Machine no longer heats milk hot enough

Ummn - something in your Q. seems not right. The milk is not heated directly - its only heated by the steam as it passes by (and picks up) by the milk using a venturi effect - same as a spray bottle attached to a garden hose. You say you have froth - but you can only get that if you have steam... (it does not just blow air thru to create bubbles). So froth = steam & steam = heat... so milk must be hot.
Suggest you check manual for the 'heat' settings for your expresso as this may have been changed. While this is adjustable, the milk is not.

Also always heat your cups before using them - the silver cup 'holder' at the top does a reasonable job but boiling water does far better.
Cheers Mike

There is no temperature adjustment for the heating element under the carafe.
The Instruction Manual says:

If coffee is too cold, machine not preheated, cups not preheated, milk not heated enough (if making a cappuccino or latté)

This is the only Breville Instruction Booklet I have been able to find:

http://www.keurig.com/customer-service/brewer-registration-and-support/~/media/Files/Keurig%20Brewer%20Manuals/Breville_BKC700XL.ashx

Sounds like a decscaling is in order.

I have the same problem, my wife complain me everyday, now we use our coiffe machine 90$ from sears it`s still better then this 3200$....

First,I'm NOT a Breville tech, but this is a very common problem with steam boilers. Your valve seal(s) are worn and needs replacement. Any leaking water or steaming from various places other than the steam tip is causing your tank to lose pressure. The heater needs to stay on longer just to keep everything up to pressure and properly heated. You probably noticed that your shots may not have the creme or very thin and watery. Milk steaming takes a long time or not enough steam to complete a froth, especially on a Latte. Your machine needs servicing. Contact your vendor or MFR for service.
** loose steam wands will fall off and be re-assembled without the ball seal or washer. Look around the machine for a round disk made of hard rubber or nylon plastic. Take apart the wand and reassemble with the washer or get a new washer and tighten,.
** other places were you can loose steam pressure is the Anti-siphon valve, Safety valve, and various pipe fittings to the steam boiler. Look for steaming plumes from unexpected areas of the machine.
** Scale that has built up to the point of causing valve problems are usually too much for DE-scaling to work properly. Usually done as a preventive maintenance rather an alternate to repair. Like a blood clot, if you remove it while still in an active system. Where does this clog end up? This debris needs to be physically removed from the pipes, valves, and/or tank. Heavy scaling is a sign of an old machine that will need a lot of servicing to bring it up to MFR specifications.
** Final; The steam wand(s) are the most used (and abused) parts of the machine. Constant cleaning is a required task that needs very diligent baristas to keep it fully functional. I've found that best operators use the following method to keep the steam wand in top condition; Remove milk froth pitcher completely from wand, Send a short blast of steam to clear milk residue from tip. Take a damp towel to grab wand an pull downward to wipe off any remaining milk residue. Leave the wand in a pitcher of cool water to soak during long break periods to help break up any dried milk. Let soak over nite when not in use. Have your operators notify you of any 'loosey-goosey" wands. Tighten them properly but make sure all the parts and washers are there. Check your manual or just ask your technician to show you the next time.
*Have a safe New year! Aloha! ukeboy57

Yes there is a small amount of condensation, just flush the steam wand before steaming your milk.

You are not supposed to put milk in the resevoir and run it through the machine. That's likely the problem. But like most parents you will continue to blame your child until he is totally alienated and your relationshio is an empty shell.

The steaming wand's tip gets gunked up with milk so make sure to clear that with a needle first. Make sure the machine is fully heated before using the stream function (should have an indicator light). Typically this model will expel water first, then a low pressure steam. After about 30 - 40 seconds it should produce meduim pressure steam. Make sure the pump is making the proper clunk, clunk sound or it could be failing. Also, the steam wand arm may be obstructed and descaler solution will have to be used to remove the deposits. Hope this helps.

The pump has gone bad - through use. This is a common problem, and has to do with the "seals" that are in the pump. Since the pump generates high pressure and heat, over time, the seals will fail, and will be unable to generate enough pressure and heat to create steam. The only remedy is to have the pump replaced through the Breville Out of Warranty repair centers.
http://www.brevilleusa.com/support/service-centers.pdf