Turn off water main when heating system is gas hot water?

[Elke Mariotti]

Originally Posted by Cuzzant

Has she checked to see if there is another valve somewhere between the main and the toilet in question? If that's the case, she can close off that valve without having to shut off the main. Of course, that valve may control water flow to other parts of the house. Just a thought.

She can't find anything
No luck with a plumber for her. Trying to help out but can't physically go to her.
I just want to be sure her heating system won't break with the main off.

Appreciate any and all input!

[InterestedOne]

Originally Posted by Elke Mariotti

I remember seeing the radiators. They're the old cast iron ones about 2.5 ft high or so and width various by room. She also has a separate water heater.

If it is single pipe system how long could the water main stay off without damage to the heating system?

Cast iron radiators do not automacially assume a closed system, please be careful with that knowledge. A two-pipe system has a 2nd pipe exiting the bottom of a radiator with a feed line entering the top opposite. The top feeder pipe usually has a top valve to adjust the steam flow rate.

The lower pipe on the radiator is called the condensate return, it does not have a valve. Steam when is cooled, via the radiator, this heated condensation returns to the boiler for reheating. In the purest sense this is a closed system however its is not uncommon that remote radiators in rooms historically hard to heat - they may have steam vents. If so the two-pipe system has become an open system by happenstance. Open systems will need refilling because steam vapor is permitted to escape the system in rooms with steam vents.

A single pipe system sends pressurized steam to all radiators and pressure release rate is compensated for through the steam vent mounted on the side of a radiator.

The situation is not that a boiler cannot heat whether or not make-up water is on. The problem is that a boiler run dry. If dry under combustion fire the either the water manifolds will crack or the expansion will break the seals between manifolds. That's bad, real bad.

Prefill first before turning off the water. On the side of the boiler there is, at least should be a sight glass with water level indicators on the glass tube. The fill valve comes directly from the cold water line within the home, any cold water line. Whether or not the boiler has an auto-fill control, manual fill should is still available. THe manual fill valve will be close inthe automatic fill control adjustments. Look for a sight glass. It is a clear or "muddied" glass tube and shoul have marks on it.

Open the manual fill valve and watch the sight glass. The static water level should be witnessed throug the tube. Static meaning the fill level afforded by the auto fill. Water level should be present through the glass. Fill to the top red line. If no red line fill until the water is nearing the top of the glass tube. Turn off the manual fill water valve as the level rises to the top of the sight glass. You are free to turn of the water mains. Also, adjust the thermostat down to 50-55 if the home is unoccupied, 65 if occupoed.

After other repairs the manual fill water valve is to remain closed however open the auto fill valve.


Hope this helps.
Hope this helps. Depending on age, output capacity, and combustion efficiency the water off situation might be 3-5 days. However you are certainly welcome to review the water level in the sight glass but by no means should the water fall below the bottom level of the sight glass in that a viewer might not see water.

Feel free to write back.

Hope this helps.

[Elke Mariotti]

Originally Posted by InterestedOne

Cast iron radiators do not automacially assume a closed system, please be careful with that knowledge. A two-pipe system has a 2nd pipe exiting the bottom of a radiator with a feed line entering the top opposite. The top feeder pipe usually has a top valve to adjust the steam flow rate.

The lower pipe on the radiator is called the condensate return, it does not have a valve. Steam when is cooled, via the radiator, this heated condensation returns to the boiler for reheating. In the purest sense this is a closed system however its is not uncommon that remote radiators in rooms historically hard to heat - they may have steam vents. If so the two-pipe system has become an open system by happenstance. Open systems will need refilling because steam vapor is permitted to escape the system in rooms with steam vents.

A single pipe system sends pressurized steam to all radiators and pressure release rate is compensated for through the steam vent mounted on the side of a radiator.

The situation is not that a boiler cannot heat whether or not make-up water is on. The problem is that a boiler run dry. If dry under combustion fire the either the water manifolds will crack or the expansion will break the seals between manifolds. That's bad, real bad.

Prefill first before turning off the water. On the side of the boiler there is, at least should be a sight glass with water level indicators on the glass tube. The fill valve comes directly from the cold water line within the home, any cold water line. Whether or not the boiler has an auto-fill control, manual fill should is still available. THe manual fill valve will be close inthe automatic fill control adjustments. Look for a sight glass. It is a clear or "muddied" glass tube and shoul have marks on it.

Open the manual fill valve and watch the sight glass. The static water level should be witnessed throug the tube. Static meaning the fill level afforded by the auto fill. Water level should be present through the glass. Fill to the top red line. If no red line fill until the water is nearing the top of the glass tube. Turn off the manual fill water valve as the level rises to the top of the sight glass. You are free to turn of the water mains. Also, adjust the thermostat down to 50-55 if the home is unoccupied, 65 if occupoed.

After other repairs the manual fill water valve is to remain closed however open the auto fill valve.


Hope this helps.
Hope this helps. Depending on age, output capacity, and combustion efficiency the water off situation might be 3-5 days. However you are certainly welcome to review the water level in the sight glass but by no means should the water fall below the bottom level of the sight glass in that a viewer might not see water.

Feel free to write back.

Hope this helps.

Sent you a DM

[Byron1022]

Behind the toilet is there no knobs to turn off the water? in the basement there is a "main" water knob BUT there should be other knobs on the pipes, that only turn of one or two pipes not the whole system. IE: the water pipe to the outside tap is leaking, so since I found out late in the fall I just found the knob that turns the water off for that pipe. In the spring I will have it fixed.

[oldtrader]

A friend discovered water running apparently in one of her toilets and she can't turn it off. Causing leak from pipe in basement.

Is the problem, one of the toilets will not stop running, or is the problem a leak in a pipe in the basement?

If the toilet will not stop running, if the home is built to code, there will be a shut off valve between where the water line enters the room and the toilet. If there is no shut off valve, try bending the float arm in the tank, so it causes more pressure to be exerted shut the valve in the toilet tank which is a common problem and this is used to fix the problem all the time.

The toilet not quitting running, would not cause a leak in the pipe in the basement.