"it wouldn't ever shut off."
First off, CONGRATULATIONS!
A Halo of Heat that will not shut off can have a problem that ranges from the simple to the nasty...
1) The little paperclip like link from the shut off solenoid to the control switch can be off or broken. (common)
2) Bad shutoff solenoid. (not likely)
3) The element can be grounded and won't cool down and let the cool down t-stat shut the motor off even though the control switch may have 'turned off' (common)
4) Bad cool down stat. (common)
5) Bad/broken control switch. (possible)
6) Bad electronic dry board. (uncommon)
7) Possible short across one of the sets of sensor bars in the drum (possible)
Do a little triage when they come home and let us know! Otherwise, that's a nice set!
RCD