Velocity MS2-030 User manual

VELOCITY LOGO CMYK COLORS
Mega-Stor®II
Stainless Steel, Indirect Water Heaters
INSTALLATION AND OPERATING INSTRUCTIONS
CAUTION
1. The heat transfer-medium must be water or other nontoxic uid having a
toxicity rating or Class of 1, as listed in Clinical Toxicology of Commercial
Products, 5th edition.
2. The pressure of the heat transfer medium must be limited to a maximum of
30 PSIG by an approved safety or relief valve.
Velocity Boiler Works, LLC
P.O. Box 14818
3633 I Street
Philadelphia, PA 19134
www.velocityboilerworks.com
5003502
980155 Rev C - 02/18

2

1
IMPORTANT INFORMATION - READ CAREFULLY
NOTE: The equipment shall be installed in accordance with those installation regulations enforced in the area where the
installation is to be made. These regulations shall be carefully followed in all cases. Authorities having jurisdiction
shall be consulted before installations are made.
All wiring on indirect water heaters installed in the USA shall be made in accordance with the National Electrical Code and/or
local regulations.
All wiring on indirect water heaters installed in Canada shall be made in accordance with the Canadian Electrical Code and/or
local regulations.
The following terms are used throughout this manual to bring attention to the presence of hazards of various risk levels,
or to important information concerning product life.
The City of New York requires a Licensed Master Plumber supervise the installation of this product.
The Commonwealth of Massachusetts requires this product to be installed by a Licensed Plumber.
DANGER
Indicates an imminently hazardous situation
which, if not avoided, will result in death, serious
injury or substantial property damage.
CAUTION
Indicates a potentially hazardous situation
which, if not avoided, may result in moderate or
minor injury or property damage.
WARNING
Indicates a potentially hazardous situation
which, if not avoided, could result in death,
serious injury or substantial property damage.
NOTICE
Indicates special instructions on installation,
operation, or maintenance which are important
but not related to personal injury hazards.

2
WARNING
Scald Hazard. This indirect water heater requires regular maintenance and service to operate safely.
Follow the instructions contained in this manual.
Improper installation, adjustment, alteration, service or maintenance can cause property damage,
personal injury or loss of life. Read and understand the entire manual before attempting installation,
start-up operation, or service. Installation and service must be performed only by an experienced,
skilled, and knowledgeable installer or service agency.
Installation is not complete unless a temperature and pressure relief valve is installed into the tapping
located on top of the indirect water heater. - See Section V of this manual for details.
Burn Hazard. This indirect water heater contains very hot water under high pressure. Do not unscrew
any pipe ttings nor attempt to disconnect any components without positively assuring the water is
cool and has no pressure. Always wear protective clothing and equipment when installing, starting up
or servicing this product to prevent scald injuries. Do not rely on the pressure or temperature gauges
to determine the temperature and pressure of the water heater. Portions of this indirect water heater
and connected piping become very hot while operating. Do not touch any components unless they
are cool.
Failure to follow all instructions in the proper order can cause personal injury or death. Read all
instructions, including all those contained in component manufacturers manuals which are provided
before installing, starting up, operating, maintaining or servicing.
All cover plates, enclosures and guards must be in place at all times.

