Weil-McLain Ultra Electric Water Heater User manual

Part number 550-100-066/0608Part number 550-100-066/0608
This manual must only be used by a qualified heating installer/service technician.Read all instructions,including this
manualand allotherinformation shipped with theboiler,beforeinstalling.Performstepsin theorder given.Failure to
comply could result in severe personal injury, death or substantial property damage.


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Boiler Manual
Gas-firedwaterboilers–Series3
Featuring
Flexibility

Part number 550-100-066/0608
g a s -f i r e d w at e r b o i l e r — Boiler Manual
2
The Gas-fired water boiler, Featuring Flexibility
1. Cast aluminum heat exchanger
2. Heat exchanger access cover
3. Blower
Theadvancedblowerdesign andairinletsilenceronUltraboilersresult
in very quiet operation.
Models Ultra-80 & 105 — Air enters the boiler enclosure through the
air intake adapter (18),ows through the enclosure,enters the air inlet
silencer (5), then enters the blower. The blower pulls air through the
silencerandpushesit intothe venturi(6),whereitmixeswithgasbefore
entering the burner.
ModelsUltra-155,230& 310—Air entersthe boilerenclosurethrough
the air intake adapter (18), ows through the enclosure, enters the air
inletsilencer(5),thenenterstheventuri(6).Theblowerpullsairandgas
through the venturi and pushes the mixture into the burner.
4. Gas valves and sense lines
Theautomaticgasvalve(4a)sensesthevacuuminthe venturicausedby
owingair,andallowsgastoowwhenpowerisapplied.Themanualgas
valve (4b) allows shutting off the gas supply for servicing or shutdown.
Models80and105useasensingline(4c)fromthegasvalvetothe blower
outlet so the gas valve references the same pressure as the venturi inlet.
5. Air inlet silencer
Thehorn-shapedairinletsilencersignificantlyreducesfannoise,provid-
ing exceptionally quiet operation.
6. Venturi
When air ows through the venturi, it creates a vacuum. This vacuum
pulls gasfrom thegas valve.So gaswill only ow if airis owing.On 80
and 105 models,the gas/air mixture enters the burner after the venturi.
On155,230,and310models,thegas/airmixtureenterstheblowerbefore
passing on to the burner.
7. Outlet water temperature dual sensor
Thissensormonitorsboileroutletwatertemperature.Thecontrolmod-
ule adjusts boiler firing rate so the outlet temperature is correct,based
on boiler outlet and system supply temperatures.
8. Boiler return water temperature sensor
This sensor monitors return water temperature. The control module
reduces or increases boiler input, depending on how close the return
water temperature is to the outlet water temperature.
9. Temperature and pressure gauge
10. Electronic display & buttons
The electronic display is used to configure boiler settings and monitor
boiler operation.
The buttons allow changing display mode, entering setting values, and
resetting after lockout.
11. Flue pipe adapter
12. Burner (not shown)
Made with high-grade stainless steel construction,the burner uses pre-
mixed air and gas.The burner and control provide modulating firing.
13. Water outlet pipe (system supply)
14. Water return pipe (system return)
15. Gas connection pipe
16. U-Control
The U-Control Module responds to signals from the room
thermostats, DHW aquastats (when used), boiler sensors
(boilerreturn,boilersupply,systemreturn,systemsupply,ue
temperature, and outdoor temperature, if used). The control
moduleautomaticallyadjustsblowerspeed(andgasowrate)
to match boiler output to space heating and/or DHW heating
demand.
17. Swing-away control panel assembly
The Ultra control panel is mounted to a hinged subpanel, al-
lowingthepaneltobeswungforwardanddownforeasyaccess
to the electrical connections.
18. Air intake adapter
19. Electrical entrance
Knockouts are provided in the jacket top panel,allowing con-
duit entry directly behind the control panel or near the wall.
20. Boiler drain valve
21. Line voltage receptacle
Use this connection to plug in line voltage meters or tools
while working on boiler. It can also be used for connecting a
condensate pump.Do not exceed 10-amp load.
22. P/T gauge temperature sensor well
Theremotesensorforthepanel-mountedpressure/temperature
gauge inserts into the outlet water pipe here.
23. Flue gas condensate drain
Connecttheboilerinternalcondensatetraplinetotheheatex-
changer here (parts supplied with boiler, but field installed).
24. Flue gas condensate drain connection
ThecondensatetrapPVCfittingsarefield-installed,connected
to the condensate trap line as shown in this manual.
25. Front door
Thefrontdoorissealedtotheboilerassemblyarounditsentire
perimeter.
26. Knurled-head jacket door retainer screws
Two knurled-head screws secure the door in place.
27. Ignition electrode/flame sensor
Theburnerameisignitedbyapplyingahighvoltagetotheig-
nitionelectrode.Thiscausesaspark(fromelectrodetoground).
After ignition,the electrode measures ame signal.
28. Flame inspection window
Thequartz glass window providesaview of theburnersurface
and ame.
29. Flue gas dual sensor
This dual sensor monitors the ue gas exit temperature. The
controlmodulewillshutdowntheboilerifuegastemperature
getstoohot.This protectstheuepipe andthe heatexchanger
from overheating.
30. ON/OFF switch

Part number 550-100-066/0608 3
g a s -f i r e d w at e r b o i l e r — Boiler Manual
The Gas-fired water boiler, Featuring Flexibility

Part number 550-100-066/0608
g a s -f i r e d w at e r b o i l e r — Boiler Manual
4
Contents
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk
levels or to important information concerning the life of the product.
Indicates presence of hazards that will cause severe personal injury, death or
substantial property damage.
Indicates presence of hazards that can cause severe personal injury, death or
substantial property damage.
Indicates presence of hazards that will or can cause minor personal injury or
property damage.
Indicates special instructions on installation, operation or maintenance that are
important but not related to personal injury or property damage.
                     4
              5
6
                       9
                   14
              24
   29
                  30
              31
   33
  36
    39
    42
     46
     48
                 50
                        52
                       54
             59
                 70
                 73
             77
          77
        78
                      79
                     84
                       89
                   92
                       104
                105
            106
Hazard definitions

