65 Unit Apartment / Condo Buidling Heating Repl Options

andrewd33

I am on the board of directors of this builidng I own a unit in.  I don't live there anymore, but we are in the process of considering a replacement of our oil fired boiler.  All of the members on the board look to me because I am an HVAC person.  I explained that although I am familiar with the system in the building that I am not a hydronics expert.  I do know that what the board has gotten as advice from their heating experts doesn't sound like the best advice. So maybe you guys can make some recommendations to us.

65 Unit apartment building mixed, studios and one bedroom apartments built in 1951.  Converted to condos in 1980s.  Has one beasty Weil McClain boiler circa early 1980s that services the hydronic loop.  Also we just replaced our Lochinvar Gas Hot water maker (not the tank)  with a New lochinvar.  The old one lasted 13 years. 

We have gas in the building so I can't figure why we haven't switched since oil is 3.50 and up / gallon and gas is only $1 per therm in our area now. 

Recommended to the board was a dual fuel burner, oil / gas tied into the loop.I thnk that the better option would be to do those cascade type systems with multiple Triangle Tube or Munchkin boilers.

Serious problems with overheating and underheating in the building.  Most convectors valves do not work.  The convectors are Universal slab coil mounted in a cabinet with grille on front top and bottom. 

Old heat timer is the control.  Only other local control is the windows!!!

Is there opportunity here to save $$ or not.  We spent $66,000 last year on oil to heat 65 apartments that are between 500 and 700 sq. feet each and the common areas.  We spent an additional $19,000 on gas and electricity which is for hot water heating pumps and common area lighting. 

Any thoughts???

Mike Kusiak_2

Controls?

How is the present system being controlled? Is it an outdoor reset mixing valve setup with continuous circulation, or simply timed circulation with cycle times controlled by the old Heat Timer?



I operate a similar system in a 1950s co-op complex. One possible problem is that these systems were designed for a water temperature of 200F on a design day. In my system any thing under 140F delivers very little heat from the convectors. This may limit the practicality of using condensing boilers.



We use conventional boilers with dual fuel burners and outdoor reset with very good results. Having the choice of fuels is definitely a plus.

andrewd33

I don't think the heat timer is even being used properly

First one of the problems is that there are convectors without bleed valves on them and some of the convectors don't heat.  Most of the complaints are overheating more than underheating.  Does it make sense to put thermostatic valves on the convectors as we are planning to put at least manual valves if not thermostatic valves on the convectors to reduce the overheating.  If we do put tstat valves does the pump need to be replaced with a variable speed pump.  I'm in favor of offering a building wide thermostatic valve install if it will help.



 

andrewd33

I don't think the heat timer is even being used properly

First one of the problems is that there are convectors without bleed valves on them and some of the convectors don't heat.  Most of the complaints are overheating more than underheating.  Does it make sense to put thermostatic valves on the convectors as we are planning to put at least manual valves if not thermostatic valves on the convectors to reduce the overheating.  If we do put tstat valves does the pump need to be replaced with a variable speed pump.  I'm in favor of offering a building wide thermostatic valve install if it will help.



 

andrewd33

I don't think the heat timer is even being used properly

First one of the problems is that there are convectors without bleed valves on them and some of the convectors don't heat.  Most of the complaints are overheating more than underheating.  Does it make sense to put thermostatic valves on the convectors as we are planning to put at least manual valves if not thermostatic valves on the convectors to reduce the overheating.  If we do put tstat valves does the pump need to be replaced with a variable speed pump.  I'm in favor of offering a building wide thermostatic valve install if it will help.