HM30 Gurgling

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algatesia

I, too, experienced a few periods where I heard gurgling in the exhaust duct of the HM30 and, at the same time, couldn't get the burner to light. In the HM30, the exhaust passes through the combustion chamber, then downward to the base of the stainless shell and then back up through the 2" PVC duct to the outside of your home. The HM30 is a "condensing" system so most of the water in the exhaust is condensed out in this "trap" at the base of the stainless HWH shell.

At the lowest point in this exhaust duct is a rubber cup held by a spring hose clamp; one thing that you may try is removing the hose clamp and emptying this rubber cup - this will stop the gurgling sound for a while, at least. While there, check if the drain tubing is clogged, causing water to build up in the lowest point in the exhaust duct. Clean out any clogs and reinstall the rubber cup and the hose clamp and then attempt to restart the system; if successful, congratulations. If not, look at the ignitor for other clues; sometimes the ignitor assembly gets moisture in it which grounds the spark; basically, water can build up between the ceramic shell around the metal ignitor rods. You may want to dry it by spraying with some compressed air cans that you can get at a computer store. Try to start the system again.

If you can get it running, you may also want to try reducing the water pressure in your home; my home has a Honeywell-Braunkman D05 back-flow preventer/pressure reducing valve required by our local water provider. This can be adjusted to reduce water pressure and give the HM30 a longer life - I have reduced ours to 50 psi - when I was trying to nurse my leaking HM30 in mid-winter I reduced the pressure even more.

Good luck to you
JohnP