How to Replace a Steam Radiator?

Although it’s not a common project, removing and replacing a radiator for hot water or a steam boiler heating system may come up from time to time. Generally speaking, it’s a job for a professional heating contractor, though a skilled DIYer can sometimes do it provided the system is not too complicated.

How to Fix a Radiator That Gurgles?

If a steam radiator makes gurgling noises, either from the air vent or from the radiator itself, it’s usually a sign that condensed water is being trapped in the radiator rather than draining back down to the boiler. This can be the result of problems with the radiator itself, the control valve, or the air vent.

1. Check the Supply Valve

Make sure the supply valve is fully open (turned counterclockwise all the way) and that it operates properly. If this valve isn’t fully open in a one-pipe system, it may be preventing condensed water from draining out of the radiator, If the valve is corroded or stuck, repair or replace the valve.

2. Ensure the Proper Slope

Check the radiator’s slope. In a one-pipe system, the radiator should slope slightly toward the end with the supply valve. Shim under the feet of the radiator as needed to achieve a proper pitch of 1 inch for every 10 feet toward the supply valve. With two-pipe systems, make sure the radiator is sloped in the opposite direction, toward the return pipe.

3. Examine the Air Vent

In one-pipe systems, make sure the air vent is positioned vertically. Make sure it is not pointing upside down, diagonally, or sideways. Usually, you can simply rotate the valve clockwise to the vertical position (it’s threaded into the radiator).

Inspect the air vent to check for obstructions caused by mineral deposits or other debris. Try to clean the vent with vinegar. If you can’t blow air through the vent after cleaning, replace the vent.

Why might you need to replace hot water or steam radiator? There are several reasons.

Reasons for Replacing a Radiator

There are several scenarios in which you might need to remove and replace a radiator:

  • First, it’s possible that the radiator is simply worn out. Cast iron radiators can rust from the inside out, and when a radiator begins to develop pinhole leaks, there’s little option but to replace it.
  • Your radiator may not be big enough to supply the heat a room needs, requiring that you replace it with a larger model.
  • Perhaps the style of the radiator is unbearably old-fashioned to you. Manufacturers today make a variety of designer radiators, such as flat-panel designs that look more like wall art than functional radiators.
  • Finally, it’s possible you simply need to remove the old radiator temporarily so that you can make wall repairs or paint the walls.

Whatever the reason for removing and replacing a radiator, the process looks much the same. Before you do so, make sure there are no other easier solutions to fix the problem at hand.

Repairs to Try Before Replacing

When a radiator stops producing sufficient heat, there are a number of fixes you can try to correct the issue.

All radiators have some form of bleed valve or air vent. In the case of hot water boilers, this is a bleed valve located at one end of the radiator near the top. This valve allows you to bleed air out of the radiator to allow hot water to flow freely. Bleeding a radiator of excess air is the first thing to try with a hot water radiator.

Steam radiators are fitted with an air valve that is designed to release cold air inside the radiator so that hot steam can rise up from the boiler to heat the room. The valve is a heat-sensitive device that closes down as soon as it senses the heat from the steam, but if it malfunctions, it may refuse to open or close. Either way, the result is a radiator that doesn’t do its job. Replacing the valve often restores the radiator’s heating ability.

Finally, there are the radiator’s main valves. In some cases, the hot water or steam flowing into the radiator is controlled by a simple hand valve with a turn knob, while in other cases, there may be a thermostatic valve or lockshield valve that controls the flow in and out of the radiator. These valves can fail, and replacing them is generally easier and much cheaper than replacing the entire radiator.

It’s also possible that the radiator has become filled with sludge and therefore can no longer heat efficiently. If this happens, the fix is to take the radiator outdoors, remove its valves and flush it thoroughly with water to clean it out before reinstalling it.

Troubleshooting a Radiator That Doesn’t Heat

If the radiator doesn’t heat up, it often indicates that the air valve is stuck shut, blocking cold air inside the radiator and preventing steam from entering

1. Open the Valve

Make sure the supply valve is fully open (turned counterclockwise all the way). Use a wrench if the valve is resistant to turning.

2. Check the Thermostat

Check to see if the thermostat in the room (as applicable) is set too low. Confirm that the thermostat is set above the current room temperature.

3. Ensure the Proper Slope

Check to see if the radiator is sloped properly. On one-pipe systems, it should slope slightly toward the end of the radiator with the supply valve and pipe. Shim under the feet of the radiator as needed to achieve a proper pitch of 1 inch for every 10 feet toward the supply valve. On two-pipe systems, the radiators should slope away from the supply valve and toward the return pipe.

How to Replace a Steam Radiator- Steps by steps

  1. Switch off the steam boiler to prevent the risk of scalding.
  2. Loosen the nut holding the radiator. Make sure the wrench is biting the nut in three different corners to prevent the nut from deforming.
  3. Carefully remove the old radiator.
  4. (Optional): To replace the hand valve, use one wrench to bite the pipe and one wrench to bite the valve. Move-in opposite directions to loosen. This step may require a pipe for persuasion.
  5. (Optional): To replace the spud, insert the spud wrench to loosen, then remove.
  6. Make all the necessary connections with the wrench: floor to hand valve, hand valve to spud. Apply the pipe dope and the wicking to each thread to ensure a secure connection. The hand valve should be parallel to the floor in order to fit back into the radiator.
  7. Carefully fit the new radiator into place and connect it with pipe dope and the wrench.
  8. Open the hand valve and turn the boiler back on.