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garvity vs forced hot water heating

Jim_109 Member Posts: 45
As a homeowner how can I tell if I have a gravity or forced heating sytem? I have cast iron baseboards and radiators on the first floor and slant fin basboards on the second floor.

I am considering purchasing a new boiler and indirect, as well as possibly adding a full bath to the second floor. Currently I have only have one bathroom on the main floor.

How much does it matter which type of heating, forced or gravity when considering a new boiler and indirect.

Also any comments about pressure boosters? I have low water pressure in the kitchen and bathroom. The water company says the pressure is on the low side, but "normal"

I would like to increase the pressure to the fixtures, plus I am concerned about the low pressure if I add the full bath to the second floor.



  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Jim, go to the boiler

    and look for a circulator. I suspect you have one. Gravity via fin-tube coupled with cast iron sounds a little odd to me. At least the upper floors have more pressure differential which can help.

    Now, noting that you have cast iron and fin-tube, I would hope that if you go to a positively circulated system that you separate them. Keep cast iron together on one zone, fin-tube or any low mass emitters on a separate zone.

    As for pressure boosting, 80 psig is code maximum in most places. 40 psig is considered a minimum. What is the actual number under a flow condition? Watts and others make a gauge that fits on a hose-end connection. To be fair, take a reading when there is flow in the system, not just a static reading with no flow. That will be an unfairly high pressure, not indicative of much.
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