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From Contractors & Distributors

What venting systems are approved for the Radiant condensing and non-condensing boilers?

Radiant condensing boilers have some of the lowest vent temperatures the industry has even seen! All Radiant units are approved for the use of standard polyvinyl chloride (PVC) venting. This is about the most inexpensive venting material available. System 636 PVC & CPVC venting is approved, as well as Polypropylene. 2″, 3″, and 4″ venting options are available. If you are being pressured to install CPVC please contact us! Please check the “allowable vent lengths” of the product you are interested in for correct specifications.

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Some manufacturers say that their boilers are field convertible from natural gas to propane, or from propane to natural gas. Does Radiant offer this feature?

Radiant provides boilers that are specifically configured to operate on natural gas or propane. We do this for two reasons. Firstly, we want to ensure that our boilers operate at the peak efficiency. To do this requires both adjustments to the way the boiler operates and ensuring that the correct burner ‘jets’ (referred to as orifices) are in place for the type of gas being burned. Second, if a mistake is made in the field and the boiler is set up to burn one type of gas, but burns the other type, serious consequences can result, up to and including carbon monoxide being released into the building. Our boilers are set up in house prior to being shipped out the customer ready to operate as they are intended with either fuel. This eliminates costly errors out in the field and down time to customer.

Can I use anti-freeze in my Radiant Boiler?

Yes. You can use propylene or ethylene glycol (not automotive anti-freeze) up to a solution of 50% by volume; that is half water, half glycol. The resulting solution is more viscous (thicker); therefore, the pump that is built into the boiler will not be able to pump as much fluid through your system compared to if you are using just water in the system. You must use an inhibitor with the glycol.

I understand you require that I must use a cleaner and inhibitor in my system when I install a Radiant boiler. Why is this?

We highly recommend that your contractor use a cleaner when installing a Radiant boiler. This is particularly true if the boiler is replacing one in an existing system. Over the years, debris from the various components of the system builds up in the system. The tolerances in your old boiler may be such that this has not caused a problem. However, with today’s new equipment having much tighter tolerances (just like your new car engine, compared to that of an older car), this debris can clog up some of the components in the boiler. With a new system, as long as the system undergoes a cold and hot flush, adding a chemical cleaner is not as crucial but still recommended, as bits of solder or solder flux, for example, may find their way into the boiler. We absolutely require that a chemical inhibitor is used in the heating loop. We have found that without this, debris can come loose, causing fouling in the boiler. In fact, if an inhibitor is not used, our warranty is invalidated. A couple of examples of commonly used inhibitors are those made by Fernox and Sentinel. We accept these products and others that are demonstrated to perform similarly. Today’s boilers are highly sophisticated, and protecting this investment is simply common sense.

How do Radiant boilers perform at higher altitudes?

There is no technical height restriction for Radiant boilers. The boilers are set up by adjusting to certain carbon dioxide percentage targets at maximum power and minimum power. These values are independent of the altitude at which the boiler is installed. However, the boiler will be de-rated depending on the altitude; for example, at 7,000 feet the boiler will operate at approximately 83% of its maximum input. Therefore, you will need to account for the fact, that at altitude the boiler will produce less heat. This is true for all heating appliances due to the fact that the higher you go, the less dense the air is.

How do I get the air out of the heating system?

All Radiant boilers come with pumps that have air eliminators built in. Your contractor will open the eliminator up to bleed the air out of your system.

Cold water holds more air than hot water, so when first filled with cold water, the system contains a lot of dissolved air. Once your boiler heats the water, the air comes out of solution and moves with the flow of water. It is important to remove the air because it can block the flow of water. Air will also cause noise as it moves though the pipes.

A heating professional will also use automatic air vents at the high points of a system to eliminate air bubbles that do not generally move downward with the flowing water back to the air eliminator because of their buoyancy. It is highly recommended that additional air eliminators are added to any heating system in addition to the air eliminators that comes factory installed in every Radiant product.

Do I need a low water cutoff added to the system?

A low water cutoff prevents the boiler from operating if the system has less than the recommended amount of water in it. Radiant boilers are equipped with a pressure transducer that cuts off power to the ignition sequence if the pressure of the heating circuit water falls below 0.7bar (10.2psi). This effectively eliminates the need to add a low water cut off. Having said that, many jurisdictions still require that a low water cut off is to be installed. Please check with your local rules and regulations prior to installing you new boiler.factory installed in every Radiant product.

