Radiant Underfloor Heating Systems - … quiet, dust and draft free radiant floor heating systems circulate warm water through pipes under the floor. Unlike complex commercial systems,

Design and Construction Manual NIBCO® Radiant Heat Panels

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Radiant Underfloor Heating Systems


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Radiant Heat Systems

Experience the comfort of warm floors. Imagine a warm basement, toasty bathroom floors, and dry garages.

Clean, quiet, dust and draft free radiant floor heating systems circulate warm water through pipes under the floor.

Unlike complex commercial systems, NIBCO® Radiant technology enables you to design and install your own floor heating system.

NIBCO® Radiant panels contain all the hard to find parts professionally assembled, wired, and tested in one neat package - ready to install. And no sweating or soldering required!

The piping is proven, reliable cross linked polyethylene (PEX) used by professionals and featured on many home improvement programs. PEX has been successfully used worldwide for over 30 years.


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Underfloor radiant heat uses the floor to heat the building by raising the floor temperature until the heating output of the floor matches the heat loss of the building. This creates a comfortable living environment and is energy efficient.

MAJOR SYSTEM COMPONENTS

HEAT SOURCE Every hydronic heat system needs a source of heat. NIBCO® Radiant Heat Panel systems are designed to be flexible and can be used with a domestic hot water heater or boiler. The type can be electric, natural gas propane, or even wood fired, but the heat source output must be sized to match the total load. The load is the amount of heat required to heat the building. If you are using the heat source to supply domestic water also, this amount is also part of the load.

NIBCO® RADIANT PANELNIBCO® Radiant Heat Panels are designed to control and pump the hot water through the floor. It includes a pump to move the water, a temperature gauge, a relay to activate the pump and other components. Some models include a timer to circulate water periodically to avoid staleness and a mixing valve to control the temperature of the water. The panels are modular so that multiple panels may be used for multiple heating zones.

MANIFOLDS The manifold divides the water coming from the NIBCO® Radiant Heat Panel and distributes it to multiple “circuits” (or “loops”). Valves on each loop allow you to “balance” the flow (and therefore heat) between loops.


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NIBCO® PEX RADIANT FLOOR PIPING NIBCO® PEX pipe comes in either an oxygen barrier (BARRIER-PEX) or standard grade. Both types of PEX offer the same longevity and performance qualities. Typically, 1/2” inside diam-eter pipe is used and is pre-cut in 250’ coils. Standard NIBCO® PEX is rated for potable water and heating where non-ferrous metals are present in the system. BARRIER-PEX pipe is used where it is important to restrict passage of oxygen into the system. This is critical when using cast iron boilers.

FLUID Water is used in most radiant floor systems. In closed systems where periodic usage creates the possibility of freezing, a stabilized glycol may be used in a 50 / 50 mix with water.

INSTALLATION METHODS

Slab on GradePour a minimum of 2” of concrete over the pipe on residential installations, 3” on commercial jobs. Insulation is shown underneath and on the edges of the slab.

These handy clips hold NIBCO® PEX either to wire mesh or styrofoam. Figure 75 clips per 250’ loop of pipe:

Foam Clip# 98200

Mesh Clip# 98201

At the exit point from the slab, use PEX-PAL tube holders (PX10328) and PEX-PAL end plates (PX10329) to support the upward turn of the pipe and protect the pipe from concrete finishing tools. The photo shows PEX pipe inserted into a PEX-PAL tube holders (one PEX-PAL tube holder per loop) and a PEX-PAL end plate which creates a protective seal for the entry and exit points. Group supply and return pipes together. Cover the above slab pipe with a garbage bag to protect against concrete splatters.


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Tubes go 8” on center (two runs between each set of joists). Place tube in thermal transfer plate and nail or screw up to subfloor. This increases the heat transfer from the pipe to the floor.

Place batts of insulation under the tubes - but provide a 1” air space between the plates and the insulation. Foil faced insulation is preferable - but not required.

The plates should be spaced from 1” - 6” apart end to end. At the end of each run, you can simply loop the pipes underneath the joists. However, if the room below is to be finished or is unheated, it is necessary to drill holes and feed the pipe through the joists.

One way to perform this type of installation is to run a loop down one end of the joists (left drawing) Then, in each joist pocket, draw a loop of pipe all the way down to the other end of the joists (right drawing). Then attach your plates.

Between Joists


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1. Maximum loop length is 250’, there is no minimum length, try to make all loops the same length. Loops should be continuous pipe without splices or fittings in the concrete. 2. Maximum circuits per panel is 5 (RHP & RHP-1) or 10 (RHP-2) 3. Pipe size is 1/2” for circuits4. Pipe Size is 3/4” between the heat source, panel, and manifolds (RHP & RHP-1)5. Pipe Size is 1” between heat source, panel, and manifolds (RHP-2)6. Spacing on pipe is 12” between runs in concrete, 8” between joists...You may need closer spacing in very cold climates, with high ceilings, or with less than excellent insulation...consult NIBCO for details 7. Assuming standard spacing, estimate 1’ of pipe per square foot in a slab, 1.7’ feet of pipe per square foot if stapling up between joists 16” on center

