Convert apt. bldg to HW?

Frank_Dobbs

This may be a long post.



I own two adjacent apt. buildings in Manhattan that I plan, at some point in the near or distant future, to renovate.  At the moment there is only 1 tenant in a 6 family building and four (including super) in the 12 family building and stores along the ground floor.



Heating costs have been insane, and I plan to reduce them now (they have been as high as $60k a year for 5 apartments.)



Currently there is a 10 yr old Eastmond steam boiler with I/O of 1680/1339 MBH.   There is a Heat Timer control that the super has been overriding every single night to satisfy a noisy elderly tenant.   It now has a padlock on it.   There is no way that the boiler was sized properly, I am quite sure.   Some but not all of the obvious leaks, etc. have been taken care of.  But this is a monstrosity and a mess.   I could measure the radiation and replace the steam boiler, but there are several reasons not to:



-Only 5 of 18 apts. are currently occupied.   That number may diminish in the future.  I may move one tenant temporarily from one building to another.    I might at some point want some heat during construction.    I suspect HW would be more efficient, since I would not heat vacant apts. and occupied stores (they are required to provide their own heat, but some use the building's system.)



HW would also be more flexible.   If a tenant moves out or I switch an apt. or put a relative in a vacant apt. the heat load would change.



So my plumber, who is not the kind of heating expert one sees here, came over today along with someone from a local wholesaler that I do not have a lot of confidence in.   I did my own heat loss calculation for the 5 apts. and came out with a total of 160,000 BTU's after addding some insulation.   I've heard good things about the Baxi Luna, and I thought 2 sequentially fired HT 1.33's, with an 80 gallon HW indirect might do the job.



For distribution, we would use pex and baseboard.  



For limit control, I would want:

Outdoor reset

Limited TRV's

A probe in the coldest apt, or in several apts.



The unreliable wholesaler suggested modulating, but not condensing Baxi or Embassy units.   He said that for condensing boilers it would be necessary to oversize the baseboard.   He may think my plumber lacks experience in this area.  He said condensing units woudl add just under $3,000 to the wholesale cost.



A couple of questions:



--Is this approach crazy?

--Wouldn't the condensing boiler pay for itself quickly?

--Would the condensing boiler be a lot harder to maintain (I have a Viessmann in my home, and it's been fine.)?

What kind of control unit, TRV's, indoor and outdoor probes would you recommend?



An input would be appreciated.



Frank

nicholas bonham-carter

water or steam, that is the question...

i suggest you have a good steam man such as john ny. to evaluate your choices. find a professional above will give you some names. if you don't have a copy of"the lost art of steam heating", get one here. with it you will be able to understand how to undo the years of neglect. 

your boiler, if it has not been too abused, has only lived a quarter of its life, and so may have many more years of service left in it. therefore it would pay to see what is required to restore the steam to its original [as first installed] state of repair. if it is oversized for the radiation, then perhaps it could be downfired.  at any rate there could be signifigant savings in putting it back into proper maintainance.

if i were to guess what will be needed to get your system working properly,as it once did, it would be very adequate main venting, replacing the heatimer with a tekmar with 4 avearging indoor sensors, and outdoor reset, a vaporstat, and good low pressure gauge. lastly but not leastly, trv's on the unoccupied area radiators, will keep those ares underheated while empty. at your present rate of fuel cost, these repairs will probably pay for themselves in a week or two!--nbc

clammy

what to do?

Well Frank there's alot of things you could do .Your supplier is correct on the needing of more baseboard to make a low temperture system worth your while ,but instead of baseboard which always get the heck beat out of it over time why not panel raditors ?Buderus makes a nice panel rad which a TRV mounts diretly to and a isolation by pass valve can also be installed making each rad it's own zone and also enabling it to be isolated and removed for what ever reason with out shutting off or draining the system if installed correctly.These rads could be set up as a mirco zone depending upon the load by doing a home run lay out with larger pex feeding a smaller distrubtion manifold located in each apartment which in turn would feed the rads.If a condensing modulating boiler where to be used the panel rads could be sized for a lower water temp on design day temperture say 140 so you would coast on your boilers out door reset control .As for room thermostats the trv would cover that and tenants would be able to control the temps each room is in the apartment with a locking feature on the trv to control the tenants urge to turn it up all the way ,Towel racks could be installed in the bath rooms as in many apartment thoughout germany have a nice feature serving  two purposes.Of course this just all thoughts and i would gather you would have to see what fits into your budget also i would not limit myself to 1 boiler i think i would use 2 smaller unit to get where i want giving me a back up unit and also if sequened together a higher modulation (1 unit say 5 to 1 turndown 2 units 10 to 1 turndown )The biggest advantage to the buderus panel rads i see is easy 2 pipe connetion build in trv capablities and a bypass valve built into the raditor supply and return hook up so there's always flow to the rads raditor valve and the system pump can be one constant cirulation based on outdoor temp.On another note each apartment would have hidden in a wall behind a access cover would be a small mainfold with flow meters just feeding either one apartment or one floor in the boiler room would be a larger manifold with flow meters feeding these smaller mainfolds all working off say 1 main system pump,with the flow meters all the flow could be properly set with out much guess work .in my eyes this would be a very effecent system and would in all likely hood have lower running costs .Hope this gives you some food for thought .You an always go to the buderus site for more of there panel rad info i would be looking at the modell 22 if i where you they are reversable ,there is also runtal ,dianorm and a few other manafatures but i feel the buderus panel rads with there close supply return piping the easiest to install using there 1/2 in compression connetion and swithing it to a pex al pex tubing .hope i did not over load you peace and good luck clammy

