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Swapping honeywell 8148E for Aquasmart 7600B

stormdrain Member Posts: 4
edited April 2017 in Thermostats and Controls
Hey all, I want to change to a Aquasmart 7600B. I purchased the unit, but before I make the change I want to make sure I am doing this right. I am a pretty solid DIY'er, but have minimal experience with heating systems / controls.

My setup:
Hydrotherm Gas Boiler (1994?)
Mizer / Johnson Controls M35BA-1 damper with 6 pin harness
B&G Pump
Single Zone system

As for the aquasmart -- L1/L2 and C1/C2 look like straightforward exchanges, but the damper controls aren't and I haven't been able to find a really thorough explanation of how to wire the vent damper. There are also two gas spill / thermal sensors on my unit that I don't know how to integrate with the aquasmart, and these sensors also tie into the damper.

My current damper has a 6 pin plug that will connect to the aquasmart. However, if you look at how the pins are configured it doesn't look like an exact match. Does this matter, or am I just grossly over-analyzing things?

This is my plug (notice where the vacant spots are in relationship to the vacant spots on the aquasmart):

This is the aquasmart (only one vacant slot on the plug, and my plug has two):

I have four wires going to my damper. The red goes to the spill switch that then connects to my burner:

The blue goes to my flue spill switch, and from then the flue sensor connects into B1:

White goes to Z:

Black goes to B2, which connects to BOTH the damper and the burner. So there are two wires on B2.

From the aquasmart manual:
B2 replaces TV
TW replaces T
TR replaces Z

My thoughts for plugging into the aquasmart are:

Plug in the damper control using the 6 pin connection as-is. The black and white wires from the current wiring harness "go away" since they'll be replaced by the plug on the aquasmart.

The gas spill switches are where I am at a loss. Right now they plug into the damper connection, but that harness is eliminated with the aquasmart. So, where do I connect the spill switches on the aquasmart?

A brief explanation of the exact sequencing of events, and how these components tie to each other would be helpful as well. I appreciate any input.



  • Fred
    Fred Member Posts: 8,542
    @ratio is a controls guy and may be able to help you.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    You just violated the built in safety with the L8148 and the vent damper. The L8148 has a fuse inside the wiring on the relay that blows on the first call for heat with the damper connected. This is required as a safety so that the system will not work if the damper is disconnected. The 6200B to the best of my knowledge does not have such a resister. You assume full liabilty should something happen such as firing against a closed damper.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537
    Tim, the damper still has to make end switch for the boiler to operate?
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  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    The fuse is still required.
  • stormdrain
    stormdrain Member Posts: 4
    Okay? I don't think I've violated anything since I haven't change anything yet. I am not sure what you're talking about. All I did was unplug the damper to see what I was working with and plugged it back in.

    Also, how does this help me connect the damper to the aquasmart correctly?

    Lastly, the 7600B has a fuse that pops once a damper is used with it. I don't know what a 6200B is, but that's not what I'm using. I assume that's what you are talking about...
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    Sorry my mistake on the numbers. As long as it has the fuse you should be all set.
  • stormdrain
    stormdrain Member Posts: 4
    No problem Tim. As I reflected on my post, I realized I really just needed one question answered (I think).

    How do I wire the the two thermal / gas spill switches to the aquasmart? Right now they both connect into the damper via a wiring harness. That harness will go away and the damper will plug directly to the aquasmart. That leaves me with a wire from each gas spill sensor that need do go somewhere...

    Apparently this isn't very common because I am struggling to find any reference to spill switches wired to the 7600B.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    They can be wired anywhere into the 24 volts to the gas valve after the damper. That way if there is any excess spillage the 24 volts will be interupted and the gas valve will shut down.
  • stormdrain
    stormdrain Member Posts: 4
    Awesome, that's exactly what I needed. Thanks!