Mendota FV46, flame going sideways

[Cook]

Morning!

Long time researcher on this forum but first time posting. I just purchased a Mendota FV46 which has been installed using duravent directvent pro 5x8 pipe (horizontal termination). Mill-pac sealant was used on the inner pipe of the venting, as recommended by the manufacturer.

I had the gas line installed last night in accordance with the manufacturers specs. We fired the unit last night (pilot only) to verify it worked. This morning I installed the glass panel so that I could test the main burners as recommended by Mendota (prior to installing all the logs).

It seems as though something is causing the burners to pull to the right, specifically the rear burner. At times, only half of the rear burner stays lit as it looks like the left side is being blown out.

Is this something I can fix through the air shutter or vent damper adjustments?

Any guidance would be appreciated.

Best,
Cook

 

[DAKSY]

Check the manual to see if there is a Vent Restrictor needed in the system.
They generally aren't used for horizontal installs, but with a 5 x 8 system,
there may be combustion air being drawn in too quickly, causing flame
agitation...

 

[Cook]

I don't see anything on a vent restrictor, would that be the same as the adjustable damper?

 

[DAKSY]

Quite possibly. I'll have to look at the manual in the morning.
I should be able to find it on-line...

 

[Cook]

Very much appreciated. I don't think it's a gas pressure problem, but will test that prior to installing the logs. Perhaps after I put the interior panels and logs in it'll be ok, but that's me being optimistic.

 

[Cook]

I couldn't upload a short video but attached is a photo of the issue

 

[DAKSY]

I couldn't upload a short video but attached is a photo of the issue

Hmmm. Does the unit burn ok with the glass off?
Looks like the flames are "ghosting" & that's usually
a sign of a venting issue. A short burn with the glass removed will tell you.
If it DOES burn ok with no glass, then maybe that "damper" you spoke
of is completely closed. Still haven't looked for the on-line manual yet, but I will.

 

[Cook]

Funny you mention that. It does work fine with no glass. I turned it on very quickly to check.

Strange that it would be the venting, I double checked all my joints, they're locked in. I used the sealant on all inner connections and even used high temp tape around the outer wall connections.

I checked the damper and it's completely open.

 

[DAKSY]

Are the inner & outer passageways clear?
Was the gasket & packing removed in the rear vent location BEFORE the venting was attached?

 

[Cook]

There is no rear vent, just a top one. There was some paper packaging that was removed prior to installing.

 

[DAKSY]

From the manual:

Make certain that the flame is "stable" and does not "lift" off burner. If flame lifts off burner, turn unit off and check that all vent pipes are "twist locked" and leak proof, the vent cap is "right side up" and that 1000º Sealant has been used on the inner pipe joints of all DuraVent pipe sections. DO NOT proceed with operation if flame is "lifting off" burner.

 

[Cook]

I saw that, which led me to double check all the joints and apply the tape. Strange that it's only lifting off the back burner left side

 

[DAKSY]

Does it lift AT ALL with the glass off?

 

[Cook]

I'd have to check again. I only had the main burner on for a second or two with the glass off.

One thing to mention is that the initial start up and the 45 minutes post-light it looks OK. Then it slowly blows out on the back left. Front burner is fine

 

[ACDKali]

Mendota highly recommends having a professional install. With that unit setup the logs and ember, keep embers away from pilot. You should be fine adjust at that point. That unit has a high output and with 5x8 venting you get a lot of air movement for which is forcing it to wanna move. Have a picture of it setup