Rinnai E50C Guide

E50C Boiler
System Piping and Applications Design Manual

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Table of Contents
Table of Contents ..................................................... 2
Note to the User....................................................... 3
General Piping Informaon...................................... 4
Frequently Asked Quesons .................................... 5
Denions & Circulang Head Pressure Chart......... 6
Calculang Zone Flow Rates..................................... 7
Calculaon of Resistance of Longest Loop /
Zone in a System................................................ 8
Example Plumbing Drawings.................................. 10
Apendix A— Piping and System Components........15
Appendix B—Properes of Water.......................... 17
Appendix C—Copper Tube Heat
Transfer Capacies...........................................17
Appendix D— Example for Calculang
Equivalent Length ............................................18
Appendix E—Diverter Tee Equivalent
Length Calculaon............................................ 21
Total Equivalent Lengths Worksheet .....................22
Notes ...................................................................... 23
Tables
Table 1—General Piping Informaon.....................4
Table 2—Copper Finned Tube Base Board Specic
Informaon....................................................4
Table 3—Copper Sweat Fings Head Loss Table ..15
Table 4—Cv Values for System Parts.......................16
Table 5—M Type Copper Tubing (Feet of Head
per 100 Linear Feet).........................................16
Table 6—M Type Copper Tubing (Feet of Head
per 1 Linear Foot).............................................16
Table 7—Properes of Water ................................17
Table 8—Copper Tubing Heat Transfer Capacity
and Flow Rate ..................................................17
Drawings
Drawing 1—Example-Calculang Pressure Drop ..... 8
Drawing 2—Single Serial Flow Loop (zone)............ 10
Drawing 3—Mulple Zone Valves.......................... 11
Drawing 4—Hydronic Air Handler..........................11
Drawing 5—One Pipe System using Diverter Tee
(Mono Flow Tee)..............................................12
Drawing 6—Mulple Zone Circulators with
Low Loss Header Plumbing Kit.........................12
Drawing 7—Single Serial Flow Loop (Zone)
(Low Loss Header Plumbing Kit Required).......13
Drawing 8—Radiant Manifold System.................. 14
Drawing 9—Example-Calculang the
Equivalent Length (Alternate Method)............ 18

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It is the responsibility of the contractor and/or engineer to ensure the system is correctly designed and installed to
allow for proper boiler operaon. The guidelines and drawings in this document are for reference purposes only. This
manual is not intended to replace proper system sizing, installaon, and design by your chosen professional. The
tables presented in this document are not representave of all possible ngs and pipes or sizes, designs, and
materials available. If they are ngs or pipe sizes and materials being used that are not covered in this manual please
contact Rinnai for further informaon. This is not a product installaon manual, please refer to the installaon/
operaon manual that accompanied the product for specic informaon regarding installaon and safety.
The drawings shown in this document are not engineering drawings; they are intended only as a guide and not as a
replacement for professional engineering project drawings. These drawings are not intended to describe a complete
system. It is up to the contractor or engineer to determine the necessary components and conguraon of the
parcular system to be installed. The drawings herein do not imply compliance with local building code requirements.
It is the responsibility of the engineer or contractor to ensure that the installaon is in accordance with all local
building codes. Confer with local building ocials before installaon. The piping arrangements shown in the drawings
herein are not representave of engineered drawings and are for illustraon purposes only and do not represent
calculated loop lengths or pressure drops.
All of the calculaons and tables in this manual are for use with water only systems. When anfreeze is added to any
system the properes of viscosity and heat transfer are altered. Please contact your anfreeze manufacturer for
addional informaon on how to perform system calculaons when using anfreeze.
Proper installaon in a proper environment with the correct tools and materials is the responsibility of the installer. It
is the responsibility of the consumer and/or installer to verify water quality at the applicaon and to check all local and
naonal codes. Rinnai America Corporaon, its agents, employees, directors, ocers, parent and aliate companies
assume no liability for any damage arising from incorrect usage of or reliance on the informaon provided in this
manual which is solely for reference or guidance, or for the failure to have adequate water quality, or to comply with
local and/or naonal codes.
NOTE TO USER

