Feedwater Heating and Economizer
In order to maximize the water temperature entering the boiler, the 5AT will be fitted with twin feedwater heaters mounted above the boiler. Heat to these will be provided from a small proportion (approx 16%) of the exhaust steam from the cylinders.
Wardale has designed the water heaters to raise the temperature of the feedwater to 105oC [refer FDC 1.3 line 94 and FDC 9].
In addition the front section of the boiler will be partitioned off to form an “economizer” or water preheating section (as described elsewhere on the website).