Model  UFLT

Overview (PDF)

Model Type UFLT
BTUH/ft Ratings

Technical Data For All UFLT Models Is Included Below

NOTE: Heat Outputs for various AWT’s include 15% Heat Effect for placement along outside walls. Use the 215° F Output Rating with the Correction Factor for more specific design conditions. High Pressure increases Dry Weight by 15%.

Heating Capacity (PDF)

Correction Factors

Correction Factors (PDF)

How To Determine Flow Rates

The flow rate through a Runtal radiator (or series of radiators) is dependent on the length of the radiator (or combined length of the radiator series), and the design Entering Water Temperature (EWT) and the design Leaving Water Temperature (LWT).

The designer picks the design EWT and LWT. For example, he might pick 170°F as the EWT and 150°F as the LWT. The median point between these two temperatures is called the Average Water Temperature (AWT), and in this example the AWT is 160°F.

The Runtal Heating Capacity charts are based on the heating capacity per foot of radiator, based on the designer’s chosen AWT, and this heating capacity per foot is expressed in units of BTUH/FT @ a given AWT. The required flow rate (GPM) is figured as follows:

Flow Rate = (Heating Capacity/Foot X Radiator Length)

DT –LWT) X 500]

The (EWT – LWT) is commonly referred to as the “Delta T”, or “DT”.

Therefore, our Flow Rate formula becomes:

GPM = (BTUH/FT X FT of Radiator) DT (DT X 500)

As an example, let’s say our designer needs 445 BTUH/FT capacity, over a
10′-0″ span of wall, and has chosen the design water temperatures as EWT = 170°F, and LWT = 150°F. This means our AWT is 160°F. Looking in the Runtal type “R” radiator Heating Capacity chart, we see that an R-4 radiator gives us the required 445 BTUH/FT at 160°F AWT. Therefore, the required flow rate for the 10′-0″ long R-4 radiator is:

GPM = (445 BTUH/FT X 10FT) DT (20°F DT X 500) = 0.445 GPM

Note that there are various combinations of EWT and LWT that can result in the same AWT. In our example above, for instance, a 180°F EWT and a 140°F LWT result in the same 160°F AWT. With Runtal’s unique flattened water tube design, Delta T’s of up to 60°F are possible without concern that the flow rate is too low for heat transfer.

As for a maximum flow rate for Runtal radiators, we recommend no more that 1.5 GPM per water tube. For our R-4 example above, this would mean a maximum flow rate of 6 GPM for an opposite end piped radiator, or 3 GPM for a same end piped radiator.

Piping Options

A Type Connections A Type Supply Left A Type Supply Right	B Type Connections B Type Supply Left B Type Supply Right
C Type Connections C Type Supply Left C Type Supply Right	D Type Connections D Type Supply Left D Type Supply Right
Opposite End Series NOTES: Air Vent standard on the Return side of each Panel Lower Pressure Drop than Same End Series Up to 7 Radiators (100 ft) in an Opposite End Series Expansion Compensation Piping is Recommended
Same End Series NOTES: Same AWT over the entire Same End Series Can Eliminate Costly Risers Higher Pressure Drop than Opposite End Series No More than 3 Radiators in a Same End Series Expansion compensation Piping is Recommended

Piping Options (PDF)

Model Type UFLT
Pressure Drop: Opposite End

RADIATOR PRESSURE DROP – FOOT OF HEAD PER RADIATOR

RADIATOR PRESSURE DROP IS FOR THE ENTIRE RADIATOR; IT IS NOT PER FOOT OF RADIATOR

Pressure Drop: Opposite End (PDF)

Pressure ratings for the radiation shall be as follows:

STANDARD: Working pressure-56 PSI maximum, Test Pressure-74 PSI maximum
HIGH: Working pressure-128 PSI maximum, Test Pressure 184 PSI maximum

Detailed Specifications (PDF)

Overview (PDF)

Model Type UFLT
Wall Mounting

Wall Mounting (PDF)

The panel radiation shall be cleaned and phosphatized in preparation for the powder coat finish. The radiation is then finish painted with a gloss powder coat finish, for a total paint thickness of 2-3 mils (0.002” – 0.003”). The color shall be selected from Runtal’s ten Standard Colors; or Runtal Optional Colors shall be available at and additional cost.