Part number 550-100-066/0608 5
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Failuretoadheretotheguidelinesonthispagecanresult
in severe personal injury, death or substantial property
damage.
When servicing boiler —
To avoid electric shock, disconnect electrical supply before per-• forming maintenance.
To avoid severe burns, allow boiler to cool before performing• maintenance.
This boiler contains ceramic fiber and fiberglass materials. Refer• to theWARNING and instructions on page 79.
Boiler operation —
Do not block ow of combustion or ventilation air to boiler.•
Shouldoverheatingoccurorgassupplyfailtoshutoff,donotturn• off or disconnect electrical supply to circulator. Instead, shut off
the gas supply at a location external to the appliance.
Do not use this boiler if any part has been under water. Immedi-• ately call a qualified service technician to inspect the boiler and to
replaceanypartof thecontrolsystemand any gascontrolthat has
been under water.
Boiler water —
The Ultra heat exchanger is made of aluminum,and requires that• system pH always be between 7.0 and 8.5 and water chemistry be
checked. Chemical treatment may be necessary. See page 71 for
details.
Thoroughlyushthesystem(withoutboilerconnected)toremove• sediment.The high-efficiency heat exchanger can be damaged by
build-up or corrosion due to sediment.
Do not use petroleum-based cleaning or sealing compounds in• boiler system. Gaskets and seals in the system may be damaged.
This can result in substantial property damage.
Continual fresh make-up water will reduce boiler life. Mineral• buildup in heat exchanger reduces heat transfer, overheats the
aluminum heat exchanger, and causes failure.Addition of oxygen
carried in by make-up water can cause internal corrosion. Leaks
in boiler or piping must be repaired at once to prevent make-up
water.Use this boiler ONLY in a closed-loop system.
Donotaddcoldwatertohotboiler.Thermalshockcancauseheat• exchanger to crack.
Freeze protection fluids —
NEVERuseautomotiveorstandardglycolantifreeze,evenglycolmade
forhydronicsystems.Useonlyfreeze-protectionuidsrecommended
in this manual (see page 71).Follow all guidelines given.Thoroughly
clean and ush any replacement boiler system that has used glycol
before installing the new Ultra boiler.
Please read before proceeding
— Read all instructions,
including this manual and all other
informationshippedwith theboiler,
beforeinstalling.Performstepsinthe
order given.
—This manual isfor use only
byaqualifiedheatinginstaller/service
technician. Refer to User’s Informa-
tion Manual for your reference.
 — Have this boiler serviced/
inspectedbyaqualifiedservicetech-
nician,at least annually.
Failure to comply with the above
couldresultinseverepersonalinjury,
death or substantial property dam-
age.
When calling or writing about the
boiler—Pleasehavetheboilermodel
number from the boiler rating label
and the CP number from the boiler
jacket.
YoushouldwriteintheCPnumberin
thespaceprovidedontheInstallation
certificate on page 77 if not already
shown.
Consider piping and installation
when determining boiler location.
Anyclaimsfordamageorshortagein
shipment must be filed immediately
against the transportation company
by the consignee.
Commonwealth of Massachusetts
When the boiler is installed within the Common-
wealth of Massachusetts:
This product must be installed by a licensed• plumber or gas fitter.
If antifreeze is used, a reduced pressure back-• ow preventer device shall be used.

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6
 Clearances required
Prepare boiler location
Installations must comply with:
Local, state, provincial, and national codes, laws, regulations and• ordinances.
National Fuel Gas Code,ANSI Z223.1 – latest edition.•
Standard for Controls and Safety Devices forAutomatically Fired• Boilers,ANSI/ASME CSD-1, when required.
National Electrical Code.•
For Canada only: B149.1 or B149.2 Installation Code,CSA C22.1• Canadian Electrical Code Part 1 and any local codes.
The Ultra boiler gas manifold and controls met safe
lighting and other performance criteria when boiler
underwent tests specified in ANSI Z21.13 — latest edi-
tion.
Before locating the boiler, check:
Check for nearby connection to:1. System water piping• Venting connections• Gas supply piping• Electrical power•
Check area around boiler. Remove any combustible materials,2. gasoline and other ammable liquids.
Failuretokeepboiler area clearand freeof combustible
materials, gasoline and other ammable liquids and
vapors can result in severe personal injury, death or
substantial property damage.
TheUltraboilermustbeinstalledsothatgascontrolsystemcom-3. ponents are protected from dripping or spraying water or rain
during operation or service.
If new boiler will replace existing boiler, check for and correct4. system problems,such as:
Systemleakscausingoxygencorrosionorheatexchangercracks• from hard water deposits.
Incorrectly-sized expansion tank.• Lack of freeze protection in boiler water causing system and• boiler to freeze and leak.
Provide clearances:
Clearances from combustible materials
Hot water pipes — at least ½”from combustible materials.1. Vent pipe — at least2. C\zn”from combustible materials.
See3. Figure 1 for other clearance minimums.
Clearances for service access
See1. Figure1forrecommendedserviceclearances.Ifyou
do not provide minimum clearances shown, it might
not be possible to service the boiler without removing
it from the space.
Wall mounting option
Ultra boilers can be wall mounted (using special wall1. mount kit) or oor mounted.No clearance is required
attherear of theunit,eitherfor serviceorfor clearance
to combustible surfaces.

Part number 550-100-066/0608 7
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Prepare boiler location(continued)
Placing multiple boilers
Locate multiple boilers in boiler room according1. to:
a. Figure 2 (side-to-side),or
b. Figure 3 (back-to-back).
c. Figure 4 (wall mounting).
Provideindicatedclearancesaroundboilersforac-2. cessandservicing.Ifrecommendeddimensionsare
not possible, provide at least the minimum clear-
ances given on page 6.Also follow local codes.
Construct boiler foundation if boiler room oor3. is uneven or if there is a danger of ooding. Size
foundation to allow for clearance and spacing di-
mensions shown in either Figure 3 or Figure 4.
Chalkline boiler locations on foundation or boiler4. room oor.
Uncrate,assembleandmountboilersaccordingto5. instructions in this manual.
Provide clearance for installation of venting, air6. piping,gaspiping,expansiontank,primarycircula-
tor and other accessories.
Wall mounting (Models 80 – 310)
Ultra boilers may be wall mounted, following the1. instructions on page 11. (See Repair parts section
for part number of wall mounting kit.)
When wall mounting boilers, provide approxi-2. mately 6 inches between boilers for easy removal
of boiler jacket door. See Figure 4.
Followallapplicablecodesregardingpiping,electri-3. cal connections and clearances.
When wall mounting boilers, verify the wall con-4. struction is suitable for the structural load. See
page 11 for details.
Side-to-side mounting of multiple Ultra boilers
Back-to-back installation of multiple Ultra boilers
Wall mounting multiple Ultra boilers