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FOLLOW ALL INSTRUCTIONS and warnings
printed in this manual and posted on the indirect
water heater.
MAINTAIN THIS PRODUCT. To keep your indirect
water heater safe and reliable, have a service
technician maintain it as specified in this manual.
IF YOU ARE NOT QUALIFIED to install or service
boilers and water heaters, do not install or service
this one.
THIS INDIRECT WATER HEATER MAY LEAK
WATER at the end of its useful life. Be sure to
protect walls, carpets, and valuables from water
that could leak from the indirect water heater.
PROTECT YOUR HOME IN FREEZING
WEATHER. A power outage, safety lockout, or
component failure will prevent your boiler from
lighting. In winter, your pipes or this indirect
water heater may freeze and cause extensive
property damage. Do not leave the heating system
unattended during cold weather unless alarms
or other safeguards are in place to prevent such
damage.
WARNINGS FOR THE HOMEOWNER
83.50
3
158.75
216.50
DANGER
BURN
HOT
!
IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF
Products, 5th Edition.
EXCEPT WHERE SHOWN OTHERWISE.
D
C
B
A
B
C
D
1
2
3
4
5
6
78
87654321
PART NUMBER 980014
can cause severe burns
Feel water before bathing or
Danger/Scald Label
available, see manual.
Children, disabled and elderly
CAUTION LABEL
0.10"
limited to a maximum of 30 psi by an
CROWN BOILER COMPANY IS PROHIBITED.
PROPRIETARY AND CONFIDENTIAL
CHANGE CBC TO VBW, CHANGED WORDING OF UNLESS OTHERWISE SPECIFIED:
in Clinical Toxicology of Commercial
heater.
See instruction manual before
0.03"
Temperature limiting valves are
Water temperature over 125°F
THREE PLACE DECIMAL
scalded.
setting temperature at water
THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE
are at highest risk of being
showering.
* The boiler water pressure must be
3. LETTERING TO BE BLACK BOLD FACED.
PROPERTY OF CROWN BOILER COMPANY. ANY REPRODUCTION
approved safety or relief valve.
0.005"
MATERIAL Noted
DRAWN
ENG APPR.
DATE
NAME
SIZE
B
DWG. NO. REV
JP
--
10-22-10
Sheet1 of 1
MS-002
DO NOT SCALE DRAWING
B
A Added Part Number JP 10-5-11
BY DATE
B
instantly or death from scalds.
PHILADELPHIA, PA 19134
TWO PLACE DECIMAL
12-17-15
DESCRIPTIONREV
VELOCITY BOILER WORKS
JP
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL 1/32"
ANGULAR: BEND 1°
ONE PLACE DECIMAL
* The heat-transfer medium must be
water or other nontoxic fluid having a
toxicity rating or Class of 1, as listed
NOTES:
1. MAT'L: ANSI/UL 969 CERTIFIED LABEL SYSTEM.
2. LETTERING BLACK ON WHITE BACKGROUND
CAUTION

4
CONTENTS
I. Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
 II. Specications........................................5
III. Before Starting Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
IV. Locating The Indirect Water Heater . . . . . . . . . . . . . . . . . . . . . . 7
V. Piping . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
A. Boiler Side Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
B. Domestic Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
VI. Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
VII. Start-up and Check-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
VIII. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
IX. Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendix A: Indirect Water Heater Sizing . . . . . . . . . . . . . . . . . . . . . . 20

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I. PRODUCT DESCRIPTION
This indirect water heater (IWH) is designed to generate domestic hot water in conjunction with a hot water boiler, or other
suitable heat source, using forced boiler water circulation. This indirect water heater consists of a stainless steel tank in which a
smooth stainless steel coil is located. Boiler water is pumped through the coil and heats the water in the tank. This product is not
intendedforuseinpoolheatingapplicationsorforheatinganyotheruidotherthanwater.Itisalsonotintendedforuseingrav-
ity hot water heating systems.
This manual shows installations where a hot water boiler is used as the heat source for the IWH, however other heat sources (such
as solar collectors) may be used provided that the following conditions are met:
1)Theheatsourcemustbeabletoprovideacontinuoussupplyof180FwatertothecoilattheowratesshowninTable2.1.
Iflowertemperaturesand/orowratesareused,theperformanceshowninTable2.1maynotbeachieved.
2)ThethermostatprovidedwiththisIWHmustbeinstalledandwiredinsuchawaythatitwillinterrupttheowofheat
source water passing through the coil when its contacts open. Failure to control the heat source ow using this thermostat
could result in unreliable operation or personal injury or death due to scalding.
3)Theuidpassingthroughthecoilmustbewaterorothernon-toxicuidhavingatoxicityratingorClassof1aslistedin
Clinical Toxicology of Commercial Products (latest edition).
4) The heat source must be used in accordance with its manufacturer’s instructions and those of the authority having jurisdic-
tion.
IMPORTANT NOTE
All models have a stored volume of less than 120 Gallons. When installed in accordance with these instructions, stored
potable water temperature in the tank is limited to a value of 210F or less by a temperature and pressure relief valve.
The maximum possible heat transfer rate across the coil (heat input) is less than 200,000BTU/hr with 210F potable
water provided that boiler or heat source water temperature is limited to:
MS2-030 – MS2-075: 250F
MS2-119: 220F
All models are therefore outside of the scope of both ASME Section IV, part HLW and ASME Section VIII when
installed in accordance with these instructions and with the boiler or heat source water temperature limited as shown
above.
II. SPECIFICATIONS
Notes:
Ratings based on 77F DHW temperature rise (135F outlet temp) and 180F boiler supply temperature. The ratings in Table
2.1wereobtainedattheheatsource(boiler)outputratesandheatsourceowratesshownabove.Otherresultsshallbe
obtainedunderdierentconditions.
Pressure Ratings:
Maximum Allowable Tank Working Pressure - 150 psi
Design Hydrostatically Tested to 300 psi
TABLE 2.1: Mega-Stor®II Series AHRI Performance Ratings
Model
First Hour
Rating
Continuous
Draw Rating Standby
Loss
(°F/hr)
Minimum
Boiler
Output
(MBH)
Boiler Water Through Coil
(Gal/hr) (Gal/hr) Min Flow
(Gal/min)
Head Loss
(ft w.c.)
MS2-030 162 138 1.4 87 8.0 2.6
MS2-040 192 162 1.1 101 8.0 2.8
MS2-050 236 193 0.9 121 8.0 2.9
MS2-075 307 238 1.0 150 8.0 4.5
MS2-119 497 417 1.4 264 14.0 4.2

