I can get rid of it by turning on the downstairs toilet sink tap but the airlock always returns within a few hours, it also affects my upstairs shower. How can I cure this please?

Hi Philrcollins...

No such thing as airlock (except with pump systems... are you on a well pump?) so I'll need you to describe exactly what is going on, OK?

Are you getting a sputtering? Are hot and cold an issue or just one or the other? Is this isolated to only the upstairs bathroom? Try to give me as many details as you can and we'll see what we can come up with...

Mark

Hi Mr. Collins, I have to agree with MassPlumber. You need to be more specific.

Robert

Well maybe these guys above are plumbers, but if you Google for it, you'll see that airlocks do occur. For some reason, mostly in the UK. Not sure what's different about their plumbing system. Maybe they don't use city mains for cold water.

Anyway, there are many suggested approaches to solving it, but they're all a variation on this theme:
http://www.fingalcoco.ie/Water/CustomerServices-WaterDepartment/AdviceandUsefulInformation/GettingRidofAirLocks/

Hi Namorando...

I am a licensed plumber going on 30 years or so and as I said... no such thing as "AIRLOCK", at least not as presented in the original question above... read on.

Here, at your very own link, they are discussing airlock "following a disruption to the Water Supply to some households". This isn't really airlock as much as it is water has been drained from the system somehow and the main water line needs to displace air with water to refill the lines in order to restore water to the house. That isn't airlock... just air in the lines, right?

Anyway, as the question above is presented, repeated "airlock" doesn't make sense and it is why we asked for more information... ;)

Finally, for what it is worth, we do find airlock in heat systems or in many "closed loop systems" where air can get trapped at high points and create issues for the circulating pump... just that none of this applies to this question. I can also see where you guys in the UK may have issues with airlock working with "airing cupboards" and the such, but can't speak too much on that as I have no exposure to them.

Anyway, wanted to clear this up for future readers is all.

Maybe Philrcollins will return someday and offer us a little more info. To work with... :)

Happy Hoiliday!

Mark

Mark aka massplumber2008,

We have a similar problem with our upstairs hot water tap. It in is a new part of the house (built in 2001) and the hot water always spluttered when coming out. Very occasionally, usually after we had been away, the hot water would stop. To start the flow again we would force water from the cold tap down the hot tap, and sometimes open up the hot water tap in the other bathroom and after a few minutes this would sort itself out.

However, the last three days, the hot water flow has stopped every day. Why it suddenly is happening every day the last few days I don't know.

We believe it may be due to the hot water pipe going up from the hot water cylinder into the attic, across and then down into the new extension bathroom. Would this cause recurring air locks? If so, would we have to get it re-plumbed so the pipes go under the floorboards and up to the sink?

airlocks do occur. For some reason, mostly in the UK. But this isn't the UK. Over there they use a storage tank and are gravity fed which can produce air locks. We use a pressurized water system where air locks don't occur.

Well maybe these guys above are plumbers, And you don't walk in here, with one post under your belt, and question our experts knowledge and experience. Not without telling us what your plumbing expertise is. Not in this page you don't and not unless you can show us you know more the we do.

Hi Gordimoose and welcome to AMHD:

There are a number of excellent plumbers here at AMHD but they are all U.S. We use a different approach to water heaters (geysers) than I understand you do. Ours are always under pressure so we don't get air locks. That is also why you see us yelling at each other about whether there is such a thing as an air lock even exist. It is questionable whether we can be of assistance to you.

It is my understanding that your geysers are (at least at times) located at some upper level and use gravity for the flow of hot water to the tap. It is also my understanding that a float valve is used to control the filling of the geyser.

If that is correct, I can imagine two principles of operation.

One would be that there is an air valve that lets air out as the tank is being filled and a valve that lets air in as the hot water is being used. Both functions may be accomplished in a single valve. If your geyser has a valve such as this, your problem is likely a faulty or clogged air valve.

A second principle of operation could be that a float valve controls the filling of the geyser as needed, and no air valves are used. The air in the tank is compressed as the water is forced into the tank and used to provide pressure to push the hot water to the tap. There is a potential problem here however. Air, especially air under pressure, is absorb by water over a period. When all of the air in the tank is absorbed by the water, the flow to the tap will stop. The float valve is closed and the water can't flow out because no air can get in.

If that is the system of your geyser uses, then you need to drain the tank and replinish the air. Of course you will have to open the tank in some manner to let air in so you can drain it.

A variation of this principle of operation would be to have an air valve that lets air in when needed. That would compensate for the air that is being absorbed by the water. If you have such a valve then that valve is likely faulty or clogged.

If you have a true gravity flow system you can have a true air lock. Water will flow out of the top of a tank, or will flow to a level higher than the tank, as long as the end of the pipe where the water is coming out, is at a level lower than the water in the tank. The weight of the water coming out the end of the pipe pulls more water up and out of the tank and into the pipe. This will continue as long as the end of the pipe stays below the water level of the tank and no air gets into the pipe. (That how, as a teenager, I use to steal gas (petrol) out of your car. Stick a hose down your filler tub, suck on it and let the gas flow.)

When you use the cold water tap to force water back up the hot water pipe, you are forcing any air that might be in the hot water pipe back into the tank. This will only be successful in restoring the flow if the problem is that air has some how gotten into the line. Repeated occurrence of this indicates some other problem.