Part number 550-100-066/0608
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8
Prepare boiler location(continued)
Flooring and foundation
Flooring
TheUltraboilerisapprovedforinstallationoncombustibleoor-1. ing, but must never be installed on carpeting.
Do not install boiler on carpeting even if foundation is
used.Firecanresult,causingseverepersonalinjury,death
or substantial property damage.
Foundation
Provideasolidfoundationpad,at least 2inchesabovetheoor,if1. any of the following is true:
oor can become ooded.•
the oor is dirt, sand,gravel or other loose material.•
the boiler mounting area is severely uneven or sloped.•
The minimum foundation size is:2. Ultra-80 to -230: 24 inches wide x 20 inches deep.•
Ultra-310: 24 inches wide x 23 inches deep•
Foundationmaybeofwood,brickorconcrete(minimum2inches3. thick) construction.
If ooding is possible, elevate boiler sufficiently to prevent water4. from reaching boiler.
Residential garage installation
Precautions
Takethefollowingspecialprecautionswheninstallingtheboilerin1. a residential garage. If the boiler is located in a residential garage,
per ANSI Z223.1:
Mounttheboilerwithaminimumof18inchesabovetheoor• of the garage to the bottom of the boiler to ensure the burner
and ignition devices will be no less than 18 inches above the
oor.
Locate or protect the boiler so it cannot be damaged by a• moving vehicle.
Provide air openings to room
Air openings — Ultra boiler alone in boiler
room
Noairventilationopeningsintoboilerroomareneeded1. whenclearancesaroundUltraboilerareatleastequalto
the SERVICE clearances shown in Figure 1,page 6.
For spaces that do NOT supply this clearance,provide2. two openings as shown in Figure 1,page 6. Each open-
ingmustprovide1squareinchfreeareaper 1,000Btuh
of boiler input.
Air openings — Ultra boiler in same
space with other gas or oil-fired
appliances
FollowtheNationalFuelGasCode(U.S.)orCSAB149.11. and B149.2 (Canada) to size/verify size of the combus-
tion/ventilation air openings into the space.
The space must be provided with
combustion/ventilation air openings
correctly sized for all other appliances
located in the same space as the Ultra
boiler.
Reinstall boiler jacket front door after
servicing.Theboilerfrontdoormustbe
securelyfastenedtotheboilertoprevent
boiler from drawing air from inside the
boilerroom.Thisis particularly impor-
tant if the boiler is located in the same
room as other appliances.
Failure to comply with the above warn-
ings could result in severe personal
injury, death or substantial property
damage.
Sizeopeningsonlyonthebasisoftheotherappliancesin2. thespace.Noadditionalairopening freeareais needed
for the Ultra boiler because it takes its combustion air
from outside (direct vent installation).

Part number 550-100-066/0608 9
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Vent and air piping (page 31)
The Ultra boiler requires a special vent system,designed for pres-1. surized venting.Ultra boilers are rated ANSI Z21.13 Category IV
(pressurizedvent,likely to condensein the vent).See instructions
beginning on page 31.
Youmustalsoinstallairpipingfromoutsidetotheboilerairintake2. adapter. The resultant installation is categorized as direct vent
(sealedcombustion).Notepreventionofcombustionaircontami-
nation on page 30 when considering vent/air termination.
Vent and air must terminate near one another and may be vented3. vertically through the roof or out a side wall.You may use any of
thevent/airpipingmethodscoveredinthismanual.Donotattempt
to install the Ultra boiler using any other means.
Be sure to locate the boiler such that the vent and air piping can4. be routed through the building and properly terminated. The
vent/air piping lengths, routing and termination method must
all comply with the methods and limits in instructions beginning
on page 30.
Remove boiler from crate
Cold weather handling — If boiler has been stored in a very
coldlocation(below 0°F)before installation,handle withcare
until the plastic components come to room temperature.
The Ultra boiler is generally easier to handle and maneuver after5. removing from crate.
Afterremovingoutershippingcartonfromboiler,REMOVEjacket6. front door by loosening two knurled-head screws at lower front.
Removingthedoorwillpreventpossible damage tothedoordur-
ing handling.
To remove boiler from pallet (after removing jacket front door):7. Remove the lag screws securing the shipping brackets.a. Unscrew the two rear boiler legs and remove the shippingb. brackets.
Replace legs.c. Discard the cardboard protector insert on the rear of thed. boiler.
Do not drop boiler or bump jacket on oor or pallet.
Damage to boiler can result.
Prepare boiler
Prepare boiler for propane
(when required)
Propane operation
    
   
.
Propane-ready boilers have suffix “LP”
afterthemodelnumber.Allotherboilers
require conversion for propane opera-
tion.
 natural gas boilersrequire in-
stallation of a burner in addition to an
orificechange. usetheinstruc-
tions in this manual for these boilers.
Use only the instructions included in
the special-order conversion kits (See
Figure 100,page 92).

   — For a boiler
already installed, you must turn off gas
supply, turn off power and allow boiler
tocoolbeforeproceeding.Youmustalso
completely test the boiler after conver-
sion to verify performance and start up
the boiler following instructions begin-
ning on page 70 of this manual.
 — For in-
stallationsmorethan5,500feetabovesea
level, obtain the high altitude propane
orifice kit.See Figure 100,page 92.
   — See Fig-
ure 5, page 10. Verify when installing
that the orifice size marking matches
boiler size. Use only the special-order
 orificeforaltitudesabove
5,500 feet.
Failure to comply could result in severe
personal injury, death or substantial
property damage.

