15 Unit Building - LOTS of Stuck Rad. valves - WHAT TO DO?

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  #1  
Old 10-21-07, 07:58 AM
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15 Unit Building - LOTS of Stuck Rad. valves - WHAT TO DO?

Hey Guys,
I'm new here, I found this forum last night - looks like an active one with lots of good info from the Pro's. I know this post is long - but I hope you guys can help me with at least parts of it. This is not technically a D.I.Y. question, because I'll probably just be acting as go-fer and doing some of the grunt work - but you guys seem to have some really good answers, so here goes:

Background - what I've got is a 15 unit apt. building in Denver that we've owned since July. Built in 1945. Big cast iron boiler, converted to nat. gas (I believe it was originally coal fired?) Hot water system with radiators. The boiler company that has serviced it tells me it's in good shape. We just had them replace a bunch of the controls & bad sensors because the system was not cycling properly. Installed a Techmar(sp?) control w/ ambient temp sensor. So, all that seems to working fine now, but.......

The problem I've got is this - being 60+ years old, there are a lot of radiator valves that are either stuck or the stems are missing handles and are badly rounded. I've got a number of tenants that are getting either not enough or too much heat. I think that there are 42 radiators total. The tech that's been to the building tells me that to replace even just one valve - we would probably need to drain the system, so he suggests replacing all the bad valves, or even sweeping through the building and just replacing ALL of them.

So I'm wondering what type of problems we're going to encounter? What's the possibility of finding the guts for these valves, and rebuilding them instead?

If we do decide to replace all the valves - I've heard that there is some kind of valve or system that would meter the tenants use of hot water - allowing us to bill for seperate utilities (possibly discouraging open windows in sub-freezing weather). Is there truly such a thing?

We're looking at the possibility of completely replacing the boiler with a modern high efficiency unit sometime down the road - is there any type of valve system that would work better or worse if we do?

If we do go the route of replacing all, or most, of the valves right now - what type of problems should we anticipate with with nipples breaking off under the floor, etc?

When we take the radiators out to replace the valves - is there usually enough slack or slip in the piping that I could put something like a piece of Hardi-Plank on the floor before we put the radiators back into place? This material would be just over 1/4" thick, and I'd like to cover the hardwood floors that have been damaged in years past by leaking valves, etc.

Once all the valves are replaced, I'm guessing that the whole system will have to be bled at every radiator?

And what's it gonna take to get the system properly balanced again so that the heat is evenly distributed throughout the building?

What's a good type of valve to use? I noticed searching the internet that some have packings, some don't, etc. Any particular brand? I should probably let the boiler company supply the parts - but just want to make sure that they're using quality parts and aren't gouging me.

And lastly - can anyone venture to guess what those valves might cost, and approximately what a reputable boiler company should charge for a job like this? I think all the valves are the same - piping comes up through the floor, 1/2" galvanized threaded, one valve has a handle, the other is slotted. I'm guessing that this is a pretty standard deal.

Again, thanks for any help or advice that you've got the time to offer. I need to make some decisions on this in the next week or so because I'm getting quite a few calls from cold tenants.

Doug in Denver
 
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  #2  
Old 10-21-07, 09:00 AM
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Replacing all the radiator valves at the same time would be the preferred method.

I would suggest that you consider self-contained thermostatic valves. Your tenants could then dial in a temperature they desired and then not have to open and close the valves manually. These won't be cheap.

Yes, equipment does exist that would allow you to meter the actual amount of heat used by each tenant. Depending on just how the piping is run to the apartments and individual radiators this could be quite expensive. I suggest that you look at BTU metering at these sites.

http://www.onicon.com/Btu_meters.shtml

http://istec-corp.com/btu.html

http://www.echelon.com/productdb/pro...=764&manID=280

Or just do a Google search for BTU metering.

If money is no object you could install pneumatic-operated thermostats and control valves in each apartment. I don't think you will find this cost-effective but using electric thermostats and electric zone valves may be in the budget. The pneumatic would probably have lower maintenance costs.

I can't really comment on the probability of breaking piping, it always exists. Usually there would be sufficient slack to accommodate a 1/4 inch addition to the flooring.

Yep, each and every radiator will need to be bled, better add some money to the budget for some new bleeder valves too.

Balancing will not be a problem as it is designed into the radiator size.

Sorry, I cannot recommend any valves or make any legitimate estimate on the costs.
 
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Old 10-21-07, 09:07 AM
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Is the apt. building single or multi-level? Have you noticed if there are zone valves, so that you have more than one central thermostat control?