Jamie Hall

This, in my view,

is one of those kind of marginal renew/redo jobs.  I agree with NBC that you would do well to get one of the really good pros on this site to come and take a look at your situation for advice.



However, before lest discount steam completely, permit me to correct a misconception or two.  The most important of which is that while HW is flexible, so is steam, if it is properly done.  The key to it in a situation such as yours is the use of TRVs on all the radiation -- this allows you to turn the temperature in unused spaces way down when you don't need it, and also allows the tenants -- within reason -- to control their own heat.  HW does the same thing, of course, with either TRVs or thermostatically controlled zones, one for each tenant.  You really don't gain much in flexibility.



Would the mod-con pay for itself?  As to which approach would give you the best return on investment, that can only be evaluated if you have someone competent with steam evaluate what needs doing to your system, and the price.  Whether you stay with steam or go to hydronic, it is very likely that you will need a new boiler.  Once you have done that, you will need to see if the slight gain in combustion efficiency from a properly controlled mod-con in a hydronic system will outweigh the capital cost of installing it in place of the existing steam system.  I would have to say that no, the mod-con would not pay for itself quickly, although it is possible that it might pay for itself and the associated system eventually; since I don't know the condition of the rest of the steam system, I would be a fool to say more than that.  I will say, however, that it is my opinion that unless the steam system is really a disaster, it's unlikely that the conversion will pay.



Condensing boilers are not much harder to maintain than any other kind.  Provided you do the recommended maintenance as scheduled.



Whichever way you go, you are going to want some kind of individual control for each space -- TRVs or thermostat controlled zones.  You will also need a master control for the boiler, whichever kind it is.  I would suggest you lean on the good professional mentioned above for that.

CMadatMe

Clammy makes a nice Case

And I like his approach. Panel rads are not as expensive as most think. They will also cut down on some labor and you may be able to run 3/8" pex to them. You would also have more control as your tenants wouldn't have the luxory of turning up a t-stat on you. They will also use less wall space and give you the benefit of both convection and radiant heat.  They work real well with a mod/con if that is the direction you would like to go. Check out [url=http://www.hydronicalternatives.com]www.hydronicalternatives.com there is a load of info on low temperature hydronics and panel type radiators.



As for mod/cons. Stay away from alum blocks and your choice should be based on which contractor you choose and what he is most comfortable with. Yes Viessmann is my choice for mod/con but others out there will do the job just fine.

Jamie Hall

I'll second that...

steam nut though I am, I like Clammy's approach.  Sounds good to me -- but find a good contractor who knows what he's doing to do it for you.

ChrisL

How about hydro-air

Is there any a/c in the building currently?  As much as I love panel rads, I'd consider a hydronic air handler and ductwork in each unit over panel rads if you have no central air currently. This would give you the ability to add central A/C ahd share the ductwork.

I own a number of vintage steam heat apartment buildings.  I would love to have the control that a hydronic zoned system would offer, but I don't think this is the time to do it.  The technology is changing so quickly now, and we still haven't sorted out what will be the paradigm for heating and what energy source.  My buildings are late 20's era, three row brick walls, no insulation.  The air currents that flow in the walls and spaces is insane.  Is it economical to retrofit these with insulation (would require major work), or do we tear down and build new?  So, my answer is to keep the steam systems operating as efficiently as I can make them right now, and wait until the picture gets a little clearer.

Chris

jmac

are you going to continue to pay for the fuel?

