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Boiler bypass???

Lawrosa Member Posts: 13
OK so I have an old Hydrotherm HC 85. I have two zones with zone valves. 68ft element on one zone and 20 ft on the other. Next yr I am going to take 8 ft I added off the first zone and put it on the second zone. This is a length of baseboard I have heating my crawl. I am also going to add an additional 8 ft in the crawl on the second zone.

So after it should be 60ft first floor zone, and 36ft 2nd floor zone. ( 16ft of the second floor zone being in the crawl at each end. This heats the floors nicely and reduces the 1st floor t stat cycles.)

OK so after I do that mod I was reading about a boiler bypass whick I dont have.The boiler is a 180F running on and off. Although its 26yrs old and works fine I probably should not touch it right? I am not that concerned with fuel savings because my whole gas bill for the yr is about $1000 bucks. Boiler, HWH, stove, Dryer. I am more concerned now with temp comfort levels. Usually its hot in the home after t stat kicks off then cold waiting for the t stat to kick on.

Also I notice the temp gauge when the cold slugs from a zone opening hit the boiler. It takes three or 4 passes of the water in the loop to stablize and start raising the temp in the boiler. So if the boiler was at 160F and the upstairs zone opened that cold slug will drop the boiler to say 120F. Then up and down two or three times as the water passes and temp rises back up. Now mind you I am oversized for my heat loss so the boiler heats fairly quickly.

Heat loss is 35,000 btu. Boiler HC 85 hydrotherm.

So I was tinkering with piping a boiler bypass. This will also set me up for my next cast iron boiler if this one goes down the road that will only hold say 1.5 gal of water. I believe this current boiler holds about 4-5 gallons but cant be sure. I have not done the calculation but I believe all my baseboard holds as much or more then what the boiler holds. And if and when I get a new boiler the ratio will be different and hence I believe a boiler bypass would be needed anyway.

So I am looking for info on the benefits. Where to put all the temp gauges, and how to tune it. There is not really any info except for diagrams how to pipe. Am I off here on my thinking? I was looking at also a way to do an outdoor reset but I dont want to spend money on controls and such. I read a boiler bypass is the pooor mans ODR. And I am poor...LOL

So Is there any literature out there and specifics for modifying an older boiler for savings and comfort. I also was thinking with the boiler bypass to lower the aquastat to 160F for fuel saving? Would I need to adjust the bypass configuartion as the temps change? I understand as far as I know you leave the valve open on the bypass at all times and restrict the flow through the boiler. How to adjust the temps and where to put the gauges.

Ok sorry to ramble. I guess you get the idea of my thinking. I know someone will say $1000 a year gas bill, and 26 yrs old boiler..".Leave well enough alone."

Funny as a kid I had a poster that said that " Leave well enough alone" and showed a bulldozer getting ready to plow over two pointed rocks in the ground. Those two pointed rocks were the ears of a giant monster under the ground as the poster portrayed.


Mike NJ
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