I had the original 50 year boiler and Beckett burner replaced 2 years ago with a L115-3 Buderus w/ Riello burner. The boiler sits on top of a 32 gallon LT series Buderus hot water tank that never was hooked up to the boiler. In addition I have the Logamatic outdoor reset sitting in a box. The installer of the boiler later professed he was stumped by the Logamatic so was never installed.
During this period of time to present I have gutted the kitchen, new windows, new doors, new oak floors, insulation, etc. so boiler updating was on back burner.

The house when first built was set up with monoflow system w/ small copper radiators with the second floor unfinished. The second floor had baseboard connected with supply and return to monoflow valves (sort of a hybrid). I had a plumber during this summer set up a second zone with the second floor baseboard with its own circulator pump and new returns and supply copper from boiler.
I have a electronic Honeywell aquastat L7248C that I would like to wire up to a Taco SR503 relay so I can supply heat to the second floor zone. I am presently heating domestic with a 40 gallon electric and want to start heating water with the boiler. I need help on how to make the wiring connections.

I am going to connect the (3) Taco 007-F5 circulators (one for each zone and zone 1 priority for domestic) to 120VAC relays.
I will remove the existing thermostat wire from Aquastat (T1, T2) and connect to (24VAC) on relay plus connect the second newly installed second zone stat to the SR503. Connect the wire from hot water heat sensor on Buderus LT indirect tank to priority zone 1 on 24 VAC (remove jumper from P & ZC terminal)

The above is straight forward now for the questions, the power from the Honeywell aquastat L1,L2 should be shared and wired to N,H of SR503?
Then assuming I am following the alternative wiring Tankless Boiler application I should place a jumper between ZC & X1.
On the L7248C aqua, ZR & ZC have no wiring connections as I assume they are soldered on the board. The SR503 calls for connection from X2 and ZC to the aquastat. Please educate me in this regard.
I hope in the spring to replace the L7248C aquastat with the Logamatic but first steps first. Thank you in advance for your heating wisdom.

 

I researched prior posts where NJ Trooper specified that X1 & X2 are dry contacts on the Taco SR503 and should be wired to previous TT contacts on the Aquastat.

My question is does the Taco relay get powered up from the Aquastat L1,L2 or from the safety shut off. Also is this a cold start or tankless application?

I was indecisive about the application because I was going to utilize a indirect hot water tank. The tankless application instructions on Taco relay specify that appropriate circulator energized only when the boiler temperture is above the set lower limit. I understand triple aqustats with Hi, low limits and diff but the L7248C does not have these manual controls

 

The SR 503 can be fed off either the service switch or L1-L2 of the
L7248. In your application, you want to follow the wiring diagram & instructions for a cold start boiler on this instruction sheet:
http://www.taco-hvac.com/uploads/Fil...ry/102-167.pdf

 

Grady, sounds good...thanks you for your advice and information, much appreciated

Jack