I had the same problem last year I got a new bulb but it went flat had to take the hose off and let air in tried keeping a warm bucket of water close by and would dunk it once in awhile. This year it started the same thing it went flat.Then I noticed with my feet cold I could not feel how much presser I was putting on the bulb. So instead of putting my foot down on the middle of the bulb I just put it on the side of bulb enough to turn on. No more problems it doesn't flatten because your putting the presser in a smaller spot of the bulb a there is a lot of bulb to spring it back out. All you have to do is turn the switch on with it not support your frozen foot with it. I just use the side of my foot. Works for me.