Live in the typical two story Colonial.
Have gas fired, forced hot water heating system.
About 30 years old.
Has two zones, and an electric circulator for upstairs, and one for
On each of these lines, there is a valve that operates sort of as a
When the circulators are Not going, these check valves apparently
prohibit any hot water from circulating by gravity. Think they have a
spring loaded ball in them.
If there is a power outage, and you back the stem out, about a dozen
turns, the spring, I guess, then puts no force on the ball, and the
hot water heat can then circulate by gravity
(the furnace just cycles between the high and low set points without any
external power required, as it has the older millivolt thermocouple
a. are these things (these check-valves)"really" needed ?
b. are they still used today in forced hot water systems, or...?
c. If they need replacement, what brands and model number are used
commonly for this sort of thing now ?
Any thoughts on this would be most appreciated.