This is a category of coal fired boiler and biomass fired boiler. It includes coal fired steam boiler, coal fired hot water boiler, biomass fired steam boiler and biomass fired hot water boiler. If you need these kinds of boilers, you can find your need here. In addition, the boilers in this category also includes two kinds of boilers, such as chain grate boiler and fixed grate boiler. The chain grate boiler can feed fuel automatically by fuel feeder. The fixed grate boiler can’t feed fuel automatically while it need to feed fuel by hand. But the fixed grate boiler is cheaper than chain grate boiler in price. Both of them can operated safely and have features of large heating surface, high thermal efficiency, precise temp. control, clean combustion, less pollution and so on. If you want to know another difference of these two boilers, please contact us. We are always waiting for your message.