Steam hot water loop

51fordf1

Steam hot water loop questions, Is a bypass necessary if you are using an aquastat? The purpose of the bypass is to temper the water to 180F, from 212F. A bypass would drop 180F water too low. B&G 100 and bronze circulators dont last. We have been using TACO 007's. One problem is they wont open two B&G flow control valves. Could use swing check on supply and B&G on return. Swing on return would just hang open. Any suggestions on flow controls to use?

Jamie Hall

If you want to hold the maximum circulating temperature in a hot water loop powered by a steam boiler, you are going to have to have some kind of thermostatically controlled tempering valve and return recirculation: when the boiler is making steam for the rest of the system, the water in there is going to be at 212, aquastat or no aquastat. The aquastat will keep it from going below that (or whatever it's set to) but won't keep it from going over.

mikeg2015

They make such thermastatic valves that are rated for that temperature. They are pretty expensive. Just use a bypass regardless. A 1/2” bypass on a 1” line would bypass about 20%, so not a ton. You could set aquastat to maybe 185 and still get 175F water.

clammy

Use full pipe size by pass and install a few ball valves to throttle your pump inlet temp .i like to install a aquastat in the boiler block if possible and if $ permits a hi limit for the pump also in the block if possible .a brass y strainer is also a good idea on the inlet to your pump and of course some purge valves to purge but to also allow u to clean .i personally I am not a big fan of hot water zones off steam boilers I know it’s done all the time for ions but they are usually neglected n when they fail there usually clogged up w mud n most of the steel piping below the water lines are done, and as my luck goes white carpet up to the boiler lol If it’s a small loop that’s fine but I see some crazy stuff like a recent steam replacement w a 1 1/4 inch mono flow system in steel pipe doin 2 floors of cast iron baseboard scratched my skull being all the homes rads had been removed n cast base installed why not just convert the last 6 pieces to hot water n be done nope I reconnected that crazy loop n took off . Usually if the loop is large or zoned I’ll suggest installing a small hot water boiler I do the same for small loops off large btu boilers I just think it’s a waste to fire a 200 to 300 btu boiler for a small load like that also now that loop is a closed pressurized system indepent of the steam boiler no mud no bronze or stainless pump .I believe in the resources on the site has some helpful diagrams and articles to the subject peace and good luck clammy