Detailed Specifications (PDF)

Color Options 

Valves & Vents (PDF)

Runtal Flex Connector (PDF)

All Runtal radiators are covered by a 5-Year Limited Warranty.

Warranty (PDF)

1. Radiators are boxed together in as few crates as possible. A box of brackets is included as a separate piece, and it is marked to denote brackets. Inside the crates, each panel is wrapped in foam sheeting. Saving this foam to re-wrap the panel once it is wall mounted will protect it from construction site damage.
2. Each radiator is tagged with a label that indicates the project name, model type, color, connection code, bracket type & quantity and tag number. The tag number will usually designate a floor level and room number for easier placement on the job. Locate each radiator as required.
3. Carefully place each radiator face down on a smooth level surface (e.g. floor or table). Distribute the K12 wall brackets for each radiator. The tag on the radiator indicates the quantity of brackets. Mount the brackets securely on wall studs, spacing them as evenly as possible at 2 to 4 feet apart, with a bracket at least 12 inches from each end of the panel. Allow a minimum of 3 inches below each panel radiator to facilitate cleaning and to assure proper output. For baseboard models, 2 inches or even 1 inch above the floor is permissible with little loss of heat output.
4. RADIATORS WITH FINS (BACK SIDE OF PANEL)
   With the radiator face down, attach each K12 clip to the fins at the stud location. With the radiator still face down, thread the K45 offset bolts (5/16” carriage bolts) into the bottom threaded positions with a crescent wrench. Once the bolts have cleared the paint away, they should turn easily by hand. Attach the K12 bracket to the wall stud with 2 lag bolts. Hang the panel onto the brackets to determine if the K45 offset bolts are properly adjusted. Check that the panel is level.
5. RADIATORS (NO FINS ON BACK SIDE OF PANEL)
   With the radiator face down, attach each K12 clip to the radiator’s perforated steel mounting channel at the K12 stud locations. With the radiator still face down, thread the K45 offset bolts (5/16” carriage bolts) into the bottom threaded positions with a crescent wrench. Once the bolts have cleared the paint away, they should turn easily by hand. Hang the panel onto the brackets to determine if the K45 offset bolts are properly adjusted. Check that the panel is level.
6. Remove the radiator from the wall, and thread the supply and return fittings into the connections on the panel. The sealing tape or pipe dope used is the installer’s choice – make sure the connections are leak tight. One quarter of a turn past hand tight is usually sufficient. Use the foam wrap as a pad for the face of the panel while tightening up the fittings. Each radiator needs to be fitted with a 1/8” air vent prior to startup.
7. FLOOR POST & PEDESTAL MOUNTED RADIATORS
   When using floor posts, each post must line up with a corresponding K45 offset bolt attached to the back side of the radiator. Using this spacing as a guide, securely fasten each floor post to the floor, using appropriate fasteners. The K12 wall bracket is attached to the floor post, and the K12 clip to the radiator, as described in step #4. The nut and bolt used to attach the K12 bracket to the floor post is to be supplied by others.
   For pedestal mounting, the pedestals should be arranged so that the end pedestals sit within 12 inches of each end of the radiator, with the remainder spaced evenly along the radiator’s length. Each pedestal should be securely fastened to the floor using appropriate fasteners. Radiators sit on the pedestals, with the “fingers” of the pedestals sticking up between the fins to provide stability.
8. Radiators expand a maximum of 0.016 inch per linear foot of length if heated to 215°F. Piping attached to the radiator must provide the necessary expansion compensation.
9. Once the radiators are installed, the system can be tested to 50 psi. DO NOT OVER-PRESSURIZE THE RADIATORS as permanent damage may be done.
   • Standard Pressure Panels: Maximum 56 psi
   • High Pressure Panels: Maximum 128 psi
   • When the system has been shown to hold 50 psi maximum air, the piping and radiators can be filled with water. As water fills the system and radiators, air is forced to the vent fittings. Vent as much air as possible before turning on the circulating pump(s).
10. When the system is filled, operate the circulator(s) to force the remaining air to the high points of the system. With the system pressurized, turn off the circulator(s) to vent the panels. Each radiator should be individually bled of air. Once cold venting has been completed, heat the system to design temperature and repeat the venting procedure as many times as necessary to remove all air from the system.

