Bypass valve on Raypak heater

[JB007]

When we installed our pool heater (Raypak P-R206A-EN-X) 2 years ago, it was recommended to also install 2 by pass valves in the plumbing.
question : if you close the in/out valves and bypass the heater completely (during the summer), do you need to drain the water from the heater/pipes inside the heater ? kind of doing a "winterizing" process ? or can you just close the valves and be done ?
i figured since i have these valves, may as well by pass the heater and extend the life of it when not in use.
Thanks for any advice.

 

[proavia]

Post a picture of your heater and bypass setup.

Fill out your signature with pool, pool equipment (including manufactuerers and model numbers) and test kit info.
This assists us in provide help specific to your pool without needing to ask you each time.

https://www.troublefreepool.com/account/signature

 

[JB007]

Not sure why the file disapeared. I repost again here.