*Output of Proheat 35 is limited to 25 kw on a single blanket air-cooled system.
The calculated “Time to Temp.” value is based on a scientific formula for heat input into a fixed mass of a carbon steel load, it does not consider the heat losses associated with thermal conduction, convection or radiation.
The “Time to Temp. + 50%” value is an approximation which artificially accounts for heat losses when pre-heating pipe, up to 52” OD (1320mm), up to 204°C with insulation on the OD only.
Times will vary based on the area you are heating, insulation coverage and environmental conditions.
When heating very large surface areas at post weld heat treat temperatures, time to temperature will increase significantly due to increased heat losses. It is recommended to contact [or specialists] for assistance.