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Description Model
MS2-030 - MS2-050 MS2-75 MS2-119
Cold Water Inlet 3/4F 1F 1-1/4F
To Boiler Return 1F 1F 1-1/4F
From Boiler Supply 1F 1F 1-1/4F
T&P Valve Tapping 3/4F 3/4F 1F
Hot Water Out 3/4F 1F 1-1/4F
Drain - - 3/4F
TABLE 2.4: CONNECTION SIZE (in. NPT)
Model
Potable
Volume
(Gal.)
Dimensions in Inches Weight
A B C D E Net Full
MS2-030 30.1 33-1/8 6-1/8 10-1/2 21-1/8 --- 69 328
MS2-040 37.9 39-3/8 6-1/8 10-1/2 24-1/4 --- 82 407
MS2-050 50.6 49-3/4 6-1/8 10-1/2 26-5/8 --- 112 545
MS2-075 74.0 68-3/4 6-1/8 10-1/2 29-3/8 --- 146 777
MS2-119 111.3 62-7/8 10-1/4 12-1/2 44 48-3/8 251 1217
TABLE 2.3: PHYSICAL SPECIFICATIONS
FIGURE 2.2: MEGA-STOR II INDIRECT WATER HEATER
MS2-030 THRU MS2-075
HOT WATER OUT
T & P VALVE
TO BOILER SUPPLY
THERMOSTAT
TO BOILER RETURN
COLD WATER IN
LIFTING LUG
DRAIN
30-3/4
A
E
D
C
B
MS2-119

7
III. BEFORE STARTING INSTALLATION
1) Be sure that the planned installation is in accordance with all local codes.
2) Be certain the domestic water supply to the indirect water heater (IWH) has physical and chemical characteristics that fall
 withinthelimitsshownbelow.Wherequestionsexistastothecompositionofthewateronthejob,aqualiedwater 
treatment expert should be consulted.
3) Read and understand all installation requirements in this manual.
4) Make sure that both this IWH and the boiler are sized to meet the domestic hot water demand. For basic sizing
information see Appendix A.
IV. LOCATING THE INDIRECT WATER HEATER
 1)Table2.3showstheweightofeachindirectwaterheater(IWH)lledwithwater.Makesurethatthelocationchosenfor 
the IWH is capable of supporting it.
2) Locate the IWH in a location where a leak in the tank, the adjacent piping, or an open T&P valve will not damage the
surrounding structure. If the surrounding area is highly susceptible to water damage, install the IWH in a pan with a drain.
 3)TheIWHmaybelocatedsomedistancefromtheboilerprovidedthezonesystemisdesignedtoprovidetheowcalledfor
in Table 2.1 through the coil. Also, the further the IWH is from the boiler, the longer the response of the boiler will be to a
call from the IWH thermostat. If long runs exist between the boiler and IWH it is advisable to insulate the piping.
CAUTION
Water used in this indirect water heater must have characteristics falling within the following limits:
PH 6.0 – 8.0
Chloride Content – Less than 80PPM
Maximum domestic hot water temperature – 150F
Water failing to meet these requirements may severely shorten the life of this product due to
corrosion. Such corrosion damage is not covered by the warranty.
WARNING
Failure to properly support an indirect water heater could result in property damage, personal injury or
death.
WARNING
Like all water heaters, this product may leak water at the end of its useful life. Where water from such
leakage could cause property damage, install this indirect water heater on a drain pan that is piped to
a suitable drainage point.