Radiator Installation Instructions (PDF)

1. Radiators are manufactured in the USA of cold rolled low carbon steel and should be used only in closed closed hydronic systems to assure no corrosion of any system components.
2. Proper radiator operation depends on adequate flow of water to the panel, which can only be accomplished when all the system air has been fully vented from the panels.
3. Radiators should each be vented, with the system pressurized but in a static state (pumps off). Venting may need to be done periodically to assure a closed system.
4. DO NOT OVER-PRESSURIZE RADIATORS:
   Most radiators are standard pressure construction. Standard pressure radiators should be tested with NO MORE THAN 50 PSI.
5. Radiator Operating Pressure Ratings:
   Standard Pressure – 56 psi max (Tested at 74 psi)
   High Pressure – 128 psi max (Tested at 184 psi)
6. Radiators expand a maximum of 0.016 inch per linear foot of length if heated to 215°F. Piping attached to the radiator must provide the necessary expansion compensation.
7. Flexible piping and elbowed piping are two simple ways to provide the 1/8 inch to 1/2 inch (typical) of flexibility required in expansion situations (usually series piping).
8. Runtal Radiators require less flow rate than other hydronic heating products. If flow noise is apparent, balance the system until the noise is reduced.
9. For a delta T of 20°F. (T supply minus T return), divide the total Btu/hr capacity of the loop by 10,000. This gives the Flow Rate in gallons per minute (GPM)
10. Many levels of control are available today for hydronic systems. Runtal Radiators will provide nice, even heating whether operated by a simple thermostat to baseboard loop system, or an advanced boiler reset controller with motorized mixing valves, constant circulation and 2-pipe distribution.

Operation & Maintenance (PDF)

1. Hydronic system maintenance should include routine checks for piping leaks (usually indicated by frequent makeup water), and a yearly diagnosis of the system water pH to evaluate its corrosive potential.

2. Internal radiator maintenance depends entirely on the system water makeup and proper venting. Hydronic system additives are available to passivate and protect against freezing. These additives will not significantly reduce the output of Runtal Radiators.

3. External radiator maintenance consists of keeping the surfaces clean, and any paint nicks or deep scratches painted with touch-up to prevent any surface rust.

4. Radiators can be painted after sanding with fine grit paper to dull the high gloss and by wiping with solvent or a tack rag. Use only oil-based enamel paint (alkyd, acrylic, urethane, epoxy) – do not use latex or lacquer paint. Use urethane or epoxy enamel for radiators located in harsh environments. Spray the paint to achieve an even coating, and let dry completely before heating the radiator.

Operation & Maintenance (PDF)

Overview (PDF)

Product Specifications (PDF)

Heating Capacity (PDF)

Correction Factors (PDF)

Piping Options (PDF)

Pressure Drop: Opposite End (PDF)

Wall Mounting (PDF)

Valves & Vents (PDF)

Runtal Flex Connector (PDF)

Warranty (PDF)

Radiator Installation Instructions (PDF)

Operation & Maintenance (PDF)

Overview (PDF)

Heating Capacity (PDF)

Correction Factors (PDF)

How To Determine Flow Rates

The flow rate through a Runtal radiator (or series of radiators) is dependent on the length of the radiator (or combined length of the radiator series), and the design Entering Water Temperature (EWT) and the design Leaving Water Temperature (LWT).

The designer picks the design EWT and LWT. For example, he might pick 170°F as the EWT and 150°F as the LWT. The median point between these two temperatures is called the Average Water Temperature (AWT), and in this example the AWT is 160°F.

The Runtal Heating Capacity charts are based on the heating capacity per foot of radiator, based on the designer’s chosen AWT, and this heating capacity per foot is expressed in units of BTUH/FT @ a given AWT. The required flow rate (GPM) is figured as follows:

Flow Rate = (Heating Capacity/Foot X Radiator Length)

DT –LWT) X 500]

The (EWT – LWT) is commonly referred to as the “Delta T”, or “DT”.

Therefore, our Flow Rate formula becomes:

GPM = (BTUH/FT X FT of Radiator) DT (DT X 500)

As an example, let’s say our designer needs 445 BTUH/FT capacity, over a
10′-0″ span of wall, and has chosen the design water temperatures as EWT = 170°F, and LWT = 150°F. This means our AWT is 160°F. Looking in the Runtal type “R” radiator Heating Capacity chart, we see that an R-4 radiator gives us the required 445 BTUH/FT at 160°F AWT. Therefore, the required flow rate for the 10′-0″ long R-4 radiator is:

GPM = (445 BTUH/FT X 10FT) DT (20°F DT X 500) = 0.445 GPM

Note that there are various combinations of EWT and LWT that can result in the same AWT. In our example above, for instance, a 180°F EWT and a 140°F LWT result in the same 160°F AWT. With Runtal’s unique flattened water tube design, Delta T’s of up to 60°F are possible without concern that the flow rate is too low for heat transfer.

