I have a hot water tank cascade 40 about 4 feet tall electric got it with the house every time we do a lot of laundry say five loads and a shower we run out of hot water also we see on the floor some water This is an old tank more than 13 years at least if more. It dose not have a relief valve on the top. there is a drain valve on the bottom with no cap. I pressume this is a check valve because water is not coming out in normal operations. My question is could the water be reliveing from this valve while the tank is trying to make of for the the demmand. At this piticular situation. by the the way the the water i find on the floor is cold. Other then the above situation the tank works fine any advice get a new tank check setting ect.The hot water tank is a Cascade 40 by John woods ltd. jwaa 525de ser.824546-8205
From your description you are using way more hot water than an electric 40 gallon heater can deliver. If you actually do not have a relief valve then the heater is in an extremely unsafe condition. After that many years, I would replace the water heater with a 50 gallon model, and have it done by a licensed plumber in order to correct any possible code and safety violations.