Q:  What are the benefits of induction vs resistance vs flame?

A: View our Comparison Chart [PDF] for more information.

Q: Why is the cost to run the Proheat 35 less than resistance and flame?

A: The Proheat 35 draws 49 amps (36KVA/37KW) from a 480V line at full output.  The Proheat 35 only runs at full output until the target work piece is up to temperature, it then runs at a lower power to simply make up for heat losses into the air which is proportional to exposed surface area and the insulation used on the work piece.  Also, majority of the Proheat 35 accessories are reusable.

Q: What are the safety issues related to EMF?

A: The ProHeat 35 does produce EMF.  Please reference the Owner’s Manual and…

Q: What kind of heating applications can I use the ProHeat 35 on?

A: The Air-cooled system can be used for preheat applications up to 400F.  The liquid-cooled system can be used for preheat, bake out, and PWHT applications up to 1,450F.  The rolling inductor system can be used for preheat applications up to 600F.  The ProHeat 35 can be used various other applications which require heat and where flame and resistance heating is currently being applied.

Q: What kinds of metals can I heat?

A: Any metal containing enough iron or steel to make it magnetic can be heated with a ProHeat heater.  Because heat is induced in the metal by placing it in a high-frequency magnetic field, non-magnetic metals such as aluminum cannot be heating using a ProHeat heater.

Q: What is the largest and thickest metal I can heat?

A: The ProHeat 35 can heat all different size and thickness of materials.  It just depends on the type of material being heated, its overall mass, the amount of insulation being used, ambient temperature, etc.  Thicker materials will require a longer time to achieve the target temperature.
We have customers heating very thick metals with induction such as 12” thick nuclear vessels or 17” shovel buckets, but there are aspects of your application that have to be evaluated to determine a good answer for this question.  Induction actually generates the heat within your metal, so it has great efficiency gains over other forms of localized heating such as flame or resistance heating, but it still only generates the heat near the surface of the metal and requires time for the heat to “soak” through the thickness of the metal for the whole thickness to become hot.  Also, there will always be heat losses as the heat moves through the thickness of the part, so you typically heat the surface slightly higher than the target temperature in order to compensate for heat losses.  

Q: How long will it take to heat up my pipe, plate, or part?

A: It depends on the type of material being heated, its overall mass, the amount of insulation being used, ambient temperature, etc.  Thicker materials will require a longer time to achieve the target temperature.  Miller does offer calculation tools online to help determine time to temperature.  Please see the System Operating Requirements topic below.

Q: Does it provide consistent heat?

A: Yes.  ProHeat 35 uses induction, which induces heat from within the part and is one of the most consistent and penetrating heating methods available.  In comparison, flame heating, displaces heat into a much wider and uncontrollable zone, while resistance heating can result in hot and cold spots if ceramic pads break or wear out.

Q: Does it magnetize or unmagnetized the part?

A: No.  We are using a high frequency alternating magnetic field, It should not magnetize or unmagnetized the part.

Q: Will it affect the welding process?

A: Only with Lincoln’s STT process, their unit is prone to interference from EMF.  The Miller RMD process however runs next to induction without interference.  I have not heard or witnessed any other issues with any other weld arcs.  It is common for operators to weld while heating with induction.  I have even turned the heating on and off to allow the welder to see if there were any adverse effects, they could not see any difference.

Q: What are the power source requirements (in shop & in field)?

A; For the ProHeat 35 demo, we require a 480V - 3 phase power drop capable of 50 amps (60 amp drops are typical). 

You can use generator power.  It needs to be rated for 460-575 Volts, 3 phase, 39KVA continuous.  Customers typically use a 50, 60, or 100 KW unit.  Smaller KW generators can be used but you must make adjustments in the System Setup menu.

Q: What is the maximum distance I can locate the power source from the work piece?

A: The output extension cable connects from the back of the Proheat 35 power source to the heating tool.  The output extension cables come in different lengths.  For the Air-cooled system, we offer 25’, 50’, and 75’.  For the Liquid-cooled system, we offer 10’, 25’, 50’, and 75’.  

Q: What is the total length of cables I can use at one time?

A: For the liquid-cooled system, you should not exceed a total length of 360’.  Any lengths beyond 360’ will strain the cooler and shorten its life.   It should be noted that the Output Extension cables are made of two blue cables inside (a supply & return).  So, a 25’ Output extension cable is really considered 50’ long.  For example: Two 25’ Output cables with two 80’ liquid cooled cables would have a total length of 260’ (50’ + 50’ + 80’ + 80’ = 260’).  The machine will also give a Fault (F61) if coolant flow is low.  Please see cooler manual for more information.

Q: Can I connect the cable/blankets together in a series?

