Why is My Hot Water Cylinder Overflowing?
Before diving into solutions, it’s important to understand what causes hot water cylinders to overflow in the first place. There are two main reasons:
Faulty Pressure Relief Valve
All cylinders have a pressure relief valve fitted. This is a safety release that will open to let out excess hot water and pressure if the temperature or pressure inside the cylinder builds up too high. Common reasons the valve can fail and cause regular water discharges include:
Age and wear/mineral build up sticking the valve open
Someone replacing the valve and installing the wrong type or installing it incorrectly
The tank overheating because of a faulty thermostat or failed heating element
Lack of Expansion Room
Hot water naturally expands as it heats up. Your cylinder needs adequate empty space for this expansion. If the tank is constantly completely full of no room for expansion, the pressure has to go somewhere – usually out the overflow. This points to issues like:
Water pressure to the property being too high
The overflow pipe not being installed properly so it drains fully
A leaky hot water tap letting new water expand into the full cylinder
Is a Leaking Overflow Pipe Dangerous?
Aside from wasted water and potentially costly hot water cylinder repairs, overflow leaks can actually pose safety risks if not addressed.
Firstly, the discharge water can be dangerously hot. Dripping near gas appliances like your home’s water heater can be a fire hazard. The moisture can also damage roof materials over time leading to costly maintenance.
Left completely uncontrolled, an overflow leak could potentially discharge enough water to cause ceiling and property damage if it overflows your roof guttering system.
So, in short – yes, while usually more of a nuisance issue, overflow leaks shouldn’t be ignored and left to their own devices long term.
How to Fix Hot Water Overflow Pipe on Roof or Any Other Area Of Your House?
Now, onto the pressing issue most homeowners want to know – how do you actually stop the overflow leak? There are both DIY and professional repair options depending on your skill level and the severity of the issue.
DIY Options Try these straightforward DIY solutions first:
Adjust the Pressure Relief Valve
9 times out of 10, an overflow is caused by the relief valve leaking when it shouldn’t be. Give it some DIY maintenance:
Lift and release the lever multiple times to try cleaning out any dirt or debris sticking the valve open
Open/close the valve fully, loosening then gently re-tightening any threaded fittings
Flush the system by running all hot taps full pressure for 5 minutes then shut off. See if the valve stops overflowing once pressure normalises.
Expand the Overflow Pipe
Check if the overflow is a simple issue of not being installed properly to fully drain away discharge. Extend the rigid pipe so it empties further from the building with room to breathe.
Professional Repair Options
If you’ve tried tackling the issue with no success, there are a few professional options to truly solve the problem long term:
Pressure Relief Valve Replacement
Given enough wear and age, pressure relief valve hot water cylinder can fail over time. A compromised valve should be replaced. This requires turning the water supply and power off, draining the cylinder, and fitting an exact match new relief valve to manufacturer specifications.
Repair Tank Leaks or Condensation Damage
If condensation, age, or corrosion creates small holes and leaks in your cylinder’s metal casing rather than originating from the hot water cylinder overflow valve, welding repairs or a cylinder reline can mend these breaches.
Water Filtration System Installation
Hard water mineral build up or debris causing relief valves and pump problems? Plumbing in a full home water filtration system can be the solution, stopping impurities from constantly gathering in your hot water system.
Complete Cylinder Replacement
For older cylinders with extensive damage or linings so worn that replacement valves continuously fail, replacing the entire cylinder may be the most cost and time effective long term fix for overflow issues.
How to Prevent Hot Water Cylinder Overflows
Alongside properly repairing existing overflows, there are preventative steps you can take to stop the issue arising again down the track:
Service Your HWC Annually
Have a licensed gasfitter or plumber inspect your entire hot water system at least yearly. They can check and adjust parts prone to fail like relief valves and build up early warnings of damage needing repair.
Flush Your HWC
Drain a few litres from the bottom of your cylinder every 3-4 months. This sweeps out mineral sediment that could stick valves or contribute to corrosion over time.
Insulate Your Hot Water Pipes
Insulating the first 1-2 metres of your hot water pipes stops conductive heat transfer keeping water hotter for longer, reducing expansion and pressure build up.
Install an Expansion Control Valve
This accessory fitting will open to dump excess pressure only when required, before the relief valve needs to activate avoiding overflow discharge. Expansion valves should be installed by certified plumbers during general system maintenance for best operation.
Keep Your Overflow Clear
Check the roof guttering around your overflow outflow hasn’t collected debris redirecting leak discharge back into your roof space. Ensure it can drain freely.
Trust the Hot Water Experts at Hot Water Solutions
Dealing with emergency hot water overflows and leaks can be an annoying, damaging, and even hazardous headache for Kiwi homeowners. Next time your hot water cylinder acts up, know that Hot Water Solutions has the parts, experience, and expertise to diagnose and repair any hot water system issue quickly and affordably.
Use our contact us page to reach us and we will be more than happy to discuss your hot water situation. Or give us a call on 0800 497658.
At Hot Water Solutions all we do is hot water!
