Here is the relevant bit.

Here is a link that might be useful: zephyr's motor

I have looked all over that brochure and also at the installation manual and have still not located the place where they describe HOW the limitation is set. What am I missing?

Do any current models offer this technology yet? If so, which ones? Would think their model specific documentation would address this.

foodonastump: yes I know at least the Venezia has DCBL, but the details get lost in the marketing-speak as quoted by kaseki above. I couldn't find flow rate setting instructions in the installation manual, so not sure where else to look.

gigelus: control "via jumpers"? Is my GC going to know how to do that if there's nothing in the manual? (On the other hand, if we can't figure it out, I don't suppose the inspector will.)

I'm not worried about safety as we have no combustion devices in the house other than a wood stove and it has to have some sort of passive vent near it that allows air in-- not sure how that works until I see it. I'm fine with using the vent hood on the low and quiet setting the vast majority of the time and cranking a window open if we need it on full blast.

I see there is a link here to a MUA system, but it shows a typical installation that includes a furnace with ducting. We'll have hydronic floors, so I don't know if this is even relevant or if so, how it would be installed. These requirements are new in our county and neither the architect nor GC have had to deal with them much yet,if at all.

Here is a link that might be useful: Zephyr Europa Venezia

Oh ok, you're reading it as all models with DCBL have ACT. I didn't read it that way, but you may well be right.

What is less ambiguous to me is the "without compromising design" clause. Obviously that just means the same hood can work for different CFM requirements.

Unless very tightly sealed, wood stoves and manufactured fireplaces will backdraft if the hood can move more air than the stove/fireplace MUA duct can supply at a pressure difference (probably about 0.04 in. w.c.) between the chimney top and the fireplace hearth. In other words, a three or four inch duct isn't going to compete successfully with an 8-inch duct and fan unless there are other sources of MUA that supply air at the low backdraft pressure difference.

A window screen could cause enough pressure drop to allow backdrafting when both hood and wood stove are operating. None of this is easy to analyze, so experimentation is called for. If you intend to cook and have a nice fire going at the same time, plan for a possible future upgrade, even if manually controlled, to force air into the house.

kas

Ok, confirmed with Zephyr. All DCBL models have ACT. Adjusted by moving a jumper on the control panel.

Thanks, foodonastump! That is what the salesman at the appliance store told us a few months ago, but I'm glad to hear it verified. (Now if someone could just tell me what a jumper on the control panel is and how one would adjust a setting on such a thing!)

Kaseki, thanks for the insights. The woodstove is a modern one and should be tightly sealed, but in practice, I don't know how it will perform. Understand about the difference between the 3" passive and the 8" plus fan situation, though! We will have a separate HRV system, but I think those are also not very high cfm. I'm still thinking opening the kitchen window during the rare high-fan use will work, but I agree about the need for experimentation. (We probably won't even install the screens on the windows. I know it sounds odd, but we have so few bugs here, we don't use them now.)

foodonastump, I got your email, but could not reply as your settings don't allow it!

Thanks I'll have to check that. In the meantime you can click on my username and email me straight from there and I'll respond.

A jumper is just a removable short. The control board will have a series of pins onto which to place the jumper. I bet that CFM numbers are printed on the board so you will know where to insert the jumper to get your desired max-speed.

Here is a link that might be useful:

Thanks, gigelus. The picture helps. Zephyr responded to foodonastump with a page that I never found in the installation guide, but it was just a sketch. It looks like something pretty simple to move, if needed. Thanks everyone who responded. I think this is what we will get. Hope this is useful to someone else someday because it was not easy to figure out!

Duplicate. How in the world did the little one manage to post on GW when fiddling with the tablet is beyond my comprehension!

This post was edited by gigelus2k13 on Mon, Oct 7, 13 at 1:31

Have you tried calling Zephyr? I felt they were very responsive to some of my basic questions. I was told by a local appliance store that I didn;t need an MUA so I didn't pursue questions about that but I would guess, they could explain it to you

thanks CT-- I think we are going to be able to make this one work. I haven't found anything I like any better, anyway, and the adjustability of the max cfm is a plus. It seems like it will be really quiet on the lower settings as well, which is how it will get used 98% of the time.

Here is the relevant bit.

Here is a link that might be useful: zephyr's motor

Little one at it again? :)

Resurrecting an old thread, but thought I'd contribute more current information. We're planning a kitchen remodel and were looking into an island hood to go above a 30" induction cooktop. We currently have a really old Jenn-Air downdraft system which is noisy and fairly ineffective.

We wanted something that looks good and will do better than the downdraft in removing steam and cooking odors. Another important consideration is noise, which led me to Zephyr hoods and the DCBL motor. The hood we're interested in (Modena) has a 715 cfm max pull. We're not sure what our downdraft pulls or if we need MUA, as we have a 1958 house that is pretty leaky. We had an energy audit done several years ago and when they hooked the test blower up in the front door, they asked if we had a window open somewhere.