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V. PIPING
A) BOILER SIDE PIPING
A typical boiler-side piping installation is shown in Figure 5.1. A circulator zone system is shown, but zoning can also be done
usingtwoorthree-wayzonevalves,aslongastheboilerwaterowratecalledforinTable2.1canbeachieved(thisrequirementis
harder to meet with some zone valves). If circulator zoning is used, check valves must be installed in each zone to prevent unwant-
ed circulation through zones which are not calling for heat.
Table5.2showscombinationsofcirculators,pipesize,andequivalentlengththatwillresultintheowratescalledforinTable
2.1.
FIGURE 5.1: BOILER-SIDE PIPING USING CIRCULATOR ZONES
CAUTION
1. The heat transfer-medium must be water or other nontoxic uid having a toxicity rating or Class of 1, as
listed in Clinical Toxicology of Commercial Products, 5th edition.
2. The pressure of the heat transfer medium must be limited to a maximum of 30 PSIG by an approved
safety or relief valve.
NOTICE
Use of the minimum pipe sizes shown in Table 7.2 is strongly recommended. Failure to size the
indirect water heater boiler-side piping and circulator may result in failure of the water heater to meet
the performance requirements shown in Table 2.1.

9
The maximum equivalent length shown in Table 5.2 is that for the indirect water heater loop (IWH loop). The IWH loop piping is
shaded in Figure 5.1. To calculate the equivalent length of this loop:
 1)Countallttingsintheplannedboilerloop.
 2)UsingTable5.3,ndtheequivalentlengthofeachttingsintheIWHloop.Indoingthis,keepthefollowinginmind:
a. In many cases, there will be more than one pipe size in the IWH loop. As long as all piping in the loop exceeds
the size shown in Table 5.2, conservative results can be obtained by treating all piping in the loop as though it
were of the smallest size.
b. The equivalent length of most cast iron boilers can be safely treated as zero. This is often not the case,
however, with condensing and water tube boilers. In such cases either use primary-secondary piping (Figure
5.4) or use an alternate method to size the pump and piping.
 3)Aftertheequivalentlengthforallttingshasbeenidentied,totalthemandaddtheresulttothetotallengthofstraight
pipe in the loop. This sum is the total equivalent length for the IWH loop and must be less than that shown in Table 5.2
in order to use the circulators shown.
4) If primary-secondary piping is used as shown in Figure 5.4, calculation of equivalent length is exactly the same as
shown above, except that IWH loop is the shaded piping in Figure 5.4 (i.e. the IWH loop does not pass through the
boiler).
Example: A 40 gallon IWH is to be installed in the IWH loop piping shown in Figure 5.1 (shaded). The cast iron boiler has a
negligible pressure drop. The loop consists of the following pipe and ttings:
Qty Size Description
3 1-1/4” 90 Elbow
1 1-1/4” Turn in Tee
1 1-1/4” Run of Tee
1 1-1/4” Air scoop
1 1” Swing check
5 1” Elbows
5ft 1-1/4” Straight pipe
15ft 1” Straight pipe.
Solution: For simplicity, treat all pipe as though it were 1”. Equivalent length is then calculated as follows:
Qty Description Equiv. Length/tting Total Equiv. Length
8 90 Elbow 2.8ft 22.4ft
1 Air scoop 3ft 3.0ft
1 Turn in tee 5.5ft 5.5ft
1 Swing Check 7.0ft 7.0ft
1 Run of Tee 1.8ft 1.8ft
20ft Straight Pipe 1.0ft 20.0ft
Grand Total Equivalent Length: 59.7 ft
Since59.7islessthanthe90ftmaximumequivalentlengthshowninTable5.2,theplannedsystemwilldelivertherequiredow
using either a Taco 007 or Grundfos 15-42F.
Model Pipe Size Max Equiv.
Length (ft)
Circulator Model
Taco Grundfos
MS2-030 1” 90 007 15-42F
MS2-040 1” 90 007 15-42F
MS2-050 1” 90 007 15-42F
MS2-075 1” 60 007 15-42F
MS2-075 1” 130 009 26-64F
MS2-119 1-1/4” 30 007
MS2-119 1-1/4” 90 0010
MS2-119 1-1/4” 190 0012 26-64F
TABLE 5.2: SELECTACCEPTABLE INDIRECT WATER HEATER LOOPCONFIGURATIONS

