An electric boiler providing hot water supply (DHW) to an apartment or a private house sometimes needs to be emptied. For example, to clean the tank or replace the magnesium anode. We will tell you how to drain water from a water heater in various ways, depending on the connection diagram. We will solve a more complex problem - emptying the storage capacity of the floor type.
Why you can not drain water through the mixer
If you close the domestic water supply and completely open the “hot” valve of the mixer, then a maximum of one and a half liters will flow out of the tap, the tank will remain full. To understand the reasons for what is happening and subsequently correctly drain the water from the heating tank, briefly familiarize yourself with its structure and principle of operation:
- The intake of heated water is provided from the upper zone of the tank - the end of the tube is located there. The water supply is organized in the lower part of the boiler.
- At the inlet of the cold water supply pipe (HVS), a poppet type check valve is installed, preventing the water from flowing back to the main. It also relieves excess pressure arising from heating and expansion of the liquid.
- When you use a storage heater (turn on the hot water tap of the mixer), water is poured out of the tank under the influence of the pressure of the main cold water pipe.
- Without pressure from the mains, the system does not work - water itself does not flow from the tank. Only a small part of the liquid, which was located above the intake pipe, can be released through the mixer tap.
Note. The orientation of the tank in space does not play a role, horizontal and vertical models are arranged identically. The feed is at the bottom of the tank, the sampling pipe on the hot water supply is at the top.
Preliminary conclusion. There is no other option than to drain the water from the boiler through the “cold” pipe, since it is located near the bottom of the tank. The method of discharge depends on the piping of the heater, in some cases the pipe connections will have to be disassembled a little.
Relief through safety check valve
This method is recommended to use all well-known manufacturers of water heating tanks - Ariston, Thermex, Gorenje, Electrolux and so on. The household appliance is connected to water supply networks according to the scheme (presented above) from the instruction manual:
- a safety group for boilers is installed on the inlet pipe;
- a shut-off valve is placed in front of the group;
- no fittings are provided on the outlet pipe or a ball valve is mounted.
Explanation. Safety group - this is a 3 in 1 automatic element, this includes a check valve + safety valve + drain valve with a plastic lever.
How to flush water through a valve:
- We block the water main at the entrance to the apartment, disconnect the heater from the mains.
- We release 1-2 liters through the nearest mixer, opening the DHW valve to the end. We leave the plumbing fixture in the open position so that air can fill the void in the tank.
- We substitute the bucket under the "nose" of the valve, turn the lever and slowly empty the tank.
Before emptying, the heater does not need to be disassembled and wait for the water to cool. The disadvantages of the method:
- due to the small flow area of the nozzle (5 ... 8 mm), the water escapes too slowly, the boiler is emptied by 80-100 liters in about 2 hours;
- the valve is often clogged, poorly leaks fluid;
- sometimes the security group is soured, the drain does not work at all.
The method is suitable for small water heaters of 25-50 liters, provided that the valve valve is functioning normally. To release large volumes will come out too long.
Quick emptying through the cold water connection
To quickly discharge water from a boiler connected according to the factory instructions, you will need a pipe (gas) or adjustable wrench. We will disconnect the pipes, otherwise nothing. Procedure:
- We wait until the full tank cools down, or turn it off and use the heated water to the maximum.
- We close the supply of cold water to the house, release some of the water from the mixer, leave the tap open. Again, turn off the power to the water heater.
- We turn off both connections to the boiler with a gas key. It is worthwhile to substitute a bucket, so as not to flood the floors and other objects under the boiler.
- We grab the key on the edge of the valve and slowly turn it off. We close the hole of the “hot” nozzle with your finger, otherwise the air will freely pass into the container, water will flow in a stream.
- Finally we twist the security group, put the bucket at the bottom and release the finger. If it is necessary to stop the flow, we again plug the boiler water supply pipe.
- Before assembling and filling the tank, thoroughly clean the pressure relief valve (preferably purge it).
