The Gradient GCx is a wall hung condensing boiler with integrated pumps and controls, made in
Calgary. It takes no floor space at all, which is why it appears in homes with hydronic heating and
a tight mechanical room. Gradient rates it at 95 percent AFUE, with a 10:1 turndown and multi zone
control for up to four temperature setpoints. 180 Plumbing and Heating services and repairs GCx
units across southeast Calgary, including units we did not install. Call 403-404-9975.
The specifications
From Gradient’s GCx brochure and installation manual. We publish what those documents state, and we
do not fill the gaps with guesses.
- Efficiency: 95 percent AFUE
- Burner input: 15 to 150 MBH. Output: 13.8 to 138 MBH
- Turndown: 10:1
- Dimensions: 32 x 18 x 20 inches. Weight: 130 lbs
- Electrical: 115 Vac, above 10A, 15A breaker
- Hot water setpoint range: 80 to 185F
- Water pressure: 9 to 50 psi, with an internal 30 psi pressure relief valve
- Primary pump: Grundfos UPS 15-78, three speed
- Two internal Caleffi automatic air vents
- Control: multi zone, up to 4 setpoints, with relays for up to 3 external pumps
- Outdoor reset: adjusts output based on the outside temperature
- Domestic hot water: pairs with an indirect stainless storage tank water heater
What it is for
The GCx is a heating boiler, not a combination appliance. It heats water for your hydronic system:
in floor loops, radiators, a fan coil, a garage slab, a snow melt loop, or any combination of them
within its zone capacity. For domestic hot water it pairs with an indirect storage tank.
It hangs on a wall. In a house where the mechanical space is a closet, a corner of a utility
room, or a section of wall in a garage, that is often the whole reason it was chosen.
Outdoor reset is worth understanding, because it is the feature owners benefit from without
knowing it exists. The control watches the outside temperature and lowers the water temperature it
sends out when the weather is mild, so the system runs gently in shoulder season instead of
blasting and stopping. It saves gas and it holds a steadier house temperature.
Servicing a GCx
A condensing boiler needs annual attention, and the reasons are the same as for any Gradient
appliance: combustion, condensate and water quality.
- Burner and combustion chamber inspection and cleaning
- Condensate trap and drain cleaned and checked for free flow
- Flue and combustion air intake checked and resealed as needed
- Igniter and flame sensor cleaned and checked
- System pressure checked, expansion verified, air vents confirmed operating
- Water quality and system water checked, with flush and treatment as required. Calgary water is
hard, and scale in a condensing heat exchanger costs efficiency first and service life second - Zone and pump operation verified against the control setpoints
- Combustion analysis and full gas safety check by a Certified Type B Gasfitter
- The manufacturer’s maintenance record completed and left with you
If the boiler is locking out or showing a fault, tell us what the display says when you call. Note
that the GCx control and the syncFURNACE controller are different, so the ALM codes on
the syncFURNACE fault code page do not all apply here.
Common things we find on GCx units
No annual service history. These units are quiet and reliable enough that owners forget they
exist until something stops working.
Low system pressure. A slow loss somewhere in the loop that nobody has looked for. Topping it
up without finding the cause just delays the next call.
Hard water damage on the domestic side where the indirect tank has never been serviced.
Nobody has checked the warranty terms. The GCx is covered by the same document as the
syncFURNACE Boiler: five years on components and ten years on the pressure vessel for a defect
resulting in a leak, conditional on documented maintenance. Unlike the Tankless, that document has
no registration extension and no hours cap. We will tell you where you stand.
If you are considering one
The GCx makes sense if you have hydronic heating and no floor space, or if you are adding hydronic
heating to a house that already has a working forced air furnace you do not want to replace. If you
want one appliance to do heating, hot water and hydronics together, look at
the syncFURNACE Boiler instead.
Replacement quotes are free, in writing, and yours to keep either way.
How we price this work
We charge by the job, not by the hour. You get one number for the finished work, agreed before
anything starts and always in writing. Parts, labour, disposal and permits are in the number you
agreed. If we find something else once we are in, we stop and re-quote, and you decide.
Call 403-404-9975.
Frequently asked questions
What is a Gradient GCx?
A wall hung condensing boiler made in Calgary by Gradient Thermal, with the pumps, controls and air vents built in. Gradient rates it at 95 percent AFUE with a 10:1 turndown, a burner input range of 15 to 150 MBH, and multi zone control for up to four temperature setpoints. It takes no floor space, which is why it suits homes with tight mechanical rooms.
Does a GCx make my domestic hot water?
Not on its own. It is a heating boiler, and Gradient specifies pairing it with an indirect stainless storage tank water heater for domestic hot water. If you want a single appliance covering heating, hot water and hydronics, that is the syncFURNACE Boiler.
Who services Gradient GCx boilers in Calgary?
180 Plumbing and Heating services and repairs GCx units across southeast Calgary, including units we did not install. The work needs a licensed gasfitter. Red Seal Journeyman Plumber and Certified Type B Gasfitter. Call 403-404-9975.
How often does a GCx need servicing?
Once a year. A condensing boiler accumulates combustion residue, its condensate drain can block, and Calgary’s hard water scales the heat exchanger. Annual service covers combustion, condensate, venting, water quality, system pressure and a gas safety check.
What is outdoor reset?
A control feature that adjusts the water temperature the boiler sends out based on the outside temperature. In mild weather it sends cooler water, so the system runs longer and gentler instead of firing hard and stopping. It uses less gas and holds a steadier house temperature.
Written by Desmond Neufeld, Red Seal Journeyman Plumber and Certified Type B Gasfitter. Last updated 23 August 2026.
