Packy Wrote:

the expandable 504 just means it has something like a telephone jack to plug into so it and another relay can communicate. you can still add a 502 for the new zones you just need to do slightly more wiring between them.
the 110V is marked just connect the two relays power together. the T-stats are clearly marked and the power to the circulators is also clearly marked. then all that is left is to connect the two end switches..
pretty simple..

the end switch from one relay is already connected to the boiler control to call on the boiler. simply connect the end switch from the new relay to the old relay end switch.
don't you remember the old days when there was no such thing as a multiple relay. there were a bunch of R845's all wired together in some fashion.





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OK, I pulled the cover off the controller and I do not have ANY wires connected to X X (End switch). The jumper between ZC and ZR is removed and I have a (14 gauge high voltage) wire connected to ZC that appears to run to the burner.

With this being said, can I still add an additional controller, by connecting the ZC connections between them?

That is not a normal connection. You have to figure out why that was done.Read the I&O manual for the boiler, and control.Usually with an advanced controller it can control central heating and domestic hot water, by itself. There would be a connection point at the boiler for an aquastat in the indirect water heater, and a connection point for the DHW circ. The TT connection at the boiler is for central heating and there is a connection for a circ, but you are limited as to the number of circs, so you add a switching relay. You're gonna have to dope it out.

I have a Buderus Logano G215/4 boiler with the Logamatic 2107 controller and Buderus indirect hot water hear.
The DHW is controller by the Logamatic directly (Not the Taco), and it has priority. When it calls for Hot Water, all the heating circulators get shutdown.

I also have an outdoor temp sensor into the Logamatic, so the heating curve is adjusted based on the outside temp.

Does this shed any light on my setup?



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start here and see if you can find out more..
[www.youtube.com]
the way i described is the only way i have seen them done.

OK, I did some reading of the Logamatic 2107 manual,

The R2107 is not a cold start control. It does not reply on a call for heat from an end switch or thermostat to fire the boiler. The boiler will maintain a range of water temperature based on outdoor temp.

The Wire going from the R21107 to the ZC (Zone Control) on the Taco is a 120V output used to energize the Taco Controller (which is why there is a jumper here from the factory) .

The end switch of the relay panel is not used. The Taco relay will "interrupted" under certain circumstances such as DHW priority or low boiler temp.

Bottom line is the Taco "doesn't care" what the boiler temp is, since that's managed by the Logamatic. If I am calling for DHW, the power gets cut to the ZC and the circs will not run.

So I am pretty sure I can just add another Taco SR402 and bridge the 2 ZC connections. I just want to do a quick check with my voltmeter.

i'm not an electrician but i would think you would run another wire from Z-C of old control to the power in terminals on the new control.
so, the new relay would be powered when Z-C sends it power and when there is a call for hot water there would be no power sent to the new control.
as i said, i am not an electrician..

That would make sense, but the book says that the 120V output of the Logamatic (feeding the ZC on existing controller) is limited to 5 amps and multi-pump applications require and additional source of power 120V power.

It seems as if the 120V power going to ZC is a reference signal, while it's still using the A/C input terminals for it's current draw.
Then again, the Taco circs only draw about 3/4 amp each,
I will do some testing with my multi-meter later tonight.

well then why not just pick up the power for the new relay from anywhere on the boiler circuit? run a 120V feed to the input on the new relay. the worst that will happen is the additional zones will run when there is a call for hot water.
I never recommend someone uses the priority function that kills all the heat when there is a call for HW. if you are away for a few days during a really cold winter blast and there is a call for HW and the circulator malfunctions, the house could freeze up because the heat will not run. just my 2.5 cents...

What is hooked up to T-T at the boiler? Where does the aquastat from the indirect go?

I hear ya Packy. I don't think I have a choice about that,
The Logamatic will throw an error if it doesn't see a rise in Hot water temp after 30 minutes (I think).

I have Wi-Fi T-stats so I can check the house temp from my smartphone.

This is the Logamatic. It has terminals for the domestic tank sensor, boiler sensor, outdoor sensor and room sensor (optional). All of which can be seen on the LCD display by turning the knob. No conventional aqaustat.


Here is a wiring diagram of the Logamatic and a controller




I found this picture online, although not my actual setup, it looks very similar.




Example view of Thermostat on iPhone (Not my actual pic)

ya gotta love those systems installed with no isolation flanges below the circulators.
also no shut off between the auto fill valve and the boiler.
whoever installed that system maximized their profit while not caring about the poor service person who follows.
the right way to do it...
or as my friend from SC calls it "best practice"

I can't figure out why they have that 120V output connected to the switching relay. At best, it would allow the controller to see more than the 5 amps max it is suppose to. Why not use the line voltage connection from the service switch to the SR. As a zone circ kicks on, the boiler will adjust its temp based on the outdoor and boiler sensors.

Packy, that looks nice. What's up with all of the gauges?
I don't have shut off valves below the circ's but do have a shutoff for the auto-fill.

After all of this hoopla, I think I am going to just go for a new SR506-4 and see if I can sell the SR504 on ebay or something.


Thanks for your time



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mike, the temperature gauges read the outgoing water temperature and the return water temperature. the circulators are 3 speed so the speed can be adjusted to keep the return water about 20 deg cooler than the outgoing feed water.

Hi,

i was wondering if BFU Room sensor could be replaced with Wi Fi controlled digital room thermostat and also what kind of relay needs to be hooked up between the R2107 and the WiFi room sensor to work flawless. Your help is appreciated. I had to ask the questio here because I had no one to ask questions about my buderus unit. No one seems to know how it works or so. Thank a lot.