You can also buy lock box(s) to go over thermostat(s), and set temp to low temp required by law. But I am not sure of the legality of doing so DURING someone's already existing lease, in cases where "heat is included" without prior notification that heat will be turned down, when the tenant did not know in advance of renting, that heat might be lowered, even if to some legal level, like 68 degrees. A landlord I do work for has girls that like 76 degrees and he found out they set stat to that, and now wants to go in there and turn heat down to 68 and put on a lock box, without ever having told them before they moved in, - and I don't know if that is legally or morally right.
 

Last edited by ecman51; 10-21-07 at 09:17 AM. Reason: added last paragraph
  #4  
Old 10-21-07, 10:54 AM
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valves

I hate to say it but this is a job better left to pros. Ive been there and done this and it can be a nightmare. With a system that old there are lots of problems you can run into once you start opening things up.
Talk to your contractor about differant options. You can control the heat output of boiler to increase as outside temp drops and have individual controls for each apt.
 
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Old 10-21-07, 11:42 AM
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Oops, I forgot to mention that the building is 2 stories. 8 units upstairs, 7 units + laundy + boiler room downstairs.

And no, having been the owner of this building for only several months - I've not noticed any 'zone' valves. I'll take a look tomorrow.

There was only one electronic thermostat, (midway, downstairs hall) - the technician disconnected it late Friday night when he was there. Can't remember exactly what he said, but there was some kind of a problem between it and the Techmar. Recommened some other type of stat, I'll have him refresh my memory when I get back in town this week. Now the Techmar with outdoor ambient sensor supposedly is in complete control - does this sound right?

awtech - yes, I too agree that "this is a job better left to pros". I'll be there just to help move radiators if needed, and install the Hardi-Plank under them if we decide to do that.

Furd - as far as "Balancing will not be a problem as it is designed into the radiator size." - if this is the case - I thought that the valve on the output side of the radiator was to balance the flow. Was I wrong about this? Should they all be open full tilt? Remember that this is a hot water system, not steam - if that makes a difference.

I also read in another thread that the operating valves at the other end (with the handle) are not meant to control the heat output, that they are meant to be full open or full closed. Is this right?

Thanks for all the help so far
 
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Old 10-21-07, 12:39 PM
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I also read in another thread that the operating valves at the other end (with the handle) are not meant to control the heat output, that they are meant to be full open or full closed. Is this right?
You read that on a thread pertaining to a steam system. With a hot-water system the valve with the handle may indeed be used to control the heat by only having it partially open. That is not always the best method but it certainly is a workable method.

With any given water temperature the physical size of the radiator is the determining factor on how much heat is released to the space. That size was calculated at the time of initial installation. It is also possible to "fine tune" this by means of a restricting valve on the radiator outlet but usually this valve is just to isolate the radiator for service.

The Tekmar controller will reset the temperature of the circulating water in relation to the outside air temperature. In an ideal system (which, of course, doesn't exist) the circulating water temperature would be just high enough to overcome the heat loss of the building. In reality the circulating water must be a bit higher in temperature to overcome the greater losses that will exist in some places.
 
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Old 10-22-07, 05:06 PM
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You raised the question about billing people for hot water used by the boiler. I'd imagine any such valve or metering system would be expensive. Then there is the legality of this which you would have to research. I do not know how you would determine the amount of the cost of hot boiler water. If there was a legal issue, a way around it might be rather than CHARGING them, you give a CREDIT instead, to those who use a set amount below some established guideline. Aside from this, I am not sure of all the dynamics involved that would make all this entirely fair. For example, maybe the lower units would have water circulating faster through the radiators than the upstairs ones (water column issue). It would seem unfair to charge downstairs tenants more, when in actuality they are helping to heat the upstairs units!

Bare in mind that often the upstairs apts. will receive free heat from below. I have had many calls to apts. where I have had to turn down upstairs radiators. Sometimes completely off. I have measured temperatures of 80 degrees and above, at first floor ceilings where the first floor stat was set to about 72 or less. Then when that stat comes on and the boiler runs, the upstairs people receive 80 degree floor heat AND their radiator heat. Hence, turning down their radiators.

Another solution that I found works, is rather than having the boiler at 12 psi, I have dropped the pressure to about 6 so that the water only goes 1/2 way up inside the upstairs radiators. You can feel the outside of the radiator and feel literally the line between (hot) water and (cool) no water. This way it cuts down on people being uncomfortable (too hot), and wanting to fiddle with the valves. Also cut down on tenants wanting to open their window, rather than tell us they were too hot.

No matter what you do to your system and the valves, to "balance" it when you are through, you simply must bleed the air from every radiator. Each radiator will have a bleeder that either turns by a female square 'key', or with a flat screw driver, depending on the type. Bleeding can be time consuming and is an art to itself because you want air to escape quickly to cut down on labor time to do so, without having to run back and forth to the basement to let more water into the boiler, and yet you want the final pressure to hold at your established PSI. If you have more questions on this mater we can address that at the appropriate time.
 
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