The following pictures show the effects of rainwater in the SAM unit. Although none of the chips were swollen, the unit was damaged beyond repair.

Unfortunately, water seems to following the wiring loom to connectors N11-8 and N11-9. These are the two multipin square connectors that are held in place with a swing-retainer. These connect to the microprocessor part of the SAM which then controls the relays on the larger passive PCB. Click on the following images to make bigger.

There is no definitive way to protect the SAM from water ingress damage short of wrapping the whole unit in a plastic cover and sealing it to every cable that connects to it. Some people have tried resin coatings but this does nothing to protect against water shorting the terminals of the connectors. You are much better off addressing the leaks in the first instance. We would advise against covering the PCBs with thick waterproof coatings as they restrict airflow over the unit and can lead to premature failure of components. Believe it or not, some chips do get hot!