After reading the above thread and the part about setting max pull through jumpers, I gave Zephyr a call today. It sounds like this process has changed a little. Apparently the instructions to limit the max pull only come with the hood (not published online). And here's the kicker: you can only set the limit on the max pull once and that setting is permanent, so if you decide you're going to put in MUA later, you are out of luck. You can't go back to a higher cfm setting.

Also, this hood has 4 fan settings (250, 390, 590, 715). If I set the limit to 390, then I only get two settings (i.e., it doesn't reset the four levels so they max out at 390).

Bottom line is that we'll probably put the hood in, leave the ventilation settings as is, and not use the top levels, just in case we want to put in MUA later if it turns out we need it.

Brett, that does not sound right unless the jumper becomes physically inaccessible after the installation of the hood. i am going to call them to find out.

I suspect they aren't using jumpers anymore. My guess is that they are using an embedded controller where the max setting is "burned" into the firmware. I'll be ordering one of these hoods in another couple of weeks, so I'll find out soon. I'll probably order their MUA damper, since we have an HVAC intake air plenum that is easily accessible in our attic.

Aha. makes sense. I called and was told the same and it has to do with code enforcement. I guess, only quick way to change it is replacing the control board. We don't have a MUA provision unfortunately.

Yikes! Next we'll learn that the control board can only be replaced if it is shipped via the local Code Enforcement Office.

In a couple of other recent threads, jwvideo has noted the utility of using CO sensors near combustion appliances to determine whether they are backdrafted at maximum hood flow rates. Such an attempt, if the results are negative, might convince the Code EO to accept that you have enough MUA. Towns and municipalities are not likely to have sophisticated equipment for testing pressure drops and just want to see that there is an MUA system, perhaps as little as an outside duct with a damper. Hence, in many cases the MUA system that you add for compliance can be modest, so long as the backdrafting risk is demonstratively avoided.

kas

The zephyr typhoon that I just installed last week uses jumpers. Zephyr may have a different definition of "permanent" than most people. For my hood it just involves taking the bottom cover down and accessing the jumper. It would be a 10 minute operation.

Barnaclebob, can you please spend 10 mites and verify that you can switch CFM as you wish by moving that jumper. I have deal with jumpers in PC motherboard, so I am not afraid of tweaking that.

Here is the instructions on how they do it...

If you look at bullet point 4, it says you can not change cfm once you lower the cfm settings on jumper. Is that really true?

On topic, Zephyr charges $100 for these control boards; what a rip off.

Yeah I see that now. They must have something in the software that makes it irreversible unless you know how to reset it.

Has anyone talked to Zephyr about this lately? Our inspector says we can use the full 650 CFMs but it was installed and first powered to limit it to 390 CFM. I'm wondering how to go about increasing/resetting the limit back to the full range.

As far as I know, it cant be done but you can call Zephyre and tell some sob story get their version of truth. It's like one time deal to reduce the CFM. I am planning to install it at 650 cfm and will not change a thing until local CO makes any fuss.

I am about to purchase a dcbl zephyr and want to install it correct and want to not be limited to any code cfm requirements. Can I just leave it alone ? I want full range of cfms.

Mine (Modena) shipped with full range of CFM out of the box. You only make the adjustment if you need to cut back the flow (permanently).

Another interesting thing we found with this hood: we have a relatively low ceiling to work with, and we ended up cutting the frame down to get more room between the counter and hood. We could only free up more room by moving the control box from its factory vertical orientation to a horizontal one. Yet there didn't seem to be enough cable available to do that. Hey, let's remove the cover on the control box and see what's inside! Look, lots more cable! Move that extra cable outside and presto, horizontal orientation (you do need to fabricate a mounting bracket for the box in this case, but Zephyr gives you enough extra metal pieces to make that simple).

Thanks for the heads up-just did my research on make up air requirements-looks like i may have to install a make up electric air damper of about 8 or 10" on the outside wall and interlock it with the hood blower and attach it to cold air duct return on furnace so the air for making up 600cfm can be drawn from outside thru cold air registers which with damper open will pull from outside. its that or go and limit the fan to a level that wont pull ashes out of my woood burning nat firplace 15f t away. or go with a 300cfm vent a hood or similar

Reviving this thread again. Are folks with the Zephyr DCBL / ACT hoods happy with them? I'm thinking about a Tempest 1 or Tempest 2.

Other options I'm considering are Zephyr Gust w/ baffle filters, or a Wolf Pro Wall Hood with the 300 CFM blower. It will be above an induction range, so it is important to me that blower is small enough that no make-up air is required (and my locality strictly enforces these things). Which is why the Zephyr ACT set to a max of 390 cfm is looking appealing at the moment.

Our Modena has four speed settings. On 1, it is barely audible. 2 is a little more noticeable, but not intrusive at all. 3 is louder, but you can tell it is starting to move the air. On the top setting, it starts getting loud.

Ours is above a 30" induction cooktop (island hood). The top speed setting can just about keep up with a home-brew wort boil, which is moving a lot of air at that point.

Nice, thanks for the feedback.