Frank this is done everyday around here but honestly it is usaully done to make the tenants pay thier own utility.in the buildings with RSA the apartments that still get converted the owner will still pay the utility but no where near the cost of maintaining the entire building. If you spilt them up consider the embassy it has been great with zero trouble for us we usually put these in apartments though not in the basement.no mention of what kind of hot water demands you have in each unit but have to assume lav sink,shower,and kitchen sink.

this will need plans and permits in this great city but it is worth it and can be done one unit at a time.

the domestic coil is probably killing you in that boiler-the fst-40 is a beast great boiler though the heating surface of that boiler alone could probbly heat two of your apartments

what area you in?

Steamhead

Well, speaking of modulation.......

here's an Eastmond (Federal) steam boiler with a modulating PowerFlame gas burner. This thing runs off an L91 modulating pressuretrol, going from full fire at 0 PSI, dropping to 1/3 or so when it reaches 1.5 PSI (which drops somewhat as it goes thru the zone valves). After the active zone(s) are filled with steam, it modulates down and just simmers along at or near low-fire until the call for heat ends. No wasteful short-cycling.



This one's bigger than yours (175 HP), but you can still get variable-rate burners for your unit. Take a closer look- you may even have such a burner that has not been hooked up properly. In one such case, simply hooking up a low-high-low setup reduced a customer's fuel consumption by 40%, which he documented for us.



The system fed by this boiler is Webster Vapor- tenants can control the heat by adjusting the radiator valves, and vacant apartments can be turned down the same way. TRVs would be a nice upgrade but will have to wait a bit. Firing cycles are controlled by Tekmar 269 controls- one for each zone, with appropriately placed sensors.



This is one of several steam and Vapor systems where we've reduced their fuel consumption by a third (also documented) so far, and we're not finished yet.



Four more reasons to keep the steam:



1- It's already there;



2- Cast-iron radiators are more durable than fin-tube baseboard or panel radiators, which both dent rather easily especially if the unit has small children living therein;



3- The radiators and most of the pipes in a steam system drain completely dry when the system shuts off. This drastically reduces the chance of freezing damage if the building should suffer an extended power failure, fuel interruption or mechanical breakdown;



4- If a hot-water system springs a leak from whatever cause, the building can be severely damaged. If a steam system springs a leak, damage is usually minimal.



My Federal catalog is at the shop, but I think most of their boilers have a range of firing rates they're designed to use. So you might be able to have yours down-fired to better match your radiation.

Mike Kusiak_2

Eastmond downfiring

The Eastmond FST-40 should be able to be downfired at least 50% from its max ratings, according to the specs, so you should be able to go to an 840 MBH firing rate. I am running three oversized FST-80's in a hot water application, and running them at 50% is working out great. Combustion efficiency on gas is about 83-84% with a 320F stack temp. Dont thing I could go any lower in firing rate due to condensation concerns.

Kevin_in_Denver_2

How big is the boiler room?

If you can hang the new hydronic boiler on the wall, maybe you can convert the old boiler room into rentable space.  Last I knew a 400 sq. ft. studio apt. in Manhattan rented for $1600/month.



Now there's your payback!

Steamhead

Did you see

the vacancy rates in these buildings?



If I were in his position, I'd concentrate on filling my existing vacancies first.

Brian_11

I did it!!

Frank:

I am a hvac contractor on Long Island and also was a slum lord for a number of years. I had a 3 story tenement building in Williamsburg which I converted from one pipe oil guzzling steam to 7 zone panel radiator system with outdoor reset. I went from 8000 gallons to 2500. I did everything in PEX and was able to convert some of the old steam rads to water. I sold the building a few years ago and that was one of the great selling points.



The guys on this wall are awesome and I am sure you'll be able to find someone in your area.



Brian

Steamhead

What condition

was the steam system in?



If it was in the usual state of band-aided together or with an ancient, inefficient boiler, as we find in many rentals, that would explain why it used so much oil.



The only meaningful comparison between steam and hot-water is with both systems in optimal condition and installed in buildings as nearly similar as possible. In all the years I've been in the business I have never seen such a comparison. It's always a neglected, broken-down steam system vs. a new hot-water system, which is not a fair comparison, never was and never will be.



Care to elaborate?

nicholas bonham-carter

before and after fuel cost comparison

the fact that professional steam experts have been able to reduce fuel consumption by up to 40 % plus  [while increasing comfort] on previously badly maintained steam systems should show  how these systems can be so unfairly compared with a brand new hot water system. let us see how that hot water system behaves after 20 years of similar neglect!!--nbc