User Guide

Part number 550-100-400/0717
46
The Gas-fi red water boiler, Featuring Flexibility
Ultra Models -299/310 and -399
1. Cast aluminum Nanogate coated heat exchanger
2. Heat exchanger access cover
3. Blower
The advanced blower design and air inlet silencer on Ultra boilers
result in very quiet operation.
Air enters the boiler enclosure through the air intake adapter (18),
ows through the enclosure, enters the air inlet silencer (5), then
enters the venturi (6). The blower pulls air and gas through the
venturi and pushes the mixture into the burner.
4. Gas valves and sense lines
The automatic gas valve (4a) senses the vacuum in the venturi caused
by fl owing air, and allows gas to fl ow when power is applied. The
manual gas valve (4b) allows shutting off the gas supply for servic-
ing or shutdown.
5. Air inlet silencer
The horn-shaped air inlet silencer signifi cantly reduces fan noise,
providing exceptionally quiet operation.
6. Venturi
When air fl ows through the venturi, it creates a vacuum. This vacuum
pulls gas from the gas valve. So gas will only fl ow if air is fl owing. The
gas/air mixture enters the blower before passing on to the burner.
7. Outlet water temperature dual sensor
This sensor monitors boiler outlet water temperature. The control
module adjusts boiler fi ring 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. Electronic display & buttons
The electronic display is used to confi gure boiler settings and moni-
tor boiler operation.
The buttons allow changing display mode, entering setting values,
and resetting after lockout.
10. Flue pipe adapter with internal drain
11. Burner (not shown)
Made with high-grade stainless steel construction, the burner uses
pre-mixed air and gas. The burner and control provide modulat-
ing fi ring.
12. Water outlet pipe (system supply)
13. Water return pipe (system return)
14. Gas connection pipe
15. U-Control-ODULE
The U-Control
Module responds to signals from the room ther-
mostats, DHW aquastats (when used), boiler sensors (boiler return,
boiler supply, system return, system supply, ue temperature, and
outdoor temperature, if used). The control module automatically
adjusts blower speed (and gas fl ow rate) to match boiler output to
space heating and/or DHW heating demand.
16. Swing-away control panel assembly
The Ultra control panel is mounted to a hinged sub panel, allow-
ing the panel to be swung forward and down for easy access to the
electrical connections.
17. Air intake adapter
18. Electrical entrance
Knockouts are provided in the jacket top panel, allowing conduit
entry directly behind the control panel or near the wall.
19. Boiler drain valve
20. Flue gas condensate drain
Connect the boiler internal condensate trap line to the heat ex-
changer here (parts supplied with boiler, but fi eld installed).
21. Flue gas condensate drain connection
The condensate trap PVC fi ttings are fi eld-installed, connected to
the condensate trap line as shown in this manual.
22. Front door
The front door is sealed to the boiler assembly around its entire
perimeter.
23. Jacket door retainer screws
Two (2) screws secure the door in place.
24. Ignition electrode/fl ame sensor
The burner fl ame is ignited by applying a high voltage to the igni-
tion electrode. This causes a spark (from electrode to ground). After
ignition, the electrode measures fl ame signal.
25. Flame inspection window
The quartz glass window provides a view of the burner surface
and fl ame.
26. Flue gas dual sensor
This dual sensor monitors the fl ue gas exit temperature. The control
module will shut down the boiler if ue gas temperature gets too hot.
This protects the fl ue pipe and the heat exchanger from overheating.
27. ON/OFF switch
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SERIES 4 GAS-FIRED WATER BOILERBoiler Manual