A: You can connect the air-cooled cables and blankets together in a series using the Series Cable Adapter (195437).  You cannot connect the liquid-cooled cables together in a series.  That is why we offer the 140’ and 160’ liquid-cooled cables.

Q: Will my welding process allow me to use a ProHeat 35 heater/induction heating?

A: Check your welding procedure specifications (WPS).  Typically, a WPS will specify a minimum or maximum temperature, but not a heating process.

Q: Can I connect more than one tool at the same time?

A: The ProHeat 35 has two outputs in the back of the power source.  You can connect two of the same exact tools at the same time.  But, you cannot combine two different tools at the same time.  It also recommended that you should use the exact same setup for each output.

Q: Can I use heat two different items at the same time?

A: No.  We recommend the setups to be exactly the same.  The geometry and temperature requirements must the same when using both of the Proheat 35 outputs because there is no independent control of each.

Q: Can I immediately remove the tools and insulation once the heating cycle is complete?

A: Yes.  Once the heating cycle is complete, the heating tools can be removed from the heat zone and moved to the next item without delay.  Although heating tools do not heat up from the induction process, the hot workpiece may transfer its own heat to them.  So always wear proper personal protective equipment when handling heating tools and insulation.

Q: Can I discount the cables while unit is still on?

A: No. Always stop the heating cycle and then power down the unit before disconnecting the tools.

Q: How long must I leave the cooler running if I decided to leave the cable on work piece after a heating cycle?

A: There is no issue with removing the heating tools from the heat zone.  But, if you chose to leave the heating tools in place, then leave the cooler running until the workpiece temperature is below 200° F.  The cooler is designed for continuous operation and can be left running for extended periods of time.

Q: What is the typical KW output?

A: The Proheat 35 can provide up to 35 KW depending on the configuration and applications.  Each application will most likely result in a different KW output level.  You can check the KW output for your application by pressing the “Parameters” button during operation.  You can study how the performance of the machine changes by either adding or reducing wraps.

Q: Is it designed for outdoor use (IP rating)?

A: The ProHeat 35 power source has a IP23C rating.  It is designed for outdoor use.  It is made to the same standards that our welding equipment is made to.  The cooler is rated for IP23.  It is designed for outdoor use.  It may be stored but is not intended to be used for welding outside during precipitation unless sheltered.

Q: At what temperature do I need insulation for each of the ProHeat 35 tools?

A: Reference the chart below.  When required, apply insulation on the workpiece anywhere a heating tool will be placed.

Q: Is there a formula used to determine the number of cable wraps required to heat?

A: No. For the liquid cooled system, we usually recommend 4-5 turns on each side of the weld joint.  For the air-cooled cables, we usually recommend 2-3 turns on each side of the weld joint.  By pressing the “Parameters” button during operation, you can see how the machine is performing.  You can study how the performance of the machine changes by either adding or reducing wraps.

Q: What is the proper way to arrange the cables and avoid cancelation?

A: TBD….Show examples??

Q: Do the cables come in different lengths?

A: The Air-cooled heating cables are available in 30’, 50’, and 80’ and the Output Extension cables are available in 25’, 50’ and 75’.  The Liquid-cooled heating cables are available in 30’, 50’, 80’, 140’, and 160’ and the Output Extension cables are available in 10’, 25’, 50’ and 75’.

Q: What is the diameter of the cable and minimum bend radius?

A: Diameter of the heating cable (thickness) is 0.875 “
Minimum Bend radius for the liquid cooled cables for winding ‘pancakes’ or ‘ear-muffs’ is 1”

Q: Are the air-cooled blankets only meant for round/pipe applications?

A: No, the air-cooled can be used for various other applications.  Besides circular applications, they can be used also be used on flat parts, or any other applications where the blanket can make contact with the metal.

Q: Can I replace the cover/sleeve on the air-cooled blanket?

A: Yes, replacement sleeves are available for every size of air-cooled blanket sold.

Q: What are the programing options for the ProHeat 35?

A: The Proheat 35 comes with three basic programs (Preheat, Bake Out, and PWHT).  The air-cooled and rolling inductor systems will allow access to only to the Preheat program.  The Liquid-cooled system will allow access to all three programs as well as a Custom program where the operator can create a custom program with multiple steps.

Q: Does the ProHeat 35 keep what I have programed?

A: Yes, it remembers the last program input for each program cycle (Preheat, Bake-Out, and PWHT).  But, we always recommend checking what has been programed before running the cycle.

Q: What are my other options besides temperature mode?

A: Miller strongly recommends running the machine in temperature mode.  But, under the System Setup 1 menu, you can change the Control Mode.  Your control options are Temp/Remote/Time/Manual

Q: How many temperature-reading thermocouples can you attach?  Do you need to use them all?