Part number 550-100-066/0608
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10
Installing propane orifice
 —Youmustturnoffelec-
trical supplyto theboilerand closethe external manual
gasshut-offvalvetoisolatetheboilerduringconversion.
Allowtheboilertocoolifithasbeenoperating.Following
conversion of an installed boiler, follow all instructions
inthismanualtostartuptheboilerandverifyoperation
of the boiler and all system components.
Locate propane orifice disc from conversion kit bag.1.
Verify that the stamping on the orifice disk matches the model2. size (see Figure 5).
With the new boiler on its back, remove jacket front door by re-3. moving two knurled head screws at lower front.
Lift the door away from boiler.4.
Remove the air inlet silencer from the adapter:5.
Models 80 and 105:Seea. Figure 105,page 97.
Larger models: Seeb. Figure 107,page 99.
Disconnect the gas valve electrical plug.6.
See7. Figure 6 or Figure 7. Remove the 4 screws securing gas valve
inlet adapter to valve.
Usea5-mmwrenchtoremovethethreeAllen-headscrewssecuring8. the gas valve to the venturi (Figure 6 or Figure 7).
Place orifice in the black rubber grommet in the side of the gas9. valve and secure in valve (Figure 6 or Figure 7).
SeeFigure6orFigure7.Inspect theO-ring betweenthe
gas valve and gas valve inlet adapter whenever they are
disassembled. The O-ring must be in good condition
andmustbe installed.Failuretocomply willcausea gas
leak,resulting in severe personal injury or death.
Reposition gas valve against venturi and replace (3) Allen-head10. screws securing valve to venturi (Figure 6 or Figure 7).
See11. Figure6 orFigure 7.Secure gasvalveinlet adapterto gasvalve
with 4 screws. Make sure the plastic hose is connected from gas
valve to inlet elbow on Ultra-80 and -105.

 The valve could be damaged by manom-
eteruid contamination.Failureto complycould result
in severe personal injury, death or substantial property
damage.
Connect gas valve electrical plug to valve terminals.12.
Re-attach the air inlet silencer.13.
Afterinstallation is complete,attachthepropaneconversionlabel14. (in conversion kit bag) next to the boiler rating plate.
Replace jacket front panel.15.
Prepare boiler(continued)
Orifice identification
Installing propane orifice (Ultra-105 or Ultra-80LP ONLY)
 Installing propane orifice
(Ultra-155, -210, -285, and -310)

Part number 550-100-066/0608 11
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Prepare boiler(continued)
Placing floor-mounted boilers
Set boiler in place and check level.1. Adjust legs, if necessary to level boiler.a.
Wall-mounted boilers (Ultra-80 through -310)
The wall-mounting kit is NOT supplied as standard equipment1. withtheboiler,andmustbepurchasedseparately.See
below.
Wall mount Ultra boilers only using the Weil-
McLainUltraboilerwall-mountingkitandaccom-
panying instructions. (See Repair parts section for
part number of wall mounting kit.) DO NOT use
the shipping bracket to wall mount the boiler.
The wall must be vertically plumb and capable of
carrying the weight of the boiler. The operating
weights for wall-mountable boilers are:
Ultra-80: 139 pounds
Ultra-105: 145 pounds
Ultra-155: 181 pounds
Ultra-230: 192 pounds
Ultra-310: 229 pounds
Failure to comply with above and the procedure
given below could result in severe personal injury,
death or substantial property damage.
Verify kit contents:2. Wall-mount bracket.a. Black iron bushing,1”x 1/8”NPT.b. Lag screws,(2) 3/8”x 3”hex head.c. Grommet,(1) 7/8”O.D & grommets,(2) 1 3/8”O.D.d. Automatic air vent,1/8”NPT.e. Items b through e are needed only if routing piping throughf. bottom of enclosure (applies only for Ultra-80 through
-230).
Verify all parts listed above are available before proceeding.g.
Studspacing:Bracketholesarespacedforstudson16-inchcenters.3. Forother studspacing,providesecure,solid mountingsurfaceon
which to attach the boiler wall-mounting bracket.
Woodstudwall:Installbracketwithlagscrews(3/8”x3”)included4. in kit,only into the studs.
Metalstudwall:Securebrackettostudswith3/16-inchtogglebolts5. and 3/16-inch at washers (not included with kit).
6. attempt to attach the wall mount bracket using anchors
or any means other than directly securing to the wall studs (or
equivalent wood structure if studs are not on 16-inch centers).
Theboilerbracketmustengagewiththewall-mountbracket.Make7. sure the brackets are not just resting edge to edge.
Mounttheboileronthewallfollowingtheseinstructions.Perform8. all procedures given in the Boiler Manual on pages 1 through 9
before mounting the boiler.
The boiler is heavy. Use caution not to drop the boiler or cause9. bodily injury while lifting and handling. Verify that the boiler
is securely attached to prevent possibility of boiler falling after
installation.
  Install
bottom-piping grommets if required
 Install wall-mount bracket
 Place boiler on wall-mount bracket

