gurgling hot water system

Mark Wolff_2

Without jumping on the bandwagon for parts replacement, let me offer a few potential causes and solutions.

Since the system didn't have these problems before two years ago, we can assume it wasn't original to the system. The gurgling you are hearing is air bubbles traveling through your piping.

The first possibility is that your circ pump was replaced approximately two years ago and slightly undersized, or it's impellers have worn to a point of diminished pumping capacity. If that is the case, you have a scenario where the pump meets demand on one or two zones first, since all three are calling. When the first zone closes, the extra flow finally can push through the offending zone, forcing the water through the air trapped section of piping.

The second possibility is that you have air residing in your system that was not purged despite the technicians best attempts. It takes 12-15 minutes for one or more of the zones to meet demand, and once it does, the extra flow finally can push through the offending zone, forcing the water through the air trapped section of piping.

Either way,the air needs to be removed properly and completely for this situation to be resolved. The one thing to note is that with the type of expansion tank you have, there should not be any air removal (auto air vents) in the system.

Purging air in the non-diaghram tank systems can be frustrating, especially if you have zones that shut down for many hours on end. The air entrained in the water will start to seperate from the water and form pockets at all high points in the system. Even when the air is removed to the expansion tank, it can still be re-absorbed into the water, thus perpetuating the cycle.

Pumping away will have absolutely no effect on this situation. Whether it is a better option or not is beyond the scope of what you were asking.

Also, if there was a leak, the water would be going out, not the air coming in.

To fix the problem, the best solution will be to do a thorough purge of the lines with pressurized water, then let the system run full on for a day or so. This will help get the air out of where it shouldn't be and back where it belongs. Hope this helps.

Mark_84

gurgling hot water system

Hi

I have a house with an oil fired hot water boiler used for heating. For the last two heating seasons, I have had gurgling noises which I suspect is air, however, it occurs at particular times. We have 3 zones controlled by zone valves and programmable thermostats. We have the thermostats programmed to go down to 17C every night and come onto 21C in the mornings. Every morning, roughly 12 to 15 minutes after the stats are programmed to come on, we get very strong gurgling noises going through the piping. This lasts about 2 minutes, then it is gone. To experiment, I've tried turning the thermostats down for a few hours and then up again simulating what occurs overnight. Everytime I to this, I get the same gurgling 12 to 15 minutes after turning them up. If I leave them turned up, all seems ok...no sounds. I have an expansion tank and an air release valve on the system which is drained on a yearly basis. I have had heating experts in to chase the lines with pressurized water to attemt to chase the air out. I have a bleed valve on one of the rads on the loop that this is occuring and have set my alarm to open this valve coinciding with the gurgling and sure enough, I do get spitting when the gurgling passes that location, but it would take forever to relieve all the air by doing this each morning. I don't have access to all the piping, but if there were leaks in the system, I'm sure I would see some signs of it by now in the form of staining on ceilings or moisture running out somewhere. Also, the pressure seems to hold constant.

Do you have any suggestions?

Unknown

suggestion, yep! Replace the steel expansion tank with a diaphragm tank and purge the zones.

Ideally change the near boiler piping to a "pumping away" set up if they aren't already.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"