Hydronicexpansion tank sizingcalculator

As a rule of thumb, higher system volume means higher system expansion volume, which requires a larger tank. This works with the capacity (kW) of your boiler and/or chiller – which primarily influences your system’s volume.

This article will outline the factors that must be considered to ensure you avoid tank-related issues on your site. You’ll be able to send manufacturers the right details and ensure fit-for-purpose tanks, helping everyone in the process make informed decisions.

With an electric underfloor heating system, a technician can put high voltage down the cable to track where the damage is. This can normally be traced down to a single tile that needs to be lifted and the heating cable repaired.  However, with a hydronic system there is simply a leaking pipe causing the water to run along the outside of the pipes making it extremely difficult to pinpoint the exact location of the leak. As a result, it is more likely that a greater proportion of the floor will need to be lifted in order to locate and repair the leak.

The water in your system will expand and/or contract more drastically, the broader its temperature range is. For this reason, a larger temperature range will correlate to the need for a larger expansion vessel.

Expansion tank sizingchilled water

HVAC expansion tanks come pre-charged at a default pressure rating, which is adjustable and should be matched to your minimum system pressure (static pressure). Most tank-related faults on site are caused by installers failing to set pre-charge correctly, which is an essential component of accurate commissioning that should be conducted by the site technician. It is strongly advised not to arbitrarily install an expansion tank with its factory default pressure setting, as this factory setting is not a one-size-fits-all pressure level.

An expansion tank is a small pressure vessel used to protect closed-water heating systems from excessive pressure. This is done using a bladder that expands with water as the system’s total volume expands with heating.

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By adding a layer of insulation below the heating, you are providing an additional level of thermal resistance which means you are forcing the heat upwards into the room which turns into hot air and rises. Insulation will increase your heat up times and reduce your heat loss resulting in increased efficiency of the underfloor heating system.

Now that you’re equipped with the information your supplier needs to identify the right tank for your system, you are ready to size and install the tank(s) for your upcoming project.

Whilst both the hydronic and electric system can be used in most applications there are some additional points to consider:

Expansion tanks that are smaller than ideal for your system will result in an inadequate ability for the tank to absorb expanded water, defeating the tank’s purpose and creating excessive stress on your plant equipment. Expanded water volume needs somewhere to go, and if your tank can’t facilitate it, it may result in ruptured pipes, creating pump cycling, splitting bellows and making relief valves excessively blow off – causing unwanted spillage and related hazards.

Both Hydronic and Electric Underfloor Heating systems can be controlled by a programable Thermostat. With an In-Slab system you have a lot less control as you will need to allow 1-2 days for the slab to heat up and then the same amount of time to cool down. This means you don’t have the ability to suddenly turn on the heating or turn off the heat with changes in the weather.

Higher flow rates will mean that in the event of excessive expansion and contraction, there is a greater risk of problems occurring within the system as the system’s components are bearing a greater load.

While it is often recommended to have extra volume in case of future system expansion, there is the potential drawback of arbitrarily restricting plant room space with a tank that is larger than needed.

Expansion tank sizingcalculator

At Masterflow, we’ve seen more than our fair share of the right and wrong ways to go about sizing and installing expansion tanks, having fabricated and supplied them for over 20 years.

AMTROLexpansion tank Sizingpdf

If your project needs an expansion tank, Masterflow, with our exacting standards and decades of experience in manufacturing, is ready to discuss your project’s individual needs and identify the best fit for your site. Contact Masterflow for a quote on your expansion tank today.

Before seeking a quote for your project’s expansion vessel, it is recommended that you compile data on the following factors, to be shared with your supplier:

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Expansion tank sizingcalculator metric

A hydronic system is more complex to install and would require a plumber. Typically, you will need to engage a professional company for installing a hydronic system to ensure the install is carried out correctly to ensure you get an even spread of heat throughout the floor.

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Whether you have a hydronic or an electric system it is still recommended to add insulation below the heating to stop downward heat loss as heat moves equally in every direction until it meets a layer of thermal resistance.

Both electric and hydronic systems are going to provide you with the warmth, comfort and luxury that only Underfloor Heating can bring. It can be difficult to know exactly what system is best for your application so if you are still unsure please feel free to reach out to us on 1300 368 631 and one of our consultant’s will be happy to discuss your exact requirement’s.

This is vital in avoiding unnecessarily early replacement of your heater/chiller and more major issues, such as flooding, by maintaining a steady system volume.

Expansion tanks compensate for fluctuating water pressure due to temperature changes within heating  water and chilled water systems. By containing expanded water and expelling water to compensate for contraction, expansion tanks will maintain the water pressure of your heater/chiller.

An Electric Underfloor Heating system consists of electric heating cables being installed beneath the floor. Electricity then passes along the resistive cables causing them to heat up and radiant the heat into the room. Whilst there are electric systems for in the slab, the majority of electric underfloor heating systems are installed above the slab either directly below the substrate or in a screed.

The higher the installation point of your expansion tank in relation to the rest of your system, the less pressure your tank should be set to. The reverse is also true – high tank pressure is needed when the expansion tank is beneath the rest of the system.

Expansion Tank SizingExcel

Underfloor Heating is rapidly becoming one of the most common methods of heating used in Australia. With the heating at the floor level, it is an efficient way to heat any room. There are two main forms of Underfloor Heating, Electric and Hydronic.

Expansion tank sizingChart

The install of an electric system is much simpler than a hydronic system. Typically, the install of an electric system is done by an electrician, tiler, builder or even the home owner themselves. The install process is simple, and the system is then tested by a qualified electrician prior to tiling.

A Hydronic Underfloor Heating system consists of a network of pipes running under the floor. Hot water heated by a boiler flows through the network of pipes to heat the substrate and therefore heat the room. Typically, in Australia most Hydronic systems are located in the slab not directly below the floor finish.

Once an underfloor heating system is installed there is little chance of anything going wrong with either a hydronic or electric system. If, however there was an issue an electric system would be easier to locate than a hydronic system.

Every project’s HVAC system has its unique specifications and parameters. The system’s expansion tank must be sized accordingly, and has important responsibilities – including pressure maintenance, compensating for changes in volume, and preventing water losses. This makes correctly sized and installed expansion tanks vital for a system to function reliably.

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An electric underfloor heating system has a lot faster heat up time. It takes approximately an hour for an Undertile system to heat up and cool down so this allows you to set the schedule to have the heating on exactly when you need it and be able to change it to suit sudden outside temperature changes.

As a result, it will take approximately two days to heat the entire slab and turn this into a heat bank and generate heat in the room. Once the slab is warm it holds the heat well and becomes an energy efficient heat bank. However, in Australian most areas experience cold mornings and evenings but have it warm during the day, so this is not an effective or useable form of heat as you are unable to reduce or turn off the heat during the day.