I take long hot showers after bike rides, so I’m used to the feeling of the water going cold in a shower. What’s interesting to me is that this happens fairly quickly, seemingly toward the end of the supply of water that was hot when you began showering.
But i’ve been thinking about boilers and it’s not clear to me how this works. It occurred to me that maybe the tank only begins refilling with cool water from the pipes once it runs low — but the tanks in most places I have lived are in the basement and don’t have obvious pumps attached. If the tank weren’t full I don’t think you’d be able to maintain constant water pressure upstairs. At the same time, the hot water seems to stay hot for 30+ minutes, even as the tank is presumably refilling itself with cold city water. How does this work? Thanks!
In: 2517
Sparky here.
There is 3 main components to your water boiler.
1. A cylinder supplied with constant COLD water.
2. A heating element that heats the water
3. A thermostat that turns the element off when the water has reached the set temperature.
The thermostat will typically be set between 55-65C (you do not want BOILING water coming from your tap for safety reasons).
Take brand new installation, the water is cold, the element will switch on until the water reaches temp, the element is turned off.
Your tank is sealed and insulated and will stay hot for quite sometime, when the thermostat notices the temp has gone too low, it will kick the element back in until it reaches temp again.
When you use water, that temp will drop faster as you are introducing cold water while losing hot water.
You likely have a large tank and a water restrictor in your shower head.
Your element is able to keep the the heat up enough to combat the fresh cold input.
At my unit I have no water restrictors and a small tank. I get about 5-10minutes of hot water before the temp drops faster than the element can heat.
Latest Answers