Tip. It is more convenient to manipulate when there is a tap on the outlet fitting. You can pre-locate a ½ ”threaded valve (internal), screw it in place of the removed pipe and adjust the air supply / water flow.
The advantage of the method is the speed of emptying, the procedure will take a maximum of 30 minutes. Negative points:
- disassembly is required - at least the HVS pipe must be removed;
- the water heater must be cooled, otherwise you will burn yourself;
- the pressure from the nozzle is difficult to control, the vacuum does not work immediately.
Using a Drain Harness
The method significantly facilitates the process of emptying the water heater. One condition: in the piping scheme, there must be a drain valve installed on the tee after the relief valve, as shown in the picture below. Next is a matter of technology:
- We cut off the HVS pipeline with a valve, turn off the power, open hot water on the mixer.
- We attach a hose of the required length to the fitting for the drain tap, prepare a bucket.
- Open the valve, drain the contents in portions.
It is not necessary to disconnect the pipes, if necessary, the flow is easily stopped by a tap. The stream from the hose does not hit, because the mixer restricts air flow into the tank. A water heater of 50 l is emptied in 10-15 minutes.
An important point. Manufacturers of water heating equipment do not welcome this option strapping. Reason: there is a tee with pipe fittings between the safety group and the boiler, which is not allowed by the rules.
Practice shows: installing an additional valve does not pose a threat if the user does not drain the sanitary water when the heater is on. In this case, the level in the tank decreases, the water heater can “emerge”, overheat in air and quickly burn out.
The second condition: the tee must not become clogged, otherwise the path to the relief valve will close. Then, when heated, the expanding liquid will break the DHW pipeline or the tank itself.
Drain from the indirect heating boiler
It will be a question of floor-mounted water heaters, whose pipes go up. Other models are equipped with a special drain fitting and empty without any problems.
Important! The secret to a successful drain from the floor heater is in the correct piping scheme. The end of the drainage pipe and the shut-off valve must fall below the apparatus body, due to which the law of communicating vessels is triggered.
How to drain water from an indirect boiler with an upper fitting:
- First, cool the container to an acceptable temperature of 25 ... 40 ° C.
- Close the heating system and cold water mains, open the drain valve.
- Make sure that the drainage channel is filled with water - slightly open the drain valve.
- If the channel is empty, turn on the cold water supply, wait until it flows out of the drain pipe. Turn off the water supply again.Further, the emptying of the “indirect man” will begin due to the law of communicating vessels - drainage will draw all the water out of the tank.
- When the drain pipe is full, it’s even easier to drain the tank - open the valve to the end and watch how the liquid leaves the tank.
Since indirect water heaters can hold 100 ... 500 liters, the procedure will take a lot of time - from 30 minutes to 2 hours. The essence of the method will once again be explained by the representative of ACV, which produces such boilers:
Do I need to discharge water and when to do it
It does not always make sense to empty the reservoir of a household appliance. For example, in the event of a breakdown of the automation unit - sensor, thermostat - the replacement is made without complete disassembly, no need to drain water. In what situations is emptying done:
- for the winter in an unheated building - a country house, a bath, etc.
- before cleaning the heater, washing the tank from the inside;
- when it is necessary to change the magnesium anode;
- in case of transfer of the boiler to another place or a complete replacement of the hot-water device.
Tip. To get rid of stagnant water and bacteria (in particular, Legionella), it is enough to “fry” the device at maximum temperature at +75 ° C for an hour. Then update the contents of the tank.
Recall how to dial a water heater. Open the valve of the HVS, the "hot" tap and wait. When the tank is full, water through the intake pipe will go to the DHW system, then it will flow out of the mixer.
Conclusion
There are only 3 ways to drain sanitary water from a storage boiler - using a safety valve, a specially installed tap, or directly through the supply fitting. The choice depends on the connection scheme and the availability of free time. In any case, do not forget to de-energize the water heater, otherwise burn the heater. We suggest watching a video on replacing a magnesium rod, where drainage is shown using an additional valve and hose.