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Faint gas smell inside a modcon

dave123
dave123 Member Posts: 67
edited August 2023 in THE MAIN WALL
So I opened a WM Aquabalance today to do the yearly maintenance, and noticed a very faint natural gas smell. The unit had been sitting idle for several hours, not from heating the house but from heating the indirect tank. I got out my combustible gas sniffer, and found an increase only at the opening of the fan intake, nowhere else. I turned off the gas supply, used a shopvac to suck out all the air around the fan, and rechecked. No gas present. Turned the gas supply back on, and a minute later, the sniffer registered again.

So I think I've proven the gas valve is letting some gas by, but apparently, a small amount is acceptable (according to honeywell?). If I leave the front panel off, and the gas is on, I don't smell anything, though the sniffer still detects gas at that same location, right inside the intake to the fan.

The gas valve is not labelled on the metal body, other than "Made in Hungary" and the number VK8205V. The boiler is 3.5 years old.

My inclination would be to replace the valve, though apparently it's not easy to get. But I could see the replacement possibly doing the same thing.

Anyone else come across this issue?


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