New steam boiler and hot water tankless combo options

mfranks68

Recently purchased a 5000 sq ft historic house in downtown Detoit that was converted into 4 apartments many moons ago. My question is will replacing the ancient boiler (huge) with a modern unit and possibly incorporating some sort of tankless hot water or boiler/ tankless combo to replace the 200 gal water tank make a whole lot of difference in efficiency/ gas bills? Looking for knowledgeable installers in the area so any recommendations greatly appreciated.

Jamie Hall

This is steam? Replacing the boiler with a new one -- properly matched to the radiation in the building, of course, might increase the efficiency, depending on how good or bad the old boiler is. Some very old boilers were pretty poor that way, however boilers since say the mid-80s aren't really that bad, and it doesn't make much sense to replace them unless they have other problems.

I would avoid tankless water heaters in an apartment situation. Very few things annoy a tenant more than not having enough hot water. What I would consider, however, is a more modern water heater -- or even better, water heaters (one for each unit) if the plumbing is set up to make that possible. That way you could make the tenants responsible for the cost of their own hot water -- which has some real positives.

You don't mention what your fuel source is, but you could do that with either gas or oil.

You do, unhappily, mention that you are in the Detroit area. Sadly, for some reason good steam system technical people seem to be really in short supply in your area.

Can you give us more particulars on your system? How old really is the boiler? What make and model? Fuel?
What amount of steam is it rated for (that will be on the nameplate)? The results of the most recent combustion adjustment and test (should be done every year, and the apparent efficiency printed out). Some idea of how much installed radiation there is?

mfranks68

Hi Jamie, Thanks for the response. I will have to get over there for pics, model/dates of boiler and approximation of radiation there is. The fuel is natural gas. I've considered the seperate hot water tanks but would have to seperate into seperate metering which opens a whole new can of worms. Crazy there aren't many boiler experts ut here considering how many boilers there are in the area. At this time I don't have any results of combustion, etc as I just purchased the building, but would guess that hasn't been done in 20 +(maybe never) years based on the maintenance of everything else. I will add that apparently there is no issue with heat as its a sauna there at all times (thermostat set at 70) and 2nd and 3rd floor tenants crack(and even open wide) their windows much of the time. Currently there is no real way to regulate each individual radiator but want to remedy all that by next season.
Mike

JDHW

If you are interested in apportioning costs for hot water without separate heaters and gas meters what about one hot water system (storage and heating) and then add heat meters to the supplies to each unit. Could do that for heating was well.

Regards John

Jamie Hall

That hardly sounds hopeless. The lack of -- or poor -- control of heat is hardly unusual, but completely unnecessary. That is actually probably pretty straightforward to remedy and -- lucky you -- something you can do on your own or with your tame plumber if you have one with a little help from your friends here on the Wall. And doing that -- with very little else done -- will probably save you a good bit on fuel costs.

When you go over there, can you get some good pictures of the boiler? Since we can't get there, what is needed is a good photo of the boiler itself, showing what controls are on it (should at least be a pressure switch or some kind, a pressure gauge, and water level sight glass, and a low water cutout (parenthetically, for an apartment building there should be two pressure switches and two low water cutouts... ). Then one of the nameplate. And then three or four from far enough back so that we can see how the thing is pipe and connected to the steam mains and any condensate returns?

Then a couple of typical radiators. In figuring out the best way to control the heat for your tenants, it's really important to know whether this is piped as one pipe or two pipe -- and, if it is two pipe, the type. So if it is two pipe, a closer picture of both the inlet valve and any outlet fittings on a typical radiator.

Then while you are at it, a diagram, if possible, of how the whole building is piped -- where the mains go, where the risers hook on, any return pipes to the boiler (and how high they are in relation to the boiler water level).

You can also look and see if there are any main vents on the system. May be lurking in odd corners at the ends of steam mains, or may be at the boiler...

We'll get you there.

mfranks68

Sounds good guys. Jamie, give me a day or two to get over there and get all the info you suggested. And John, it is steam and not hot water but if having one boiler but seperate usage metering at each unit is an option that would be a great idea. I am somewhat familiar with steam and hot water boilers, as I've had several properties with that type of heating and fairly handy, so no problem making simple changes such as adjustable vents, etc.

dopey27177

Hopefully your boiler is in a serviceable working order.
Installing a tankless heater heater in the boiler may not be the best way to go because the boiler may be to small to fit the right sized coil into the boiler.
Call one of the hot water tank manufacturers to come to your building to size your tank.
Remember one thing the cost of producing sufficient hot water is based on usage. In many cased supplying domestic hot water i more costly than heating a building, that is because you supply hot water 12 months a year nearly 24/7.

About your overheating situation w need to know what type of stem system you have and the pressure setting of the system.

Jake

mfranks68

Ok Thx jake, I'll try to get all that info over the next few days. I believe I would like to replace the boiler, regardless of function, just for peace of mind and resale value down the line so weighing my options with all your inputs and hopefully someone knowledgeable to make the proper changes.