Heating Help

hot water zone off steam boiler 4/3/2000

The Hot Topics article on 4/3/2000 explained how to do this. My set up looks pretty much like the diagram. The article says that the supply water must be less than 180 degrees. My concern is that I may be exceeding that temperature because after a while, my return water may be coming back too hot. I have to close down the valve from the boiler water to a trickle (barely opened) to minimize the hammering. But then it takes a long time for the circulating water to heat up if it hasn't called for awhile (like over night). I'd be very grateful for any ideas to help with this issue. Thanks very much.

hot water zone off steam boiler 4/3/2000

The Hot Topics article on 4/3/2000 explained how to do this. My set up looks pretty much like the diagram. The article says that the supply water must be less than 180 degrees. My concern is that I may be exceeding that temperature because after a while, my return water may be coming back too hot. I have to close down the valve from the boiler water to a trickle (barely opened) to minimize the hammering. But then it takes a long time for the circulating water to heat up if it hasn't called for awhile (like over night). I'd be very grateful for any ideas to help with this issue. Thanks very much.

Did you plumb in a bypass? Dave in Denver

bypass line

Yes, I have a 1 inch line teed off the return line that goes in just in front of the circulator. Pretty much like the diagram in the article. (What format would be best for me to include my own diagram?)

Consider this way

It seems everytime that I only used the boiler water always have problems. Sometimes at start up or a couple of years later with pumps. So now I only use heat exchangers ie: tankless coil, now zone water and boiler water never see each other and away go the problems.If your boiler doesn't have a tankless opening they also make ones that can be installed outside the boiler. This isn't a cheap or quick fix but once done its priceless as well as problems. Hope this helps John@Reliable

John

do you mean an external coil like an Everhot? regards, Robert

Yes ,Robert the old \"sidearm\"

Ithink your approach

is a good one. the few that I have been involved with have had mud in the pumps every few years, Ron Wheeler says to use a three piece pump with a bronze impeller. Thankfully i don't have many of these to deal with. Have a good holiday John. All the best Robert ME

Tankless

I do have room for a tankless in my boiler, and did wonder about it. But I thought that when the system reached a steady state the tankless water would come out at the same temperature (more than 180 degrees) as the boiler water and therefore would still hammer.

sorry i don't

have advice to make your system work . Others might. But in a coil set up you can pressurize the loop 12-15 psi and should make things quiet Regards, Robert ME

If you are pulling the water directly out of the boiler you should have a pump with a bronze impeller. The non-ferrous impellers do not hold up to the heat. The better idea is to use a coil of some sort- your preference. If you have a coil your water temperatures are typically lower so there is no need for a more expensive pump and the hydronic part of the system will stay cleaner. You will need a feed valve, expansion tank etc... if the coil is being used on a closed system.

chas, I'm in the Boston area with plenty of steam systems

Your right as far as the temperate it will never really be able to be controlled. Without main thermostat (steam) calling for heat you would be able to control zone temp. with a simple aquastat, but once boiler is called upon for steam all bets are off as water now has to get hot enough to make steam which will overheat water for zone. With that said I have done many like this over the years and for the most part they do work. I have tried by-pass valves in the past and found they really don’t help unless it’s a big (long run) as the water will still return too fast to be controlled. I wouldn’t be afraid on using a tankless if I were you just pipe it like any other HW zone with purge valve, pressure gauge, and I like using a manual fill and a small x-tank with no air vent. I also install pump on return side in this system to reduce the amount of “hot” water it will see over time. Hope this helps John@Reliable

what about a thermostatic

mixing valve installed at the connection where the return meets the feed water from the boiler just in front of the circulator pump. Could this work, and be cheaper than putting in a tankless system?

It would clog

within minutes.

wow -

is that because the boiler water is inherently "dirty" all the time?

Yep.

Steam is an open system. It's constantly rusting and the rust washes down into the return lines. The space is pretty tight inside a mixing valve.

Oh right, a pressurized loop

would not be able to "boil" so it wouldn't hammer. Thanks for that insight.