Weil-McLain WM97+70 Specifications download pdf (Page 71)

Part number 550-142-120/0113

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WM97+ gas-fired water boiler — Boiler Manual

WM97+ control operation

Temperature settings — You must ensure that the

WM97+ control is set for the proper water temperatures

for the system. Excessive water temperature can cause

signiﬁcant property damage in some applications.

Multi-temperature systems — If the heating system

includes circuits that require lower temperature water

(radiant slab circuits, for example) as well as higher

temperature circuits (DHW, ﬁnned tube baseboard, etc.),

it is recommended to protect low-temperature circuits

with limit controls that are wired to a WM97+ control

external limit circuit. Failure to provide regulation can

result in substantial property damage.

Figure 82 Control sequence of operation

Display

status

graphic

Control action

(also see Figure 83, page 72)

POWER

• Check the boiler model listed on the power-up

screen. If it is not correct, turn off the boiler. See

page 75 to change setting.

• When power is turned on, the screen lists sen-

sors that are detected. If any sensor is not listed,

make sure it is connected correctly. Turn off

power and restart.

Standby

• Standby — no calls for heat

• Toggles through no dots, 1 dot, 2 dots, then

3 dots while in standby (wrench symbol will

show instead if maintenance is needed)

Blower on

• Call for heat detected

• Display on with BLUE light (space heating) or

PURPLE light (DHW)

• Start min/max on timers if more than one system

is calling — highest priority starts ﬁrst

• Start circulators for this priority setup

• Calculate target temp — If sensor temp is below

target temp, begin ﬁring sequence

• Blower to ignition speed for prepurge

Ignition on

• After prepurge times out, begin ignition cycle

• Activate gas valve and ignition spark

• Continue ignition spark for ignition period

• Turn off spark and use electrode to check for

ﬂame signal

Space

heating

• Flame detected

• Release boiler to modulation

• NOTE: If ﬂame is not detected, the gas valve

is turned off, blower turns on (postpurge), and

control starts cycle again. After 5 failures, the

control waits 60 minutes, then tries again.

• If priority timer times out, switch to next priority

and start priority timer

• If demand satisﬁed, go to postpurge

DHW

heating

CWH

• Flame detected

• Release boiler to modulation

• NOTE: If ﬂame is not detected, the gas valve

is turned off, blower turns on (postpurge), and

control starts cycle again. After 5 failures, the

control waits 60 minutes, then tries again.

• If priority timer times out, switch to next priority

and start priority timer

• If demand satisﬁed, go to postpurge

Blower on

• Demand satisﬁed (temperature reaches target

temperature or limit setting)

• Gas valve off

• Blower to ignition speed for postpurge

• Return to standby after purge

Maintenance

• Display turns RED, toggling between graphic

screen and maintenance screen (occurs if main-

tenance schedule timer times out)

• Will show during standby only

• Boiler operates as normal

Error/fault

• Display turns RED due to error or limit event

• Flashing display means lockout condition —

display toggles between three screens as in

Figure 112, page 104.

WWSD

• Warm weather shutdown — the boiler will not

be allowed to ﬁre on space heating if the outside

temperature is greater than the WWSD setting.

DHW operation is not affected by WWSD.

WM97+ control features



Blower speed modulation to control the WM97+ boiler’s ﬁring rate.



Advanced PID response to anticipate system needs based on response

to heat input.



Graphic and robust text display for ease of operation monitoring and

troubleshooting.



Preset operating parameters for typical heating systems (ﬁnned tube

baseboard, radiant ﬂoor, DHW, and others), including target tempera-

tures, reset curves and circulator assignments.



Control of up to three circulators or zone devices, assignable for each of

the three possible zone inputs. (Boiler circulator controlled internally.)



Programmable priority assignment for DHW input.



Integral outdoor reset option (see page 133), with reset curves matched

to the system type selected.



Dual sensors for boiler outlet temperature and ﬂue temperature, pro-

viding redundant protection.



Integral low water cut-off.



Boiler is shipped with an outdoor sensor, allowing outdoor reset opera-

tion for maximum boiler efﬁciency. See page 133.

Sequence of operation

1. Figure 82 is a summary of the operating sequence for the WM97+

control.

2. The symbols shown appear in the display as the WM97+ control cycles

the boiler.

3. The wrench symbol appears when a scheduled maintenance date ar-

rives. This informs the homeowner to call the contractor for service.

4. The exclamation mark symbol appears if a problem has been detected.

WM97+ control setup

BEFORE PROCEEDING, perform essential control

settings as instructed on page 73.

1. See page 74 for an overview of the WM97+ control menus. This page

also gives the location of instruction manual information for each of

the main menus.

1 2 ... 66 67 68 69 70 71 72 73 74 75 76 ... 135 136

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Weil-McLain WM97+70 Specifications Page 71

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