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Fitting Nominal Pipe Size
1” 1-1/4”
90° Elbow 2.8 3.8
45° Elbow 1.4 1.9
90° Turn in Tee 5.5 8.0
Run of Tee 1.8 2.5
Gate Valve (Open) 0.7 0.8
Full Port Ball Valve 0.7 0.8
Swing Check Valve 7.0 10.0
Zone Valve (3.5 Cv) Not Recommended
Zone Valve (8.0 Cv) 46.1
Air Scoop 3.0 8.0
TABLE 5.3: EQUIVALENT LENGTHS FOR SELECT VALVES AND FITTINGS
(MAY BE USED FOR COPPER OR THREADED FITTINGS)
FIGURE 5.4: PRIMARY-SECONDARY PIPING OF INDIRECT WATER HEATER

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B) DOMESTIC SIDE PIPING
BASIC DOMESTIC PIPING
Figure 5.6 shows typical domestic water piping. All components except the control are provided by the installer. The function of
the components shown are as follows:
a) Temperature Control (required) - This control is provided by the factory and must be installed in the control
well location shown in Figure 2.2. Remove the cover and loosen the clamping screw. Apply the silver heat conductive
compound supplied to bulb. Insert the capillary bulb so that it is “bottomed out” in the control well as shown in Figure
5.5 and screw the control clamp securely in the well groove at the end of the well. See Section VI for wiring details and
Section VII for instructions on adjusting the temperature setting.
b) Shut-ovalves(recommended) - Use to isolate the indirect water heater (IWH) for servicing.
c) BackowPreventer(requiredbysomecodes) - Use to prevent water from backing out of the IWH in the event that
inlet water pressure drops.
d) ExpansionTank(requiredwhenabackowpreventerisused)-This expansion tank absorbs the increased volume
causedbyheatingwater.Ifabackowpreventerisinstalled,thisexpansiontankisrequiredbecausetheincreasedwater
volume will otherwise have no place to go and the T&P valve will open. Use an expansion tank designed for use on
domestic water systems. Refer to the expansion tank manufacturer’s literature for the proper size expansion tank to use.
e) Unions (optional) - Use to disconnect the IWH in the event that this is necessary.
f) Drain (Required) - Used to drain the IWH for inspection or servicing. This drain valve is supplied by the installer. For
models MS2-030 through MS2-075, install this valve in the cold water supply where it can be used to drain the tank. A
dedicated drain valve connection is provided on the MS2-119.
g) Temperature/Pressure Relief Valve (“T&P Valve” – Required) - Opens to relieve excess pressure or temperature which
has developed in the Indirect Water Heater’s storage tank. This valve must comply with Z21.22 Standard for Relief
Valves and Automatic Gas Shut-o Devices for Hot Water Supply Systems and must meet the following requirements:
Maximum Pressure Setting - 150psi
Maximum Temperature Setting - 210F
Inlet Size ¾” NPT Male.
Temperature Probe Element length (below male thread) 3 – 8 inches.
Minimum CSA capacity – Per Table 5.7
 NotethatminimumrequiredCSAratingisspeciedinBTU/hranddependsuponthemaximumhighlimitsettingon
the boiler. For low pressure steam boiler installations (where boiler water is drawn from below the water line) use the
221 - 250F column.
Pipe this valve as shown in Figure 5.6. Run the discharge pipe to a location where hot water will not cause injury or
damage. Leave a 6” gap between the T&P valve pipe termination and the drain or closest obstruction. Do not run the
CAUTION
If an expansion tank is used, do not put any valves between the expansion tank and Indirect Water
Heater inlet.
WARNING
Do not put any valves between the relief valve and the tank.
Do not reduce discharge pipe size.
Do not pipe the relief valve to a point where it could be exposed to freezing temperatures or become
plugged by debris.

