My central heating use to take around 30 minutes to heat my home to a comfortable temperature, now though it seems that it takes anywhere up to an hour or more, what is wrong with my central heating?
This is a common question that seems to get asked a lot now days.
There are a couple answers to this question, that I will now go through and try and explain as to what may be happening.
The first thing we need to do is make sure the pump is working properly.
Most pumps have a center screw that can be removed to vent any air, once removed we can check the pump spindle with a small screwdriver, once inserted, if the spindle stops then the pump is on its way out and will need to be replaced.
The next thing we need to do is check the internal water inside the central heating system, when I say say I mean the color of the water, is it a dirty brown / black color?
If the water is really dirty it will start to slow down the water circulation within the central heating system, the central heating pump is put under a lot more pressure and will eventually stop working.
The dirty water is normally referred to as sludge, and if not treated will eventually kill the central heating boiler and pump.
So What is sludge and how does it get into the central heating system?
Sludge starts to form as soon as the central heating system is filled with water, it does not take long to notice the water starting to change from a nice clear color to dirty color. Overtime it will start to clog up the boiler and pump along with the radiators.
If you have noticed when the heating is on that some of the radiators may be hot in some places and cold in other, this is an indication of sludge build up within the radiator.
Sludge is made up of iron oxide from all the different metals within the central heating system and other debris. Water acts like a conductor and all the different metals start to react with each other, eventually they start to break and sludge starts to form.
Sludge is more noticeable in newer boilers as they have smaller waterways that the water passes through to heat up, on older boilers the waterways were a lot bigger so you did not notice it as much.
To cure the sludge from your central heating system, the whole system has to be flushed out with a cleaning agent, once clean an inhibitor needs to be added. The inhibitor will prevent the sludge build up. Every year the inhibitor should be check and topped up if needed.
Now days most boiler manufactures recommend fitting an inline filter to the boiler return pipe to stop sludge entering the boiler, which is this a good practice it will still need to be checked annually along with the inhibitor.
Overtime the inhibitor will dilute down and no longer protect your central heating system from sludge, so it's very important to have it checked annually, the same time as the boiler service.
Many of today's boiler breakdowns are due to sludge buildup within the system, most of the boiler manufactures now will not repair a boiler if still under warranty if the fault is down to sludge within the system.
They will advise you to have the central heating system cleaned first then they may return to carry out any repairs needed.
Sludge is a killer of boilers, its worth noting when your annual boiler service is due to have the inhibitor checked at the same time.
When the water inside the heating system is clean, the water flows quickly and freely through the pump, boiler and radiators.
We all want to cut back on our spending, but cutting out the annual boiler service and inhibitor check could have made a lot more expensive than you think.
I hope this article has helped you in understanding why your central heating system has started to take longer to heat your home up.