Tekmar 279 indoor sensor location question

delcrossv

We're finally going to bite the bullet and put a 279 in our 4 flat. Question is, what's the best location for the two indoor sensors.

The building has a warm side (over the boiler) and a cool side (opposite the boiler). The apartment right over the boiler always runs really warm, even with the slowest available vents, while the upstairs apt on the far side runs as much as 10 degrees cooler.

So, do I put the sensors on the cool side and average those, or average the hottest and coolest apartments?

Thoughts from those who have these?

EBEBRATT-Ed

I am under the impression that with a 279 one sensor is the indoor condensate temp and one is outdoor air temp. If you have two indoor sensors I have not seen those.

The one I am familiar with is with and outdoor air sensor located outside on the north wall of the building away from the sun.

The indoor sensor goes on a condensate pipe the farthest distance from the boiler

delcrossv

EBEBRATT-Ed said:

I am under the impression that with a 279 one sensor is the indoor condensate temp and one is outdoor air temp. If you have two indoor sensors I have not seen those.

The one I am familiar with is with and outdoor air sensor located outside on the north wall of the building away from the sun.

The indoor sensor goes on a condensate pipe the farthest distance from the boiler

Yep, it has those and two more optional indoor temp sensors. Outside, condensate, Room1,Room 2.

E.g. Tekmar 077.

KC_Jones

Are you installing this to try and balance out the differential of 10 degrees that you mentioned?

Dave in QCA

I installed a Tekmar 279 over 10 years ago. It is on a 1910 2-pipe vapor system. I used two indoor sensors connected to room 1 and room 2. I set the control to follow the coldest sensor (not the average) I put one sensor in the largest space on first floor, south side. This room is a above the boiler room and also has a lot of southern glass exposure. The other sensor is in the largest room on the north side. It too has a lot of glass exposure, but never any sun. The north room always runs the coldest, unless we have a few days of cloudy weather. Then, the rooms will be the same temperature. If we have a continuous breeze out of the south, then the south will be the coolest and that sensor takes over.

I have one outdoor sensor, one condensate sensor (actually end of steam main sensor) and two room sensors. The building is tight and well built, plus the original radiation is excessive, as they usually did in those days. As a result, the general settings on the Tekmar had to be set quite a bit different the the manual suggests to achieve proper operation.

I have been very happy with the device. It seems to do a great job of heat anticipation and runs steam cycles in a manner that the radiators are always comewhat warm and the space temp is even, with no perceptable fluctuations in temperature.

I do not use the nighttime set back.

I would be happy to share the settings that I have used, if that would be of help.

delcrossv

Thanks Dave, that would be a big help.

Dave in QCA

Here are my settings.

Room 71

Outdoor design. -10

Boiler. 50%

Indoor design 60

Cycle. Auto

Steam established 190

Lockout 5f

Wwsd 50

F/C = F

Our building has tremendous mass, all masonry walls and partitions, reinforced concrete floor structure at all levels.  These things affect the characteristics.  

Hope this helps you. 

delcrossv

Great! Thanks!