How To Fix Low Water Pressure

There’s nothing more frustrating than discovering your boiler has low water pressure and has shut itself off.

Fortunately, homeowners often can fix their boilers’ low water pressure themselves. Before we discuss how to fix low water pressure, what is the ideal boiler pressure?

The Ideal Boiler Pressure

Your boiler’s pressure level matters as it is directly responsible for how efficiently and effectively it works.

Most modern boilers recommend that pressure levels read between 1 and 1.5 bar when cold and up to 2 bar when operating.

It’s always best to refer to your boiler’s manual for the best operating pressure level. If you see a reading on the boiler’s gauge below 1 bar, you should start fixing low water pressure.

You can take steps to fix your boiler’s low water pressure.

Steps To Fix Low Water Pressure

The first step when fixing a low water pressure starts by checking your boiler’s pressure gauge:

Step 1: Check The Pressure Gauge

Most boiler pressure gauges are located on the front of the unit; however, some will be incorporated into a digital display.

It’s always best to confirm that the pressure is too low for the boiler to operate.

Step 2: Repressurise Your Boiler

Repressurising your boiler could also be phrased as topping up the water in your heating system.

While an easy task to complete, there are a few steps to be taken, which include the following:

1. Turn off the boiler and allow it to cool. Some manufacturers recommend waiting for hours.
2. Locate the filling loop, which is used to connect the boiler’s heating system to the cold water mains for repressurisation. There are two types of filling loops:
   1. External Filling Loop — A detachable metal braided hose with two valves.
   2. Internal Filling Loop — Built into modern boilers, often requiring a key or lever.
3. Open the valves slowly to allow water into the system, you should hear water flowing.
4. Watch the pressure gauge closely, and stop the water when it reaches 1.2 to 1.5 bar or the level recommended by your boiler’s manual.
5. When ready, close the valves securely and remove the filling loop if detachable.
6. Turn the boiler back on and check if the issue is resolved.

Step 3: Check For Leaks

Even small leaks in your heating system can cause pressure loss, leading to potential shutdowns.

Signs of a leak include:

• Damp patches on walls, ceilings, or near radiators.
• Uneven heating across radiators.
• Gurgling or hissing noises.
• An unexpected increase in water usage.

Since most heating pipes are concealed, leaks can be hard to detect. If you suspect one, contact a Gas Safe registered engineer who can quickly locate and repair the issue using advanced tools like thermal imaging.

Step 4: Faulty Pressure Relief Valve (PRV)

PRVs are a critical safety feature that releases excess pressure.

However, if it malfunctions, your pressure relief valve could open unnecessarily, causing a leak and lowering the system’s pressure.

It’s important to note that you should not attempt to fix this issue yourself. Only a Gas Safe registered engineer is qualified to handle such repairs safely.

Step 5: Bleed the Radiators (if air is trapped in the system)

Bleeding your radiators usually means you’re trying to lower your boiler’s pressure.

However, if air is trapped in the system, it can stop water circulating, reducing the water level in certain parts of the system.

To correct this issue, use a radiator key to release trapped air, especially if some radiators aren’t heating properly.

After bleeding, check the boiler pressure again and repressurise if needed.

Step 6: Check The Stopcock And Mains Supply

A stopcock is a valve that controls water flow from the main supply into your home. Usually, your home’s stopcock is found under the kitchen sink, in a utility cupboard, or near the water meter.

If your home has low water pressure, a simple fix is to ensure the stopcock is fully open. A partially closed valve can restrict water flow to your boiler and heating system.

Step 7: Boiler Part Failure

Your home’s low water pressure could be related to a boiler part failure.

Two issues that could cause a low water pressure are:

• Faulty boiler pump
• Expansion vessels issues

Both of these problems will require a Gas Safe register engineer.

Step 8: Check for Frozen Pipes (Winter Issue)

For those who live in areas where it snows, your boiler’s low water pressure could be caused by a frozen condensate pipe.

To unfreeze your condensate pipe, try pouring warm (not boiling) water over the pipe to thaw it.

However, if you’ve taken all these steps and your boiler’s water pressure is still low, you should call a Gas Safe registered engineer to fix it.

But who are you going to call?

Call WarmZilla To Fix Your Low Water Pressure

Contact a qualified Gas Safe registered engineer if you’re having trouble fixing your boiler’s low pressure.

WarmZilla provides nationwide service, with Gas Safe registered engineers available to assist you within 48 hours.

Contact one of our experienced professional consultants today to discuss your issue and find the right solution for your needs.