Tekmar 260

[dougcarlo]

I have a brand new Tekmar 260 I bought around two years ago for my oil boiler that I have not installed yet. My wood boiler is currently installed in series with my oil boiler. I usually shut my wood boiler down around the middle of this month and fire it up around october. Can someone tell me what I would expect from installing the Tekmar, and what is outdoor reset? Thanks

 

[afblue]

I am not sure on the actual function of a tekmar 260, but an outdoor reset is a temp sensor control that will operate a modulating circulator pump or mixing valve, to control the output water of the system based on the outdoor temp. If the temp gets colder it speeds up the pump, or in the case of a 4 way valve it will turn up the heat of the valve.

 

[nate379]

Depends on how complicated your setup is. Simple outdoor reset will dial back water temp to reflect outdoor temp where a more complicated one will do that and can also throttle back the boiler (modulating boiler) and control mixing valve and/or variable speed pump.

Basic outdoor reset will adjust boiler water temp to reflect outdoor temp. In other words if it's 50* out and a T Stat calls for heat, instead of the boiler making the water 180* it might only make it 140*. And if it's -30* out, it would kick that up to your max water temp.

It helps save energy and also in the case of a slow reaction setup, like radiant floor heat, helps with temp overshoot (less stored heat in the slab)

 

[timberr]

Doug,

i run a Tekmar 260 on my system and I use a primary/secondary system. I have forced hot water through baseboards, and last winter I couldn't use the reset function because the baseboards where sized for 180* water. So when I ran cooler water (140*) the system just ran all the time. Last fall I converted to a more efficient baseboard and I am really happy with the reset function. My storage is lasting longer and the house is more comfortable. The Tekmar has an outdoor temp sensor and I have the other sensor on my secondary loop just before the circulator. When the temp on the loop is reach the supply circ (either storage or propane boiler) is turned off. I wish I had done more research and got the Tekmar unit that will actually control my propane boiler which is a modulating unit.

Good luck

 

[heaterman]

You want to watch yourself with the OD reset. A standard cast iron boiler should not be operated below 140* and depending on the "curve" you program into the 260 and the outdoor temp, it could easily fall below that. From what I can gather, the 260 is direct setback via limiting of the boiler itself, not through a mix valve or variable speed pump.

 

[timberr]

I thought about that, the heat from the wood boiler side comes from storage so the return water never return to the wood boiler. The manufacture of the propane boiler said as long as return isn't below 120* no problems. Still the lowest I have seen is 130* on the return side.

 

[nate379]

There is a min temp setting on it so you can adjust accordingly.

You want to watch yourself with the OD reset. A standard cast iron boiler should not be operated below 140* and depending on the "curve" you program into the 260 and the outdoor temp, it could easily fall below that. From what I can gather, the 260 is direct setback via limiting of the boiler itself, not through a mix valve or variable speed pump.

 

[Don2222]

Hello Doug

I also own a Tekmar 260 and really like it. The inexpensive Tekmar 256 is just an outdoor reset for for a boiler with no indirect DHW.

The Tekmar 260 can be used with Zone Valves or separate circulator pumps for each zone. The 260 also has a separate water zone for saving more energy when heating an indirect DHW tank. I recommend a SuperStor-Ultra for that. The "Post Purge" feature on the Tekmar 260 will dump the residual heat from the boiler into the DHW water tank after the a zone comes up to temperature! Pretty cool!

I also want to say that even though it will work with zone valves, it does work better with separate circulator pumps for each zone.

Anyways, the heat algorithm only heats the water as hot as needed to heat the zone, however if there is an Indirect DHW tank the min temp is approx 140 degrees F since a good 20 differential is needed to heat the DHW.

The baseboard can be Copper or Iron and there is a setting in the Tekmar to switch it from one to the other.

Here are the settings I use in my Tekmar 260 for southern NH. Your settings may vary slightly. Hope this helps?
I suggest you make a chart for your settings. Good Luck