What is the warranty policy and process for the Radiant product line?

RADIANT branded products are guaranteed for two years from the date of acquisition and/or installation (based on invoice or other financial document). In the absence of an invoice or fiscal document, the warranty shall be for a maximum of 2 1/2 years from the date of manufacture of the product. The date of manufacture can be determined from the first four digits of the 10-digit serial number:

Example:  E   A   34  19  44  5126

                   1     2    3    4     5       6

  1. Export Production: E = Export ( I = Italy domestic)
  2. Brand of Product: A = Radiant
  3. Country of Destination: 34 = Canada ( 01= Italy)
  4. Year of Manufacture: 19 = 2019 ( 20 = 2020, 21 = 2021)
  5. Week of Manufacture: 44 = 44th calendar week
  6. Serial Number


Warranty for RADIANT branded products sold in Canada

  • 10* years on the Combi Tech Heat Exchanger – ALL MODELS
  • 2 years on every component within the cabinet.

Exclusions under warranties for RADIANT branded products

  • Scaling, impurities or other deposits in the water feed circuit due to lack of treatment, filtration or incorrect installation
  • Scaling, impurities or other deposits in the waste water circuit due to lack of treatment, filtration or incorrect installation
  • Breakage during transport, lack of water, freezing, fire, theft, storm, vandalism, corrosion, condensation, poorly performed descaling, sludging, ineffective chimneys, insufficient or improper

ventilation, presence on site of any other equipment which may discharge noxious or dangerous gases, improper evacuations and discharges, improper use of the equipment, installation in an unsuitable place.

  • Normal wear, such as anodes, circulators, gas regulators, diaphragms, etc.
  • Failure to follow maintenance instructions for the product, according to the applicable laws
  • Failure to follow applicable standards of electrical installation, hydraulic assembly and fuel feed
  • Failure to follow the instructions in the product documentation
  • Damage caused during assembly, disassembly or modification of RADIANT products by persons other than Thermal Hydronic Supply Ltd. personnel
  • Lack of invoice or fiscal document (in the case of §2 extensions only)
  • This warranty does not cover the labour and shipping costs associated with installing a repaired component or replacement of a boiler.

Important Information

  • The warranties mentioned cover the replacement of the part found to be defective; transportation, labour and taxes are the client’s responsibility
  • Replacement of a portion or all of the parts of RADIANT branded products and/or original accessories does not change the original validation date, effective date or duration of the warranty

Thermal Hydronic Supply Ltd. is the sole company authorized by Radiant Bruciatori S.p.A. Italy to execute the warranty work outlined above.

*Unless otherwise noted.

Warranty Registration Card (Please click here for online Warranty Registration Form)

From Home & Business Owners

Most people in North America heat their homes using forced air furnaces. As this is the case, why is heating with water using a boiler better than heating with a forced air furnace?

It is true that most homes in North America are heated using forced air furnaces. In Europe, and other parts of the world, where energy is much more expensive, virtually all space heating and domestic hot water heating is done with boilers. Simply put, water is a much more efficient way of heating; greater efficiency means lower energy costs. In addition, increased efficiency means lower carbon dioxide emissions. And if space is a concern, a wall hung boiler is about as space efficient a heating appliance as you can get. A wall hung boiler large enough to heat a home is not much bigger than a kitchen cupboard. There are other advantages to heating with water. If you are using an in-floor system, the comfort level, with the heat below your feet is noticeably better and with in floor or radiator systems, because you do not have the air movement associated with forced air systems, circulating dust is greatly reduced; this is especially important for people who experience dust allergies. You also have the option to couple your boiler with a Vulcano air handler and traditional duct work in your home. You now have the combined benefits of a high efficiency hydronics heating system with the ability to operate a central air conditioning unit. Your home will function and operate just as it does the use of a furnace, but now you will benefit from the savings of only one combustible source to generate your heating and how water demands, not two. One gas line, one vent, one outside termination, and one appliance using fuel and consuming energy, which also allows you to eliminate the need for a hot water tank in your home. Lowering household expenses and saving you money. The benefits are endless.

I currently have a forced air furnace. Can I change this out to a boiler?

The simple answer is yes. In cases like this, the boiler, which can produce heat both for space heating and domestic hot water, is coupled with a device called an air handler for space heating. Hot water flows through the air handler and air passes over the heated coils, much like the way a car radiator works; the hot air circulates through your existing ducting. On the domestic hot water side, the boiler replaces your hot water tank, meaning that you only heat water when you need to use it. This system will significantly reduce your energy consumption and costs for heating and hot water.

