Inlet Duct Connection To Boiler; Intake Duct Materials And Sizes; Category Ii Installations - Patterson-Kelley SOLIS SL-1500 Installation & Owner's Manual

Inlet Duct Connection to Boiler

Connect the air supply duct to the inlet air collar on the boiler. The air inlet collar is 11.875" OD. Fasten
the air inlet duct to the collar with sheet metal screws at 90° angles and seal with aluminum tape or
sealant.

Intake Duct Materials and Sizes

The air intake duct can be fabricated from PVC, CPVC, single wall galvanized steel, or other suitable
materials. The duct must be rigid enough to maintain the full required cross sectional area under all
operating conditions. Proper sealing of the intake ductwork is necessary to prevent infiltration of air
from conditioned space. Joints in PVC or CPVC must be cemented. For galvanized duct, wrap each
joint and seam with adhesive aluminum tape or other sealant. The installation of a birdscreen on the
intake termination is recommended. Ensure that the screen does not become blocked with snow, ice,
insects, etc.

Category II Installations

The SOLIS boilers are dual-certified for either Category II or Category IV operation. Category II
appliances operate with a non-positive vent static pressure and with a vent temperature that may cause
excessive condensate production in the vent. There are several requirements for reliable operation of
the boilers under Category II conditions:
1. A stainless steel vent adapter is required to mate the boiler exhaust connection and the vent pipe.
See the table below for the applicable part numbers.
2. A normally-closed motorized damper is required on the boiler's air intake. See the table below for
the applicable part numbers.
3. The draft, measured inside the vent at the rear of the boiler, must not exceed -0.05"
Excessive negative draft will cause nuisance trips such as flame failures.
4. The vent system must be properly drained of condensate before returning to the boiler. See
for information on installing condensate drains in the exhaust vent.
Table of Required Stainless Steel Vent Adapters and Category II Motorized Dampers
Boiler Nom. vent
Size Size
SL-1500 8"
SL-2000 8"
SL-2500 10"
SL-3000 10"
A normally-closed motorized combustion air damper with end limit switch is required for Category II
vent installations and is optional for Category IV vent installations. 120VAC motorized dampers with
end limit switches are available for purchase from Patterson-Kelley. Other damper motor voltages are
acceptable, provided they do not exceed 240VAC. The Air Damper Interlock circuit for the end limit
switch is always 120VAC which is sourced from the boiler itself. All end limit switches must be rated for
a minimum 120VAC.
Revised: March 15, 2021
Released: March 15, 2021
Stainless Vent Vent adapter
Adapter size
2701000075 8"
2701000075 8"
2640000133 10"
2640000133 10"
© Patterson-Kelley 2021
All Rights Reserved.
P-K SOLIS™
Technical Service 1.877.728.5351
Boiler Combustion Combustion air N.C.
Air inlet Motorized Damper
8"
8"
10"
10"
2701000090 P-K SOLIS NURO Installation and
Gas Fired Boiler
W.C.
3.7.6
Size
1004906944 8"
1004906944 8"
1004906945 10"
1004906945 10"
Owners Manual (Rev A).docx
Page 35