Part number 550-100-066/0608
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12
Prepare boiler(continued)
 Bottom-piping configuration only (Ultra-80 to
-230 only)
See1. Figure 11.
Remove pipe caps from bottoms of supply, return and2. gas lines to route piping through bottom.
Install:3. 1” pipe cap on top of return pipe (a. Figure 11,
item 7).
½”pipe cap on top of gas line (b. Figure 11,item 8)
1”x 1”x ¾”tee (c. Figure 11,item 4).
¾”steel elbow (item 5),relief valve (item 6).d. 1”x 1/8”bushing (item 9).e. Air vent (item 10) on top of the supply pipe asf. shown.
Seeinstructionsbeginningon4. page14toconnectboiler
piping. Connect piping to:
1”NPT male boiler return (a. Figure 11,item 1).
1”NPT male boiler outlet (item 3).b. ½”NPT male gas (item 2).c. DO NOT use automatic air vent on systems
with closed-type expansion tanks. Instead,
replaceitem10abovewithalinetotheexpan-
sion tank.
Prepare boiler for wall mounting
Remove the jacket front panel.This will simplify lifting and han-1. dling the boiler when mounting.
When piping will be routed out the top of the boiler, no special2. preparation is needed other than that given in this manual.
Ultra-80 to -230 only: Toroutethe pipingthroughthe bottom of3. the boiler enclosure:
Removeknockoutsfrombottompipingpenetrationsasshowna. in Figure 8,page 11.
Insert grommets into the penetration holes as shown.b.
Install wall-mount bracket
Locate studs.1. Place the wall-mount bracket on the wall, using a level to align2. correctly.
Place the bracket so the mounting slots are centered over the3. studs.
Level the bracket and trace the outline of the screw slots with a4. pencil.
Remove bracket and drill holes 1/4” diameter by 3 inches deep,5. centered on the screw slot outlines. (For metal stud walls, using
3/16”toggle bolts, drill required clearance holes.)
See6. Figure 9,page 11. Position bracket on wall.Insert and loosely
tighten the two lag screws (or toggle bolts for metal studs).
Level the bracket. Then tighten screws securely. For drywall or7. plaster lathe installations,avoid tightening so much that brackets
dig into wall surface.
Place boiler on bracket
Measure 301. 3/4inches below the bottom edge of the wall-mount
bracket for Ultra-80 to -230 (35 5/8”for Ultra-310). Strike a line
orplacea pieceof masking tapeon thewall withits topedge even
withthe30-inchmark.(Thisline,ortape,willindicatewhetherthe
boiler has been properly seated onto the wall-mount bracket.)
Obtain assistance to lift the boiler into position (see2. Fig-
ure 10,page 11):
Lift the boiler high enough that its rear bracket will be abovea. the wall-mount bracket.
Let the rear of the boiler slide against the lag screw heads asb. you lower the boiler into place.
When the brackets are engaged correctly, the bottom of thec. boiler enclosure will be at or near the pencil line,or tape, you
applied in step 1.
If the boiler does not slide down close to the mark, or tape,d. adjust until the brackets properly engage.
Piping through the bottom of the boiler
Use two wrenches when tightening piping at boiler,
using one wrench to prevent the boiler pipe from turn-
ing. Failure to support the boiler piping connections to
preventthemfromturningcouldcausedamagetoboiler
components.
Use the following procedure to arrange piping through the bot-1. tom of the boiler.

Part number 550-100-066/0608 13
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Prepare boiler(continued)

  . This is the maximum allowable relief
valve setting for the Ultra boiler.
Perform hydrostatic pressure test
Pressure test boiler before permanently attaching water or gas piping
or electrical supply.
Prepare boiler for test
See1. Figure 12 for reference in following steps.
Remove supply line tee* and ¾”street elbow from accessory bag.2. Pipe to boiler supply connection as shown. Use pipe dope spar-
ingly. (*1”x 1”x ¾”tee with Ultra-80 to -230 or 1¼”x 1¼”x ¾”
tee with Ultra-310)
Temporarily plug the ¾” relief valve tapping in the street elbow3. with a ¾”NPT pipe plug.
Connect a hose to the boiler drain valve,the other end connected4. to a fresh water supply. Make sure the hose can also be used to
drain the boiler after test.
Connect a nipple and shutoff valve to system supply connection5. on the supply tee. This valve will be used to bleed air during the
fill. (Valve and nipple are not included with boiler.)
Connecta shutoff valveto systemreturn connection.(Valveis not6. included with boiler.)
Toavoidgettingwateronboiler,youmaywanttopipestreetelbows7. on top of shutoff valves and attach catch-buckets beneath.
If convenient, install the boiler circulator and any other piping8. compatiblewith Figure12thatwouldstill allowbleedingairfrom
shutoff valves.
Followguidelinesinthismanualforpipingcomponents,locations9. and sizing.
Fill and pressure test
Open the shutoff valves you installed on supply and return con-1. nections.
Slowlyopen boilerdrainvalveand freshwatersupplytofill boiler2. with water. The boiler will fill quickly because of its low water
content.
When water reaches shutoff valves,close boiler drain valve.3. Close shutoff valves.4. Slowly reopen boiler drain valve until test pressure on the pres-5. sure/temperature gauge reaches at least 45 psig, but no higher
than 55 psig.
Hold at test pressure for 10 minutes.6. Do not leave boiler unattended.A cold water fill could
expand and cause excessive pressure,resulting in severe
personal injury,death or substantial property damage.
Makesureconstantgaugepressurehasbeenmaintainedthrough-7. out test.Check for leaks.Repair if found.
 Failure to do so
can damage boiler, resulting in substantial property
damage.
Donotusepetroleum-basedcleaningorseal-
ingcompoundsinboilersystem.Gasketsand
sealsin thesystemmaybe damaged.This can
result in substantial property damage.
Drain and remove fittings
Disconnect fill water hose from water source.1. Drain boiler through drain valve. Remove hose after2. draining.
Remove nipples and valves unless they will remain for3. use in the system piping.
Removeplug fromrelief valvestreetelbow.See4. page14
to install relief valve.
 Hydrostatic test piping connections

Part number 550-100-066/0608
g a s -f i r e d w at e r b o i l e r — Boiler Manual
14
Install water piping
Usetwowrencheswhentighteningwaterpipingatboiler,
using one of the wrenches to prevent the boiler interior
pipingfromturning.Failuretosupporttheboilerpiping
connections to prevent them from turning could cause
damage to boiler components.
General piping information
Additional controls, when required
The U-Control module uses temperature sensors to
providebothhighlimitprotectionandmodulatingtem-
perature control. The U-Control module also provides
low water protection by sensing the temperature of the
heat exchanger. Some codes/jurisdictions may require
additional external controls for high limit and/or low
water cutoff protection.
Additional limit controls
Followingstandardindustrypractices,if installationistocomplywith
ASMEorCanadianrequirements,anadditionalhightemperaturelimit
maybe needed.Consultlocalrequirementsforothercodes/standards
to determine if needed.
Installamanualresethightemperaturelimitconstructedtoprevent1. atemperaturesettingabove200°Finsystemsupplypipingbetween
boiler and isolation valve. (Note that the U-Control module op-
erating limit function shuts the boiler down at 195°F, or lower if
set to a lower value.)
 — If the heating system
includes circuits that require lower temperature water
(radiant slab circuits, for example) as well as higher
temperaturecircuits,it isrecommendedto protectlow-
temperaturecircuitswithlimitcontrolsthatarewiredto
aU-Controlexternallimitcircuit(P13terminals1and2
formanualreset,orP13terminals3and4 forautomatic
reset).
See instructions beginning on2. page 54 for wiring information.
Manual reset operation: If external limit controls are to causea.  of the U-controlmodule,connect series-wired
isolatedcontactstoP13terminals1and2(seepage54forwir-
ing information).
Automatic reset operation: If external limit controls are tob. cause   of the U-control module, connect
series-wired isolated contacts to P13 terminals 3 and 4 (see
page 54 for wiring information).
If using a manual reset limit control or wiring in the manualc. reset circuit, set U-control boiler limit at least 20°F less than
the external manual reset limit (i.e., set U-control no higher
than 180°F for a 200°F external limit,for example).
Separate low water cutoff
A low water cutoff device is recommended when the boiler is in-1. stalled above piping level,and may be required by certain state or
localcodesorinsurancecompanies.Consultlocalrequirementsto
determine.Seethe NOTICEaboveregardingthe inherentprotec-
tion provided by the U-Control module.
The U-Control’s integral protection is accepted in many jurisdic-2. tions as meeting the requirement for low water protection. See
page 57 for details.
Whenrequired,usealowwatercutoffdesignedforwater3. installations.Electrodeprobe-typeisrecommended.See
Replacementparts sectionat theendof this manualfor
the Weil-McLain low water cut-off kit.
Purchase low water cutoff and install in a tee in the4. supply piping above boiler.
See field wiring instructions beginning on5. page 54 for
wiring additional limit controls.
Backflow preventer
Use backow check valve in cold water supply as re-1. quired by local codes.
Install relief valve
Install relief valve in ¾”street elbow piped from boiler1. supply piping tee (Figure 12, page 13). Pipe the relief
valve only as shown,in the location shown.
Connectdischargepipingtosafedisposallocation,fol-2. lowing guidelines in the  below.


