giant lists a top-mounted heavy-duty magnesium anode rod; inspect and replace it as the instruction manual directs, more often with softened water.
- Giant lists an easy-to-access combustion chamber and a brass drain valve; the instruction manual governs flushing, sediment removal and vent inspection intervals.
Fault codes documented for this model
None documented yet.
Services
Hot water and scalding
- Water above 49 °C at a tap can scald in seconds, and children and older adults are at most risk. BC's plumbing code limits shower and bathtub water to 49 °C.
- Storage tanks are normally kept hotter (Health Canada advises 60 °C) to limit Legionella growth, with a thermostatic mixing valve tempering the water to the fixtures.
- Never bypass or remove a mixing valve, thermostat or high-limit control to get hotter water.
Official guidance: Government of Canada on water temperature and scalds and HealthLinkBC.
Frequently asked questions
Is the Giant UG40 sold in Canada?
Yes. It is listed on Giant's Canadian residential gas pages (giantinc.com) under atmospheric vent, with a Canadian specification sheet, instruction manual and parts list linked from the product page.
What size is the Giant UG40?
Giant lists a 40 US gallon (151 L) storage capacity and a 40,000 BTU/h input on both natural gas and propane. Giant does not publish a first-hour rating for this model on the product page.
Does the Giant UG40 need electricity?
Giant lists a piezoelectric (push-button) igniter and a thermopile pilot design for the atmospheric family, which light and run the pilot without a standing electrical supply. The instruction manual governs the installed unit.
Is the UG40 available in power vent?
Giant lists separate power-vent and power-direct-vent families with their own UG model numbers. Those are different venting families with their own spec sheets; the model is chosen by the vent route and the flue available at the site.
Questions about the Giant UG40?
Describe what the water heater is doing and get a straight answer about the next step.
On-site service in Metro Vancouver, BC. Call to check availability.
Sources and verification
- Giant — Atmospheric Vent residential gas water heaters (UG40: 40 US gal, 40,000 BTU/h natural gas and propane, 6-year tank / 6-year parts, FVIR, glass-lined tank, magnesium anode, thermopile, turbulator dip tube, piezo igniter) · Canadian source · accessed September 21, 2026
- Giant — Residential gas water heaters (family structure: atmospheric, powered damper, power vent, power direct vent) · Canadian source · accessed September 21, 2026
- CANRO Heating & Cooling — Contact (brands serviced) · Canadian source · accessed September 7, 2026
Facts checked September 21, 2026. Last updated September 21, 2026. Technical reviewer: not yet assigned.