Heating Help

Burnham Plug and play

I recently installed a Burnham MPO IQ boiler with a Vaughn Indirect Hot Water Heater. I want to intall (Plug in) the outdoor temperature reset but my electrician says that he thinks I need a relay so that the indirect gets to the proper temp. I have a Tacco box. I think I should just be able to plug in the Outdoor reset and have it function properly. Does anyone have any experience with this?

IQ Card

The outdoor reset card has priority built into it. Terminals 3 & 4 on the card. You use ZC ZR in the IQ control to power the domesitc pump. The installation manual gives clear directions as well as the wiring. Suggest you take a few minutes to review it and then pass it on to the electrician..

Burnham

Im assuming your using the 'outdoor reset card'(102294-01)
If you look at the card, or page 44 IO maual, there should be 4 terminals, 1+2 are the outdoor sensor, 3+4 are for your DHW aquastat. I'm sure the IQ board is smart enough to go to hi temp with a DHW call.

It is

we've used that card in just the way you describe. But, at least on the version we got,  you do need a relay to start and stop the indirect's circulator.

Honeywell's RA832 or R845 is good for this since it has two contacts. One is line voltage for the circ, fed from the relay's power feed, the other is low-voltage for the indirect priority on the plug-in card. The indirect's aquastat wires to TT on the relay. When the indirect calls, the relay sends line voltage to the circ and closes the low-voltage contact for the indirect priority, which lets the boiler tamp max out and stops the main system circ for up to 90 minutes while the indirect is calling.

Re: Plug & Play

Hauss,
Wire "TT" terminals on the TPI control on the Alliance SL to terminals "3&4" on the Outdoor Reset Card.  This provides a domestic demand to the boiler. The Outdoor Reset card has a separate Domestic Set point, so when it senses a hot water demand, it can raise the boiler temperature to ensure it can make plenty of hot water. Sounds like your electrician may be overlooking this feature.
Wire the circulator for the Alliance SL to the Purple & White wires in the junction box of the MPO-IQ, and the boiler will control the circulator without needing any other relays or controls. You can then utilize the DHW Set point, DHW Priority, & Priority Protection features in the Outdoor Reset Card.
The only reason you would need to add the taco relay you mentioned would be if there were more heating zones that you needed to control. If you have one heating zone, and the Alliance SL, you don't need any extra controls.

I've attached two wiring diagrams to show how this is done. One uses a zone relay for additional heating zones (Drawing 3.4), and the other (Drawing 3.2) does not include the zone relay.

Steamhead...the MPO-IQ has two circulator relays in it, so this can be done without adding extra relays. Currently the ES2 and Series 3 boilers control one circulator, and would require a second relay for the DHW pump. Notice that I used the word "currently" here! The scenario you described would work for the ES2 or Series 3, but the built-in second relay on the MPO-IQ makes it a little simpler.

Hope this helps!

Excellent!

Burnham really is "on the move" here. With the new setup, that's one less item we need to install.