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,andallowsgastoowwhenpowerisapplied.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(andgasowrate)
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
Theburnerameisignitedbyapplyingahighvoltagetotheig-
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
controlmodulewillshutdowntheboilerifuegastemperature
getstoohot.This protectstheuepipe andthe heatexchanger
from overheating.
30. ON/OFF switch
