Hi,
I currently have a pretty simple one-zone baseboard loop with a regular dunkirk gas boiler. Last winter the aquastat on the boiler failed and I replaced it with a Beckett AquaSmart aquastat.
Recently I decided to change my current 40 gal electric water heater to an indirect one. I also got a good deal on 1 year old Buderus S120 tank + circulator, so thats what I will be using for the indirect.

The water heater didn't come with an aquastat so I know I will have to buy one, but before that I'm trying to figure out how to connect it to Beckett Aquasmart(which has indirect priority) The schematic in the Beckett manual shows the circulator pump for the indirect connected via a zone relay. That all make sense, I could just buy something like a simple L4006 aquastat+Taco SR501 relay. However, that solution seems a little clumsy(also not cheap)

My question is, is there an aquastat I can buy for the indirect tank that will also control the circulator pump or is the solution described above my only choice?

 

Unfortunately, that's your only choice... even if there was a DHW aquastat like that, it would be basically the same thing...

When you install the indirect, make sure you install the proper check valves in the correct positions so that you don't get flow through the indirect when the zone pump runs.

 

I figured I would post some pictures from the install, since someone might find it useful. Few notes: * T&P pipe wasn't complete at the picture time, but has been added since.
* I reused the boiler circulator but I didn't realize that it didn't have IFC built in, so there's some flow from the indirect to the heat zone(which actually kind of works out well as the bathroom is the first room there and it needs more heat)
* There's more heat migration from the indirect then I'd like it to be(even though there's heat trap piping) I suspect it's more due to expansion.

 

What's the plan to stop this in the summer when you don't want ANY heat in the home?

Your 'five finger tool' tells you this by feeling the pipes?

You may be right about the expansion. The heat trapping on my heater is much longer than yours, essentially going all the way to the bottom of the tank before turning and going into the crawlspace to the fixtures. I feel warm pipes on BOTH sides... the hot side is warm almost to the point where it turns horizontal, and the cold side is warm about 1/4 of the way down (of course only after it's sat with no cold entering the tank)

BUT, I doubt you are getting anywhere NEAR the kind of migration you would if the pipes were going straight up!

Khoroshaya rabota !

 

The hacky way is to close the ball valve at the purge station.

More appropriate way is to install a circulator with IFC. I have also heard that all taco 007 circulators allow adding IFC inside, but I do not know if that applies to black(boiler manufacturer supplied) pumps.

 

I can't say if that's true or if it's not... but if it were true I can't see why the OEM pumps would differ.

Is it even possible to purchase a replacement FC valve for the 007 ? I've never looked, or tried.

 

Taco 006-047RP IFC Replacement Kit for Taco 003-009 00R Circulator Pumps

All my new 007-IFC's are installed. I'll check papers later but iirc they discussed just popping out the IFC if needed. I don't know if my old 007's had what must be a groove for the O-ring to sit/snap in.

Speaking of expansion- I don't see in the pics a potable water expansion tank on the cold water side feeding your indirect. If you don't have it, you want to get it!

 

Only imperative if there is any form of check valve between the city supply (presuming you have city water and not a well) and the home's domestic piping.

If there is no check valve the pressure from the tank heating will be absorbed by the city supply.

MOST of the newer water meters DO have built-in check valves.

If on a private well, in general, the well system's pressure tank has the capacity to absorb the pressure from the water heater.

It's never a bad idea to know what the domestic system's pressure range is... could check it, just to be sure, with one of those screw on the hose bib gauges with a 'lazy hand' that will record the highest pressure it sees over a period of time.


image courtesy homedepot.com