Need Tekmar XX terminal connected to the IBC boiler still once a buffer is used?
Good day
Do we remove this current "XX" connection to the boiler on this Tekmar 306V valve control once we install a buffer tank?
If I understand correctly, our IBC SL 10-85 G3 has some of a control/logic to turn the boiler burner on/off based on buffer tank's temp.
The Tekmar is basically going to be separated from the boiler. All it does is to receive heat call from room thermostats to open zone valves and run the system/radiant pumps
Thanks much
Comments
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I would say if your system resembles this you don't need the XX connection. If you explore other options like in your other thread the wiring may change.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
"If I understand correctly, our IBC SL 10-85 G3 has some of a control/logic to turn the boiler burner on/off based on buffer tank's temp."
That's the part you need to know. are you putting some sort of a sensor, or aquastat, temp probe of some kind that then connects back to the boiler?
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Generally the buffer runs at a fixed temperature, or at an outdoor reset temperature. Then the zone pump PS turns on when any zone valve opens.
The boiler should have a function and a sensor to go into the buffer to operate the boiler to maintain the desired temperature.
The boiler just sees the buffer tank as it's load.
What is your smallest zone? With a 10-1 turndown boiler you should not need much if any buffer. Unless you have micro zones way below turn down?
If you don't have it piped already a two or three pipe buffer is a better opotion for a buffer on a mod con.will
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Appreciate all feedbacks.
Our house is seven-zoned with only 2700sq ft. Two are less than 200sqft each. OR is in use always.2-piped buffer has actually been installed, but never explored the option of letting buffer's water temp dictate boiler's firing (which I think is a better approach as hot_rod alluded and not by room thermostats that we are doing).
I realize this IBC can do that since I can view buffer's temp. as well as with this setup. Just not sure if I need to disconnect Tekmar's XX terminal to the boiler or doesn't hurt to leave it?
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If the buffer tank does not have its own temperature sensor (or aquastat) in the tank and you disconnect the XX there is nothing to activate the boiler. You could try and see what happens. Just shut off the power when working with the wires, don't want any accidents.
I suspect presently the XX to the boiler stimulates the boiler's water circulation so the boiler's sensors see the water temperatures of the buffer tank since the water is moving. By disconnecting the XX there is no demand to start the boiler or the boiler's circulator.
I don't believe the boiler will randomly or even a scheduled event of turning on the circulator to sample water temperatures away from the boiler with the boiler's temperature sensors.
I assume your system has two circulators but you never know.
If this is the only circulator in the system then you presently need demand from a zone to run the circulator and start the boiler with the XX.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
I guess another way of looking at it, to analyze the situation, if you just shut off the power the Tekmar 306V only does the boiler maintain the buffer tank temperature ? Keeping in mind the Outdoor Reset curve and WWSD (Warm Weather Shut Down) may be a factor too.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
We have three pumps : DHW, Boiler, and System (radiant) which is connected to Tekmar.
There is a wall switch that powers off the Tekmar, but in doing so, boiler's power is also cut off the same time. There is not a separate wall switch for the boiler.
I can trace back to where the Tekmar's XX wire connects to the boiler as shown above.
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What is the purpose of the tekmar control?
The boiler and a basic relay box should run the entire system. The boiler handles the dhw, system pump and odr
An optional (tank) ) sensor it calls on the boiler to keep the buffer warm
The relay box controls the zones and initiates the zone pump
Some boilers can now control zone valve from the onboard control, if so everything could control from the boiler
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Indeed, the Tekmar 306V acts exactly like a 'relay box" that controls all the zvs and runs the one zone pump whenever room thermostats call for heat.
Pretty sure this IBC can't control all zvs and just am not sure and confused about what to do with the isolated end swith XX on the Tekmar. Do I leave it connected to the boiler (before with thermostats as the trigger) or need to disconnect (now with buffer water temp being the trigger)?
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the 306 just needs to turn on the system SP pump.
The sensor from the boiler into the buffer runs the boiler/ buffer assembly
Should also be a DHW sensor on the boiler for an indirect if that is in the mix.
If you run the boiler/ buffer via the ODR, then at 68 or 70f, or whatever you chose for the ODR low setting, the heating of the tank will end .
