thermostat options in multifamily rowhouse?

Jells

Even after reading many posts on controls I still don't have a clear idea of what is the best setup for my 4 family rowhouse with a basement studio and 3 identical apartments above.  Right now all there's only a thermostat in the 2nd floor unit. But the boiler was firing the other day when it was nearly 70 out. I don't know if that tenant had the windows open but I wouldn't be surprised at all. I believe he's a smoker, and he's not a dependable person. I need some redundancy.



Some folks here don't think thermostats averaging sensor temps in different units is a good solution. But parsing what I've read, I'm not sure it's that bad when the sensors are in identical locations in identical apartments, rather than in areas with different sun exposures, etc. I could average with another sensor in either the top floor or the 1st floor units, or both and lose the 2nd floor sensor. Or I could go the 2 thermostat in series route, so that 2 of the units need to be calling before it heats. In that case I suppose it should be the 2nd plus the 1st floor, which would tend to be cooler than the top floor. If the top floor overheated I could then add TRV's in that unit.



In his posts Clammy seems to think that a Ranco temp controller as a WWSD is a good idea to add in these situations too.



Thoughts?

Rod

Tekmar 279 Boiler Control / Thermostat

You might want to take a look the Tekmar 279. It has the capacity for multiple indoor sensors plus outdoor reset and warm weather shut down.

- Rod

http://www.tekmarcontrols.com/images/_literature/279_d_06.pdf

nicholas bonham-carter

best boiler control

if the outdoor temperature was nearly 70. and the boiler was running, then what was the thermostat set for?

a more economical solution would be the honeywell visionpro with remote indoor sensor. the sensor could be in the coldest corner of the house, and the control panel could be in a secure location. the sensors can be averaged in groups of four. the thermostst is steam settable, in it's setup. pexsupply.com is a good source for the thermostat and the extra gorton #2 vents you may need, and they have the tekmar 279 as well.

you could then spend the considerable difference in cost between that and a more elaborate control on making sure that your system is in tip-top shape. the steam should arrive at all the radiators simultaneously, which often a matter of good main [not rad] venting.--nbc 

Jells

Wow, that Tekmar is costly!

Thanks but I think I need to try cheaper solutions 1st. So no one thinks the series idea worth trying?



The requirment of the Honeywell that you use 4 remotes to average is a pain, I saw this Robertshaw that has a remote option with averaging, but doesn't have a steam cycle setting. Do I really need that? http://s3.pexsupply.com/manuals/1302550420353/53211_PROD_FILE.pdf

nicholas bonham-carter

sensor averaging

if you can get the radiators to get steam all at the same time you won't need the 4 averaging sensors. just go with one in the cold corner where the window will never be opened, and all will be well. if your system is badly deferred on maintenance, then be prepared for an investigation from the gas company into why your meter is reading 2/3's of what it used to. in our case they replaced the meter 2 months after we did all the work!

money spent on insulation will be paid back fairly soon, as well.--nbc

Jells

"steam setting" vs differential?

I'm still learning about all this, but BS with the tenant messing with the thermostat in his unit has already started and I need to change the configuration. Can anyone educate me about the difference between controlling cycles with a "steam setting" on the thermostat, and doing it with the differential setting? It seems like 2 ways to get to the same place. I'd really like to get the Robertshaw unit I referenced above, as it has a security lockout, and gives me the most flexibility and options since it can use just the remote, or average between the unit & remote, a feature no other unit seems to have. But it lacks a steam setting.



I'm thinking for my first configuration to try the 1st & 2nd floors in series, so basically the 1st floor (which should be cooler than 2nd) has to concur that a heat call is needed, so even if the 2nd floor tenant throws open the windows, there won't be a call till the 1st floor also calls. If that doesn't work well I can try averaging between floors 1 & 3.

nicholas bonham-carter

System balance

You definitely need a steam applicable thermostat. You also need a thermostat which will be unavailable to the tennants. The Honeywell visionpro with remote sensor in the place now coccupied by the old thermostat fills all of these needs. Averaging thermostats will not overcome any system imbalance, caused by deferred maintenance.

Check your venting, and pressure and get the steam into all the radiators at the same time, and get ready to save some fuel.--NBC