I have an "opportunity" to buy a used pool heater. It is a Hayward, 100,000 BTU originally purchased three years ago. Was used one season in a pool sanitized with Nature 2. Supposedly it worked perfectly. After one year the original owner moved and gave his pool and heater to his son, who has used the pool but stored the heater unused for two years and has ultimately decided his family does not need the pool warmer than it is without hooking up the heater. Thus, it is offered for sale for $300 including the regulator, which he said would normally be an additional purchase. He says the heater lists for $900 (although I'm seeing it for 699 after a rebate). He mentioned the ignition is electric.
1. Anyone have any specific questions one should ask before buying a used heater?
2. Does it being used on a pool with Nature 2 in anyway effect its future function or life?
3. Does $300 seem like an appropriate price?
Thanks in advance for any insight -- I need to make a decision in a few days so I'm hoping you all can help. OH - I would plan to put it on a bigger pool next year, likely at least 18' x 48" and maybe bigger. The next pool will have 1.5" hoses.