Weil-McLain SlimFit Manual page 18

SlimFit
™
commercial condensing gas
Install water piping
Zoning with zone valves — primary/
secondary piping — alternate method for
High-flow-rate/high-head-loss DHW circuits
1. For applications requiring DHW circuit flow rates higher than allow-
able for the boiler, or for high pressure-drop coil-type DHW tanks,
connect the piping as in Figure 17. The DHW water only flows through
the secondary circuit connection piping. NOTE: Make sure to size the
connection piping (Figure 17, item 23) for the total flow it must handle.
2. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure 15, page 16.
3. 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 priority
4. — Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be ON during DHW. The flow/check
valve shown on the boiler outlet piping prevents gravity circulation in
the boiler loop.
5. Controlling the pumps
a. The Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump, system 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 B — System pump
Pump C — DHW pump.
For systems with low-temperature radiant heating, the sys-
tem pump (item 7) MUST be OFF during DHW heating to
prevent possible overheating in the radiant system.
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
7 System pump (see information above for wiring)
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
13 Zone valves, typical
18
-
fired water boiler
(continued)
Figure 17
Legend — Figure 17
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
23 DHW secondary connector piping — no more than 8 pipe diameters apart
25 Systems using high-head pumps require a bypass pressure regulator to
prevent damage to control valves.
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
Zone valve zoning plus optional DHW
piping
Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
Part number 550-100-116/0713