Sometimes air can get into the central heating system and prevent it from working at its best. You can usually check this with a simple test.
When your heating is on, touch your radiator. If it’s warm downstairs and cold upstairs, it might have air in it. This usually happens when new water has been added either from the supply and expansion tank, or simply when it is refilled as a result of water removal or periodic maintenance.
In the case of radiators, this can prevent warm water from circulating from the base to the top. The usual remedy is to bleed the radiators or, in some extreme cases, to drain them completely.
If the coolant is filled in incorrectly (for example, from the upper point), turbulence is created: the water tends downwards and the air upwards. In the process of movement, the fluid displaces air; if there are suitable irregularities on the inner surface, it stops in them. Gradually, the volume of trapped air increases.
Why it is important to get rid of it in time
Even a small amount of air in the system is highly undesirable, although a plus can be found here: the appearance of a plug signals a malfunction in the system. But the troubles are much bigger:
- Poor or no heating of the radiators;
- noises, vibrations create noticeable discomfort;
- The combination of air and hot coolant leads to undesirable chemical processes, which leads to additional layers on the internal surfaces;
- Part of the chemical processes causes the acidity inside the system to increase, creating conditions for corrosion;
- If the system has a circulating pump, its work can go idle, it will lead to a breakdown.
The problems of air accumulation in the heating system
In closed heating systems, air accumulates in the radiators for several reasons. Bubbles form in the coolant when heated. When filling the system with water air can enter. For this reason, it is recommended to do it slowly, especially in complex systems with many turns. Choking of pipes also occurs after local repair of the pipeline.
- First, the heat distribution process can be disturbed. Because of the air lock, the radiator becomes a little warm at the top and very cold at the bottom.
- Secondly, extraneous sounds can be heard from the system: hissing, gurgling, etc.д.
- Third, air accumulation can cause corrosion, especially in aluminum and bimetallic radiators.
To get rid of the air in the heating system will help cocks Maevsky. You don’t have to call a plumber to deflate. You can handle on their own. The main thing is to know how to do it correctly.
The cost of manual and automatic air vents
for air vent valves for heating systems depend mainly on the metal from which they are made, the manufacturer and the size of the valve. up to several thousand for imported devices.
A comparative table of of the main types and modifications.
| Air vent nomenclature | Cost in regions, retail price, / unit, without VAT | Cost, retail price, /pc, excluding VAT |
| Automatic Broen Ballofix (Spain) | 395,00 | 373,00 |
| AE32-17 automatic DN 25 (DN 1) PN40 f | 49 850-50 400 | 49 350 |
| Air vent Navien pump Deluxe 13-40K, Deluxe Coaxial | 1000-1200 | 890-1000 |
| Manual air vent FHF-EM (Danfoss) | 710-740 | 705 |
| Manual air vent, simplified | 12,00-15,00 | 11,50-12,50 |
| Manual air vent, 15, under screwdriver | 19,75-22,00 | 18,00-20,00 |
How to deflate the air from the radiator
If with the arrival of the heating season your radiators are barely warm, in all likelihood, air has accumulated in the sections. Detecting the problem area with the naked eye is quite difficult. If the air cap is in one of the sections, you can tell it by touch it will be cooler than the rest. Professionals use a thermal imaging camera to diagnose the hot and cold areas of objects. At home, such a diagnosis is resorted to only if you could not solve the problem yourself.
We will tell you how to deflate the air from the battery in a private and apartment house. Choose your variant. And at the end of the article you will find recommendations that will help you to understand the causes and prevent the recurrence of such a problem.
Plugs on cast iron radiators
To bleed air from old-style cast iron batteries, special valves were sometimes installed on stopping plugs.
Cut the taps Maevsky or ordinary water taps.
This is what a water valve looks like when you cut it to let the air out.
How To Bleed A Radiator. Don’t try it until you watch this
If the cast iron radiator of the old type has a standard plug, it is not possible to bleed air directly through it. Therefore, in a private home, it is recommended to equip all the radiators with valves, resorting to the services of professionals or yourself.
Installing devices in apartment buildings is impractical, since a higher pressure of the coolant and the construction of heating schemes involve centralized deflating the entire riser.
Working with valves and cocks installed on cast iron radiators is similar to the algorithm of bleeding with a Maevsky valve.
How to remove an air lock from a heating system: 4 scenarios and 4 solutions
If some radiators remain cold when the heating system is turned on, this is a consequence of them being air-logged. That is, air bubbles form in them and must be removed. In some cases, the system begins to visibly gurgle and murmur, like small forest streams do. All this indicates that the heating system needs to be vented. Let’s see how to bleed the air from the heating battery and what tools we will need for this. We will also tell you where air comes from in closed and open type systems.
Causes of airblow in the radiator
If there is no valve: how to deflate a deaf battery
In old heating systems with cast iron radiators Maevsky cocks were not provided, the outflowing was performed by gravity or by unscrewing the plug of the radiator.
To deflate the battery, you will need:
Clean the top edge of the battery from the paint, put a rag soaked with penetrating lubricant (WD-40, kerosene, brake fluid). After a few hours trying to unscrew the plug.
Reference! The thread can be either left or right! Apply alternating forces alternately to one side and to the other. Watch which way the plug starts to move away from the battery.
As soon as you hear air movement, stop unscrewing the plug.
We put a basin and put rags around the plug along with the air will definitely break through the coolant spray.
Once the hissing stops, wrap packing or Fum line under the plug and screw it in place.
If possible, to facilitate repeated deflating, we replace the deaf plug with the same one, only with a installed Maevsky faucet. To do this it is necessary to isolate the battery from the heating, to drain the water from it.
Important! Under no circumstances must you try to replace the plug on the radiator under pressure the flow of hot water will not allow you to screw in the thread.
In a private home diluent must always be accompanied by a check on the amount of coolant, and if it is not enough, refill. In open expansion tanks at least half of the tank of liquid, in closed tanks the pressure is pumped up to 2 atmospheres.
