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Need help with our Heatilator gas direct vent fireplace

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by tsand, Nov 14, 2007.

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  1. tsand

    tsand New Member

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    We have a Heatilator direct vent gas fireplace model NB3630. It was installed 1.5 years ago by the builder of our new home (Lennar).
    The fireplace is on an interior wall with a fan, direct vented up to the roof. room is 20 x 20 with two story high ceiling.

    Our issue is, even after hours of use per day, the fireplace doesn't seem to produce much heat. Also, the flame is only 3-4 inches, just barely clearing the log set. You have to stand at leat 1-2 feet from the fireplace to feel the heat.

    We have complained to the builder who had the contractor that installed the fireplace to come out and look at the box, they say all is working as it should.

    We have thought about replacing the fireplace with a furnace rating unit, but because of the smaller box size of the Heatilator, we can't install a much larger unit without tearing out the wall and mantle to re-frame.

    My question are

    What should we expect for heat on this unit? Shouldn't we feel heat 4-5 feet away?

    How can the heat be measued?

    Should we get a third party to check the fireplace?

    Can we turn up the flame and get some heat?

    If this is all the heat we can get, does anyone have suggestions on how to change out the unit with something that will produce some real heat, without re-framing.

    thanks

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  2. jtp10181

    jtp10181 Minister of Fire

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    Ok... lets get some terms straight, it is NOT an insert, it is simply a gas fireplace. Inserts get "inserted" into other fireplaces. This is a built in prefab gas fireplace box. Second, it is NOT "direct vent", I can tell by the "B" in the model number that it is a B-Vented fireplace. What this means is that when it burns it is using room air for combustion. And it also pulls room air out the chimney through the draft hood ( similar to an open wood fireplace). This is why you get very little heat out of it. If they had installed the "ND3630" you would get quite a bit more heat. It would still not be an amazing amount of heat (with the ND version) since this is basically the smallest and most basic Heatilator gas fireplace available. As far as heat output goes, the one you have now probably has the LEAST heat output of ALL the Heatilator gas fireplaces. Also about the flame height, that is probably as tall as it gets, there is a certain HI pressure setting set from the factory that should not be exceeded. The tech probably verified it was set correct when he came out. Turning it up higher can make the firebox get hotter than it was tested for and cause it to warp or crack. It could also heat up nearby combustibles too much and start the house on fire.

    To change the unit out without re-framing.... your easiest would be to go with a Heatilator ND3630 which is direct vent and gives a much better efficiency rating. You also could upgrade to a Heat & Glo SL-350TRS-IPI or a Heat & Glo SL-550TRS-IPI-E (whichever fit in the hole better). Those units will put out much more heat and also have a better looking flame.
  3. tsand

    tsand New Member

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    Thanks for setting me straight, but if you will re-read my post you may find that I never said anything about an insert. But I am incorrect about the venting, it is a B Vent fireplace.

    Her are my questions:

    How can the heat output be measured? Even though this is a "decorative appliance" the heat is way to small for the amount of gas burned.
    Should we get a third party to check the fireplace?
    Can we turn up the flame and get some heat? I am not sure how turning up the flame could heat up conbustibles as the installation instructions for both the NB and ND are exactly the same.

    Lastly how much to change the venting (approximate) from B vent to Direct vent. The current venting is straight up the wall to a second story roof vent.

    thanks
  4. jtp10181

    jtp10181 Minister of Fire

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    Wow I could have sworn the topic said something about an insert before.... anyway...

    You could use an infared temp gun to measure heat I guess... but what will you compare it too?

    What would a third party do? I doubt there is anything wrong with it.

    The flame is probably already set to its MAXIMUM setting, you can check underneath for the HI/LOW knob and make sure its on HI. Messing with the valve itself and turning the flame higher than the factory set maximum would be a safety issue on both the NB and ND models.

    You cannot simply change the venting, you would need an new fireplace as well. With the direct vent you could vent right out the side wall, it would probably be a couple thousand at least.

    You said yours is "decorative" which I am not sure of since I don't usually deal with B-Vent units, but I know for certain that the Direct Vent units are "heater" listed. I thought that most of the B-Vent units were listed as "heating" appliances as well.
  5. thechimneysweep

    thechimneysweep Minister of Fire

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    The Decorative listing is the giveaway. Fireplace manufacturers like Heatilator need to offer fireplace models for use in warmer climates and other instances where just the atmosphere of the fire, not the heat, is the goal (think Florida or Southern California, or an installation in a hotel room, for example). Decorative-listed fireplaces are designed to spill the heat from the fire out the chimney, and there's nothing you can do to redirect that heat into the room except trade out for a heater-rated unit.
  6. tsand

    tsand New Member

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    Thanks for the information.

