We just bought a house that has a 50 gallon electric water heater that has the cold line of the water heater piped into the boiler. What is the purpose of this? Also it has a Fast fill valve. What is this?
without any further info, i will guess you have a heating boiler. hot water or steam heating in your home possibly ? heating boilers have a cold water line piped in till it gets heated for heating purposes, best of luck -
Joea is a Master what? A boiler is a closed system as Cadty sort of explains , once it fills it should maintain pressure but it does not use any water . It can have a domestic Hot water coil which is what Cadty is referring to and she has a good question a electric hot water heater will only make 18 gallons an hour with most elements and your boiler should be able to heat at least 100 gallons an hour and alot cheaper .
That is the water supply to the boiler , that maintains the pressure in the boiler for your heating . The boiler runs on low pressure between 12 and 25 psi . the fast fill line is for filling the boiler after maintenance or to purge air when the boiler is first filled, the drain valves are opened and the fast fill valve pushes the air out of the system with full pressure , after all the air is purged from the system the fast fill is closed and the pressure is allowed to drop to 12psi and then the drains are closed and the other valve is opened which maintains pressure in the boiler . What does not make sense is why the boiler isnt being used to replace the electric water heater .
Hi Mike, I'm really shocked that with all the professionals giving you advice, no one's hit the nail on the head YET, until me, of course. I live in New England, and see this configuration all the time. We have one heck of a long heating season here. Let me explain the reasoning behind what you have, because it is used constantly in this part of the country. Your electric hot water heater can be expensive to run, and if you have several people standing in line for showers in the morning (like mine), can find itself unable to recover the water temp after a shower or two. Since your boiler will run extensively during the heating season anyway, they are using the boiler to pre-heat your supply even before it gets to your water heater. It evidently has a small tankless water heater that couldn't keep up with the household demand, necessitating additional capacity. The aquastat that is in the main boiler (for the boiler's water heater) is certainly disconnected, so it will only pre-heat when your heat is being run. The free-standing water heater is on it's own in the non-heating season. This is a very green way to exploit as much value as humanly possible from every gallon of oil burned, and you had to run the boiler anyway!
