I don't know about a heater but I would expect it to have drain plugs. I drain the filter and pump. My DE filter has a bottom drain, the pump has two drain plugs. The filter drain has a value so I open the valve and let the filter drain while I'm blowing the lines. After that I close the valve since I don't want anything getting into the filter. I usually leave the drain plugs out of the pump. The only problem I've had with that is one year ants moved in for the winter. I had to clean the impeller and the pump housing before it would start. Did you know that some ants in Ohio can bite? Once I got the impeller to spin they all got to experience a little white water rafting.
I have unions for the skimmer and main drain where they "T" into the pump. I remove the piping, blow the lines, add the plugs and loose fit the "T" back in place to protect the plugs. The return also has a union. After I add the anti-freeze everything is loose fit back together.
I have unions for the skimmer and main drain where they "T" into the pump. I remove the piping, blow the lines, add the plugs and loose fit the "T" back in place to protect the plugs. The return also has a union. After I add the anti-freeze everything is loose fit back together.