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How To Repair A Hot Water Heating System Leak Repair Without Draining

By Edited Nov 13, 2013 1 0

Properly piped Hot Water Heating System


Todays heating systems are not that much different then they where twenty years ago. They have the same basic elements only some have been updated with new features and innovations.

Hot water heating systems are basically very simple and easy to understand as well as repair if you have a little insight and any mechanical aptitude. Working on this type of system themselves can save a homeowner up to 125.00 dollars an hour on service calls.

This type of system should be researched and well understood before going into any repair attempts I recommend this article; Hot Water Heating Systems ,for a basic run through of a typical system and some explanation into some of the elements and equipment that goes into the manufacturing of one of these systems in a home.


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Preparing Your Hot Water Heating System For Repairs

Depressurize and pull a vacuum

When repairing a system of this type it is necessary to prepare the system. This will consist of draining out the pressure. This does not have to mean we need to drain the system. A lot of time and labor can be saved on many repair jobs by pulling a vacuum on the system rather then draining the entire thing.

This is also a handy operation if you have valuable anti freeze within the system for freeze protection. Draining the entire system in this case will require we reclaim the anti freeze and put it back in with a pump when the repair is completed.

Hot Water Heating Automatic Air Vent
To pull this vacuum, we must first eliminate any way that air can get into the system. This means that all auto vents installed within the system have their little caps closed.

There are many different brands and styles of auto vent. They all look pretty much the same.

Find all the air vents around your boiler and close the caps hand tight to prevent air from being sucked into the vent as we drain the pressure off the system.

Once the vents are closed we need to shut off the water supply line to the system. This is usually a 1/2 inch copper line that will come from the city water supply or the house main from a well. Find the auto feeder on the system and there should be a stop and waste valve or a ball valve to turn off the water to the system.

Shut off the emergency switch to kill the power to the system. This will be a red covered switch box usually on the side of the boiler or above the boiler. If you can't find a switch for the boiler then find the right breaker in the electrical panel and kill the power there.

After the power is off, the water is off and all of our vents are closed, we are ready to remove the pressure from the system and pull our vacuum.

Have two 5 gallon buckets on hand with no holes in them and locate a boiler drain around the boiler to open. This can be any purge setup or the actual boiler drain which will be located at the bottom of the boiler. Sometimes it's better to use a higher valve if one is available as the factory installed boiler drains are prone to leak if the boiler is more then a couple of years old. Purge setups are usually located higher up in the piping around the boiler and as long as the valve is in the loop somewhere it will release the pressure on the entire system.

Once you locate a suitable drain to use hold one 5 gallon bucket up to the drain and slowly open the valve. There will be pressure for a while and the slower you release this pressure the better. As the water comes out it will diminish in speed and volume, until after a gallon or two the pressure has been eliminated and the water coming out has pulled down on any water left above it. At this point the draining fluid will come to a stop. Open the drain valve all the way and let every drop come out. Now close the valve and the entire system is now under a vacuum.

What this means is that the interior of the boiler and the entire heating system is under atmospheric pressure. If an opening in this system occurs now water will not come out, air will suck in to equalize the pressure with the outside world.



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You Came This Far Might As Well Make It Right

Make All Repairs At Once

Hot water heating systems require constant vigilance to operate at the best. Any leaks will cause the boiler and other components to prematurely fail and a huge expense can be incurred.

Maintaining your hot water heating system can be as easy as checking for these leaks and cleaning once a year. There are procedures that are performed annually to keep everything running smooth. Neglecting a yearly checkup so to speak, will end up costing way more then the actual call would have been. One thing to remember is that leaks cause more leaks and not only that but they very seldom get smaller.

Having a good service company on hand is another recommendation that can keep you from stumbling through the phone book at three in the morning on a holiday Sunday. You certainly don't want to see the rates you will be charged for an emergency service call of that nature.

Take care of all repairs at the same time. This process of draining and pulling the vacuum takes time. Note all of the needed repairs before you start and get the parts you need as well as the tools lined up and ready. Also it is recommended to start the job in the morning so supplies will be available all day if you realize you missed something.


Refilling Restarting And Purging Your Hot Water System

Get The Air Out

After the repairs have been made and we're ready to restart the heating system, we first need to turn the water supply back on very slowly and check all repairs for leaks. If you find any, you will need to repeat the whole procedure and fix the leak and then start this section again.

After the water has pressurized, this you will hear when the noise from it filling stops, let the system rest for at least five minutes. This will help to allow any air to gather toward the top of the system where you'll be able to push it out during the purging process.

Connect a garden hose to your purge valve. This is a boiler drain associated with a ball valve or other stop, that makes the water your feeding in go the right way through the loop and then out the drain, rather then just going in at the boiler and then coming right out the hose.

Multiple zone systems will require purging all zones. Start with the zone that is the farthest away from the boiler and work your way to the closest. Pushing the air out of each zone as you go. Once all zones have been purged, all valves should be put back in the position they were in before you started. Then we can turn on the power switch and reactivate the system.

Turn any thermostat up to make it call and once the initial slug of moving air and water quiets down, (Maybe a minute or two) then listen for any rushing or babbling water in the system that would indicate there is still air in the lines. If you have noise in the piping and it doesn't subside in a few minutes then you will need to re purge the system because there is still air in it.

When Purging a system. Placing the outlet of the hose your using outside in a five gallon bucket and watching for the bubbles to subside is a good way to be sure you have all the air out of a zone.

Once you have a nice quiet system the auto vents can all be opened and checked for leaks. If you have one dribbling water, try tapping on it and most of the time they will stop. If you must change one then cap it for now until you can get one. After you do you will need to refer back to this article and repeat the process in order to perform this repair.

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