The ECO Series 2 Gas-fired water boilers
Part number 550-142-190/1218
3
1. Stainless steel firetube heat exchanger
2. Heat exchanger access cover/burner mounting plate
3. Blower
The advanced blower design and air inlet silencer on
ECO
Wall
Mount boilers result in very quiet operation.
Air enters the boiler enclosure through the air intake adapter (16),
flows through the enclosure, enters the air inlet silencer (5), then
enters the blower. The blower pulls air through the silencer and
pushes it into the venturi (6), where it mixes with gas before entering
the burner (11).
4. Gas valve
The automatic gas valve senses the vacuum in the venturi (6) caused
by flowing air and allows gas to flow when power is applied. A manual
gas valve is shipped loose with the boiler. It allows shutting off the
gas supply for servicing or shutdown. See instructions in this manual
for manual gas valve installation.
5. Air inlet silencer
The horn-shaped air inlet silencer significantly reduces fan noise,
providing exceptionally quiet operation.
6. Venturi
When air flows through the venturi, it creates a negative pressure.
This vacuum pulls gas from the gas valve (4). Gas will only flow if air
is flowing. The gas mixes with air in the venturi. The gas/air mixture
then flows into the burner (11).
7. Supply water temperature dual sensor
This dual sensor monitors boiler outlet water temperature. The
ECO
control adjusts boiler firing rate so the outlet water temperature
is correct, based on the calculated (if outdoor reset used — see
page 127) or fixed target temperature.
8. Return water temperature sensor
This sensor monitors return water temperature. The
ECO
control
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 configure boiler settings and
monitor boiler operation. The buttons allow changing display mode,
selecting and adjusting control settings, and resetting the control
after lockout. This display can be mounted either on the boiler (as
shown) or on the wall.
10. Flue adapter (fits 3" PVC)
11. 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.
12. Water outlet pipe (system supply)
13. Water return pipe (system return)
14. Gas connection pipe
Other ½” NPT gas connection pipe, manual gas valve, and fittings
(including union) shown must be supplied by the installer.
15. Control module
The
control module
responds to signals from the room thermostat,
DHW aquastat (if used), boiler sensors (boiler return, boiler supply,
flue temperature, and outdoor temperature, if used — see page 127).
The control automatically adjusts blower speed (and gas flow rate) to
match boiler output to space heating and/or DHW heating demand.
The control provides for one heating zone and one DHW zone.
16. Air intake adapter (fits 3" PVC)
17a. Electrical entrances (line voltage)
The top left side knockouts are designated for line voltage wiring
only. Ensure all wiring entrances are sealed.
17b. Electrical entrances (low voltage)
The top right side and bottom knockouts are designated for low
voltage wiring only. Ensure all wiring entrances are sealed.
18. Boiler drain valve (not shown)
Shipped loose for field piping. Pipe drain valve on reducing tee at
the lowest point of return piping to boiler. See instructions in this
manual.
19. Condensate trap nozzle
The outlet at the bottom of the condensate collection dish. This is
where condensate is discharged from the boiler. The condensate trap
assembly attaches here.
20. Flue gas condensate drain trap assembly and bracket
The condensate trap assembly and bracket are field-installed,
condensate drain trap is connected to the condensate trap nozzle
as shown in this manual.
21. Jacket door
The jacket door is sealed to the boiler assembly around its entire
perimeter.
22. Jacket door screws
Two screws secure the jacket door in place.
23. Ignition electrode/flame sensor
The burner flame is ignited by applying a high voltage to the ignition
electrode. This causes a spark (from electrode to ground). After
ignition, the electrode measures flame signal.
24. Flame inspection window
The quartz glass window provides a view of the burner surface, the
flame, and the ignition electrode.
25. Flue gas dual sensor
This dual sensor monitors the flue gas exit temperature. The ECO
control will shut down the boiler if flue gas temperature gets too hot.
This protects the flue pipe and the heat exchanger from overheating.
26. Gas valve reference hose (ECO 70 only)
This rubber line connects the gas valve diaphragm reference chamber
to the venturi intake to insure the valve senses the correct reference
pressure.
27. Transformer
The 120V/24V transformer provides 24V to low voltage control
circuitry.
Do
NOT
splice wiring into transformer.
28. Air baffle
The air baffle protects internal boiler components by diverting any
incoming moisture or debris away from critical components. It
must be temporarily removed while servicing the heat exchanger.
®
S
ERIES
2
G
AS
-
FIRED
WATER
BOILER
—
Boiler Manual