    In our installation the stove is in an interior wall where the fireplace vents straight up through the roof. The fireplace is on the ground floor of a two story home. Any general cost estimates on how much $ we should expect to Direct Vent for a replacement stove?

    Also, a previous poster mention a heatilator ND model to replace our current stove as well as a Heat and Glow model. Would you have any other brand suggestion to replace this small fireplace without having to reframe the wall?

    Thanks
  7. thechimneysweep

    thechimneysweep Minister of Fire

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    20' of 4/6 Coaxial Direct Vent Pipe will run you about $350.00, with flashing, storm collar and cap. Sorry to say, our smallest gas fireplace needs an opening measuring 37-1/8" wide. Presuming your builder framed your opening at 36" (the minimum size for your fireplace), none of the fireplaces we carry would fit the existing framing.
  8. tsand

    tsand New Member

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    Thanks for the pricing, it is helpful. You are correct in that the opening on our unit is framed at 36 inches, with a 15 5/8 depth.

    The the heatilator NB 3630 unit has an Input Rate at 20,000 Max btu and a 14,000 min btu for NG. We live at 7000 ft so I believe that we have to decrease that output by 4% for every 1000 ft above 2000ft. Or in our case 5000 ft or 20%?? Is this contributing to the low heat output?

    Also this unit uses tempered glass. The sales person at the local Heat and Glow dealer said that buying a fireplace with Cermaic glass would make a big difference in output as well. Would this make sense if we kept the current unit?

    Lastly, the ND3630 is a direct vent with the same Max/Min Input rate of 20,000/14,000. it has the same dimensions are the NB3630. It would cost me about $1500 dollars to change the venting and switch the fireplaces. For the money, how much warmer would this unit, or any other Direct Vent fireplace be?

    Thanks
  9. thechimneysweep

    thechimneysweep Minister of Fire

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    It doesn't look like the direct vent version will give you much heat either. I had a peek at the installation manuals for both the B-vent and the D-vent versions, and both bear the same disclaimer:

    NOT INTENDED FOR USE AS A PRIMARY HEAT
    SOURCE. This appliance is tested and approved as either
    supplemental room heat or as a decorative appliance. It
    should not be factored as primary heat in residential heating
    calculations.

    Heatilator doesn't list any heating efficiency numbers for either model that I could find. If heat is your goal, I'd be looking for a different unit with a higher btu rating and a listed heating efficiency rating of 75% or better.
  10. jtp10181

    jtp10181 Minister of Fire

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    Almost all the HHT fireplaces have that disclaimer, because even if its heater rated it is for ZONE heating. I could check out efficiency ratings for both models later. I would recommend something like the 350TRS though for better heat output. Also you don't NEED 20' of venting, you can just 90 off the top and out the side wall with a direct vent model. Then you just put a blank flashing on the chasetop.

    I'll get back to this later.

    ---

    Hmmm... can't find any of the efficiency ratings. Not sure where they are hiding. I know the direct vent is much more efficient than a B-Vent
  11. david Lee

    david Lee New Member

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    Lennox Merit Plus 3530 will fit into your opening 35 1/4 w x 16" d. The Merit is tested to the ANZI Z21.88 vented gas fireplace heater standard vs. B- Vent models which test to Z21.50 vented decorative appliance standard. Merit's are in the mid 60's efficiency range, 20K BTU's and would be considered a slight step up from the builder grade NB or ND series. 20 foot system (box and pipe) will run around $1,700+/- MSRP + demo and reinstall.

    If your not locked into the 16" depth and can go to 20", then look at the Spectra by Lennox. Ceramic Glass, 35" framing width, standard blower, full function remote, 33K BTU's and 72% efficiency. Here your looking at $3,500+/- MSRP (box and pipe) + demo and reinstall.
  12. jtp10181

    jtp10181 Minister of Fire

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    FYI when I was looking for the efficiency ratings yesterday I did find this which is talking about all the Novus fireplaces (NB or ND) "Heater listed to ANSI Z21.88 standards". So they are listed heaters but the B-Vents just don't put a lot out.
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