Pratt & Whitney Rzeszów S.A.
MAINTENANCE MANUAL
PZL-10W ENGINE
75-32-00
1997.07.15
Page 4
Export Control Classification: PL/UE 9E999
At the extreme low ambient temperature may occur "beat" and engine shut-down during the starting. At that case at
least one valve with the spring of low rigidity (designed as in subitem (1))shall be replaced for the valve with the
spring with high rigidity (designed as in subitem (2)).
NOTE:
The engines have got both 19.31.0460 valves installed (see subitem (1)). The valve 19.31.0370 (see
subitem (2) is added (one per two engines) in the spare parts of - these engines.
To provide reliable engine starting, i.e., to protect against stopping to increase the turbocompressor speed or surging a bleed valve
with adjustable valve head is installed on the combustion chamber case of engines produced and general overhauled since 1997. It
needed, this adjustment enables to set the valve in a position:
-
fully opened - marked on the adjustment plate with the letter "O";
-
half-opened - marked on the adjustment plate with the letter "½O" ;
-
fully closed - marked on the adjustment plate with the letter " Z"
The selection of the adjustment position depends on engine individual parameters, type of operation (summer, winter), current
weather conditions. Suitable adjustment position of the valve is obtained by switching the adjustment plate. It is recommended to
use the following adjustment positions of the valve:
-
when the turbocompressor speed stops to increase - set the valve to decrease the air stream flowing through the valves, e.g.,
set from "½O" position to "O "position from "½O" position to "Z" position;
-
when surging occurs - set the valve to increase the air stream flowing through the valves, e.g., set from "Z" position to "½O"
position or from "½O
"
position to "O" position;
-
when operating the engine in winter (when the ambient temperature is 10 ÷ -4°C or below), set the valve in the open
position.
It is permitted to set a position that is different from the ones above mentioned. The adjustable bleed valve of the right engine is
installed on the right side of the engine and the one of the left engine is installed on the left side of the engine. Adjust the valve
according to 75-32-00, REMOVAL AND INSTALLATION, item 3).