As for a maximum flow rate for Runtal radiators, we recommend no more that 1.5 GPM per water tube. For our R-4 example above, this would mean a maximum flow rate of 6 GPM for an opposite end piped radiator, or 3 GPM for a same end piped radiator. 

Piping Options (PDF)

Pressure Drop: Opposite End (PDF)

Pressure ratings for the radiation shall be as follows:

STANDARD: Working pressure-56 PSI maximum, Test Pressure-74 PSI maximum
HIGH: Working pressure-128 PSI maximum, Test Pressure 184 PSI maximum

Detailed Specifications (PDF)

Overview (PDF)

Wall Mounting (PDF)

The panel radiation shall be cleaned and phosphatized in preparation for the powder coat finish. The radiation is then finish painted with a gloss powder coat finish, for a total paint thickness of 2-3 mils (0.002” – 0.003”). The color shall be selected from Runtal’s ten Standard Colors; or Runtal Optional Colors shall be available at and additional cost.

Detailed Specifications (PDF)

Valves & Vents (PDF)

Runtal Flex Connector (PDF)

All Runtal radiators are covered by a 5-Year Limited Warranty.

Warranty (PDF)

1. Radiators are boxed together in as few crates as possible. A box of brackets is included as a separate piece, and it is marked to denote brackets. Inside the crates, each panel is wrapped in foam sheeting. Saving this foam to re-wrap the panel once it is wall mounted will protect it from construction site damage.
2. Each radiator is tagged with a label that indicates the project name, model type, color, connection code, bracket type & quantity and tag number. The tag number will usually designate a floor level and room number for easier placement on the job. Locate each radiator as required.
3. Carefully place each radiator face down on a smooth level surface (e.g. floor or table). Distribute the K12 wall brackets for each radiator. The tag on the radiator indicates the quantity of brackets. Mount the brackets securely on wall studs, spacing them as evenly as possible at 2 to 4 feet apart, with a bracket at least 12 inches from each end of the panel. Allow a minimum of 3 inches below each panel radiator to facilitate cleaning and to assure proper output. For baseboard models, 2 inches or even 1 inch above the floor is permissible with little loss of heat output.
4. RADIATORS WITH FINS (BACK SIDE OF PANEL)
   With the radiator face down, attach each K12 clip to the fins at the stud location. With the radiator still face down, thread the K45 offset bolts (5/16” carriage bolts) into the bottom threaded positions with a crescent wrench. Once the bolts have cleared the paint away, they should turn easily by hand. Attach the K12 bracket to the wall stud with 2 lag bolts. Hang the panel onto the brackets to determine if the K45 offset bolts are properly adjusted. Check that the panel is level.
5. RADIATORS (NO FINS ON BACK SIDE OF PANEL)
   With the radiator face down, attach each K12 clip to the radiator’s perforated steel mounting channel at the K12 stud locations. With the radiator still face down, thread the K45 offset bolts (5/16” carriage bolts) into the bottom threaded positions with a crescent wrench. Once the bolts have cleared the paint away, they should turn easily by hand. Hang the panel onto the brackets to determine if the K45 offset bolts are properly adjusted. Check that the panel is level.
6. Remove the radiator from the wall, and thread the supply and return fittings into the connections on the panel. The sealing tape or pipe dope used is the installer’s choice – make sure the connections are leak tight. One quarter of a turn past hand tight is usually sufficient. Use the foam wrap as a pad for the face of the panel while tightening up the fittings. Each radiator needs to be fitted with a 1/8” air vent prior to startup.
7. FLOOR POST & PEDESTAL MOUNTED RADIATORS
   When using floor posts, each post must line up with a corresponding K45 offset bolt attached to the back side of the radiator. Using this spacing as a guide, securely fasten each floor post to the floor, using appropriate fasteners. The K12 wall bracket is attached to the floor post, and the K12 clip to the radiator, as described in step #4. The nut and bolt used to attach the K12 bracket to the floor post is to be supplied by others.
   For pedestal mounting, the pedestals should be arranged so that the end pedestals sit within 12 inches of each end of the radiator, with the remainder spaced evenly along the radiator’s length. Each pedestal should be securely fastened to the floor using appropriate fasteners. Radiators sit on the pedestals, with the “fingers” of the pedestals sticking up between the fins to provide stability.
8. Radiators expand a maximum of 0.016 inch per linear foot of length if heated to 215°F. Piping attached to the radiator must provide the necessary expansion compensation.
9. Once the radiators are installed, the system can be tested to 50 psi. DO NOT OVER-PRESSURIZE THE RADIATORS as permanent damage may be done.
   • Standard Pressure Panels: Maximum 56 psi
   • High Pressure Panels: Maximum 128 psi
   • When the system has been shown to hold 50 psi maximum air, the piping and radiators can be filled with water. As water fills the system and radiators, air is forced to the vent fittings. Vent as much air as possible before turning on the circulating pump(s).
10. When the system is filled, operate the circulator(s) to force the remaining air to the high points of the system. With the system pressurized, turn off the circulator(s) to vent the panels. Each radiator should be individually bled of air. Once cold venting has been completed, heat the system to design temperature and repeat the venting procedure as many times as necessary to remove all air from the system.