12
T&P valve discharge to the outdoors or to other locations where water in this pipe could freeze or become blocked by
debris. Make sure all discharge piping is pitched so as to allow complete drainage of any water in the line.
h) Heat Trap (Optional) - The heat trap retards the migration of heat from the IWH up the hot water supply pipe.
i) Vacuum Breaker (Recommended) - This valve protects the IWH in the event that the pressure in the tank falls below
atmospheric. Use a Watts N-36 or equivalent.
PIPING WITH A “TEMPERATURE LIMITING VALVE”
Usually, the maximum temperature of the outlet water will stay near the setting of the control. In some cases, however, hot water
usagepatternscancausetheoutletwatertemperaturetorisesignicantlyabovethecontrolsetting.Thetemperatureofwater
goingtothexturesmaybemorecarefullycontrolledthroughtheuseofathermostaticmixingvalve.Thisdeviceblendsa
controlled amount of cold water with the hot water leaving the IWH so that water at a more constant temperature exits the mixing
valve. Typical thermostatic mixing valve piping is illustrated in Figure 5.8. Consult a licensed plumber or the local plumbing
authority for requirements in your area.
FIGURE 5.5: AQUASTAT INSTALLATION
WARNING
A thermostatic mixing valve does not eliminate the risk of scalding.
Set the thermostat as low as practical.
Feel water before bathing or showering.
If anti-scald or antichill protection is required, use devices specically designed for such service.
Install these devices in accordance with their manufacturer’s instructions.

13
FIGURE 5.6: BASIC DOMESTIC WATER PIPING
WARNING
If IWH is replacing a tankless coil, drain tankless coil and leave open to atmosphere. Do not plug coil.
Model Max Boiler Water Limit Setting
220°F or Less 221° - 250°F
MS2-030 100,000 112,300
MS2-040 100,000 133,700
MS2-050 100,000 156,300
MS2-075 115,000 195,600
MS2-119 199,900 Note 1
1. Not permitted unless the combined output of all boilers
connected to this indirect water heater is less than 200,000
BTU/hr. If this condition is met, install a T&P valve having a
capacity of 200,000 BTU/hr.
2. Maximum T&P Valve Pressure Setting - 150 psi
3. Maximum T&P Valve Pressure Setting - 210°F
TABLE 5.7: MINIMUM T&P VALVE CAPACITY REQUIREMENTS (BTU/hr)

14
WARNING
If anti-scald or anti-chill protection is required, use devices specically designed for such service.
Install in accordance with their manufacturer’s instructions.
FIGURE5.8:DOMESTICHOTWATERPIPING USINGAMIXINGVALVE
CAUTION
Do not attempt to use the anode rod tapping to make eld connections of any type. Attempts to do so
may result in unreliable operation or premature tank failure.

15
VI. WIRING
The following general notes apply to all wiring:
1) Wiring must be done in accordance with all codes. In the absence of any codes the system must be wired in
accordance with the National Electric Code (ANSI/NFPA 70).
2) The indirect water heater (IWH) is equipped with Honeywell a L4080B series temperature control. This control has a
 setofcontactswhichmakeuponacallfordomesticwaterandbreakwhenthistemperatureissatised.
A. BASIC CIRCULATOR ZONE WIRING
Figure 6.1 is a connections diagram for a non-priority circulator zone system using Honeywell R845A’s. The R845A is equipped
with two sets of contacts (3,4 and 5,6) which become made when the T and T terminals are made. Terminals 1 and 2 on the
R845A are supplied with 120 VAC to power its internal transformer. In this application one R845A is provided for each zone
including that of the IWH.
When any thermostat (including the thermostat on the IWH calls for heat, the relay in the R845A for that zone becomes energized.
Terminals 3 and 4 become “made”, energizing the circulator. Terminals 5 and 6 are also made which start the boiler.
FIGURE 6.1: CIRC. ZONE WIRING (NON-PRIORITY)
USING HONEYWELL R845’S

16
B. ZONE VALVES
Figure 6.2 is a connections diagram for a zone system using Honeywell V8043F motorized zone valves. The motor on these
valves is connected between TH and TR. TH/TR is provided for the electrician’s convenience as a binding post and is connected
to nothing inside the valve. The “end switch” terminals are connected to a set of switch contacts inside the valve which become
made when the
valve is open.
A call for heat from any thermostat or the IWH aquastat results in the application of 24 volts across the motor in that zone’s zone
valve. This drives open the zone valve. When the valve has opened, the endswitch in that zone valve makes and brings on the
boiler.
FIGURE 6.2: ZONE VALVE WIRING
WARNING
•Regardless of the control system selected, the L4080B on the indirect water heater must be the only
control that will permit boiler water to ow through the indirect water heater.
•Use of other temperature controls in place of the L4080B supplied with this indirect water heater
could result in personal injury or death due to scalding.
C. ZONE PANELS
Consult the zone panel manufacturer’s instructions for proper indirect water heater wiring.