:
Dischargelinemustbeconnectedtorelief
valve outlet and run to a safe place of
disposal.Terminate the discharge line in
a manner that will prevent possibility of
severeburns orproperty damageshould
the valve discharge.
Discharge line must be as short as pos-
sible and be the same size as the valve
discharge connection throughout its
entire length.
Discharge line must pitch downward
from the valve and terminate at least 6”
abovetheoordrainwhereanydischarge
will be clearly visible.
The discharge line shall terminate plain,
notthreaded,withamaterialserviceable
for temperatures of 375 °F or greater.
Do not pipe the discharge to any place
where freezing could occur.
No shutoff valve shall be installed be-
tweentherelief valveandboiler,orinthe
discharge line. Do not plug or place any
obstruction in the discharge line.
Test the operation of the valve after fill-
ing and pressurizing system by lifting
the lever.Make sure the valve discharges
freely. If the valve fails to operate cor-
rectly,replace it with a new relief valve.
Failure to comply with the above guide-
lines could result in failure of the relief
valve to operate, resulting in possibility
of severe personal injury, death or sub-
stantial property damage.

Part number 550-100-066/0608 15
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Install water piping(continued)
System water piping methods
All piping methods shown in this manual use primary/
secondary connection to the boiler loop. These designs
ensureproperowthroughtheUltraboiler,forthemost
efficientandreliableoperationoftheboilerandtheheat-
ingsystem.Forotherpipingmethods,consultyourlocal
Weil-McLain representative or see separate Ultra boiler
piping guides.
Circulators
The boiler circulator (Taco 007 for Ultra-80 and -105; Taco 0014 for
Ultra-155,-230,and-310)isshippedloose.Locateitinthereturnpip-
ing, as shown in the appropriate piping diagram in this manual.
 use the boiler circulator in any location other
than the ones shown in this manual.The boiler circula-
torisselectedtoensureadequateowthroughtheUltra
boiler.
Installtheboilercirculatoronlyontheboilerreturnpip-
ing. This ensures the pressure drop through the boiler
will not cause low pressure in the circulator intake.
Failuretocomplycouldresultinunreliableperformance
and nuisance shutdowns from insufficient ow.
Circulator flow rate
Size circulators based on the ow rate required to achieve the tem-
peraturechangeneeded.Youcancloselyestimatetemperaturerise(or
drop) through a circuit by using the following formula, where TD is
temperature rise (or drop), FLOW is ow rate (in gpm), and BTUH
is the heat load for the circuit:
 =BTUH 

:
Consider a system loop for a system with total heating load equal to
210,000Btuh.Thedesiredtemperaturedropthroughthesystempiping
is 20°F.Then the required ow rate is:
 = 
 =
Circulator head requirement
Thecirculatormustbecapableof delivering therequiredowagainst
the head loss that will occur in the piping. Determine the pipe size
needed, and the resultant head loss, using accepted engineering
methods.
Fortypicalresidentialapplications,youcanestimatethetotalequiva-
lent piping length (TEL) of a circuit as 1.5 times the measured length
of the circuit. Then use Figure 13 to determine the head loss for the
circuit.
Sizing system water piping
Seerecommendedpipinglayoutsbeginningon1. page17.


.
Size the piping and components in the space heating2. system using Figure 13 or other recognized method.
To use this table, select a pipe size with a ow rate just
larger than that required. The head loss for the circuit
is the value in the heading of the column selected. See
the examples in the table notes.
For pipe sizes up to 2 inch, ensure a minimum ow3. velocity of 2 fps (feet per second) and a maximum of
4 fps. This ensures effective air removal and minimal
noise.(FortypeMcopperpiping,thismeansowrates
of: 1-inch — 5.5 to 10.9 gpm; 1¼”— 8.2 to 16.3 gpm;
1½”— 11.4 to 22.9 gpm; 2”— 19.8 to 39.6 gpm.) For
largerpiping,sizeforamaximumheadlossof 4feetper
hundred feet of pipe.
Head loss in type M copper pipe (140°F water)
Pipe size
(inches) Maximum recommended water flow rate in pipe (GPM) for head loss of either:
2.5 feet head loss per
100 feet of piping 4.0 feet head loss per 100 feet of piping
17 9
1¼ 12 16
1½ 19 23
240 not recommended
(velocity more than 2 fps)
2½ 70 91
3112 146
:
Total head loss for a piping circuit equals the loss per 100 feet
times the TEL (total equivalent length) of the circuit in feet.
TELincludeshead lossforvalves andfittingsin equivalentfeet
of piping(i.e.,howmuchstraightlengthofpipingwouldcause
the same head loss as the valve or fitting).
Forexample,if apipingcircuithasameasurelengthof 250feet,
and includes valves and fittings with a total of 175 equivalent
feet,the TEL for the circuit = 250 + 175 = 425 feet.
:
Consider the circuit given above,with a TEL of 425 feet. If the
ow rate required for the circuit is 21 gpm, as in the example
at left,select a pipe size from above.
Using1½-inch pipewouldcause aheadloss of 4.0feet per100
feet of piping. Since TEL is 425 feet, head loss would be:
Head loss = 4.0 x 425 / 100 = 4.0 x 4.25 = 17.0 feet
Using2-inchpiping would causea headloss of 2.5feet per100
feet of piping. Since TEL is 425 feet, head loss would be:
Head loss = 2.5 x 425 / 100 = 2.5 x 4.25 = 12.3 feet.