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General Piping Informaon
Copper Finned Tube Base Board Specic Informaon
1) Assumes copper nned baseboard with an output of 510 BTU per linear foot @ 2.0 gpm ow rate and 170°F
entering water temperature.
2) Based on the use of type M copper tubing
3) Based on 2.0 gpm ow rate, higher ow rates will reduce the maximum loop length.
4) Refer to example located in Appendix D.
Zone Pipe Size ½” ¾” Single Heang Loop
Minimum Header Pipe sizing 1” 1” ¾”
Maximum system ow (gpm) 4.5
Maximum Available circulator
head pressure for heang loop
(/psi)
4.6 feet of head
(2.0 psi)
Table 1
Table 2
Noce
The gures in tables 1 & 2 are for use with copper tube aluminum nned baseboard only. If the boiler is installed in a
system that ulizes other types of heat emiers or piping such as:
 cast iron base board
 cast iron radiators
 steel panel radiators
 air handlers
 black iron piping
 PEX piping
 piping, ngs, and emiers other than copper
Then the maximum ow rate and available pump head should be used to determine if the boiler is suitable for
installaon without the addion of a Rinnai low loss header plumbing kit (part number 804000061). It is the
responsibility of the contractor or engineer to calculate the pressure drop through the system and the required ow
rate for the heat emiers and the enre system to operate correctly.
Zone Pipe Sizing ½” ¾” Single Heang Loop
System
Maximum ow per loop @20°F ∆T
(gpm) 2.2 2.2 4.5
Maximum BTU output (MBH) 45
Maximum BTU load per zone (MBH) 22.5 22.5 45
Minimum number of zones
22NA
Maximum number of zones
33NA
Maximum feet of nned tube
baseboard 43’143’143’
Maximum loop length (equivalent
feet)250’3200’392’

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In a mulple temperature system ulizing a thermostac mixing valve or a third party motorized mixing control, a low
loss header plumbing kit (part number 804000061) must be used.
ATTENTION
How to decide if a low loss header plumbing kit is required or not for the E50C boiler?
The following instrucons will guide you through how to determine if the E50C boiler can be used for your applicaon
and then how to correctly pipe your system for use with the E50C boiler.
How to conrm your system is suitable for use for the E50C:
1) Is the system a single zone or mulple zone system?
Answer: The E50C boiler can be used for both types of systems.
2) If the system has mulple zones; can zone valves and/or circulators be used?
Answer: The E50C boiler (as shipped from the factory) should only be ulized in systems with zone
valves. Systems which ulize mulple zone circulators instead of zone valves must be coupled
to a Rinnai boiler that has a low loss header as standard equipment or a low loss header
plumbing kit part number: 804000061 must be purchased and connected to the E50C boiler.
The following models are supplied with a low loss header from the factory: E75C, E110C, Q85S,
Q130S, QP85, and QP130. Rinnai strongly recommends the use of full port ball valve type
zone valves to allow for the best performance of the boiler and system.
3) What is the pressure drop across the longest loop/zone in the system or what is the total pressure drop in the
single zone system?
Answer: See table 1 and/or gure 1 to determine if the boiler circulator has enough feet of head to
properly pump the enre system without the addion of a low loss header plumbing kit.
4) What type heat emiers can be ulized?
Answer: The E50C boiler can be ulized with some types of heat emiers without a low loss header
plumbing kit as long as the total system ow requirements and pressure drop requirements are
observed, which means no more than 4.5 gpm of ow and 4.6 feet of head (2.0psi) of pressure
drop through the longest loop in the system.
5) When doing a boiler replacement in a single zone with a system (loop) circulator how do you know if a low loss
header is needed?
Answer: The rst thing that should be done when installing the E50C boiler is to calculate the pressure
drop through the loop. Do not include the exisng pump in the pressure drop calculaon. If
the pressure drop in the loop is less than 4.6 feet of head, then the exisng pump should be
removed and the boiler can be piped directly to the system. If the pressure drop is greater
than 4.6 feet of head, then a low loss header plumbing kit should be installed in between the
boiler and the system pump as shown in drawing number 7.
If the E50C boiler is installed in a system with zone valves and the constant recirculaon funcon is acvated, then a
dierenal pressure bypass valve or a low loss header plumbing kit is required to be installed.
Frequently Asked Quesons
When installing the E50C boiler in systems with dissimilar metals, Rinnai strongly recommends the use of dielectric
unions in between the boiler and the system.
ATTENTION

6
Circulator Head Pressure
Figure 1
2 psi =
The dierence between the resistance curve of the heat exchanger and the circulator curve is the available pump
head for the system. The maximum available head pressure from the boiler circulator for the system is 2 psi = 4.6
feet of head at 4.5 gpm.
Single Heang Loop System – A single heang loop system can be considered any of the following piping
arrangements: series loop, one pipe with diverter tees, or two pipe reverse return. These types of systems will have
only a single room thermostat centrally located that controls the boiler.
Zoned System – A zoned system is a heang system that ulizes mulple zones which are individually controlled by
room thermostats. The individual zones can be congured in series, with diverter tees, or a two pipe reverse return.
Diverter Tee – A diverter tee is a device that creates a pressure dierenal through the use of an orice inside a tee
pipe ng. The pressure dierenal forces water into the branch o of the main line. A diverter tee is also commonly
known as a mono ow tee.
Zone pipe Size – This is the diameter of the zone or branch of piping that comes o of the main or header.
Denions