Insulation

General Notes

Insulation is vital! Heat conducts to the coldest place - especially down into the ground. 1. Place polyethylene moisture barrier on top of fill 2. Under concrete, place 2” of extruded styrofoam 3. In moderate climates, place 1” of extruded styrofoam under concrete 4. On outer edge of slab, place 1” of extruded polystyrene

Kits: Pressure Testing / Filling & PurgingKits are available from NIBCO to facilitate filling and purging and enable a pressure test. See page 11 for more details. The Pressure Test Kit is reusable and includes a pressure gauge and tire type fill valve so you can use your air compressor to fill the system to 100 pounds for the pressure test. Then check the system in 24 hours. Plus or minus 10 pounds may be expected from expansion and contraction of the pipe. You may choose to leave the pipes pressurized during a concrete pour so you can make quick repairs to an accidental puncturing of the pipe.

PX10287 Fill and Purge Kit(Includes air eliminator) The Fill and Purge Kit contains the valves and

fittings for you to connect garden hoses for filling the system with fluid and for purging the air out. Also included is an air eliminator to screw on after purging to pull out any remaining air in the system.

Important: Do NOT use bubble or foil type insulations under concrete


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Placing The PipeAbsolute precision is not necessary. A perfect arrangement is a waste of time. Use the following tips: 1. Do not cross tubes to avoid them being too shallow in the concrete 2. Keep tubes 6” from where a partition will go, otherwise someone may puncture tubes with a nail or screw, otherwise use adhesive to attach partitions 3. Place tubes on reinforcing wire grid and attach with plastic mesh clips every three feet. If installing on styrofoam, use foam clips to hold pipe every three feet. (see page 4). 4. Ideally, initial runs should be along outside walls to deliver the most heat there 5. Concentrate tubing some in areas like bathrooms where more heat is wanted 6. At the entrance point to the slab, extend tubing up 2 -3‘ about 3-6” from an inside wall. Space the tubes in a row 2” on center with the outflow tubes grouped together and the inflow tubes grouped together. This will simplify attaching the manifolds. 7. Seal the ends of the tubes with duct tape until the manifolds are attached to keep debris out. Cover ends with a garbage bag to protect against concrete splatters. 8. Tag the ends of the tubes with a description of their location. For example, “Out to back bedroom”, “In from storage room” etc. 9. Refer to the NIBCO® PEX Installation Manual and our web site at www.nibco.com for more information. 10. You should consult your boiler vendor and / or local building inspector for other tips or code issues.

When you have purchased your system, NIBCO will prepare a custom layout at no additional charge.

Layout of NIBCO® PEX Pipe

Tubing Layout Sample

Field RepairsBefore covering the pipe, make a final inspection to detect kinks, cuts or slits. Repair or replace pipes as necessary. If you see a drop in pressure or bubbles appear during the pouring, stop immediately and repair the pipe. Or, you may place a foam block in the concrete to keep the pipe uncovered and then easily make a repair later.


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SunlightAll polyethylene pipe is sensitive to ultraviolet rays and exposure to sunlight should be minimized. If Pex will be exposed where it enters the slab for anything more than a few days, cover it with garbage bags or a similar light blocker.

Floor CoveringsFor best results, floor coverings should be consistent through each heating zone. If you have different type in different rooms, you can run separate circuits in each room, and use the valves on each circuit for balancing the heat distribution. Use of parquet or laminated wood products is acceptable, however you should use the limiting sensor function of the NIBCO® Radiant panel thermostat to prevent overheating of the floor. In any case, check with the flooring manufacturer.

Never install a wood floor over concrete until after a month of operation. Heating the concrete the first time will drive excess water out, even on a slab months old. This water can cause major damage to wood floors

Total Length of 1/2” pipe x .00921 = ______ GallonsTotal Length of 3/4” pipe x .01837 = ______ GallonsTotal Length of 1” pipe x .03025 = ______ GallonsSize of water heater or boiler = ______ Gallons

Total System Volume = _____ X .088

Minimum Expansion Tank Size = _____ Gallons (round up)

You need an expansion tank if you have a closed system. A closed system maintains the same fluid in it at all times. When the water is heated and expands, it needs a place to go, and the expansion tank fills that role. In contrast, an open system has water entering it via the municipal supply and water leaving it via plumbing fixtures. An open boiler (such as an outdoor, non-pressurized wood furnace) is also an open system. If you have a backflow preventer, this creates a closed system and you will need a tank even if you have a direct system.

To size your expansion tank, you first need to know how much water is in the system. See below:

Sizing an Expansion Tank


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TYPES OF SYSTEMS

Closed SystemA closed heating system is one where the fluid is self contained and remains in the system unless removed for maintenance. The fluid is heated by a boiler or water heater. When the thermostat calls for heat, a pump moves fluid through the floor and returns it to the heat source until the thermostat is satisfied

RHP-2 Only

PEX Pipe


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Direct (Open) SystemA direct system uses the hot water source to provide both domestic hot water and radiant heat. A timer, included with NIBCO® Radiant Heat Panels RHP-1 & RHP-2, periodically moves water through the system in off season to prevent a stale condition. A check valve may be necessary just before the fill valve to prevent domestic hot water being drawn through the floor.