Look in the wiring manual that shows the sensor connections. Here is one IBC example, Add a sensor to the secondary loop sensor if you have this control. Some boilers ship with a spare sensor that would be connected there and go into the tank. The boiler pump, to the tank, should run when this sensor call for the tank to be heated.
You next need to get into the boiler control to set parameters, enable and program ODR, etc.
The SP connects into the 306.
The 306 does not need to send a signal to the boiler, it powers the zone valves and runs SP, that is all.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Great! Thanks very much for your response hot_rod and everyone's feedbacks, I understand it now, and in my case I do not have to use XX end switch on the Tekmar.
The sensor is in the buffer which the boiler looks at and it shows the water temp in it on the portal. I hope the IBC setup I have posted earlier should do it on the buffer control side.
I need to run the buffer temp a bit higher due to the type of emitter we have.
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This is wrong and makes no sense, trace it again.
If I had to guess, the terminals 9 &10 probably supplies the 120 VAC power to the Tekmar 306V. It is not connected to the XX.
I would expect the XX to be connected to one of the Thermostat inputs, Load 1 through Load 4 .
I'd venture to say with the system wired the way it presently is, if you disconnect the XX you will have no heat. DHW would probably still work.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
How is your DHW managed ?
What controls the DHW circulator ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
109A_5, the dedicated DHW circulator is wired here as a separate Load #3 under priority and all set up in the boiler's control on this DHW load
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Since you say the sensor is in the buffer tank, if the boiler can be configured so that sensor can be the demand stimulus it should work with the XX disconnected.
I find the manual very vague in this situation maybe there is another manual or I did not find the right paragraph.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Agree, 109A_5, there is actually nothing about third-party control option in the manual when you have more than 4 zones with 4 thermostats than what's allowed on the connection/wiring board in the boiler.
This should be the demand stimulus upon IBC's setup on its controller on buffer tank. They refer it as the "Secondary Loop". And "Temp. Sensor" is the buffer's temp sensor.
I have yet to trace how/where the Tekmar's XX is wired to the boiler. but I am determined to have another look when I have a moment.
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was the buffer just added?
If it was wired and plumbed without a buffer then the tekmar xx probably called on the boiler
It could be they were using the tekmar xx to switch 120 v the boiler
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I also could not find the association between the DHW sensor and in your case 'Load 3 Pump' or any circulator. Other than the boiler "runs a smart DHW routine". So it may search for a temperature change and electronically store the Pump that stimulated the DHW sensor appropriately.
Third party zone control via circulators and/or zone valves is quite common. Only more modern boilers have added that feature / functionality built in.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Buffer and Tekmar zone valve control are there all along since day one.
Five years after installation, just wanted to change the control logic to let the buffer controls the burner and not the room thermostats to turn on the boiler whenever there is a call.
I think boiler control is all set up to do that as posted and wired the system pump to 306V but don't want to pull the trigger by setting the Summer Shutdown (SS) real low and boiler not running until I understand how the XX connection works without damaging anything.But I can risk it to increase the SS temp to try and let the XX connect as currently is.
Right now, DHW works without any issue at all.
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" It could be they were using the tekmar xx to switch 120 v the boiler "
So the boiler is off (powered down) unless there is a thermostat call from a thermostat connected to the Tekmar 306V. How would the DHW work ?
And the way the OP drew it the XX would short out the Line and Neutral when XX closed. Which does not seem correct.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
109A_5, The boiler is just in standby mode when radiant heat is satisfied, but not powered down. DHW sensor is wired here on the boiler's control board.
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Disconnecting the XX safely and securing the wires so they can not touch anything else electrically and also not to themselves, should not hurt anything. Worst case if the XX is needed for climate heat, the climate heat would not work.
If so you could just connect them back up OR try to find (in the settings) if the sensor temperature stimulus can trigger the heat demand for climate heat.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Yes I believe that, which is why I believe your annotation of the place the XX wires are connected to the boiler is incorrect. I would think they (the XX) would go to one of the Thermostat input connections.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System
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Bingo! 109A_5 . You are right on! Ran down to the crawlspace last night and retraced the XX wires from Tekmar 306V and indeed the wires are connecting in the boiler here off the control board:
Didn't do anything then, but after work today, I am going to disconnect off either here or off 306V and watch how the buffer tank controls the boiler.
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