Radiator Installation Instructions (PDF)

1. Radiators are manufactured in the USA of cold rolled low carbon steel and should be used only in closed closed hydronic systems to assure no corrosion of any system components.
2. Proper radiator operation depends on adequate flow of water to the panel, which can only be accomplished when all the system air has been fully vented from the panels.
3. Radiators should each be vented, with the system pressurized but in a static state (pumps off). Venting may need to be done periodically to assure a closed system.
4. DO NOT OVER-PRESSURIZE RADIATORS:
   Most radiators are standard pressure construction. Standard pressure radiators should be tested with NO MORE THAN 50 PSI.
5. Radiator Operating Pressure Ratings:
   Standard Pressure – 56 psi max (Tested at 74 psi)
   High Pressure – 128 psi max (Tested at 184 psi)
6. Radiators expand a maximum of 0.016 inch per linear foot of length if heated to 215°F. Piping attached to the radiator must provide the necessary expansion compensation.
7. Flexible piping and elbowed piping are two simple ways to provide the 1/8 inch to 1/2 inch (typical) of flexibility required in expansion situations (usually series piping).
8. Runtal Radiators require less flow rate than other hydronic heating products. If flow noise is apparent, balance the system until the noise is reduced.
9. For a delta T of 20°F. (T supply minus T return), divide the total Btu/hr capacity of the loop by 10,000. This gives the Flow Rate in gallons per minute (GPM)
10. Many levels of control are available today for hydronic systems. Runtal Radiators will provide nice, even heating whether operated by a simple thermostat to baseboard loop system, or an advanced boiler reset controller with motorized mixing valves, constant circulation and 2-pipe distribution.

Operation & Maintenance (PDF)

1. Hydronic system maintenance should include routine checks for piping leaks (usually indicated by frequent makeup water), and a yearly diagnosis of the system water pH to evaluate its corrosive potential.

2. Internal radiator maintenance depends entirely on the system water makeup and proper venting. Hydronic system additives are available to passivate and protect against freezing. These additives will not significantly reduce the output of Runtal Radiators.

3. External radiator maintenance consists of keeping the surfaces clean, and any paint nicks or deep scratches painted with touch-up to prevent any surface rust.

4. Radiators can be painted after sanding with fine grit paper to dull the high gloss and by wiping with solvent or a tack rag. Use only oil-based enamel paint (alkyd, acrylic, urethane, epoxy) – do not use latex or lacquer paint. Use urethane or epoxy enamel for radiators located in harsh environments. Spray the paint to achieve an even coating, and let dry completely before heating the radiator.

Operation & Maintenance (PDF)

Overview (PDF)

Product Specifications (PDF)

Heating Capacity (PDF)

Correction Factors (PDF)

Piping Options (PDF)

Pressure Drop: Opposite End (PDF)

Wall Mounting (PDF)

Valves & Vents (PDF)

Runtal Flex Connector (PDF)

Warranty (PDF)

Radiator Installation Instructions (PDF)

Operation & Maintenance (PDF)