A: You can attach up to six temperature reading thermocouples, but you don’t need to use them all.  The first one must be selected as controlling when using temperature mode.  You can have up to four as controlling if you chose.  Specific thermocouple requirements for a given welding procedure should be outlined in your welding procedure specifications (WPS).

Q: What is the best location to place the temperature sensor?

A: The control TC should be placed in the center of the induction coil layout, under the insulation and directly on the part being heated.  Please reference Owner’s Manual for more information.

Q: What happens if the temperature sensor falls off?

A: If using the Contact Thermocouple sensor/probe (200202), the sensor will continue to provide temperature feedback to machine and the Proheat 35 will continue to provide power.  So, it is very important to make sure the sensor does not get displaced during operation.  If this is issue, it is recommended that you use the Thermocouple wire (194999) and attach the wire with the thermocouple attachment unit (194959)

Q: Can I leave the unit running unattended or overnight?

A: This is possible only if the Proheat 35 is running in Temp Mode, the setup is done correctly, the TC are positioned correctly and securely, and providing proper temperature feedback to the unit.

Q: How do I determine proper temperature at the weld joint?

A: For Preheat application, the temperature displaced on the Proheat 35 is the TC placement temperature.  It is always recommended that you verify the temperature at the weld joint to confirm it is the correct temperature according to your weld procedures prior to welding.

Q: Does the ProHeat 35 record any data?

A: To record data, you must purchase a digital recorder.  Miller offers a 6-channel and 12-channel digital recorder which easily attaches to the power source.

Q: What is the warranty?

A: The Proheat 35 power source and cooler are covered by a one-year warranty and the heating tools (blankets, cables, etc.) are covered by a 90-day warranty.  Warranties only cover manufacturing defects; they do not cover customer damage/abuse. Digital recorders are warranted separately by the manufacturer.

Q: Do I need to calibrate the Proheat 35?

A: First, let me mention that the ProHeat Thermocouple (TC) inputs are designed with precision components and the analog temperature signal is immediately converted to digital data when received in the ProHeat 35, making analog drift and the need for calibration very unlikely.  There is no facility on the ProHeat 35 to alter these signals in any way, and it does not require calibration to run properly.
We do realize that some codes, such as ASME section 9, require that the thermocouple inputs be verified/calibrated annually if the unit is used for PWHT on welds that meet section 9.  This is the instance where someone would need to verify the calibration of the unit.  This is typically done by a local lab or TC calibration service, Miller does not provide the service.  We do however post full instructions, in the owner’s manual and on the Millerwelds.com website, on how Miller verifies calibration on the production line for new units.  This can be used by anyone wanting to do the service in the field.  Local calibration services can usually be found on Google or in the Thomas register. Miller does not have any data on available calibration services.

Q: Why do I need to use the Miller coolant (043810)?

A: We strongly recommend the use of Miller coolant because:

• deionized, not to be affected/ heated up by magnetic fields
• have hi glycol % to prevent fast heating
• have antifreeze quality
• have lubrication ingredients for pump’s rubber parts
• have anti algae growth ingredients

The Safety Data Sheet (SDS) for the coolant can be found on the Miller Induction website under Support.

Q: When do I need to add coolant?

A: Coolant should be added when the machine is new.  Coolant should be checked and added whenever a new liquid-cooled cable is installed because coolant will flow and remain in the new cable.  The machine will give a Fault (F61) if coolant flow is low.  Otherwise, please follow instruction in the Owner’s Manual.

Q: How often do I need to replace the coolant?

A: The cooler Owner’s manual recommends the coolant be changed every 12 months if using Miller coolant (043810).

Q: Where do I send the ProHeat 35 power source or cooler in for repair?

A: Please contact your local authorized Miller service center.  Your closed service center can be found in the Miller website under “Where to Buy”.

Q: Can the cables be replaced or repaired?

A: Yes.  The cables can be replaced with no issue.  Please contact your local Miller authorized distributor.  The cables can also be repaired.  The Cable Repair Quote sheet can be found on the Miller Induction website under Support.  

Q: What is the sales channel for the ProHeat 35?

A: In the US, we interview our end users to configure a system and sell direct to the end user.  To learn more about the Proheat 35 and for question related to purchases, please call 844-IND-HEAT (844-463-4328) or email InductionSales@MillerWelds.com.
International customers, please contact your local ITW sales office.

Q: What if customer does not want to buy direct from Miller?

A: In the US, Miller sells its ProHeat induction heating systems direct from the factory.  We do allow authorized Miller distributors to purchase the accessories to support their customers who already have a ProHeat systems.  International customers, please contact your local ITW sales office.

Q: Where can I rent this?

A: Check with your nearest Red-D-Arc Welderentals location.

Q: What are my training options?