Part number 550-100-066/0608
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16
Install water piping(continued)
Expansion tank and make-up water
Ensureexpansiontanksizewillhandleboilerandsystemwatervol-1. ume and temperature.Allow 3 gallons for boiler and its piping.
Undersized expansion tanks cause system water to be
lost from relief valve and make-up water to be added
through fill valve.Eventual boiler failure can result due
to excessive make-up water addition.
Tank must be located as shown in this manual, or following rec-2. ognized design methods. See tank manufacturer’s instructions
for details.
Connecttheexpansiontanktotheairseparatoronlyif thesepara-3. torisonthesuctionsideofthecirculator.Alwaysinstallthesystem
fillconnectionatthesamepointastheexpansiontankconnection
to the system.
Most pipingdrawings in this manual show diaphragm expansion4. tanks.SeeFigure14forpipingfromairseparatortoexpansiontank
and make-up water line using a closed-type expansion tank.
Most chilled water systems are piped using a closed-type tank, as5. shown in Figure 19,page 21.
Diaphragm (or bladder) expansion tank
(1. Figure 14) Always install an automatic air vent on top of the air
separator to remove residual air from the system.
Whenusingdiaphragmorbladdertanksonly—whenthe
boiler is installed above the system main piping, install
an automatic air vent in the top of the outgoing boiler
piping to prevent air pocketing.
Closed-type expansion tank
See1. Figure 14, Alternate, for piping connections when using a
closed-type expansion tank.
Pitch any horizontal piping up towards tank 1 inch per 5 feet of2. piping. Connect to tank with at least ¾”piping to allow room for
air to rise.
DO NOT install automatic air vents on closed-type
expansion tank systems.Air must remain in the system
andreturntothe tank toprovide its aircushion.Anau-
tomaticairventwouldcauseairtoleavesystem,resulting
in water-logging the expansion tank.
 Expansion tank piping

Part number 550-100-066/0608 17
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Legend — Figure 15
1 Ultra boiler
2 Indirect water heater (DHW), if used (see page 22)
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 for details)
5 DHW circulator (see page 22 for suggested sizing)
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm(orbladder)typeexpansiontank (seepage 22forpipingof
closed-type expansion tank,if used)
9 Airseparator[withautomaticairventonlyonsystemsusingdiaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
13 Zone valves,typical
20 Make-up water supply
21 Primary/secondary connection
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systems using high-head pumps may require a bypass pressure regulator
to prevent damage to control valves.
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least the following pipe sizes on all boiler
loop piping (connecting boiler to and from the
primary/secondary connection, item 21). Use only primary/secondary piping
as shown. Failure to follow these guidelines could result in system problems.
•Ultra-80orUltra-105–1”orlarger.
•Ultra-155or-230–1¼”orlarger.
•Ultra-310–1½”orlarger.
Install water piping(continued)
 Zone valve zoning plus optional DHW piping
Zoning with zone valves
Connect boiler to system as shown in1. Figure 15 when zone valve
zoning. The primary/secondary piping shown ensures the boiler
loopwillhavesufficientow.Italsoavoidsapplyingthehighhead
of the boiler circulator to the zone valves.
Whenusing aclosed-type expansiontank,connect the expansion2. tank and make-up water piping as shown in Figure 14, page 16.
Connect DHW (domestic hot water) piping to indirect storage3. water heater as shown.
Bydefault,theU-ControlModuleturnsoffspaceheating
during DHWheating (if DHW input ispriority 1).The
boilercirculatorwillturnoff,preventinghotwaterfrom
circulating to the system (optional timeout setting can
beusedtooverride).Theow/checkvalveshownonthe
boiler outlet piping prevents gravity circulation in the
boiler loop during DHW heating.
Controlling the circulators4.
The U-Control can control up to three circulators (boiler cir-a. culator and two others). Refer to Field wiring, beginning on
page 54,for instructions on wiring to circulators.
The factory default settings are: DHW circulator as Circula-b. tor 1, boiler circulator as Circulator 2 and system circulator
as Circulator 3. See Field wiring instructions, beginning on
page 54,for details.

Part number 550-100-066/0608
g a s -f i r e d w at e r b o i l e r — Boiler Manual
18
Legend — Figure 16
1 Ultra boiler
2 Indirect water heater (DHW), if used (see page 22)
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 for details)
5 DHW circulator (see page 22 for suggested sizing)
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page 22 for piping of
closed-type expansion tank,if used)
9 Air separator [with automatic airventonly onsystems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
13 Zone valves,typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 12 inches apart)
23 DHW secondary connector piping — no more than 12 inches apart
24 Strap system supply and return sensors to lines as shown,at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systemsusing high-headpumps mayrequirea bypasspressureregulator
to prevent damage to control valves.
Items supplied with boiler
Items supplied by others
NOTE 1: Useatleast thefollowing pipesizes onall boiler
loop piping (connecting boiler to and from the
primary/secondaryconnection,item21).Useonlyprimary/secondarypiping
as shown. Failure to follow these guidelines could result in system problems.
•Ultra-80orUltra-105–1”orlarger.
•Ultra-155or-230–1¼”orlarger.
•Ultra-310–1½”orlarger.
Install water piping(continued)
 Zone valve zoning plus optional DHW piping
Zoning with zone valves — alternate
High-flow-rate/high-head-loss DHW circuits
ForapplicationsrequiringDHWcircuitowrateshigherthan al-1. lowable for the boiler, or for high pressure-drop coil-type DHW
tanks, connect the piping as in Figure 16. The DHW water only
owsthroughthesecondarycircuitconnectorpiping.NOTE:Make
suretosizetheconnectorpiping(Figure16,item23)tohandlethe
total ow it must handle.
Connect boiler to system as shown in2. Figure 16 when zone valve
zoning. The primary/secondary piping shown ensures the boiler
loopwillhavesufficientow.Italsoavoidsapplyingthehighhead
of the boiler circulator to the zone valves.
Whenusing aclosed-type expansiontank,connect the expansion3. tank and make-up water piping as shown in Figure 14, page 16.
Connect DHW (domestic hot water) piping to indirect storage4. water heater as shown.
Bydefault,theU-ControlModuleturnsoffspaceheating
during DHWheating (if DHW input ispriority 1).The
boilercirculatorwillturnoff,preventinghotwaterfrom
circulating to the system (optional timeout setting can
beusedtooverride).Theow/checkvalveshownonthe
boiler outlet piping prevents gravity circulation in the
boiler loop during DHW heating.
Controlling the system circulator and boiler circulator5. YouwillhavetosetuptheU-Controltooperateboththeboilera. circulator and the DHW circulator during DHW operation.
ThesystemcirculatorshouldbeoffduringDHWheating.Read
theinstructionsonU-Controloperationandsetup,beginning
on page 59.

