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GARN System Design ManualHot Water Supply2” FPTHot Water Return1-1/2” MPTDECTRA CORPORATION 3425 33rd Ave NE St Anthony, Minnesota 55418Phone: 612-781-3585 Fax: 612-781-4236 www.garn.com 2012 DECTRA CORPORATION. All rights reserved. No part of the contents of this manual may be reproduced or transmitted in any form or byany means without the written permission of DECTRA CORPORATION.Hydronic System Design Manual DECTRA CORPORATION - March 20131

The GARN unit, all related heating equipment (including pumps, piping, fan coils, hot water baseboard, radiantfloor heating systems, etc) and all electrical equipment (including power wiring, controls, control wiring, back upelectric heating, etc) must be installed by a qualified installer or competent licensed personnel in strict compliancewith all Federal, State and local codes. All electrical equipment, devices and wiring installed with the GARN unitmust be UL listed. Installer to supply and install all code required electrical over current and disconnect devices.Table of ContentsA.SYMBOLS, ABBREVIATIONS, and safety symbols: . 4B.PROMOTING CONSERVATION AND EFFICIENCY BEFORE ANYTHING ELSE: . 5PROBLEMS WITH IMPROPERLY COMBUSTED FUEL: .5HEATING A SWIMMING POOL: .5C.RULES OF THUMB FOR AN INITIAL ESTIMATE OF EQUIPMENT SIZE . 6COMMERCIAL HEAT LOSS: .6RESIDENTIAL HEAT LOSS EXCLUDING VENTILATION: .6RESIDENTIAL VENTILATION: .6RESIDENTIAL DOMESTIC WATER HEATING: .7HOT TUB HEATING: .7RADIANT FLOOR HEATING: .7FORCED AIR HEATING: .8HOT WATER BASEBOARD HEATING: .9GLYCOL CORRECTION FACTORS AND FREEZE PROTECTION TABLES:.10The difference between freeze and burst protection: (DOW Chemical).11PUMP LAWS AND FAN LAWS: .11D.PIPING AND PUMP SIZING . 12PIPING DESIGN AND CALULCATION GUIDELINES .12EQUIVALENT FEET OF PIPE FOR SCREWED FITTINGS AND VALVES .12EQUIVALENT FEET OF PIPE FOR PEX FITTINGS .13Flow and heat capacity @ 4' of head loss per 100' of pipe length .13Flow and heat capacity @ 6' of head loss per 100' of pipe length .14PRESSURE LOSS CHARTS: STEEL, COPPER, PEX .15PIPING INSTALLATION AND HOOKUP GUIDELINES .16PLUMBING WITH COPPER: .16PLUMBING WITH STEEL: .16CALCULATION OF NET POSITIVE SUCTION HEAD FOR PUMPS .17UNDERGROUND PIPING:.19DRY AREA BURIED PIPING DIAGRAM: .19MOIST AREA BURIED PIPING DIAGRAM: .20ROADWAY AND PARKING LOT BURIED PIPING DIAGRAM: .21PUMP SELECTION AND INSTALLATION GUIDELINES: .21E.SYSTEM DISTRIBUTION CONNECTION AND SCHEMATICS . 23ZERO PRESSURE, FIXED TEMP - PRIMARY ONLY PUMPING: .23ZERO PRESSURE, FIXED SUPPLY TEMP – PRIMARY SECONDARY PUMPING: .24ZERO PRESSURE, MULTIPLE ZONE – PRIMARY SECONDARY PUMPING: .25CONNECTING TO AN EXISTING PRESSURIZED OR GLYCOL TREATED DISTRIBUTION SYSTEM: .27Hydronic System Design Manual DECTRA CORPORATION - March 20132

