No flow from Megaflo.

[Tony_P]

I’ve a Megaflo system with a conventional boiler, and yesterday, with no warning, it stopped passing any water.

The cold flow is fine, there’s only the tiniest trickle from the hot taps on the lower floors, nothing on the higher ones.

I’ve checked the combination valve for blockages, and there’s nothing in there, and have re-established the air gap, but it’s stopped flowing entirely. To be clear, it’s not that the water is cold, it’s that nothing is coming out from the taps or showers.

The boiler has been showing error messages recently, asking me to check valves, which clear after a reset, and I’d not checked further as it’s getting serviced this Friday.

Because of this I switched to using the immersion heater a week ago, and all was fine until this sudden event last night.

Any help or suggestions gratefully received.

 

[fowlerboi]

re-established the air gap? I presume you mean the expansion bubble inside the cylinder?

I'm going to presume its the check valve inside the combination valve. They are simple bits of kit, the only thing impeding the hot water flow is probably some isolation valves and the combination valve. If you haven't touched an isolation valve before it stopped working it won't be that, its highly likely its the combination valve.

 

[Tony_P]

re-established the air gap? I presume you mean the expansion bubble inside the cylinder?

I'm going to presume its the check valve inside the combination valve. They are simple bits of kit, the only thing impeding the hot water flow is probably some isolation valves and the combination valve. If you haven't touched an isolation valve before it stopped working it won't be that, its highly likely its the combination valve.

Yea, the expansion bubble.

And no, no isolation valves touched at all.

It’s a real head-scratcher. The only vaguely unusual activity was the cold tap in the garden being run fully open for a while yesterday to clean the patios.

 

[fowlerboi]

If all your colds are working fine and its just the hots that aren't then the only thing separating them is the check valve in the combination

 

[Tony_P]

For anyone else with the same issue, the problem was the tiny plastic hemisphere that sits on the end of the plunger in the combination valve had broken off, made its way to a pressure reducing valve, and blocked it.

Removing this valve showed the obstruction, and while it was off I replaced it with a new one. Once reassembled, everything is now working perfectly.