Weil-McLain SlimFit Manual page 19

SlimFit
™
commercial condensing gas
Install water piping
Zoning with pumps — primary/secondary
piping
1. Connect boiler to system as shown in Figure 18 when pump zoning.
The boiler pump cannot be used for a zone. It must supply only the
boiler loop.
2. Install a separate pump for each zone.
3. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure 15, page 16.
4. Connect DHW (domestic hot water) piping to indirect storage water
heater as shown. Connect from the DHW tank aquastat to the DHW
terminals on the SlimFit boiler.
DHW tanks piped using this arrangement need to be sized
for the required load, with a DHW pump selected to provide
a flow rate through the boiler and tank that is within the al-
lowable flow rate range listed in Figure 13, page 15 of this
manual.
DHW priority
5. — Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be OFF during DHW — it is not needed.
The flow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop.
Controlling the pumps
6.
a. The Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump and DHW pump.
b. Refer to Field wiring, beginning on page 51, for instructions on
wiring to pumps.
c. The factory default settings are:
Pump A — Boiler pump
Pump C — DHW pump.
d. The zone pumps in Figure 18 must be controlled by pump relays
activated by the zone thermostats or zone controller.
1 SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 for details)
5 DHW pump
6 Isolation valves
8 Diaphragm (or bladder) type expansion tank (see page 16 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler pump
Part number 550-100-116/0713
-
fired water boiler
(continued)
Figure 18
Legend — Figure 18
14 Zone pumps, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
26 External drain/blowdown valve, when used
33 Strainer, recommended
Items supplied with boiler
Items supplied by others
NOTE 1:
from the primary/secondary connection, item 21). Pipe sizing is based on a
temperature rise of 30°F, corresponding to the recommended maximum flow
rate. Failure to follow these guidelines could result in system problems.
— Boiler Manual
Pump zoning plus optional DHW piping
— primary/secondary piping
Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
19