How to Maintain Radiators

Taking care of your home heating radiators is a fairly easy, but necessary task each fall. During the summer when the system is turned off-air can enter the system-and once air gets in-the hot water cannot move freely in the closed system-so you get uneven (or even worse)-no heat. Here's how to take care of your hot water radiators.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Straight screwdriver or radiator key
• Level
• Adjustable wrench
• Radiator packing (available at home and hardware stores)

1. Remove air from your hot water heating system by "bleeding" the air from the system at the start of each heating season.

2. Start by turning the heat on and giving the system time to heat up. Turn on the radiator supply valve (if it was turned off during the summer).

3. On the end of the radiator, near the top, is a small vent (or bleed) valve that can be opened using a straight screwdriver or radiator key (a 12-point socket key available at home stores). Hold a small cup under the valve and open it by turning counter-clockwise. Any air trapped in the system will come hissing out followed by a stream of hot water. Once the water starts to come, close the vent valve tightly.

4. Check the slope of your radiator. Since older houses sometimes move and shift you should also check the "slope" of your radiators. They should have a slight (1/4-inch) slope towards the inlet pipe (the pipe that comes up through the floor or out of the wall). If there is no slope, or even worse, the slope is the wrong way, slide a thin wedge of wood underneath the radiator to get it sloping the proper way.

5. Look for signs of moisture near the supply valve. Over time the "packing" around the threads can deteriorate and allow water to leak out. If you see any signs of leakage, use an adjustable wrench to tighten the nut and see if simply tightening fixes the problem. Check again in a week or so; if there are new signs of moisture you should replace the packing.

6. Replace the packing on the supply valve by first closing the supply valve, then loosening the packing nut. Wrap the valve stem with more packing and tighten the nut down again, then reopen the supply valve. You may see some moisture oozing around the packing for a little while, but it should stop within an hour or two.

7. Banging in hot water pipes is often the result of air trapped in the system or pipes moving as they expand and contract with heating and cooling. If your heating system makes noises (and you already bled the system) look to see if any pipes have come loose or are rubbing against floor joists (particularly in the basement). Securing loose pipes will usually eliminate banging noises.

Tips & Warnings

• When bleeding air from your radiators in the fall, start at the highest point (e.g. on the second floor) or the radiator furthest away from the furnace.
• Packing looks like string you wind around the valve stem.

[alfredaa2]

on 9/8/2009 The article says nothing about replacing the air with water. Fairly modern closed systems do this automatically. My house is quite old and has an open system. There is a pressure guage involved which has to be reset to a correct pressure. Is this pressure 30lbs per square inch? The pressure drops when air is removed. This then becomes a two-man job. Please verify.