PRESSURIZED, FIXED SUPPLY TEMP – CONSTANT SPEED PUMPING .28PRESSURIZED, FIXED SUPPLY TEMP – VARIABLE SPEED PUMPING.29F.SYSTEM COMPONENT CONNECTION AND SCHEMATICS . 30CONNECTION TO FORCED AIR FURNACE: .30FORCED AIR GUIDELINES:.30COIL SELECTION.31HIGH LIMIT SWITCH (DUCT STAT) .31BLOWER SPEED AND CFM ADJUSTMENT .31CONNECTION TO HOT WATER BASEBOARD SYSTEM: .32HOT WATER BASEBOARD GUIDELINES .32NEW CONSTRUCTION .33CONVERTING AN EXISTING BASEBOARD SYSTEM .33CONNECTION TO HYDRONIC RADIANT FLOOR SYSTEM: .34RADIANT FLOOR GUIDELINES: .34CONNECTION TO AN EXISTING PRESSURIZED SYSTEM .35WATER TO WATER FLAT PLATE HEAT EXCHANGERS .36CONNECTION TO AN ELEVATED SYSTEM .37CONNECTION TO DOMESTIC HOT WATER .37SOLAR INTERFACE: .39G.BACKUP HEATING WITH THE EXISTING SYSTEM OR ELECTRIC . 40H.EXAMPLE PROBLEM – HOUSE WITH REMOTE POLE BARN/WORKSHOP . 41EXAMPLE PROBLEM SETUP: .41HOUSE DESIGN:.41MAIN FLOOR DESIGN: .41BASEMENT LEVEL DESIGN: .43SIZE THE main floor HOUSE PUMP.43SIZE THE BASEMENT PUMP .44DISTRIBUTION PIPE AND PUMP SIZING .44SIZE DISTRIBUTION PUMP.45POLE BARN DESIGN .45SIZE POLE BARN PUMP .46Hydronic System Design Manual DECTRA CORPORATION - March 20133

A. SYMBOLS, ABBREVIATIONS, AND SAFETY SYMBOLS:ABBREVIATIONSSYMBOLSBTUHBTU’s per hourPumpEWTEntering Water TemperatureStrainerFPSFeet per secondFlow ArrowFPTFemale Pipe ThreadMixing ValveGPMGallons per minuteIsolation ValveHWS/HWR Hot Water Supply/Hot Water ReturnFlangeMBHMBTU’s (1,000 BTU) per hourThermometerMMBHMMBTU (1,000,000 BTU) per hourTemperature SensorMPTMale Pipe ThreadCheck ValveNPTNational Pipe ThreadDrainODOutdoorConnect to ExistingRWTReturn Water TemperatureA notice provides a piece of information to make a procedure easier or clearer.A caution emphasizes where equipment damage might occur. Personal injury isnot likely.A warning emphasizes areas where personal injury or death may occur but is notlikely. Property or equipment damage is likely.A danger emphasizes areas or procedures where death, serious injury, or propertydamage is likely if not strictly followedHydronic System Design Manual DECTRA CORPORATION - March 20134

B. PROMOTING CONSERVATION AND EFFICIENCY BEFOREANYTHING ELSE:PROBLEMS WITH IMPROPERLY COMBUSTED FUEL:Improperly combusted wood fuel emissions are toxic to humans and animals. These emissions include:finely atomized liquid oils (creosote), very fine particulates, aromatic hydrocarbons, polycyclic organicmatter, carbon dioxide, and carbon monoxide. In fact, population densities in suburban and urbanlocations create significant local air shed pollution issues that essentially preclude the use of coal, woodand other fuels. Complete combustion reduces these by-products significantly.BUT! Remember this: Eliminating fuel usage is the same as burning fuel with absolutely zero emissions,impossible for any fuel, even natural gas! A well designed and constructed energy efficient building canreduce heating demand and fuel usage by at least half or more when compared to a “code built house.”By following the simple suggestions below, you will reduce fuel usage and annual fuel bills, create acomfortable and healthy environment for the occupants, contribute to a healthier local air shed, andrealize a reasonably quick return on investment. Install good insulation and caulking.Install double glazed, argon filled energy efficient windows (or better).Install insulated thermally efficient doors and storm doors, with good quality weather stripping.Install an air-to-air heat exchanger (heat recovery ventilator) to provide ventilation.Insulate and caulk all rims joists.Insulate basements walls from floor to ceiling with methods that prevent the formation of moldand mildew.Utilize passive solar techniques whenever possible.Install water saving toilets, showers and faucets throughout.If you have access to natural gas, use a high efficiency natural gas condensing furnace or boilerto provide space and domestic water heating. Don’t burn wood unless you want to.Install only high SEER air conditioning equipment with variable speed fans to effectively controlindoor relative humidity.HEATING A SWIMMING POOL:This is best accomplished with solar heating and an evaporation prevention blanket. Solar heating hasproven cost effective, dependable and efficient for many years in many countries. Solar heating isefficient in almost every area of the US. Most people do not realize that a swimming pool requires aheater that may be several times the size and capacity of their residential space heater. However, duringthe spring, summer and fall the amount of energy required to heat a pool is easily provided by solarpanels.For more information on solar pool heating products com/http://www.h2otsun.com/Hydronic System Design Manual DECTRA CORPORATION - March 20135