A: For ProHeat 35 training, you have three viable options:

1. Self-train – have your operators review the owner’s manual and ProHeat 35 videos on their own.
   Manuals: https://www.millerwelds.com/support/manuals-and-parts
   Videos: https://www.millerwelds.com/products/induction-heating-systems/induction-heating-resources
2. Training at Miller (Appleton or Houston) – 1 day, no charge from Miller, but your company will need to pay for attendee’s expenses.
3. Onsite training - 1 day of onsite training with a Miller induction heating specialist.  For additional information and pricing, please call 844-IND-HEAT (844-463-4328) or email InductionSales@MillerWelds.com

Q: How do I access the program setup screen for the Rolling Inductor?

 A: To view the system setup screen for the Rolling Inductor, simultaneously press the Parameters and Program buttons. The following settings are available:

• Deg Units Displayed (°F or °C)
• Tolerance (±5 to 99)
• Travel Detect (On or Off)
• Control Mode (Manual, Temp, Time or Remote)
• Max Output (1 Kw to 35 Kw)
• System Lock (Yes or No)
  (For more information on the setup screen, please consult the Rolling Inductor Owner’s Manual)

Q: Can I get a full 35 kW of output power with the Rolling Inductor?

A: No, the Rolling Inductor is limited to 300 amps which results in about 20 kW of output power. If 35 kW at 100% duty cycle is desired, a two rolling inductor arrangement is required. The external cooler heat exchanger (300993) is recommended for two Rolling Inductor arrangements. (See owner’s manual for additional information on this topic)

Q: If I already own a ProHeat 35, will the Rolling Inductor work with my system?

A: Yes, all ProHeat 35 systems are capable of running the Rolling Inductor, but if the system was purchased before August 2014 (serial number prior to ME320092G) a software update is required to run the Rolling Inductor and a hardware update is required to run the Travel Detect System (301183). If an update is needed, call Miller’s service department at 920-735-4001 for more information on how to update your systems software.

Q: Will the Rolling Inductor work with the Intellifire 250 or other induction power sources?

A: No. The ProHeat 35 is the only power source that works with the Rolling Inductor.

Q: Can I use the recorder to document heating with the Rolling Inductor?

A: Yes. If the Rolling Inductor is used with compatible temperature measurement devices (customer supplied) you can record heating temperatures. Measurements should be taken within two inches of the Rolling Inductor.

Q: What happens if I run the Rolling Inductor without rolling the pipe or moving the induction head?

A: Depending on output, material type and material thickness, if the Rolling Inductor remains stationary for too long it can overheat the work piece and cause irreversible damage to the work piece and Rolling Inductor. For this reason it is extremely important to ensure that either the work piece or Rolling Inductor is moving at all times. Using the Travel Detect System (301183) helps minimize the chance of overheating a stationary, object by constantly sending feedback to the power source and limiting output if limited or no motion is detected.

Q: What’s the difference between the mounting arm and mounting stand that Miller offers?

A: The mounting arm (301119) allows heating from the top side of the pipe and will provide the most amount of flexibility and configurability. The mounting stand (301258) is ideal for heating from the bottom of the pipe.

Q: How fast can I expect my part to reach its target temperature?

A: There are many variables that affect the time to temperature of the part being heated; the thickness of the part, amount of surface area, travel speed and type of material being heated.
Example: A carbon steel pipe with a diameter of 12” and a wall thickness of ¾”, traveling at 34 ipm, took under 4 minutes in our lab testing to reach 400°F on the entire interior of the pipe.

Q: How do I determine a travel speed for optimal heating?

A: A larger diameter part should be rolled faster because it will dissipate heat quickly between passes of the induction head. A smaller part can be rolled slower because it will dissipate less heat between passes of the induction head. Speeds below 15 ipm will take longer to heat because the power ramp rate is limited. Below 30 ipm maximum output is limited to about 1 kW per ipm of travel speed.

Q: Do all four Rolling Inductor wheels need to be in contact with the work piece at all times?

A: Power coupling to the part decreases as the distance to the part increases. Maintaining constant distance between the rolling inductor and the work piece will ensure consistent heating, using the wheels is the best way to maintain a constant distance. The wheels should be the only part to contact the work piece, if any other part of the rolling inductor stays in contact with the work piece damage can occur.

Q: Does it matter which way I roll the pipe/work piece when using the Rolling Inductor?

A: When using the Rolling Inductor always roll away from the power cable. (Clockwise when the cable is exiting left and counterclockwise when the cable is exiting right)

Q: What applications are best suited for the Rolling Inductor?

A: While there is no set configuration for the Rolling Inductor, primary applications include preheating fabricated pipe sections, preheating tower bases and preheating longitudinal submerged arc welding passes.

Q: Who can I contact for additional support or information about the Rolling Inductor?

A: For more information regarding setup, troubleshooting, or operation of the Rolling Inductor contact Miller’s service department at 920-735-4001