Tenant keeps making repairs without notifying landlord

[Sabine Franklin]

Good morning, Bigger Pockets,

I could really use some advice about this situation. We have a tenant staying in a condo near Miami, Florida, these apartments are designated for over the age of 55. Over the years, there have been some instances where a repair was needed, and the tenant would make the repair and only tell us afterwards by sending us a copy of the receipt. We would normally reimburse the tenant but ask them (multiple times) to please let us know first because we should have the responsibility to address it and find a licensed repair person. 

A few weeks ago, I receive an email from the tenant that there was a problem with the central AC (April or May) and he called a repair person to fix it right away because elderly mother is ill and cannot be without AC. However, the AC is new and is under warranty. So, had I had known this, I would have called the manufacturer to come and fix it. Now I am concerned he voided the warranty, so the manufacturer may not make future repairs, at least not for free.

They are good tenants, but I do not understand why he insists on making repairs. There is a clause on the contract that says they are responsible for repairs less than $100 (say like kitchen sink leak), but these repairs they are making (without letting us know) are more costly.

What would you do or perhaps what action is best to take?