Water Heater Circulation Problems

Boilers and water heaters are, for the most part, rugged machines that don’t need a lot of troubleshooting. They are, however, complex machines, and that means that there can be all sorts of problems with the systems that are attached to the boiler or water heater.


One common problem we see is when the water that’s been heated by the boiler doesn’t circulate through the home. This is particularly problematic if you’ve got a combi boiler, as your boiler would be both a water heater and a source of heat for your home. 


Let’s address a couple of the problems that can affect water circulation for both water heaters and boilers:

Problems with the circulation pump

Modern water heaters and boilers come with a number of handy gauges. You can use these gauges to assess which issues are plaguing your system – some advanced models even have error codes to tell you exactly what the problem is.


When it comes to diagnosing circulation issues, your first step is to check that your boiler/water heater is doing what it’s supposed to. In other words, check your pressure gauge to ensure that the pressure is right, and check the temperature gauge to ensure that the water is being heated appropriately.


If everything seems normal, the next place to check is your circulation pump. It’s pretty simple to figure out whether or not your circulation pump is the cause of the problem. You can listen to the pump – is it active? You can also feel the pump to see if it’s pumping. Further still, you can feel the pipe at the other end of the pump to check if hot water is making it to the other side.


Circulation pumps can have all kinds of problems – discussing all of them falls outside the scope of this article. Fortunately, Hunker has an excellent piece on troubleshooting circulation pump problems

Air in the pipes

This is the second most common cause of circulation problems. Pockets of air in your pipes can block hot water from passing through. 


In the case of boilers, clearing air from the system is often as simple as bleeding your radiators. Check the pressure of your boiler. Then, turn off your boiler and wait for your radiators to cool off completely. From there, put a bucket under the bleed valve, put the radiator key in the bleed valve, and twist counterclockwise. You’ll hear a hiss of air. When that hiss stops and water starts draining out, turn the key clockwise. Do this with all of your radiators, then check the pressure of your boiler to make sure it has stayed the same.


To clear air from your water pipes (for water heaters), turn off your water supply. Then, attach a hose to your lowest faucet and run water through it until no more water comes out (point the hose away from your home’s foundation to avoid water damage). Then, turn on all the faucets in your house until you can no longer hear the sound of air coming through. After that, turn all of your faucets off, and turn your water supply back on.


There are a number of other problems that might cause poor circulation. If you’ve tried these steps with no success, or if you don’t feel comfortable doing the troubleshooting we’ve laid out here yourself, give us a call! We do water heater and boiler maintenance in Winnipeg