Another data point- we have installed Sienna model over our gas range, about 30 inch from the range top. The hood works very well at settings 3 and above which is what I need. The touch buttons are little wonky and it did not get any better after a replacement under warranty. The touch sensors works erratically everytime I clean up the surface.

Thanks for the info.

Wondering if it's possible to get an update from anyone - I am considering the Zephyr AK9440AS and want to know whether there is any way to reset the board after setting the speed. I really would like to retain the option to add make-up air at a later date.

There is no known way to reset it without replacing the board. Why do you need to derate it anyway? I would take the chance that the inspector wont notice it. If he does, see if you can find a fake jumper that wont actually make electrical contact or something.

Inspector insisted on us lowering our Tempest 1 down to 390 with the ACT. Our house is very far from sealed, so I don't think MUA is really an issue. Apparently there's a new inspector who is now enforcing this.

Am I stuck having to replace the entire board if I want to add MUA and get back the full CFM? Has anyone actually tried to just switch the jumper position? I'm curious if the language Zephyr uses in its install material is just to cover themselves. Or does moving the jumper actually alter the firmware on the board?

Nk Gerber, I'm wondering which Titan model you have? We are looking at purchasing the Zephyr Titan 42" AK7642AS to go over a WOLF CT36G/S that has been converted to propane. Wish I understood more about MUA and wish that I could comfortably trust local contractors to install it correctly.

NK-- have you continued to have success with your ACT reset now that's it been a few months?

Has anyone else had success with this?

Thank you!

I have a Zephyr Typhoon undercabinet hood (850 cfm) that was reset to 390 cfm (on accident, by the contractor who installed it). Per our city inspector, there was no reason we couldn't have the higher cfm. I tried resetting the jumper pins to the original settings on the control board, but that didn't reverse the cfm limit to 850.

After multiple calls, we obtained new parts from Zephyr- a new control board and a new switch assembly (the part with the buttons that you press to increase and decrease the speed). I replaced the control board, and surprisingly, the new control board did not reverse the cfm limit to 850. I then switched back to my old control board so I could play around with it. I connected the new switch assembly to the old control board, and that was what actually made the cfm limit go up to 850.

I'm sharing because my experience with the Zephyr Typhoon is that you can reset the ACT by changing the jumper pin location on the board and replacing only the switch assembly. A new board was not necessary, and in fact, I have my old board in there now with the new switch assembly. My fan is working nicely at 850 cfm now!

Thanks, HandyLady. Did Zephyr require any documentation that the higher CFM was allowable before they sold you the new parts? Do you mind sharing what you paid for them? I have a Zephyr hood that can go to 600CFM, but the city won't let me use 600 (and wants me to cap it to 400 or get make-up air) because they're counting our brick fireplace/chimney as an "appliance" capable of exhausting air from the home, even though we have no other gas appliances inside (water heater is outside in an AquaHut). The fireplace doesn't even work (needs a couple grand in repairs)! So, I'm looking at finding a way to change it to 600 after inspection because, in the spirit of fairness I still would be within limits as if not having a fireplace (closed and not used is just as good as not having one).

Dave M- Zephyr did require our town inspector to send a note to them saying that it was ok to increase the cfm to 850. I don't know how much the parts would cost because Zephyr graciously sent them free of cost (because the contractor who installed the hood was playing around with the jumper pin on the board and accidentally set the cfm to a lower limit). I'm not sure why they sent both the control board and the switch assembly though, as only the switch assembly was necessary to reset the cfm to 850.

@Nk Gerber Thanks for the steps for resetting the board back to factory default. I was just not too clear about your step 3:

3) remove the ACT jumper from the pins and install it on the pins labelled CN3 (right by the speed pins)

Is this CN3 the original factory jump position or it's a separate position? I have a Tempest model and am thinking to do the similar thing.

FB Wu do you have any success on resetting your tempest model to factory CFM?

Nk Gerber, thanks for the instruction to disable ACT. I had a make up air put in when we bought our Zephyr AK2100 4 yrs ago and the contractor set the CFM at 390 but told me I could switch the jumper to get it up to 715CFM. 2 yrs ago, I noticed the vent is not pull as mich air as before and I did shut the power then switch the jumper to 715 CFM configuration but noticed no difference. I called Zephyr and the technician told me to press the power button for 3 second and I saw 390CFM on the display. He said ACT was enabled and the only way is to swich the motherboard and the switch which will cost ~$250 (no refund and no quarrantee that it would work plus i need to provide a letter saying I have a make up air put in by my contractor). I read your post here and simply pressed the two outer buttons for 5seconds and magically the display showed 715CFM. I then tried turning the vent on and when I imcreased the speed to the highest setting (6), I heard a significant louder blower sound with the diaplay now showing ”burst”. I want to thank you for sharing this tip as we have been dealing with a smelly house every time we cook as I have a 6 burner total aboit 120,000 BTU range so 390CFM was not cutting it. Thanks.

How do you know if your CFM is limited by ACT? Would the higher speed level on the switch control board not work and stop at speed 3 or 4 (if the hood has 6 speed levels)?