using steam boiler to pre heat domestic hot water

hotwired

I have an OLD steam boiler in my 4 unit apartmetn building (1 zone, so old there's not even any writing or markings on it. THEN we have an electric hot water heater 3-4 feet away from it. It seems to my layman's mind that it's a terrible waste of all that wonderful heat generated by that over firing, constantly running hulk of a steam boiler if it's not helping out with the water.  Can I or my heating tech get "creative" and invent something to "create" a pre heater of some sort? I know of course the water from steam heat is so much hotter than normal hw boiler so it might be incompatible ... but my scientific mind says "harness a little o' that energy."  Any thoughts would be appreciated ....

Charlie from wmass

Get a new boiler

Then install an indirect off of the boiler for your hot water needs. The electric bill will go way down, the tenants will have plenty of hot water, and your fuel bill will drop by 30% or more.

hotwired

follow up

Hi,

Thanks for that reply. Do they make "boiler mates" for steam boiler? Also, my guess was that it would not be very efficient way to heat the hot water during the summer, the boiler is usually shut down from May till Sept. I was thinking that some sort of "system 2000" type of heat plate exchanger between the steam boiler and electric hot water heater to "assist" the electric hot water heater during the winter .... no?

hotwired

test

test

hotwired

sorry

sorry, i see the title was "get a new boiler." I should've made myself more clear. I already understand that option, converting from steam ot hwbb, etc. etc. I will not be doing that. I'm looking for answers to the specific question I asked simply becuase we won't be changing boilers any time soon. I know it might be the right thing to do, but regardless, I can't change every boiler I have this year, I have to pace myself.

Charlie from wmass

No no no

I am not saying convert to hot water! We use Super Stor indirect water heaters with steam boilers. You should use a bronze three piece circulator.

Charlie from wmass

The indirect gets piped

off the front and back of the boiler and the boiler water gets pumped through the indirect. The boiler is controlled by an aquastat when the indirect needs to heat up on a call for domestic hot water. It shuts down below the boiling point so you do not make steam in July when you need hot water. A competent professional should be able to pipe it up with no issues. If the person you ask to do it says it can not be done they are not who you want to do it. It would become a self fulfilling prophecy.

hotwired

thank you!

Thank you, that is most excellent advice. I did NOT know you could set it up quite like that. Of course I have a brand new electric hot water heater already and was hoping to "jury rig" that into the mix, but I'll do some local consulting and see what we can come up with.

Mark Eatherton

A followup recommendation...

To avoid over heating your home, I'd recommend you use a reverse indirect DHW heater, like a Turbomax. It only needs a water source temperature roughly 10 degrees F hotter than your target water temperature, i.e. if you want 130 F water, the boiler water needs to be at 140 degrees F. The typical North America indirect DHW heater has such a small coil in them that they require much higher water temperatures, and those temperatures could be high enough to cause the boiler to generate steam, which means you could be getting heat from your stream radiators during the Summer months.



Not a good scenario.



Don't forget to incorporate a good ASSE 1017 anti scald tempering valve on the outlet of the DHW system.



And be sure to use a good ol' 3 piece circulator, like a B&G Series 100. It's life expectancy is 10 times that of a cartridge circulator in this application.



You will have to eliminate the automatic air vent that comes with the tank, but it should still work great. During times of compounded loading, the DHW system could draw off enough btu's to the point that the boiler can't kick steam, but it is no different than having a DHW priority logic in place. As soon as the DHW load ceases, the boiler should be capable of generating steam, if need be.



ME

Charlie from wmass

Mark I like your suggestion,

But I do have one issue I really do not like ever having water heights above the water line of the boilers I install. Vacuum is hard to maintain in nature. I also steer away from the reverse indirects in my area due to lots of minerals in the water. The old side arm heaters that the reverse indirect evolved from hangs useless at the side of hundreds of boilers in my area due to the coils getting plugged. The extra mass would be nice, I just would not expect the coil to stay open very long.

Mark Eatherton

I hear you Charlie...

But I ain't skeered :-) I've actually done the hot water trick with radiators that were on the virtual edge, height wise above the steam boiler and never had any issues. The system MUST be tight, but what system SHOULDN'T be tight as a drum?



As for failed, plugged, limed up coils, may I suggest that you look into electromagnetic water conditioners, like the one that Field Controls puts out.



I've been working with these things for well over 30 years, and I have yet to see it NOT work. Anecdotal evidence, sure, but Field Controls is not a company to be taken lightly. They've been around for a LONG time. And the cost is extremely reasonable especially considering the ability to keep the coil operating efficiently through the life of the DHW generator. In some cases, I think the item may pay for itself in 3 years or less, depending upon how often the coil needed chemical treatment for de-liming.



They are truly a plug and play item.



ME

Charlie from wmass

Mark do you remember the

Magnets in the plastic pipe nipple they were pushing in the mid 1990's? I do as we were sold a case of them for a great deal. We installed all but three in the case and found not a one helped the customers scaling issue. I am sure Fields unit is more science and less voodoo then the ones I dealt with but I will remain with what works for me. I lost a $50k a year client because I installed those magnets at their request and they did not work. People do not like being told their miracle is false. Tact is something I am still working on learning.

Mark Eatherton

SO, what do you currently do???

As for bogus products, absolutely. Not all conditioners are the same, nor are water conditions. In fact, I will tell you straight away that if the corrosion is silica based (AKA Glass Water) don't waste your time. These conditioners will not work on that problem. But if it is a calcium based corrosion, it will definitely work. I've seen it delime limed up water heaters, to the point that the tank failed, because some of the cracks were being sealed by the lime scale.



I have learned in all of my years, that when I speak about magnetic water conditioners, to expect people to look at me like I've got three eyes, and they have two jaundiced eyes. I also think you know me well enough that I would not attempt to blow smoke up your skirt... or kilt, whatever...



Working on tact is a life long proposition.



ME

Charlie from wmass

Mark I was referring to

The customer with the magnets in PVC pipe nipples. The use of proper systems have lots of science to back them up. I know you would not blow smoke up my kilt. My CO detector would go off. As for water conditioning I leave that to the people with the yelling lady in their ads. I have a great third party lab that tests the water I give the report to the customer and they call in a conditioning company.

Mark Eatherton

Do your customers and yourself a favor....

Purchase a Clear Wave from Field Controls, put it on your system (assuming you have the same hard water conditions) and see if it works. IF it does, you can then start supplying it to your customers, saving them a TON of money spent on salts, and make money for yourself in the process.



If it DOESN'T work, come back here and let us know.



ME

Charlie from wmass

This is the odd thing Mark

I have hard water at Dad's house and his coil still works after 39 years of service. The well is 225 feet down through marble, limestone and granite. I will look into the units since you believe so strongly in them and you have seen them work.