Twin Aerco boilers installed this week. Really like these boilers.

JohnNY

Have some details to complete (forgive the fresh air) since we rushed to get these in and working in a client's home during a cold snap here in NYC this week.



20:1 turndown, each boiler has redundant modulating gas valves (1 per section), inducer fan, ignition system, controller. These are beauties. Expensive, but beauties.



With two boilers, I can go from ~15,000 BTU to 642,000 BTU.

Armadillo

Thermostat

VERY pretty install!



I am just finishing up an install with my fitter whom I dragged into this modulating/condensing world.  I have two modulating wall hung boilers hanging on the wall and want to use an E8 cascade manager like you show in your picture.  PROBLEM: nowhere in a sea of manuals does it say in newbie-speak where to hook up a good old fashioned 7 day programmable room thermostat!    Wire-or'd to each boiler's thermostat leads in the cascade?? Or somewhere on the E8 pins???  [this issue is driving me NUTS]    Once I solve that my next question is about max water temp...I forced my pair to 120F but I gather you want the E8 to handle the turn-down and leave the boilers at 160 or 170F max?   For now I just wire-OR'd the thermostat's 2 wires across the 2 boiler{s} thermostat pins, no cascade management,  a call for heat gets responded to by both boilers set at 120F that STOP firing at about 125F after they'd been thermostated on AND water is below 120 setpoint at start of fire. 



Any ideas where I hook my simple thermostat?

Zman

Very nice

Nice work in a tight space!

I am curious what kind of combustion numbers you are seeing at low fire?



Too the second post, If you start another thread and provide the boiler model and type of zoning, you will get better results.

It doesn't work that well to piggy back a different topic.

Carl

Zman

Controls

John,

How did the controls side of this go? The manual looks pretty cryptic? Is it set as always on or a T-stat.

Carl

JohnNY

Armadillo

It looks like terminal strip one's 1 and 2 pins are for simple on/off space heating contacts.



I'm also just getting familiar with the control and have an open issue with tech support on how best to have the E8 control the boiler pump. They're telling me I need an external relay, I'm telling them my small pump is well within the tolerance of the A10 pump contacts provided, they telling me "it doesn't work that way", I'm asking why on earth not, I'm getting shrugged shoulders.



So, it's a process.



Meanwhile, I've got 2 more of these boiler sitting in another home being renovated, waiting to be installed. Again, I need to get more familiar with it, but so far I really like the boilers.

JohnNY

E8

The controls/wiring is indeed cryptic. It's from Germany and in their efforts to create a universal language, it becomes an exercise in hieroglyphics-to-practical translation.



See my comments above.

Armadillo

Your Pump relay, etc

A10 on the E8 can be defined numerous ways as you see, software-wise.

"IV (1): A8 = Mixer motor heating circuit 1 on/

Multifunction relay 1

IV (2): A9 = Mixer motor heating circuit 1 to/

Multifunction relay 2

IV (3): A10 = Collector pump 2/Switching valve to

solar tank 2/Multifunction relay 3

IV (4): A11 = Collector pump 1 (speed controlled)

multifunction relay 4"

  One thing about doing what they say is I'll wager the relay you want to use IS pretty small, and likely soldered in place, thus if it does die you end up swapping out the E8, or figuring it out and harvesting/desoldering the relay for replacement -- that is something I could do [the relay swap], but as you know, if you were on a no-HEAT call and a fresh controller worked...  I stocked another E8 as a spare because it is SO complex, and the heart of a cascade//outside reset situation.   I see various companies use the E8, some have better documentation than others, mostly just translated though. 



The FBR must be an industry abbreviation?  Or German for something?  The commercially available "FBR2" that mates to the E8 [and maybe I should buy] is documented thusly:



Remote control FBR2

Electrical connection: HC1: Connector I; 2, Ground and 3

or HC2: Connector III; 1-3



On connector III  FBR2 shows pin 1 = Licht 0-10V, 2= GND, 3 = IMP



in a different place in the docs  "The heating system can be switched to Heating mode h

with a telephone switch. The connection terminals of the

controller for the remote control FBR (see connection

diagram) are used for installation. As soon as a short

circuit between terminal 3 of the FBR and ground (FBR

terminal 2) is detected, the assigned heating circuit is

switched to heating mode.".  Again, I am inclined to throw in the towel and buy a FBR2, or,  the remote controller for the CanBus version of the E8 {only?} the BM8.  None of this was offered to me by the importer.  I'm not MAD it's just frustrating when the documentation is so "holy" and we're trying to get the E8 cascade controller GOING, which means placing the boilers in different modes at differing addresses and SOMEHOW calling for heat and proving that they both cascade properly...or I have to turn back, so I KNOW I can make heat.  My fitter is a wonderful man but *I* dragged *HIM* into it so FWIW I am consulting a professional... who's not been this ModCon cascading road yet.  Everyone involved is starting to see that GAS is likely to go up and that the savings day#1 with long slow full condensing fires vs my leaking 60YO? GE steamer??  



Yah I've been through the boilers pumps relay problem too; the Alkon 50 wall-mount boilers that ship with no pumps also do not ship with an easy way to power pumps, unless you break off empty sockets of a connector and stuff on gold female DB-25 socket pins -- lucky me I'm an IT guy. 



I also worry about these E8 being tied to the grid... one good hit? [I've seen lightning in Winter here]    No heating, and a huge mess.  I will use some industrial surge suppression at the panel feeding the E8, but I'd feel safer fully isolated from the grid for the boiler{s} logic boards and the E8.  ON THAT NOTE, one of my helpers flipped hot and neutral on the boilers power [after first doing it correctly], the failure-mode for that is the boilers will fire 2 seconds and fail to sense flame [hot neutral and the sensor is with reference to neutral/ground], THAT WASTED a day...boilers didn't know what to say about it, neither did the supplier.  



Thanks for replying John, I KNEW you'd done some E8 battles by now, I can see you plunked in a few!  By the way my install is an old 3000SqFt 2-flat but just one thermostat and we converted the old circa 1910 2-pipe steam mains to counter-flow return warm water...with PEX-AL-EX for the piping to the far ends of the old returns.  So one "zone"...I thought I'd use the old thermostat but golly, the docs do NOT spell that out definitively.  I'm not 100% clear on if I should use the included flow-sensor, well, many E8 related questions I'll pick away at once I can rely on it to do the core things: cascade and turn up/down, rotate boiler{s} firings, outside reset...   SO, I may hunt for the closest source for FBR2 or BM8, unless I can prove the simple contacts-closure method soon and easily. 



Thank you and The Wall SO VERY MUCH!!



-Pat

RobG

Nice Install

Very nice install especially for such a tight space. My only question is regarding the size of the gas piping, It looks awfully small for 300K plus BTU's? What kind of units were there before? It sounds like this is a residence, how big is it?

Rob 

JohnNY

The gas....

...is 2" pipe to within 6 feet of the boilers, where they reduce to less than 6' of 1" pipe.

Plenty of BTUs.