WÄRTSILÄ WARTSILA32, Product Manual, Page: 144 / 254

The temperature control valve is installed directly after the engine. It controls the temperature
of the water out from the engine, by circulating some water back to the HT pump. The control
valve can be either self-actuated or electrically actuated. Each engine must have a dedicated
temperature control valve.
96°C Set point
9.3.5 Temperature control valve for central cooler (4V08)
When it is desired to utilize the engine driven LT-pump for cooling of external equipment, e.g.
a reduction or a generator, there must be a common LT temperature control valve in the
external system, instead of an individual valve for each engine. The common LT temperature
control valve is installed after the central cooler and controls the temperature of the water
before the engine and the external equipment, by partly bypassing the central cooler. The
valve can be either direct acting or electrically actuated.
The set-point of the temperature control valve 4V08 is 38 ºC in the type of system described
above.
Engines operating on HFO must have individual LT temperature control valves. A separate
pump is required for the external equipment in such case, and the set-point of 4V08 can be
lower than 38 ºC if necessary.
9.3.6 Temperature control valve for heat recovery (4V02)
The temperature control valve after the heat recovery controls the maximum temperature of
the water that is mixed with HT water from the engine outlet before the HT pump. The control
valve can be either self-actuated or electrically actuated.
Especially in installations with dynamic positioning (DP) feature, installation of valve 4V02 is
strongly recommended in order to avoid HT temperature fluctuations during low load operation.
The set-point is usually somewhere close to 75 ºC.
9.3.7 Coolers for other equipment and MDF coolers
The engine driven LT circulating pump can supply cooling water to one or two small coolers
installed in parallel to the engine, for example a MDF cooler or a reduction gear cooler. This
is only possible for engines operating on MDF, because the LT temperature control valve
cannot be built on the engine to control the temperature after the engine. Separate circulating
pumps are required for larger flows.
Design guidelines for the MDF cooler are given in chapter Fuel system.
9.3.8 Fresh water central cooler (4E08)
The fresh water cooler can be of either plate, tube or box cooler type. Plate coolers are most
common. Several engines can share the same cooler.
It can be necessary to compensate a high flow resistance in the circuit with a smaller pressure
drop over the central cooler.
The flow to the fresh water cooler must be calculated case by case based on how the circuit
is designed.
In case the fresh water central cooler is used for combined LT and HT water flows in a parallel
system the total flow can be calculated with the following formula:
9-14 Wärtsilä 32 Product Guide - a21 - 7 September 2016
Wärtsilä 32 Product Guide 9. Cooling Water System