This old house we bought this past summer has a hot water circulating system for heat and I need to find out what kind of oil to use to lubricate the pump. There was an oil can there with the furnace when we moved in but it's about empty. The pump is a Dunham horizontal circulator that looks old but seems to work okay. The label says to use #40 or 50 oil. Can that be 40 or 50 weight oil? Seems very heavy oil for that. Also we get some oil from the circulator into the water (but no water out of the circulator) as I get some when bleeding the radiators. Is that a problem to be concerned about? Thanks.

Fellow who's going to install my new HW boiler system this coming Tuesday, stopped by today to make some sketches for plumbing, etc. In reviewing the components to be installed I asked about a Spirovent, mostly because our water has alot of air in it at times (1245' flowing artesian). He said they're nice pieces of equipment, and it would only add another $100 (cheaper to put it in now with new system). I had originally planned to have him install an Extrol bladder tank to replace old steel expansion tank, but he believes the money for the Extrol would be better spent on the Spirovent; he's had fewer problems with the old style expansions tanks vs. the Extrols. Any opinions would be welcomed. Thanks.