Steam Boiler with Hot Water Zone


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Old 04-12-16, 08:07 PM
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Steam Boiler with Hot Water Zone

I have recently had a hot water zone added to a steam boiler. It am not sure it was piped correctly since the water flow through the circulator, zone valves and boiler dont make sense. When I checked another boiler I have on another home I was surprised to find the water flow didnt make sense. I have looked everywhere trying to figure out the correct direction the water should be going through the system and everyone has a different opinion.

When I look at the Taco zone valves there are arrows on the sides. Am I correct to assume that is the direction of the water flow.

When I look at the Taco circulator there is an arrow on the cover. From what I have read the water flows in the direction because of the shape of the cover regardless of the direction of the pump and if the pump is not turning in the right direction it will only reduce the flow but not change the direction. Is that correct?

Next, when I look at the home that seems to be working properly I was surprised to find that the the highest pipe coming out of the boiler and what I thought was the feed out of the boiler and to the individual zones is set up as follows: the high pipe coming out of the boiler connects to the circulating pump (with the flow pointing back into the boiler) and next the circulating pump is connected to my zone valves and piped from the zone valves to the individual radiators for that zone. Each the zone valves have the arrows pointing back to the circulating pump and the boiler. I expected both the arrows to go the other direction. Is this the correct method to pipe the boiler? All the returns from the radiators zones are joined piped into one pipe back that goes into the boiler which is also the lower pipe.

I was also told the if the circulating pump is piped on the return side it will give it a longer life because then the water isnt as hot when it gets back around to return to the circulating pump and then the boiler. If this is a better location, which direction would the arrow be pointing on the circulating pump?
 
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Old 04-13-16, 11:52 AM
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Does your system work correctly?

Assuming there are no check valves in the loop, the circulator will send the water the way it wants to regardless of whether the direction is "forward" or "backward" through the boiler. Running the forced hot water "backward" won't cause problems except if the pipe being drawn from is high enough to suck steam instead of water and then the loop empties out its water and stops heating the room.

Better results are had if the FHW loop is isolated from the boiler using a heat exchanger.

Most FHW systems have the circulator in the return line pulling the hot water up from the boiler and through the radiators.
 
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Old 04-14-16, 12:28 AM
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Old 04-14-16, 05:42 PM
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The pumps should always pump away from the boiler which will add pressure to the system and have less chance the system water not flashing to steam.
The pipe should come out higher in the boiler and return to the opposite side low. When the supply comes out of the boiler it should drop close to the floor to keep steam out of the circulator if the boiler is surging.
Normally there is a blend loop from return to supply to temper down the temp a bit.
Here is a link, not the best drawing but proper location of items.
http://www.comfort-calc.net/steam_indirect_piping.cfm

BTW, same as pump should always pump away from boiler after expansion tank on a how water system.
 
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Old 04-15-16, 05:49 PM
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Quote by Heatworm
"See Thread: pump failures on hot water loop off steam boiler [by NJT]"

The link does not work. Server not found.
 
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Old 04-15-16, 10:23 PM
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