Part number 550-100-066/0608 19
g a s -f i r e d w at e r b o i l e r — Boiler Manual
Legend — Figure 17
1 Ultra boiler
2 Indirect water heater (DHW), if used (see page 22)
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 for details)
5 DHW circulator (see page 22 for suggested sizing)
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm(orbladder)typeexpansiontank (seepage 22forpipingof
closed-type expansion tank,if used)
9 Airseparator[withautomaticairventonlyonsystemsusingdiaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
14 Zone circulators,typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 12 inches apart)
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least the following pipe sizes on all boiler
loop piping (connecting boiler to and from the
primary/secondary connection, item 21). Use only primary/secondary piping
as shown. Failure to follow these guidelines could result in system problems.
•Ultra-80orUltra-105–1”orlarger.
•Ultra-155or-230–1¼”orlarger.
•Ultra-310–1½”orlarger.
Install water piping(continued)
 Circulator zoning plus optional DHW piping
Zoning with circulators
Connect boiler to system as shown in1. Figure 17 when circulator
zoning. The boiler circulator cannot be used for a zone. It must
supply only the boiler loop.
Install a separate circulator for each zone.2. Whenusing aclosed-type expansiontank,connect the expansion3. tank and make-up water piping as shown in Figure 14,page 16.
Connect DHW (domestic hot water) piping to indirect storage4. water heater as shown.
Bydefault,theU-ControlModuleturnsoffspaceheating
during DHWheating (if DHW input ispriority 1).The
boilercirculatorwillturnoff,preventinghotwaterfrom
circulating to the system (optional timeout setting can
beusedtooverride).Theow/checkvalveshownonthe
boiler outlet piping prevents gravity circulation in the
boiler loop during DHW heating.
Controlling the circulators5. The U-Control can control up to three circulators (boiler cir-a. culator and two others). Refer to Field wiring, beginning on
page 54,for instructions on wiring to circulators.
The factory default settings are: DHW circulator as Circula-b. tor1,boilercirculatorasCirculator2.SeeFieldwiringinstruc-
tions,beginning on page 54, for details.
The zone circulators inc. Figure 17 must be controlled by
circulator relays activated by the zone thermostats or zone
controller.

Part number 550-100-066/0608
g a s -f i r e d w at e r b o i l e r — Boiler Manual
20
Legend — Figure 18
1 Ultra boiler
2 Indirect water heater (DHW), if used (see page 22)
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 for details)
5 DHW circulator (see page 22 for suggested sizing)
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm(orbladder)typeexpansiontank (seepage 22forpipingof
closed-type expansion tank,if used)
9 Airseparator[withautomaticairventonlyonsystemsusingdiaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
13 Zone valves, when used (zoning may also be done using manifold-
mounted valve actuators)
20 Make-up water supply
21 Primary/secondary connection (tees no more than 12 inches apart)
22 Optional high limit temperature control,set to protect radiant tubing
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systems using high-head pumps may require a bypass pressure regulator
to prevent damage to control valves.
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least the following pipe sizes on all boiler
loop piping (connecting boiler to and from the
primary/secondary connection, item 21). Use only primary/secondary piping
as shown. Failure to follow these guidelines could result in system problems.
•Ultra-80orUltra-105–1”orlarger.
•Ultra-155or-230–1¼”orlarger.
•Ultra-310–1½”orlarger.
 Typical radiant heating system piping plus
optional DHW
Radiant heating applications
The Ultra boiler is ideal for use in radiant heating. The Ultra1. boiler’s unique heat exchanger design allows it to work well even
in condensing mode.So there is no need to regulate boiler return
water temperature in radiant heating applications.
Connectboilertosystemas shownin2. Figure18fortypical radiant
heatingapplications.Theprimary/secondarypipingshownensures
theboilerloopwillhavesufficientow.Sizethesystempipingand
circulator to provide the ow and pressure drop needed for the
radiant system.
Adding the recommended high limit control (3. Figure 18,item 22)
can help ensure supply water temperature will not exceed the
maximumallowablefortheradiantsystem.Wirethislimitcontrol
in eitherthe manualresetor automatic reset external limitcircuit
of the U-Control.
Whenusing aclosed-type expansiontank,connect the expansion4. tank and make-up water piping as shown in Figure 14, page 16.
Connect DHW (domestic hot water) piping to indirect storage5. water heater as shown.
Bydefault,theU-ControlModuleturnsoffspaceheating
during DHWheating (if DHW input ispriority 1).The
boilercirculatorwillturnoff,preventinghotwaterfrom
circulating to the system (optional timeout setting can
beusedtooverride).Theow/checkvalveshownonthe
boiler outlet piping prevents gravity circulation in the
boiler loop during DHW heating.
Controlling the circulators6. The U-Control can control up to three circulators (boiler cir-a. culator and two others). Refer to Field wiring, beginning on
page 54,for instructions on wiring to circulators.
The factory default settings are: DHW circulator as Circula-b. tor1,boilercirculatorasCirculator2.SeeFieldwiringinstruc-
tions,beginning on page 54, for details.
Install water piping(continued)