First year with my new Hayward H 250fd heater. Closing pool this weekend and live in Michigan so you understand our winters. What do I have to do other than opening the drain plug if anything.

either blow water out with a blower then follow with a little antifreeze to make sure all water is out then remove freeze plugs on sides of heat exchange then remove pressure switch turn off gas valve and put a board or something on the top to keep out snow and weather

Make sure that you drain all of the water out of the pool heater to prevent damage during freezing weather. That is the most important thing you can do to winterize pool heaters. If you have a cover, you might want to use it to prevent weather related exposure, but as long as you have the water out, you will be ok.

Replace the thermistor. It is a stainless steel plug ~1/2" pipe thread with three wires leading from it to the back of the control panel. Shut the heater down and the pump too; remove it from the header and install a new one. Route the lead wire thru the chassis to the control board and plug it in...problem solved.

John

There should be a drain plug on the bottom of the header. This is common on most of Hayward's in-ground pool heaters. Since you did not give your model Number, I can't say 100%. You can also check Hayward's website for the manual and look under "winterization". you should be able to find your product manual here: http://www.haywardnet.com/inground/products/manuals.cfm#HeatersGas_Heaters Hope this helps. If you need further assistance post a reply in the comments, and don't hesitate to leave good thumb rating if you found this helpful. Thanks, and good Luck!

check pressure switch,if it is faulty or out of adjustment it wont allow it to go tomain burner

Find the pressure switch that senses H2O is going to the heater. There is a hose for the H2O on each side. Use a wire to "jump" the two electrical connections, which will simulate them closing from proper H2O pressure. If the heater actually lights, you need a new pressure switch(assuming H2O is actually going through the switch). You can buy one "on line" cheaper than the pool stores.

What state do you live in, what is the brand name and model number of the heater. If you live in a state that gets cold during the winter, call you local pool store and schedule a closing. If the pump is running and water is not circulating, most likely the pump lost prime or your filter needs to be backwashed, or there is some debris in the impeller.