In this article, we will discuss pressure problems (both high and low) in Ariston boilers. There are various reasons why a boiler’s pressure can rise or fall beyond normal limits. Read further if you would like to find out about all the potential pressure problems in Ariston boilers and how these can be solved effectively.
Low pressure errors in Ariston boilers
Problems with low pressure in Ariston boilers are often associated with a lack of water in the system. The most basic solution for this is to, obviously, open the inlet valve and fill the system until the pressure normalizes between 1 and 1.5 bars.
This begs the following question: What has caused the boiler to lose water? This is where the issue can get complicated. It may be because of a routine water loss through evaporation, but it could also be due to other reasons. The vast majority of these solutions should be carried out by a qualified technician.
Faulty safety valves
It is normal and necessary for the safety valve to expel water when there is too much pressure in the boiler or in the system. However, if the safety valve is broken and frequently expels water when the pressure is not excessive, or it even leaks, this is one of the possible causes of the water loss. Once the safety valve can no longer perform its function, it is best to replace it with a new one.
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Incorrectly sized expansion vessel
One possible reason for low pressure is due to an improperly sized expansion vessel that is not able to regulate the boiler’s water flow and the home’s water demands. The expansion vessel may have have a hardened or torn inner membrane, causing the water to flow into the chamber, where it should be dry.
Whether your expansion vessel is the incorrect size for your system, or the membrane is broken, it is best to replace it with a new part.
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Stuck or faulty circulation pump
There may be low water circulation due to a blocked or damaged water circulation pump causing a drop in pressure: this can also cause the temperature to be too high. The solution is to unblock the pump if it is stuck, or replace it if it is faulty.
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Leaking through individual parts or the entire unit
As you know, a leak from any part or at any point in the unit results in water loss and, consequently, a decrease in pressure. Leaks are sometimes difficult to detect because they can be small or hidden.
A sign that you can rely on is this: If the pressure drops due to a leak, it means that the leak is within the closed heating system, and not in the DHW system. If the leak is in the heating system, it will cause low pressure.
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High pressure errors in Ariston boilers
Faulty or open filling valves that are undetected
This kind of filling cock failure is the opposite of what we saw earlier. In this case, the fault is causing the filling valve to remain stuck in the open position, or to leak and continuously allow water to enter. The part should be either repaired or replaced.
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It could also happen that the filling cock has simply been left open accidentally, and the excess water in the system is producing a raised pressure level. To resolve this, you can remove the water by bleeding a radiator until the pressure normalizes.
The boiler needs to be bled
Speaking of bleeding, when your boiler needs to be bled, it can show signs of the pressure being too high. You can follow this tutorial to bleed your boiler.
Or it simply hasn’t been maintained
There can be many signs that a boiler hasn’t been maintained, and one of them is excess pressure. Boilers should be serviced at least annually, according to the law.
Pressure-related Ariston error codes
Ariston error codes can reveal 2 kinds of faults:
- Temporary ones that resolve on their own
- Permanent ones that require human intervention to be fixed
Pressure-related Ariston error codes tend to be related to what Ariston calls the main circuit’s (ie. the unit’s circuit) Functional Group.
This makes sense because pressure problems are related to the closed heating circuit and not to the water’s open circuit.
Most pressure error codes are between 102 – 118, and also include codes 1P1, 1P2, and 1P3, referring to insufficient water circulation due to a stuck or faulty circulation pump.