FAQs

PIPING
1. What size boiler supply/return piping is recommended for the WM97+
boilers?
WM97+70 and 110 utilize 1” piping.
WM97+155 utilizes 1 ¼” piping.
2. Can the WM97+ internal circulator be increased in size?
No, a Taco 007 IFC (with an integrated flow check) is provided with the
WM97+70 and a Taco 0015 IFC is provided with the WM97+110 and the
WM97+155 boilers to provide proper flow through the boiler. If multiple
circulators or a larger circulator is required, the additional circulators must
be external to the boiler. And the boiler’s internal primary/secondary by-
pass valve should be opened to hydraulically separate the boiler’s
internal flow requirement from the system’s requirement.
3. What circulator can be used for replacement in the WM97+?
The quickest and preferred method would be to change the circulator
cartridge, it can be easily replaced on both models without removing the
circulator and is available at both WM and Taco distributors (WM part #
511-405-142 for the WM97+70 model, and part 511-405-143 for the
WM97+110 & 155 models). If replacing the circulator is desired, the Taco
007 or equivalent can be used for the WM97+70. For the WM97+110 &
155, a Taco 0015 can be replaced with a Taco 00R 3 - please note that
the 0015 for the 110 is the standard flange 00R-3, and the 155 uses the
0015 w/ rotated flanges, 00R-3 w/ rotated flanges. The factory installed
boiler circulators have an integrated flow check (IFC) in them-either
replace with a circulator that has this feature, or know that you no longer
have this capability.
4. For a small zone or zones, can the primary/secondary connection be
disabled in order to utilize the internal boiler circulator as the system
circulator?
Yes, the WM97+ 70 & 110 boiler circulator alone, can be used satisfy a
small zone(s). The boiler has an internal primary/secondary by-pass
valve which allows selecting whether the boiler is direct connected or
primary/secondary connected to the system. If only piping to a single
zone (may require multiple branches) or multiple small zones with zone
valves, the primary/secondary connection can be turned off, which
removes the primary/secondary connection to the system. Zone valve
systems, in which the valves are not controlled by the boiler, require a
pressure differential bypass valve to be installed.
The WM97+ 155 boiler circulator should not be used to satisfy the system
by itself.