Hydronic heating is one of the oldest technologies of modern man, which is used for warming a home by circulating hot water or steam through a set of pipes to radiators that release the energy. While after a long time of use, you need to replace the radiator valve. So here are some tips on replacing in-home radiator valves.
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1), Turn off the boiler and allow the system to cool. Once cooled, drain the water from the system.
2), Heat the union joint, which connects the valve to the unit, with a heat gun. This will assist in the loosening of the joint.
3), Turn the union joint with a pipe wrench until it is disconnected from the radiator.
4), Remove the valve from the supply pipe with the two pipe wrenches, using one to turn the valve and one to hold the pipe.
5), Remove the spud from from the radiator using the spud wrench. The spud is what connects the valve body to the radiator. Use a pipe wrench to turn the spud wrench. If the spud is tight, use the heat gun to expand the radiator and assist in its removal.
6), Clean the threads on the supply pipe and radiator using the wire brush. The paint on the radiator could contain lead so use necessary precautions to protect yourself.
7), Remove the new spud and nut from the new valve. Wrap the treads in thread sealing tape and apply a small amount of plumber's putty as well. Use the spud wrench and pipe wrench to install the new spud.
8), Apply tape and putty to supply pipe and thread on the new valve. Use the wrenches to tighten.
Next time when you face the same problem, you can use these tips to replace in-home radiator valves on your own.

Steam radiators are important elements for our house especially in the cold weather. But after a long time of use, it will go out of work, causing leaks of the valve. So you need to know some basic knowledge about replacing a leaking steam radiator valve. Below are the tips for you.
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1), Turn off the thermostat and allow the system to cool. Close the intake valve on the leaking radiator by turning the handle in a counterclockwise direction.
2), Remove the screw on top of the valve handle with a screwdriver; lift the handle off the valve assembly. Locate the packing nut at the bottom of the valve stem. Loosen the nut with a crescent wrench, turning counterclockwise. Remove the packing nut from the stem. Remove the old gasket and any other debris from inside the nut with the needle-nose pliers.
3), Wrap 3 to 4 inches of graphite valve packing loosely around the valve stem in a clockwise direction. Do not stretch or break it.
4), Replace the packing nut and tighten it  by using the crescent wrench in a clockwise direction. When the nut is tight, it will compress the graphite packing into a new gasket. Replace the handle and the screw. Turn the handle in a clockwise direction to open the valve.
5), Turn on the thermostat to check if there is leaks.
Since you've got the basic knowledge about tips on replacing a leaking steam radiator valve, next time you can solve the problem on your own.

A safety relief valve is used to prevent the interior pressure of a heater from explosing or causing other dangerous situations. The size and design of a safety relief valve is important for industrial process safety. Here are some guidance for sizing a steam safety relief valve. 
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1), Decide all of the credible overpressure scenarios for a steam boiler. This will be the basis for the sizing of the valve. For example, in a natural gas boiler the gas burner could malfunction, causing excessive heat for boiling the water.
2), Decide the maximum steam generation capacity and the maximum pressure rating of the boiler. For example, assume the boiler has a maximum steam generation of 50,000 pounds per hour with a maximum pressure of 300 psi and a temperature of 422 degrees Fahrenheit.
3), Decide the minimum required orifice size of the valve using the formula from API 520. The formula is A = W/(C x Kd x P x Kb x Kc) x √(T x Z)/M where A is the orifice area in square inches, W is the steam generation, C is a steam coefficient equal to 330, P is the pressure, Kd, Kb and Kc are all constants equal to 1.0 in this case. T is the temperature of the steam, Z is the steam compressibility factor (assume it is 1.0) and M is the molecular weight of the steam, which is 18.01. This calculates out to be 2.44 square inches.