reducing btus in boiler

John McArthur_2

We have a rental 4 fam. Each apt has its own zone with a separate thermostat. One gas boiler Burnham 209 (~270 k input and ~230k output), and superstore 40 gallon off on the side for a priority 5th zone. Each apt is around 700 sq feet, average insulation, good replacement windows, insulated attic. Its a 4 plex with 2 units one above the other, and side by side.

With one large boiler we are paying the heat. Some tenants will leave the windows open as "hey the heat is included in the rent". Being that there is nothing made to shut off heat to a zone when a window is open I wonder if anyone has any reasonable ideas. I am not going to install boilers due to depreciation rules and there is nothing wrong with the current set up. Hey it will push apts to 87 degrees with windows open. Obviously everything is oversized & there were no complaints of being cold in the last cold snaps.

So:

1. if I throttle down full port ball valves for each zone say half way would that lower half the btus going upstairs? Its a loop in the basement for each apt. Its 1 & 1/4 cast iron with risers to each convector. Obviously there is a monoflow on each return side. Total loop is around 100 feet off a 007 circ pump. There are 7 risers to each apt's convectors. I cannot remember exactly but for 4 rooms I think that it was figured out around 40k btus needed. What would be the guess of how much to throttle down the valve to reduce btus upstairs by maybe 25 percent? Or is there a way to reduce the recovery time to a unit?

2. I was thinking of a thermostat that I would install that would not allow the temp to go over 72. Not a visual locked one - a programmable one. However the residents are engineers so I would need some sort of good excuse why I wnat to replace them. FWIW - we have programmable ones in some other units and we have yet to see anyone use them to lower temps at off hours when heat is free.

3. Are there any metering devices made that I could measure the gallons and water temp and bill a person directly? Not sure I could do it in this state - Massachusetts.

4. Heard that trick of a finish nail into a honeywell round thermostat that limits the set point. However if tenants take off the cover & removes it then it was a waste of my time...

I feel that this forum is the place to ask this. Although I doubt its rare that someone wants to reduce the boiler output.

Legally in this state we are requited to have a min temp of 68. We have seen people in bathing suits and t-shirts in winter time with heat at 85 degrees.

TIA.

Mike T., Swampeast MO

1) Full port ball valves really aren't designed for throttling flow--particularly at higher flow velocities. Good metering valves that offer low restriction and accurate adjustment are made, but rather pricey. Reducing the flow considerably may well result in temperature imbalances in the spaces served.

2) All sorts of thermostats with all sorts of "locking" provisions. Doubt you'll be able to stop a determined engineer though

3) Such metering devices are made, but high accuracy implies high expense. I have zero idea of any legalities involved.

4) Yea, sure. The engineer won't find that finish nail?

One possibility is outdoor reset. Not only will you likely reduce fuel consumption regardless, but with a well-selected curve you can limit the "headroom" available to heat the apartments to obscene settings while in no way affecting the ability to maintain the legally required temperatures. Well, I say "in no way affect" but if they start opening windows in cold weather they might not be able to maintain 68°. Surely you aren't legally required to heat the place to 68° with windows wide open in cold weather!

Have you tried the direct approach of writing a polite but firm letter to the tenants? Explain the problem and the fuel cost/waste involved. Possible consequences: raise rent to cover the cost of the waste; raise rent to cover to cost of limiting their ability to waste.

John Cockerill

overheated

First thing is to look at your aquastat at the boiler. Tun it back 5 degrees perday until you are comfortable in your apt. Not below 140 F. You will know if the temperature is high enough as your thermostat will not satisfy if temp in boiler is too low. For the fianl solution go to "Exquisite heat" and find out how you can GET control. Hope to hear from you. Contact me directly through the web site or share our chat on this BB. John

John McArthur_2

ah this is a boiler

running a 4 fam and an indirect water heater. That equates to 5 circ pumps. If I reduce the high limit that will obviously reduce btu output. But what about the other 3 apts that are no abusing the heat? I do not want them cold. And the offensive tenant is closest to the boiler so they will get the heat first.