17
VII. START-UP AND CHECK-OUT
1) Make sure that the system is free of leaks and that air is purged from the system.
 2)Manysolderinguxescontainzincchloridewhichcancauseseverecorrosiondamagetostainlesssteel.After
completingalldomesticwaterconnections,ushtheindirectwaterheater(IWH)thoroughlybeforeleavingthe 
installation. This is particularly important if the IWH will be unused for an extended period of time after installation.
3) Make sure that all electrical connections are correctly made and that no exposed high voltage wiring is present.
4) Temporarily disable the burner.
5) Make sure that each zone valve or circulator operates when, and only when, its thermostat calls for heat. Let each zone
operate long enough to purge any remaining air from the system.
6) Re-enable the burner and allow the IWH zone to operate. Make sure that the IWH control shuts down the zone when it
 issatised.
 7)Thesettingofcontroldeterminesthemaximumwatertemperatureinthetank.Thedierentialofthecontrolisaxed
8°F with a 150°F maximum setting, set by the manufacturer to the lowest setting of 100°F.
 Forthemostenergyecientoperation,adjustthecontrolfortheminimumwatertemperaturenecessarytomeet 
domestic water needs. Because hot water presents a scald hazard, it is best to set the control at 120ºF or lower and raise
it only if necessary to provide adequate hot water. See Table 7.2 for more information about scalding.
a) Adjust the dial shown in Figure 7.1 until the desired temperature setting on the dial is aligned with the arrow
shown.
b) After the IWH completes a heat-up cycle, check the water temperature at the faucet. Allow enough
watertoowtoensurethatthewatertemperaturereectsthetanktemperature.AdjusttheIWHtemperature
setting as necessary.
   i)Adjustingtoalowertemperaturesettingwillnotimmediatelyaectthewatertemperature.Draw
sucientwaterorallowthewaterheatertosituntilaheat-upcycleisinitiated.Repeatstepsa)andb).
   ii)Adjustingtoahighertemperaturesettingmaynotimmediatelyaectthewatertemperatureif
aheat-upcyclebegins,returntostepsa)andb).Ifaheat-upcycledoesnotbegin,drawsucient
water or allow the water heater to sit until a heat-up cycle is initiated. Repeat steps a) and b).
DANGER
Never attempt to ll a hot empty boiler
WARNING
Fix any leaks found before proceeding further. Leakage from the boiler piping can result in severe
damage to the boiler.

18
VIII. MAINTENANCE
This indirect water heater (IWH) is an extremely simple device and as such requires very little maintenance. There are, however,
several items which should be checked out on an annual or as needed basis to ensure a safe reliable supply of hot water:
* If the indirect water heater is equipped with an anode rod, inspect the rod on an annual basis and replace if necessary.
This anode rod is located above the boiler supply on the MS2-030 and above the thermostat on the MS2-040 thru
MS2-075 as shown in Figure 2.2. To inspect it, drain the tank and then unscrew the rod. When new, it is approximately
¾” in diameter and 19” long. If it has lost more than half of its original size, or if the aluminum portion of the rod is no
longer securely bonded to the brass nut, replace the rod.
* Verify proper operation of the L4080B control.
* Make sure the boiler and domestic water piping is free of leaks.
* If there is an oil lubricated circulator in the system, make sure that it is lubricated as called for by the circulator
manufacturer.
FIGURE 7.1: TEMPERATURE CONTROL
APPROXIMATE TIME/TEMPERATURE
RELATIONSHIPS FOR SCALDING
120°F More than 5 minutes
125°F 1-1/2 to 2 minutes
130°F About 30 seconds
135°F About 10 seconds
140°F Less than 5 seconds
145°F Less than 3 seconds
150°F About 1-1/2 seconds
155°F About 1 second
TABLE 7.2: SCALD RISK
WARNING
The water in the tank is normally hot and under pressure. It may cause scald injuries if the anode rod
is loosened without removing pressure and draining the tank. Anode inspection and replacement
should only be attempted by a professional plumber or HVAC technician.
NOTICE
• Failure to inspect/replace the anode rod as prescribed above may cause premature failure of
the indirect water heater, which is not covered under warranty.
• The tapping for the anode rod is ¾” “G” thread, which relies on an “O”-ring for sealing. Use
only the anode rod shown in Parts section of this manual as a replacement. Do not apply
Teon tape, or other sealants, to the anode rod threads.