When we reported that it was opening by itself the manager sent a repairman over to look at it.

Their excuse was the repair man had family issues and that's why it took so long (they had only one repair man, and instead of hiring someone in his place, the entire area was left unrepaired while he was gone).

Ask a repair man about the cost of replacing the unit.

The repairman added some type of heater to the line and corrected the problem.

We have hired a full time repairman, and would like to keep track of requests sent, etc. 

Also include a paragraph in the lease to let tenants know that any repairman will be acompanied by management whenever tenant is not home and can not be contacted,  for security reasons. 

Unless it's extremely obvious, like the repairman pulled a hunk of metal out of the broken disposal or diapers out of a clogged toilet that you just had cleared before they moved in, plan on paying for the repair.  

Occasionally you'll get a dud of a repairman that doesn't show up promptly because you're a home warranty client, but I've had pretty good experiences with the repairman.

I am the repair man and I have learned a lot about houses (and people) in the 5 years I have done this. 

That is when they got mad.I've had other tenants go through everything that needed fixing while the repairman was there and everything was completed in one stroke.