radiator disaster

Radiator Disaster: How and Why?

The Call

I just got a call from a long time customer of mine saying that the upper floors in her home were colder than normal. These folks have a radiator system for home heating as it is an older home here in the Pittsburgh area. Radiator systems can sometimes be “tricky” to figure out. A radiator disaster can occur when they are not operating as intended. A lot of homes in Pittsburgh have radiator heating. And I must admit, they are an efficient way of heating your home.

I was off to see what was wrong as quickly as I could! If it’s cold outside, it’s certainly no treat being inside your home without any heat. And, although this is technically a mild Pittsburgh winter, this one just doesn’t want to end!

Tracking down the problem

When I arrived at the homeowner’s house, I began my investigation. It appeared that a couple of the upper floor radiators were not really that hot. The heat provided by individual hot water radiators, usually is controlled by a valve at each radiator. You should make sure that the control valve at the heating radiator is “open” or “on”. If a radiator is not getting hot, checking to see if the radiator control valve has been turned off is your first step in trying to determine what’s wrong. In our current homeowner’s case, it did appear that the control valves were off for two of their upstairs radiators. How this can happen is anybody’s guess, but this problem is relatively somewhat easy to correct. Thank goodness!

Radiator Disaster Solution

The control valves for most radiators are typically found at the floor level. Sometimes the “open” and “close” directions for a radiator control valve are adequately marked by the manufacturer. Other times, they are not. First, you should try turning the valve counter-clockwise to see if it will open. If the radiator valve does not turn counter-clockwise, then try turning it in the other direction (clockwise or “closed”) to see if it might be stuck.

The valve could also be broken internally and you may be just turning the knob with the valve staying closed inside. So, while turning the radiator valve from “closed” to the “open” position, if you look closely at the valve stem (which is the metal rod or shaft extending below the knob in your hand and also extending into the body of the valve itself), you’ll see that as you “open”, the valve stem gets “longer” and is often less-oxidized. The shinier part of the valve stem will become exposed as it moves outwards from having been inside the valve body.

That’s a great way to convince yourself that yes, the valve is probably opening internally, and you’re not just turning the knob. If the valve body has broken loose from the valve stem, that’s an internal problem that you can’t see, and turning the radiator valve knob, even if it rotates, will not open a broken, stuck, or frozen valve.

When the hot water radiator control valve needs to be replaced, consider having a new valve installed that incorporates a thermostat. Think of it as an automatic radiator valve. This (more expensive) radiator control valve lets you treat each individual radiator as a “heating zone” (more efficient). As long as the thermostat is calling for heat, each radiator is then regulated automatically.

PS: Please be careful!

You should be cautious though when doing this. Excessive force should not be used to try to turn a “stuck” radiator valve. You may be trying to open a valve that is already in its fully-open position! The valve might be jammed. If it is, excessive force can break a jammed valve or even cause a leak, neither of which would be pleasurable!

Another Possible Cause with Solution

Another possible cause for only some of your hot water radiators not getting hot when the individual radiator valves are open (turned counter-clockwise) is that you may need to bleed air out of the radiator so that hot water from the boiler can flow into the radiator. Many hot water radiators have an air bleeder valve that the homeowner can operate when bleeding just the air, if they take care to avoid possible scalding risks such as could happen on steam heat system.

By looking at the radiator control valve, you can conclude that you do have a hot water heating system and not a steam heat system because there is no automatic air vent found on steam radiators. The hot water radiator control valve includes an “air bleeder”, a nut on the side of the valve body.

You should not attempt to take apart a radiator valve while the heating system is on and hot; you risk getting sprayed with hot water and/or starting a leak that’s hard to stop and ultimately having to shut down your whole heating system.

Below is a short procedure on how to open your radiator’s manual air bleeder valve to bleed out air on a hot water radiator system:

This can help to correct noisy gurgling pipes or to correct the loss of heat due to an air-bound radiator.

Step 1: Turn the heat on and “crank” it up:

First, make sure that your thermostat is calling for heat. Then make sure that the heating system boiler has been running for ten minutes or so. This will ensure that the system is warm and up to normal operating pressure.

This step is necessary to ensure that heating system pressure will easily push out air from the air-bound radiator, and subsequently force hot heating water into the previously cold radiator. The removed air could have been preventing heat from rising into that unit.

Step 2: Find the air-bound radiator:

Give it a moment and let the heating system get up to operating temperature and pressure. If you have not already done so, check each radiator to see if it has warmed up. If you find one or more that remain cold, and provided that the cold heating radiator’s valve is in the “open” position (counterclockwise), then check to see if that unit is air-bound.

Manually operated air bleeder valves are opened (turn counter-clockwise) using either an air bleeder valve key (if the bleeder valve stem is square) or a simple flat-bladed screwdriver (if the air bleeder valve stem is slotted). The valve key is a “roller skate key” like device that may be needed to turn the recessed square end of older manual air bleeders on radiators. In a pinch if the valve stem is not slotted you may also be able to open and close the valve using needle-nose pliers that have a point fine enough to reach into and grasp the square end of the valve control.

Step 2: Part 2:

Open the air bleeder valve to let out the air. Close the valve immediately when water begins to come out.

If you don’t have one, a radiator air bleeder valve key can be readily purchased. This little key tool is widely sold in several sizes of which 1/8″ square is standard; it’s described as a Radiator Air Vent Key or Radiator Air Bleeder Key. You’ll find these at local hardware stores. Air bleeder valves are also sold by local plumbing suppliers. They are also sold at building supply stores such as Lowes and Home Depot. And if you strike out with the first two options, you can always order from online plumbing suppliers.

Caution: Please note if no air comes out of the air bleeder valve. If just water being dispersed, then the radiator served by that valve is not air-bound. There’s also a chance that nothing comes out of the air bleeder (no air and no water). The system could still be air-bound, or it may just not be hot enough yet.

Step 3: close the air bleeder valve:

Again, when water begins to come out of the valve, close it.

Step 4: you then should feel heating entering the pipes and radiator:

Provided that the room thermostat is calling for heat give it a minute or so. The pipes and radiator should begin to warm up and eventually become hot. If this does not occur, either the heating system is off, there is another air-bound location, or there is a separate problem with the heating system, in which case Proudfoot Plumbing Heating & Air would be more than happy to assist you!

Click here, to learn about more radiator disasters!

In summary

Listed above are just a couple of potential radiator problems that you may face in dealing with your heating system. Attempting to fix simple mechanical problems may be to your advantage in cost savings. But if you have any serious concerns, please give us a call at 1-412-461-2198. You can also contact us here, especially if your home is cold in the winter time! We’re always glad to help out and/or make recommendations.

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