Install Instructions
34
Installation & Service Manual
5 Electrical connections
Pump Wiring for a Heating Boiler
The heating boiler circulating pump must be purchased
locally. Follow all manufacturer’s installation and
maintenance instructions provided with the pump. Solution
boilers are equipped with a pump relay, located near the
two-stage thermostat in the control panel (FIG. 5-2). The
temperature controller energizes the pump relay, which
operates the pump on a call for heat. The pump will operate
either continuously from a 120V supply, or whenever the
“W1” terminal from the wall thermostat or zone control is
energized. The maximum load for the pump switched by
the internal pump relay must not exceed 1 HP. The current
draw for a field installed 120 VAC pump MUST be added to
the boiler’s current draw to determine the minimum wire size
for 120 volt service. Reference Table 5B for boiler operating
control current draw data.
IMG00280
TRANSFORMER
MANUAL RESET
HIGH LIMIT
(IF EQUIPPED)
TST20036-2
PUMP RELAY
IGNITION MODULE
TST20036-1
Figure 5-2_Intermittent Pilot System M9 Control Panel
TABLE - 5B
AMP DRAW DATA
45,000 thru 260,000 Btu/hr Models
FIRING CONTROLS
MAXIMUM
TOTAL AMPS
@ 120 VAC
M9 with Performance Loop Pump 1.25
Boiler Operating Temperature Control
The two-stage thermostat is located in the control panel,
behind the control panel front access door. To access the
temperature control, remove the control panel door on the
front of the unit. The temperature controller operates a
two-stage firing system, which increases system efficiency by
starting the boiler on low fire and turning on high fire only
when extra capacity is needed. After the water temperature
reaches the operating set point, the temperature control shuts
off the burners.
The Solution boiler is also equipped with outdoor air
reset, a feature that saves energy by reducing the boiler
water temperature as the heating load decreases (reference
Temperature Adjustment section on page 35). The thermostat
control consists of two interconnected boards. The upper
board controls outdoor air reset and DHW priority functions,
while the lower board manages burner and pump operation.
The installation of outdoor air reset is necessary to comply with
the United States Energy Policy and Conservation Act, and the
boiler will not function if both boards are not installed. In the
event that the outdoor air sensor is not functioning, a flashing
red light will indicate fault and the boiler operating temperature
will default to maximum set point.
DHW Priority
A boiler used in water heating applications should be piped
as a hot water loop (zone) in a Primary/Secondary piping
arrangement (see FIG. 4-6 on page 31). A DHW priority
function on the Solution boiler is available by connecting a field
supplied tank Aquastat to the upper control board (TST20036-
2). When the control receives a DHW call for heat, the boiler
set point will change to 180°F (82°C). The boiler will operate
at this set point until the DHW demand is satisfied. In the
absence of water heating demand, the operating set point is
based on the outdoor air reset curve. For boilers using DHW
priority, mixing valves are required for the protection of low
temperature zones.
Additional Temperature Controls
High Water Temperature Limit Control
The appliance is supplied with a fixed setting, auto-reset
high water temperature limit control. The setting of this
control limits maximum discharge water temperature. If water
temperature exceeds the setting, the limit will break the control
circuit and shut down the appliance. The limit control will only
be reset after the water temperature has cooled well below the
setting of the limit. The auto-reset high water temperature limit
control is mounted in the outlet side of the front header.
Blocked Vent and Flame Roll-Out / Flame Interlock
All units are equipped with manual reset blocked vent and
flame roll-out / flame interlock switches. These temperature
switches are located in the controls compartment and in the
relief opening of the boiler’s built-in draft hood. Each switch
has a red reset button. In the event the system has actuated
to shut off the main burner gas supply, wait for the boiler to
cool, then press the red reset to return the boiler to operation.
Operation of a blocked vent and/or flame roll-out / interlock
switch usually indicates a problem with the venting system,
obstruction of the heat exchanger flue gas passageway and/or
a combustion air supply problem. The cause for operation of
the blocked vent and/or flame roll-out / interlock switch must
be determined and corrected. If the boiler cannot be restored
to normal operation, contact a qualified service installer, service
agency or the gas supplier.