Would TapBoost be okay to boost hot water supply to taps from a coal heated back boiler?

You can use TapBoost to boost hot water supply from a coal heated back boiler however, you should fit a Hot Water Supply Thermostatic Mixing Valve. We recommend doing this because TapBoost has a maximum temperature of 60 degrees, but coal heated back boilers don’t have temperature control therefore, it is important to prevent causing any damage.