Weil-McLain 550 MBH Nstallation And Operation Manual page 12

®
SlimFit Series 3
Install water piping
Use two wrenches when tightening water piping at
boiler, using one of the wrenches to prevent the boiler
interior piping from turning. Failure to support the
boiler piping connections to prevent them from turn-
ing could cause damage to boiler components.
General piping information
Additional controls, when required
The Control module uses temperature sensors to
provide both high limit protection and modulating
temperature control, and is UL353 Limit Controls
certified to meet ASME CSD-1 and Section IV require-
ments. The Control module also provides low water
protection, both with a low water cut-off inside the
boiler jacket and by sensing the temperature of the
heat exchanger. Some codes/jurisdictions may require
additional external controls.
Additional limit controls
1. Consult local requirements for other codes/standards to deter-
mine if additional limit devices are needed.
tem includes circuits that require lower temperature
water (radiant slab circuits, for example) as well as
higher temperature circuits, it is recommended to
protect low-temperature circuits with limit controls
that are wired to a Control external limit circuit (P13
terminals 1 and 2 for manual reset, or P13 terminals 3
and 4 for automatic reset).
2. See instructions beginning on page 50 for wiring information.
a. Manual reset operation: If external limit controls are to cause
of the Control module, connect series-wired
isolated contacts to P13 terminals 1 and 2 (see page 50 for
wiring information).
b. Automatic reset operation: If external limit controls are to
cause
series-wired isolated contacts to P13 terminals 3 and 4 (see
page 50 for wiring information).
Low water cutoff
1. A push-to-test low water cutoff is included with the boiler. The
low water cutoff is mounted on the boiler supply manifold, and
is available for test by removing the boiler jacket.
2. Operation of the low water cutoff is manual reset through the
Control.
Backflow preventer
1. Use backflow check valve in cold water supply as required by
local codes.
12
COMMERCIAL CONDENSING GAS
— If the heating sys-
of the Control module, connect
—
-
FIRED WATER BOILER
Install relief valve
1. Install relief valve (female) on the ¾" nipple in the
2x¾" bushing on the boiler supply piping tee (Figure 3,
page 11). The relief valve must be piped with no smaller
than ¾" pipe and fittings.
2. Connect discharge piping to safe disposal location, fol-
lowing guidelines in the
Discharge line must be connected to re-
lief valve outlet and run to a safe place
of disposal. Terminate the discharge
line in a manner that will prevent
possibility of severe burns or property
damage should the valve discharge.
Discharge line must be as short as pos-
sible and be the same size as the valve
discharge connection throughout its
entire length.
Discharge line must pitch downward
from the valve and terminate at least
6" above the floor drain where any
discharge will be clearly visible.
The discharge line shall terminate
plain, not threaded, with a material
serviceable for temperatures of 375 °F
or greater.
Do not pipe the discharge to any place
where freezing could occur.
No shutoff valve shall be installed be-
tween the relief valve and boiler, or in
the discharge line. Do not plug or place
any obstruction in the discharge line.
Test the operation of the valve after
filling and pressurizing system by
lifting the lever. Make sure the valve
discharges freely. If the valve fails to
operate correctly, replace it with a new
relief valve.
Failure to comply with the above
guidelines could result in failure of the
relief valve to operate, resulting in the
possibility of severe personal injury,
death or substantial property damage.
Boiler Manual
below.
:
Part number 550-100-168/0516