FAQs

VENTING
1. What vent material can be used on the WM97+ boilers?
The boiler is approved to be vented with PVC, CPVC, Polypropylene (PP)
or AL29-4C stainless steel.
Special PP note: if one wants to sidewall concentric vent the 155 model
using Centrotherm’s pipe system (Eco Systems InnoFlue Single-wall),
Centrotherm’s stainless steel concentric termination kit must be used.
2. Does a vent/intake termination come with the WM97+ boiler?
Yes, the same black 3” PVC sidewall termination as the Ultra gas boiler.
3. Can the included PVC vent/intake termination plate be painted?
Yes.
4. What is the clearance to combustibles for the PVC vent?
3/16” (or to state and local codes, whichever is greater)
5. What is the approximate vent temperature of the WM97+?
Approximately 10 to 15 degrees F above system return water
temperature.
6. How can I vent with PVC when flue gas temperatures are as high as
approximately 190 degrees Fahrenheit?
There is a difference between flue gas temperature and vent material
temperature. In the case of flue gas going through the pipe, it is not able
to transfer as much heat into the pipe as could be transferred with water.
The WM97+ boiler is designed, tested, and certified to ANSI Z21.13/CSA
4.9 which limits the PVC vent material to 158 degrees Fahrenheit. The
WM97+ also utilizes a flue temperature sensor to insure the flue gas
temperature does not exceed 216
o
F.
7. What size vent can be used with the WM97+ boilers?
2” or 3” for the WM97+ 70 and 110, pipe size depends on vent length and
number of elbows.
3” only for the WM97+155.