The bottom is formed by a water-tank and the ashes are quenched here.
If the pressure alters as the water tank empties, a discontinuity occurs in the trace when the tank is refilled, and a fictitious element may be introduced into the diurnal variation.
The mixer shower uses cold water from the hot water tank and cold water from the cold water cistern in the loft.
Reduce heat losses by fitting a hot water tank jacket, insulating hot water pipes and consider installing double-glazing.
This room also contains the immersion heater, hot water tank and airing cupboard.