Having a good understanding of how your system works is the best thing you can have to avoid calling the plumber. Rest assured that it isn't rocket science. Repairing is usually fairly simple, it is the diagnosis that is tricky, and you can't do that unless you know how it is suppose to work. The plumber simply knows how it is suppose to work. You can too with a little study.

You said you would like to fix this yourself. Do an internet search for the make and model and get a breakdown (picture) of all the parts and pieces. You can probably determine from its name, the purpose of each valve or device and how it works.


I know this is more than you ask for, but it is a quite Sunday evening here and maybe there will be something here that will help.

See your other post.

Hi hkstroud,

I am new to this forum and posted the same thing before I realized I was not asking a question but replying to an existing one.
I then put this in as my own question because I could not see anything that would help me. Do you have any advice that could help me?

Hi Gordimoose and welcome to AMHD:

There are a number of excellent plumbers here at AMHD but they are all U.S. We use a different approach to water heaters (geysers) than I understand you do. Ours are always under pressure so we don't get air locks. That is also why you see us yelling at each other about whether or not there is such a thing as an air lock even exist. It is questionable whether or not we can be of assistance to you.

It is my understanding that your geysers are (at least at times) located at some upper level and use gravity for the flow of hot water to the tap. It is also my understanding that a float valve is used to control the filling of the geyser.

If that is correct, I can imagine two principles of operation.

One would be that there is an air valve that lets air out as the tank is being filled and a valve that lets air in as the hot water is being used. Both functions may be accomplished in a single valve. If your geyser has a valve such as this, your problem is likely a faulty or clogged air valve.

A second principle of operation could be that a float valve controls the filling of the geyser as needed, and no air valves are used. The air in the tank is compressed as the water is forced into the tank and used to provide pressure to push the hot water to the tap. There is a potential problem here however. Air, especially air under pressure, is absorb by water over a period of time. When all of the air in the tank is absorbed by the water, the flow to the tap will stop. The float valve is closed and the water can't flow out because no air can get in.

If that is the system of your geyser uses, then you need to drain the tank and replinish the air. Of course you will have to open the tank in some manner to let air in so you can drain it.

A variation of this principle of operation would be to have an air valve that lets air in when needed. That would compensate for the air that is being absorbed by the water. If you have such a valve then that valve is likely faulty or clogged.

If you have a true gravity flow system you can have a true air lock. Water will flow out of the top of a tank, or will flow to a level higher than the tank, as long as the end of the pipe where the water is coming out, is at a level lower than the water in the the tank. The weight of the water coming out the end of the pipe pulls more water up and out of the tank and into the pipe. This will continue as long as the end of the pipe stays below the water level of the tank and no air gets into the pipe. (That how, as a teenager, I use to steal gas (petrol) out of your car. Stick a hose down your filler tub, suck on it and let the gas flow.)

When you use the cold water tap to force water back up the hot water pipe, you are forcing any air that might be in the hot water pipe back into the tank. This will only be successful in restoring the flow if the problem is that air has some how gotten into the line. Repeated occurence of this indicates some other problem.

Having a good understanding of how your system works is the best thing you can have to avoid calling the plumber. Rest assured that it isn't rocket science. Repairing is usually fairly simple, it is the diagnosis that is tricky, and you can't do that unless you know how it is suppose to work. The plumber simply knows how it is suppose to work. You can too with a little study.

You said you would like to fix this yourself. Do an internet search for the make and model and get a breakdown (picture) of all the parts and pieces. You can probably determine from its name, the purpose of each valve or device and how it works.


I know this is more than you ask for, but it is a quite Sunday evening here and maybe there will be something here that will help.'

Hi Harold, Thank you for your response. I live in Pickering Ontario Canada. I am on city water the same as most US cities. My Water heater is in the basement and always under pressure, I am not sure if this is an "airlock" or not but the water in all of my hot taps slows to a trickle and stops. I don't profess to have any great knowledge in plumbing. Last night when I posted I had no hot water, I tried forcing water from the cold side into the hot side multiple times but it just pressurized the hot line for a couple of seconds and then faded to a trickle. I then left it for about 2 hours and turned on the hot tap it started slow and then came back to full flow. This seems to happen fairly regularly now. This is why I seek someone with your expertize. Let me know what you think, Thanks again I appreciate any advice you can give.

Gord

Obviously I made the erroneous assumption that you were UK. Sorry

Check the water heater piping for heat traps. Replace (or simply do away with). With a pressurized system you don't get air locks.

When you forced cold water into the hot water line, you just opened a clogged or corroded heat trap temporarily. They are now apparently corroded beyond that point.

Obviously I made the erroneous assumption that you were UK. Sorry

Check the water heater piping for heat traps. Replace (or simply do away with). With a pressurized system you don't get air locks.

When you forced cold water into the hot water line, you just opened a clogged or corroded heat trap temporarily. They are now apparently corroded beyond that point.

Thanks again Harold!

I will check for heat traps when I get home this evening, I have a rental water heater provided by the Gas company, this issue only started after it was replaced about a year ago...

Gord

What you have is a blocked line, not an air lock. About the only thing I can think o fthat might be causing that blockage, would be the heat traps.
If this is a rental item, in my opinion, the problem should be the rental companies. I would assume that the heat traps would have been changed out at the time of installation. Then again maybe not.

What you have is a blocked line, not an air lock. About the only thing I can think o fthat might be causing that blockage, would be the heat traps.
If this is a rental item, in my opinion, the problem should be the rental companies. I would assume that the heat traps would have been changed out at the time of installation. Then again maybe not.

Thanks again, I will let you know the outcome.

Gord