Operating instructions
17
5603 882 - 01 
Pyrotec Installation & Operating
Safety
 Mechanical Room
No temperature-sensitive pipes or lines may be installed 
in the floor beneath the heating boiler.
The temperature in the heating room must not exceed 
104° F (40° C) while the system is in operation 
(in the area approx. 3 ft. (1 m) away from the boiler).
The temperature in the heating room must not fall below 
50° F (10° C) while the system is in operation (measured 
at the inner side of exterior walls).
Dimensions shown in. (mm) 
Hatched surface   Heat-resistant floor
Medium grey surface  Boiler supporting surface
Ensure the mechanical room complies with the requirements 
in these instructions and local codes. 
Viessmann recommends the installation of an additional 
electrical disconnect switch and a fuel shut-off valve (if 
possible) outside the mechanical room or enclosed area 
of installation.
A separate, dry heating room must always be provided 
for the PYROTEC Grate Firing System. No combustible 
materials may be stored in the heating room. The heating 
boiler may only be set up on a fire and temperature-
resistant floor. 
The load-bearing capacity of the heating room floor must 
be designed for the weight of the system plus filling with 
water and fuel. The load-bearing capacity of the floor in 
the area of the boiler bearing surface must be 512 lb/ft² 
(2500 kg/m²). 
IMPORTANT
Always follow the most up-to-date local, municipal and 
building regulations and codes.
The minimum distance to the walls and ceiling required 
according to the table of dimensions for proper cleaning 
and maintenance of the boiler must be complied with. 
A sufficient supply of fresh air must be provided directly 
from outdoors into the heating room. Induced ventilation is 
necessary for heating rooms that are confined or enclosed.
Foundation dimensions
Boiler Model KPT- 390 530 720 950 1250
a in. (mm)
40e (1026) 40e (1026) 43c (1112) 53b
(1360) 53b (1360)
b in. (mm) 71
7
/
8
 (1826)
71
7
/
8
 (1826) 75a (1912)
85 (2160) 85 (2160)
c in. (mm)
166d (4221) 166d (4721) 193e (4912) 200f (5096)
222
1
/
8
 (5641)
d in. (mm)
49f (1260) 49f (1260)
55
1
/
8
 (1400) 64
1
/
8
 (6030)
64d (1630)
e in. (mm) 100
7
/
8
 (2561)
120b (3061) 122b (3112) 120c (3066) 142d (3611)