Joe Brix

remote temp sensors

instead of thermostats. Don't let them adjust anything, just display the temp. Checkout Tekmarcontrols.com Now if they want to rap the sensor in ice or extend the sensor wires and put the sensor in the fridge, I guess they could get around it. You could even setback durring the night from the central console. The open Window is a tough one. I think outdoor reset will help here. Since the reset will run cooler water temps, the cold outdoor air will keep the circulator constantly running but the room will never reach a comfortable temp unless they close the window.

Greg_15

Guess it is Time

..To add the heating costs to the rent. Just use this years heating costs, divide by the number of months it covers, divide again by 4 familes, and tell the residents that this is what will be added to their monthly rent.

This will give you some of the other warmer months to build up for price increases of fuel and or parts/ repair.

This way if they want to keep the windows open they can.

Another question may be that they get too hot cause the system is oversized too much. Thats what we used to have to do because it WAS just too hot and the humidity was to low to make it halfways comfortable.

jmho,

greg

John Cockerill

As you lower aquastat the circulators in the apartments will run longer at lower temps and make a more efficient even delivery to those apartments. The abuser will only have fewer BTUs to waste. The other will satisfy and be comfy. You can check your temp settings by observing the circulator times on the good tenants. As long as they are happy 50% -60%/hr. the abuser will be wasting less. You could automate the whole process by puting a control on a behaving apartment. Withy a behaving aprtment geting exact BTU replacement at 60% circulation the waster can only waste 40 % more with ice on the thermostat at 100%. Not bad as they are only using 25 % of the heat. It might turn out that the reduction will give better circulation to a cool room in that apartment and he will turn the thermostat down. Is the abuser on a ground floor with a cold hall, exposed windows and an outside wall?? Maybe you should talk to him and find out if there is a real problem you need to address.

John Cockerill Exquisite Heat
www.Exqheat.com

Steve Garson

In MA you can't charge for heat, unless the tenant has a separate heating system that they pay for.

I would install the fixed temp t-stats that use the glass mercury tube.

Boiler Guy

Indoor/otdoor

seems to be a logical place to start here. IMHO

kevin_22

tekmar

Fixed a 48 unit apartment with the same problem last year oversized boilers with constant circulation no insulation on any of the lines some apartments had no way to regulate the heat being let off the 3" mains in the ceilings and walls hence the windows and doors were left open. We installed a tekmar control and repiped the boiler room with an injection loop worked like a charm. But now the residents are complaining they can't heat the rooms with the windows open.

John McArthur_2

next visit

I plan to roll high limit 10 degrees lower. I would guess its around 180 degrees now. And I am going to throttle the ball vavle down to this one apt. I do not live in the building, its all rentals, its 40 minutes away, and I do not go there on any set schedule. Also every tenant has their own thermostat. I think that the best way to do this is to have less btus for the house so if windows are open then maybe they will get a bit cold and shut the windows. From now on all thermostats will be changed with new tenants to one that I have programmed to not go over 72 or 70 degrees.

In one unit we manage we got a call from a new tenant that had seen her first heating bill ever. She was appalled that it was 125 for a cold month. I thought that was pretty reasonable. It happened that she had lived at home, then gone to college, and this was her fist apt. The windows were closed my next visit. And the heat was set down to 65 degrees. Another instance we had a 4 fam with one boiler. People were constantly "airing out the apt". When we went to 4 individual boilers... no one airs out at all now.

I really wish metering devices were allowed so we could bill each apt individually.

John Cockerill

I would leave the ball valve allone for now. The reduction of temp should do the job. The resriction may just be to noticable. You might get an infrared sensor to see what your return temps are before fussing with the valves. It is so hard to tell the effect of valve adjustment with out taking a lot of time. Same for aquastat adjustments. "Exquisite Heat" technology takes care of all of that temp adjustment.

John Cockerill Exquisite Heat
www.Exqheat.com