We currently have an old boiler in our home. Is there a reason why we should be considering a new one?

There are actually a few reasons to consider changing out an old boiler, assuming you mean your boiler is older than 20 or 25 years. Firstly, the technology has advanced a long way in the past couple of decades, so a new boiler will use a lot less energy than your current old one (see the question about condensing and non-condensing boilers below). Second, parts may not be available for your old boiler, should you have a problem. If this happens in the middle of winter, you are going to have to make a very quick decision about replacing a non-functioning boiler. Most boilers get changed before they completely fail for these reasons. Updating to new technology has many benefits.

What is the difference between a condensing and non-condensing boiler?

All boilers under certain conditions will condense. The difference between a condensing and non-condensing boiler is that a condensing boiler is designed to operate and survive long term in a condensing evironment. A non-condensing boiler will not last, because condensate is corrosive.

The condition that causes a boiler to condense is reduced flue gas temperature. The point at which condensing will occur, also called the dew point of the products of natural gas (or propane) combustion, is about 130F. Above this temperature, the moisture entrained in flue products as water vapor will remain vaporized. Below this temperature, the water vapor will change phase and condense out of the flue products as liquid. When this phase change occurs, additional energy is released that is beyond the sensible heat of the flue products. In a boiler, this phase change occurs on a heating surface and the released energy transfers through the heating surface into the boiler water on the other side. By capturing this energy, which is lost out the exhaust stack on a conventional system, a condensing boiler gains efficiency, thus making it much more efficient.

Naturally, the products of combustion cannot be reduced in temperature to 130F unless some of the heating surfaces in the boiler are also less than or equal to 130F. The only way to accomplish this is to have an entering boiler water temperature of less than or equal to 130F. Simply stated, if return water to the boiler is higher than 130F, condensing cannot occur; even if the boiler modulates and is at its lowest firing rate. This is determined by the laws of physics. The highest achievable efficiency that can occur without condensation forming inside the boiler is approximatley 87%.

The highest efficiency numbers occur when cooler water return temperatures are combined with the ability of the boiler to reduce its firing rate by modulating or staging. Under optimum conditions, reduced firing rate efficiency of condensing boilers can exceed 95%.

What is AFUE? What is the difference between AFUE and thermal efficiency?

AFUE stands for the “Annual Fuel Utilization Efficiency. AFUE is an energy efficiency value determined through a simulation test that represents the operating efficiency of an average installation over the course of a heating season. While AFUE provides a true indication of operating fuel costs, thermal efficiency represents steady state efficiency. Steady state efficiency does not consider efficiencies throughout the input range and typical on/off cycles the boiler is expected to operate. ENERGY STAR® provides AFUE values for products that have an ENERGY STAR® designation and the American Heating and Refrigeration Institute – AHRI provides AFUE values for products listed with that organization.

How do I know if I am buying the right size boiler?

Your boiler needs to produce enough heat to compensate for the building’s loss of heat on the coldest day of the year. Heating professionals have sophisticated computer programs that can calculate the right size boiler you need. These are called heat load calculations and, among other things, take into account the size of the building, its age, amount of insulation, type and number of windows, building openings, and the climate in your area. The contractor will then select a Radiant boiler that operates within the maximum heat loss of the building. Since Radiant boilers modulate, the Radiant boiler selected will operate at the heat output that matches the heat loss of the building on the coldest day, or on milder days at optimal efficiency at all times thanks in part to a 9:1 or 10:1 modulation rate depending on the model you choose.

How do modulating boilers provide operating efficiencies?

Most of the time when your boiler is operating, it will not be the coldest day of the year. In these cases, you do not want your boiler to operate at its maximum output as it will then cycle on and off more frequently than necessary. This will result in it operating at less than its best efficiency, using more fuel and greater wear and tear on the appliance, much like a car driving in stop-and-go traffic, compared to on the highway. Radiant boilers are designed to ‘modulate’, that is match their heat output with the heat required by the building. In this way they operate at the highest possible efficiency, for the conditions, all of the time.

What is the warranty policy and process for the Radiant product line?

Your Radiant product comes with a 10 year warranty on the heat exchanger, and a two year warranty on all components. Please refer to your owners manual for the exact terms and conditions.

Warranty Registration Card (Please click here for online Warranty Registration Form)