Megaflo Problems

Megaflo unvented cylinders are popular for their ability to provide mains pressure hot water, making them an ideal choice for many homes. However, like all systems, they can sometimes encounter problems. One such issue that has been highlighted is low hot water pressure, particularly impacting shower flow.

Identifying the Problem

The issue can be characterized by:

• A shower that has significantly reduced flow when set to warm or hot.
• Pulsing of water from the shower, indicating that it might be attempting to regulate temperature.
• Other hot water taps in the home might have decent, albeit not excellent, flow.
• Despite these symptoms, the actual water temperature seems to be appropriate, and the electric immersion elements function correctly.

Several potential causes for this issue have been identified:

1. Issues after External Work: Some homeowners reported that the problems began after utility work occurred nearby, suggesting the potential influence of external factors.
2. Air Gap Issues: One potential issue could be related to the air gap inside the cylinder. While the air gap’s primary role is to accommodate water expansion when heating, if not maintained, it could potentially cause other issues.
3. Shower Hardware: With the problem being most pronounced in the shower, the thermostatic shower unit itself might be at fault.

Suggested Solutions

1. Check Inlet Control Valve: Ensure that the inlet combi valve and any associated components are functioning correctly. These systems require regular service; if not maintained, they might cause problems like this. Check for something similar to a Caleffi – 22mm Inlet Control Multibloc Valve Group. If uncertain, consider consulting with a G3 certified plumber.
2. Drain and Refresh the Tank: One recommended approach involves draining the tank entirely, ensuring the water has gone, then refilling it. This might help restore the internal air gap.
3. Check for Strainers and Debris: The main pressure-reducing valve often contains a strainer that could get clogged and might need cleaning. The shower might also have non-return valves (nrv’s) and strainers. It’s a good idea to check if either the hot or cold strainers contain debris, which could affect water flow.
4. Thermostatic Shower Cartridge: If the shower has a thermostatic cartridge, this might need replacement, especially if the problem is localized mainly to the shower.
5. Pressure Relief: If the air gap is lost, the pressure relief system might activate during heating, allowing some water to vent. This can be checked by observing the tundish for any evidence of water after a heating cycle.

In conclusion, while the Megaflo unvented cylinder system is relatively straightforward, there are multiple components and factors that can influence its performance. If homeowners experience reduced hot water pressure or other related problems, it’s crucial to diagnose the issue carefully and seek expert advice if needed. Maintenance and regular checks are also essential to ensure the system’s longevity and optimal performance.