No Hot Water? Drain the Excess from Your Boiler Expansion Tank
Has your morning shower gone cold? Are you wondering why the hot water seems to run out so quickly? If so, excess water in your boiler expansion tank may be the culprit. Though essential for boiler function, when overfilled, this component can leave you shivering under tepid tap water.
With some simple maintenance, you can restore a steady flow of hot water to all your home's fixtures.
Why Your Expansion Tank Fills With Water
Before diving into solutions, it helps to understand what causes expansion tanks to overflow.
Sediment Buildup and Internal Corrosion
Over years of use, mineral deposits, sand, and corrosion particles can accumulate inside your boiler system. As debris slowly builds up, it restricts water circulation, forcing excess through weak points into the expansion tank.
Like arterial plaque, sediment blockages place unnecessary strain on the entire hot water system. Pressure keeps building until the weakest point gives way - usually the expansion tank.
Excessive Water Usage
Drawing too much hot water too fast also overworks your system. Using multiple fixtures at once - running the dishwasher, shower, and taps together for example - boosts water pressure and volume beyond your boiler's normal scope.
With insufficient time to reheat, cold flows back into the system. The incoming supply shunts hot water out into the expansion tank due to rapid pressure spikes.
Faulty Pressure Relief Valve
Finally, a leaky or faulty pressure relief valve can also overfill expansion tanks. These safety release valves open when interior boiler pressure grows dangerously high, venting excess heat and water.
However, worn out or broken valves stick open. As pressure drops, cold makeup water flows backward while the valve leaks hot water out - directly flooding your expansion tank.
Step-By-Step Process to Drain Excess Water
While the problem may originate inside your boiler or pipes, the solution starts at the expansion tank drain valve. Follow these simple steps to remove excess water:
Turn Off Power to Boiler
Before handling any boiler components, flip the breaker switch or unplug the unit. This safety step ensures water Won't flow or heat while maintaining your system.
Locate the Drain Valve
| The drain valve sits at the very bottom of the expansion tank or along the side, secured by a bolt or screw cap. Remove any insulation or protective housing to access it fully. Be aware that years of sediment may obstruct the valve itself or the opening. |
Place Bucket Underneath
With the valve in sight, slide a large bucket beneath the drain outlet to catch released water. Choose a vessel with ample capacity to accommodate the entire expanded tank volume without overflow or splash-back.
Open Drain Valve
Insert a flathead screwdriver into the valve head and turn it counterclockwise slowly to avoid stripping. Allow all trapped water to gravity flow out of the tank and into your receptacle. Be patient as sediment often clogs initial outflow.
Flush Water Lines
For optimal results, attach a hose to the tank inlet and flush fresh water through the system. This scours any remaining interior sediment buildup so it drains freely with the excess water.
Check Water Level
After thoroughly draining, close the valve and refill the expansion tank by reactivating your boiler. When cold, the interior water level should fill only one third of the tank to leave ample space for heated expansion.
Preventing Water Buildup
While periodic draining provides a quick fix, preventative maintenance keeps expansion tanks from flooding repeatedly:
Inspect Pressure Relief Valve
Test the pressure relief lever manually 4-6 times per year and listen for free flow. Replace older valves every 5-7 years or at the first sign of weeping or odor.
Routinely Flush Water Lines
Annually flush all water lines leading to and from the boiler to keep mineral scale, sediment and corrosion at bay. Preventative cleansing enhances efficiency and longevity.
Follow Maintenance Schedule
Beyond flushing, maintain your boiler and expansion tank according to the manufacturer's schedule. Key tasks include draining and replacing the expansion tank air diaphragm every 3-5 years and inspecting the anode rod and gaskets.
If you need to drain your expansion tank repeatedly in quick succession or see no improvement in hot water supply after draining, contact a technician immediately. Chronic water logging suggests serious tube corrosion, flow restriction, or component failure.
By following these draining steps and preventative system maintenance, however, your supply of hot water can flow bountifully for years to come.