C. RULES OF THUMB FOR AN INITIAL ESTIMATE OFEQUIPMENT SIZEThe following are approximate values that may be used to estimate the size of the primary woodheating equipment. Once a project is given the “go ahead” an exact heat loss should be calculatedaccording to ASHRAE Fundamentals or Manual J methods to ensure correct sizing. Over-sizingequipment leads to excessive first cost, inefficient operation, and increased emissions.There are software packages that calculate an accurate heat loss value based on the detailedconstruction of the building. An example is Elite Software’s RHVAC program. DECTRA CORPORATIONcan run an in-depth heat loss analysis for a fee.To learn more about Elite Software RHVAC or to purchase a software license visit:http://www.elitesoft.com/COMMERCIAL HEAT LOSS:Calculating the heat loss for commercial buildings can be more complicated than for residentialstructures because the building type and application vary significantly. The easiest way to get a handleon heat loss figures for a commercial facility is to use a computer software package. A good commercialheat loss packages is Elitie Software’s CHVAC program.To learn more about Elite Software CHVAC or to purchase a software license visit:http://www.elitesoft.com/RESIDENTIAL HEAT LOSS EXCLUDING VENTILATION:Above Grade FloorArea (BTUH/sq. ft.)Below Grade FloorArea (BTUH/sq. ft.)Old/Poorly Insulated HouseUninsulated basementNewer HouseInsulated BasementEnergy Efficient HouseInsulated Basement25 to 3513 to 248 to 1518 to 3010 to 208 to 12RESIDENTIAL VENTILATION: In newer, tighter energy efficient houses, mechanical ventilation is required at a generallyaccepted rate of 15 cfm per person. The following should be added to the heat loss for newerhouses, but not added to the heat loss of older houses (unless the older house has beenreinsulated and tightly sealed against air leakage).Heat Recovery Ventilator Not Used Heat Recovery Ventilator Used6,000 BTUH/person3,000 BTUH/personFor more information on HRV products dential.fantech.net/Hydronic System Design Manual DECTRA CORPORATION - March 20136

RESIDENTIAL DOMESTIC WATER HEATING: Maximum delivered water temperature must be 120 F or less. An anti-scald valve is required bymost codes on the discharge of the water heater. Maintain the water heater at 140 F or higherto kill bacteria and virus.Normal Family of 4, Modest Size House Larger Family in Larger House40,000 BTUH recovery rate75,000 BTUH recovery rate50 to 75 gallon water heater100 to 120 gallon water heaterHOT TUB HEATING: Small (7’ to 10’ square x 4’ deep) insulated outdoor hot tubes with an insulated cover generallyrequire only 2,000 to 2,500 BTUH to maintain temperature when the tub is covered at outdoortemperatures of –20 F. It is assumed that the hot tub is used for brief periods (say 1 to 2 hoursper day) during which time the evaporative cooling of the water’s surface is the primary heatloss and may equal 6,000 to 9,000 BTUH. Any heat exchanger used to heat a hot tub should besized for this larger value.RADIANT FLOOR HEATING: Normal temperature drop is 10 F to 20 F per tube length.Try not to exceed a floor surface temperature of 85 F (comfort and finish materials limitations).Always insulate beneath a radiant floor system whether on or above grade. 2” of blue, pink,green or yellow board (not white bead board or polyurethane) is strongly recommend for slabon grade concrete slabs and R13 is the minimum recommended for upper level wood floors.Maximum Flow1/2” PEX Tubing5/8” PEX Tubing0.575 gpm1 gpmMaximum Length ofIndividual Tube Run300 ft450 ftTypical Maximum Numberof Tubes per Manifold812GARN recommends the use of oxygen-barried, PEX-a tubing. For more information mfortprosystems.comOXYGEN-BARRIED PEX-A TUBING IS NECESSARY IN ORDER TO MINIMIZE THEPOTENTIAL FOR CORROSION.Hydronic System Design Manual DECTRA CORPORATION - March 20137