PEX Pipe


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MATERIALS LISTFor most installations of NIBCO® Radiant, the materials list is simple. It includes pipe, a NIBCO® Radiant Panel, 2 fitting kits, and tools. These modular kits include everything needed to install radiant heat. You just provide the heat source. Instructions also included.

This chart covers most installations for concrete slab projects. Determine the amount of pipe footage - which in most cases is 1’ of pipe per square foot of space. In very cold climates or with higher than standard ceilings, consult with NIBCO for a custom quote since you may need closer spacing of the pipe.

HEAT REQUIREMENTSThe amount of heat needed for a structure (measured in BTU’s / hour) is equal to the amount of heat lost from the structure during the same time period. Therefore you need to know the heat loss from your building in order to size your heat source. Heat loss calculations can be quite involved, and there are numerous vari-ables which can be incorporated to get an extremely accurate result. The following simplified version makes certain assumptions which, in general, concern standard building materials. If your situation is out of the ordinary, consult a building professional or engineer. For wall and ceiling calculations, use square footage less windows, doors and skylights. Once the analysis is complete, you need a boiler or water heater rated at this output. Do not forget to add the peak requirements of domestic hot water, if using a direct (open) system. This is a guide only, and no guarantees are made that the results will be accurate. Consult your local codes and a building professional or engineer.

CLIPS:*Choose BARRIER-PEX if you are using a cast iron boiler, otherwise use standard NIBCO® PEX**The RHP model should be used for closed system only, water heater based installations Styrofoam (#98200R25) 3 bags per loopWire Mesh (#98201R25) 3 bags per loop

1/2” Pipe Feet* # 250’ Coils

3/4” Feet

1” Feet Panel Fill & Purge

Kit Pressure Test Kit (REUSABLE) Tools

250’ - 1,250’ 1 - 5 100’ — (1) RHP #PX10231 or (1) RHP-1 #PX10232** (1) #PX10287 (1) #PX10286 (1) Combo Tool #PX02555

(1) Cutter #88200

1,500’ - 2,500’ 6 - 10 5’ 100’ (1) RHP-2 #PX10233 (1) #PX10287 (1) #PX10286(1) Combo Tool #PX02555(1) Combo Tool #PX02565(1) Cutter #PX01390


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Average Seasonal Low Temperature……> -20 -10 0 10 20

CEILING (unheated above) A. R-11 Insulation 9 8 7 6 5 B. R-19 Insulation 6 5 4 3 2.6 C. R-30 Insulation 3.5 3 2.5 2 1.8 D. R-38 Insulation 3 2.5 2 1.8 1.5 _____ Factor x Sq. Ft. = _______ OUTSIDE WALLS A. R-11 Insulation 9 8 7 6 5 B. R-19 Insulation 6 5 4 3 2.6 _____ Factor x Sq. Ft. = _______ FLOOR (unheated below) A. Uninsul.Wood Frame w/ Crawl Space 21 18 15 12 10 B. R-11 Insulation Over Crawl Space 9 8 7 6 5 C. R-19 Insulation Over Crawl Space 6 5 4 3 2.6 D. R-30 Insulation Over Crawl Space 3.5 3 2.5 2 1.8 E. Uninsul. Wood Frame w/ Unheated Cellar 9 8 7 6 5 F. R-11 Insulation Over Cellar 5 4 5 2.5 2.3 G. R-19 Insulation Over Cellar 3 2.5 2 1.5 1.3 H. R-30 Insulation Over Cellar 2 1.5 1 0.9 0.8 I. Uninsulated Slab On Grade 15 13 12 10 8.5 J. R-10 Insulated Slab On Grade 4.5 4 3.5 3 2.5 _____ Factor x Sq. Ft. = _______ WINDOWS/SKYLIGHTS A. Single Glazed 90 80 70 60 50 B. Single Glazed With Storm 45 40 35 30 25 C. Double Glazed 45 40 35 30 25 D. Double Glazed (Low-E) 36 32 28 24 20 _____ Factor x Sq. Ft. = _______ EXTERIOR DOORS A. 2” Wood 40 35 30 26 22 B. 1.75” Steel With Insulated Core 40 30 30 26 22 _____ Factor x Sq. Ft. = _______ INFILTRATION Note: Cubic Feet Used for This Calc. A. Room With One Exterior Wall 0.7 0.7 0.6 0.5 0.4 B. Room With Two Exterior Walls 1.1 1 0.9 0.8 0.6 C. Room With Three Exterior Walls 1.6 1.4 1.2 1.1 0.9 D. Bathroom 1.6 1.4 1.2 1.1 0.8

_____ Factor x CUBIC Ft. = ______

TOTAL BTU’s / HOUR NEEDED: _______

NIBCO’s Customer and Technical Services Departments are available for comments, order placements, product information and technical assistance 888-446-4226

Documents

Radiant Underfloor Heating Systems - … quiet, dust and draft free radiant floor heating systems circulate warm water through pipes under the floor. Unlike complex commercial systems,