7
Noce
Zones should be balanced using balancing valves to ensure the correct output (ow rate) of each zone. Use the
hydronic formula to calculate the ow rate for each zone. The constant 500 is based on the use of water as the heat
transfer uid in the system, where 8.33 pounds/gallon of water x 60 minutes per hour = 500. If glycol is used please
contact the manufacturer to nd the correct value for the density of the glycol water mixture.
Calculang Zone Flow Rates
Hydronic Formula
20’ x 510 BTU = 10,2000 BTU
170°F 150°F
A zone has 20 total feet of nned tube base board. The baseboard has a BTU output of 510 BTU per linear foot
according to the manufacturer. The design day temperature for the baseboard is 170°F and the zone will be run at a
20°F delta T. What is the correct ow rate for this zone?
Total BTU for the loop = 510 BTU x 20 = 10,200
Example of the use of the Hydronic Formula
GPM= 10,200 BTU
20 X 500
GPM= 1.02

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In order to correctly calculate resistance rst determine the longest equivalent length loop in the system. The length
of this loop is calculated starng at the supply connecon of the boiler and ending at the return connecon to the boil-
er. Select this loop for your calculaons.
The system/longest loop head pressure can be determined by adding up all the ngs in the longest loop and the total
length of straight pipe in the longest loop to get an equivalent length.
If the pressure drop in the loop/system is greater than the available head pressure from the boiler circulator a Low
Loss Header Plumbing kit part number: 804000061 must be used.
If the boiler is to be installed in a system that ulizes zone circulators and not zone valves, a low loss header
plumbing kit is required to be installed.
Rinnai strongly recommends the use of full port ball valve zone valves; these valves provide a lower pressure drop than
a gate valve type zone valve. The lower pressure drop will allow for longer loop lengths and beer ow through the
zones.
ATTENTION
= specic weight of uid at operang temperature (the specic weight of water is given in appendix B table 7)
Flow rate = ow rate through the device
Cv = value from the device manufacturer
To calculate the resistance for a ng, reference Appendix A tables 5 and 6 (when using copper tubing).
Example – Calculang the Pressure Drop
Drawing 1
Calculang the Resistance of the Longest Loop/Zone in a System

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The single zone serial ow system in Drawing 1 consists of the following copper ngs and tubing and is designed to
operate at 4.0 gpm ow rate at 170°F supply temperature. (Below is a list of each type of component and quanty of
the components contained in drawing 1.)
a. 6 - 90° elbows ¾”
b. 8 - Tees (straight run) ¾” (PRV tee, Tridicator tee, boiler drain tee, purge tee, 2 x bypass tees)
c. 3 - Ball valves (standard port) ¾”
d. 40 feet of 3/4” copper type M tubing
e. 1 – air separator ¾”
f. 1 – dirt trap ¾”
1) To calculate the total equivalent length, add up the number of each type of ng and mulply the number of each type of
ng by its equivalent length. See Appendix A table 3 for equivalent lengths of ngs. The chart below is an example of the
calculaon (also a blank worksheet is included on page 22 of this manual) . Add up the equivalent lengths of the ngs using the
worksheet for your calculaons.
2) Add the total equivalent length of the ngs from step 1 to the length of straight tubing:
3) Convert equivalent feet pipe from step 2 to feet of head. (See Apendix A table 6 for the feet of head per linear foot.)
equivalent feet of pipe x feet of head per liner foot = feet of head
61.8’ x 0.035 = 2.16 feet of head
5) Convert the pressure drop calculated in step 4 from psi to feet of head. (1psi = 2.3 feet of head)
6) Add the feet of head from step 3 with the feet of head of the two ngs calculated in step 5.
2.16 + 0.472 + 0.472 = 3.1 feet of head
4) Calculate the pressure drop of the addional ngs e and f by using the Cv value of ngs from Appendix A table
4 and for the values of from appendix B table 7:
Pressure Drop (psi) = 2.3 X Pressure Drop (psi) from step 2
Pressure Drop (feet of head) = 2.3 X 0.205
Pressure Drop (feet of head) = 0.472
Pressure Drop (psi)
Pressure Drop (psi)
Pressure Drop (psi)
(Abbreviated Sample of Worksheet 1)

10
Example Piping Drawings
The drawings in this secon represent only a few of the piping opons and system concepts the boiler can be
connected to and are not intended to serve as engineering or design drawings.
Noce
Rinnai recommends that the tee ngs for the pressure relief valve and the boiler drain are placed directly below the boiler as
shown in the drawing above. These ngs then can be ulized as connecon points for taking a dierenal pressure in the
event it is required for nding the pressure drop through the system.
Drawing 2
Single Serial Flow Loop (zone)
Less than 4.6 feet of head pressure drop