The wife and I bought a house built in 1850 that had been completely renovated about 9yrs ago. It was fitted with a burnam alpine 210bw. A few months ago we started have what sounded like pipes banging and had a local contractor come out to look at it. He did standard maintainance on it but the problem got worse. We got another "authorized" burnam contractor out and apparently the water is not circulating but rather "boiling" in the heat exchanger causing it to pop and bang. They closed of the valves and ran tap water directly through the heat exchanger and it looked fine. He found that the primary loop pump was seized and replaced that but the issue remained. We also closed of the water heater loop to see if the problem was there but to no luck. As this boiler is very expensive and out of the 5yr warranty I am at my witts end.