Low pressure on a Worcester boiler
Low pressure on a Worcester boiler is when the pressure goes below 0.5 bar or into the red zone of the pressure gauge. This means you must refill the system.
For several years, a white plastic key has been used as a special filling loop, causing numerous headaches for those trying to top up the pressure. This confusing key has discouraged many people from filling up the system themselves, especially if they lack confidence. While this may benefit plumbers and boiler engineers, it may not be ideal for your bank account.
Where is my Worcester boiler filling loop?
What is low pressure?
Most domestic boilers with a sealed system depend on a pressure of between 1 and 1.5 bar to operate properly.
In a perfect world the pressure would be set when the boiler was installed and never touched again.
In the real world however tiny leaks, bleeding radiators or faulty parts can cause the pressure to drop.
Click this link for more reasons the boiler pressure can go down.
Is low pressure a disaster?
Low pressure isn’t a disaster, it’s a pretty normal part of having a boiler with a sealed system.
If you are constantly topping up the pressure it’s a fault that has to be investigated and fixed but certainly not a disaster.
Most pressure drops are from tiny leaks on the radiators or boiler that can be easily repaired so no need to worry.
Where is my Worcester boiler filling loop?
This is the tricky bit with Worcester boilers.
There are three types of filling loops.
- External filling loop.
- Keyed filling loop.
- Keyless filling loop.
External
The simplest way to top up the pressure.
The caps should be removed and the hose should be reattached between the two valves. (Most of the time the hose is left on but it should be removed every time).
One valve is turned on either by the handle or a screwdriver.
The other valve is slowly opened until the pressure rises to between 1 and 1.5 bar.
Both valves are closed, the hose removed and the caps reattached.
A replacement filling loop kit can be bought from this link.
Advice on using an external filling loop is available on this link.
Keyed
This method is more complicated and has been causing Worcester customers trouble for many years.
This video is the official Worcester guide on how the keyed filing loop works.
Keyless
This is Worcester finally getting it together and solving the problem of topping up the pressure.
The keyless kit turns filling the system up into a very simple job.
Pull down the blue handle to begin filling. The pressure gauge will slowly rise.
When the pressure gets to between 1 and 1.5 bar release the blue handle.
Summary
If you experience low pressure on your Worcester boiler, don’t worry as it can be resolved. Begin by identifying the reason behind the pressure drop and fixing or isolating it. Afterward, utilize the filling loop to refill the pressure.
Follow this link for more advice on why your pressure is going down.