Lopi 1750 damper won't close

TomatoLover

Member
Feb 26, 2014
76
Western MA
Our 4 year old Lopi 1750i flue damper won't close. Last season, it was really loud when opening and closing, kind of sticky and difficult to use. I started just not using it, leaving it closed. I rarely load when it's hot, so smoke coming into the house when I opened the door was not a concern. Today, we had a new stove installed downstairs and the Lopi and chimneys swept. The sweep opened the damper. I loaded and started it after he left, and now I cannot get the damper to close. So, now what do I do? I profess that I really don't know what the damper does and what happens if I burn with it open.
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,546
South Puget Sound, WA
By damper do you mean the air control situated in the center just under the ash lip? That is critical to stove operation. It controls the air supplied to the fire. The stove should not be run wide open, especially not with dry wood.

This is a simple slider valve connected to the handle in the front. If the sweep got it open then it might just be stiff. Take a mirror and flashlight and use them to follow the rod back from the front of the stove to where it moves a plate over the air intake port for the stove. Look for rusting or a slightly bent guide.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
775
Texas
You’re talking about the bypass damper at the top of the stove, right, not the air control at the bottom?

On our Revere (same firebox as the 1750i) the bypass damper could catch if my husband left it open too long. We always assumed that it was some slight expansion of the metal with the heat. My husband found that a tap with a hammer directly on the ring of the handle would dislodge it and allow it to move. He didn’t use much force. It sounds like your difficulty is something more long-standing, but perhaps you could try the hammer. We never wanted to burn with the bypass open to send all the heat straight up the flue.

We never lubricated ours, but I’ve read that you can use some sort of graphite powder. Maybe that would be a wise step when the stove is cool again.

By the way, we found that bypass damper great for using a sooteater to clean the chimney. It was easy to do from the bottom up.
 

blacktail

Minister of Fire
Sep 18, 2011
1,419
Western WA
The 1750 still has bricks on top of the firebox doesn't it? I wonder if one if those bricks could get bumped out of place and interfere with the bypass damper.

Sent from my moto e5 plus using Tapatalk
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,546
South Puget Sound, WA
I thought the 1750 didn't have the bypass damper, it's on the Lopi Endeavor/Revere.
 
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webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
I thought the 1750 didn't have the bypass damper, it's on the Lopi Endeavor/Revere.
It does have a bypass damper, the 1250 does not.

Unless the stove has been overfired and warped parts, it most likely that the baffle just needs disassembled and cleaned. The baffle gets a lot of fly ash built up on top of it, especially likely since you said you don’t use the damper. Your draft is excellent or possibly excessive, which pulls even more ash over the baffle. I always pull the bricks down and clean around the damper. I’m guessing the sweep did not? Most sweeps aren’t familiar enough with stoves to take anything apart.
 

webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
The larger freedom and freedom bay have a small bypass damper frame that sits directly on the bricks. The 1750 has a large piece of steel that covers the back 1/3 or so of the baffle that the bypass damper slides on. This piece can warp if the stove is over fired. Usually Caused by a bad door gasket or leaving the door cracked for long periods of time.
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,546
South Puget Sound, WA
Boy, it would really be nice if my manual showed this and included that info. Not a peep about it, nada. But I just checked and my manual is from 2008 to 20014. It looks like this changed in 2016. I haven't seen a Republic in years and defer to your more recent knowledge. Thought it was the same as the Avalon. Thanks for catching that.
 
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webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
Boy, it would really be nice if my manual showed this and included that info. Not a peep about it, nada. But I just checked and my manual is from 2008 to 20014. It looks like this changed in 2016. I haven't seen a Republic in years and defer to your more recent knowledge. Thought it was the same as the Avalon. Thanks for catching that.
Every 1750 insert I’ve seen has a bypass. The freestanding stove does not. I think that’s where the confusion is.
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,546
South Puget Sound, WA
Oops, I missed that this was the insert. My bad. I haven't seen the insert yet. Seems like now the docs are even more incorrect. Here is the change I noted in the 2016 freestander docs. This is not in the prior freestander docs.

Depending on your heater, the chimney, and the outside environment, you may need to leave your bypass open for up to 20 minutes after lighting the fire. If the fire dies when you shut the bypass you will need to leave it open longer.

This being an insert explains why the sweep opened the bypass. If it's warped he should have told the customer of the issue.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,586
central pa
I have had the holes in those bypasses get ash built up in them before. That does not allow the pins of the arm to go all the way in which causes binding
 

webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
I have had the holes in those bypasses get ash built up in them before. That does not allow the pins of the arm to go all the way in which causes binding
That can happen, more common is ash build up within the bypass frame itself though.
 

webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
Let’s be honest. Most cleanings on an insert with a bypass like this one takes about 30 minutes. There’s no excuse for not dropping the baffle to clean there too. The only reason is unfamiliarity...
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,586
central pa
Let’s be honest. Most cleanings on an insert with a bypass like this one takes about 30 minutes. There’s no excuse for not dropping the baffle to clean there too. The only reason is unfamiliarity...
Yeah no excuse. Lopis can be a little bit of a pain compared to many other inserts but still not a big deal.
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,546
South Puget Sound, WA
So back to the @TomatoLover's question. You can run the insert with the bypass damper open, but it's going to waste a lot of wood and will definitely reduce heat output and send it up the chimney instead of into the house. This should be looked at and fixed. If it just needs cleaning in that area then it's not a big chore. The sweep should have done that.
 

webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
So back to the @TomatoLover's question. You can run the insert with the bypass damper open, but it's going to waste a lot of wood and will definitely reduce heat output and send it up the chimney instead of into the house. This should be looked at and fixed. If it just needs cleaning in that area then it's not a big chore. The sweep should have done that.
The sweep should have definitely done this. Most aren’t familiar enough to bother though unfortunately. Running with the bypass open is inefficient, but more importantly can cause an overfire situation. In this case, they don’t bother opening the bypass, which leads me to believe ash build up in the bypass itself is the issue.
 

Beas87

New Member
Nov 6, 2018
1
USA
You’re talking about the bypass damper at the top of the stove, right, not the air control at the bottom?

On our Revere (same firebox as the 1750i) the bypass damper could catch if my husband left it open too long. We always assumed that it was some slight expansion of the metal with the heat. My husband found that a tap with a hammer directly on the ring of the handle would dislodge it and allow it to move. He didn’t use much force. It sounds like your difficulty is something more long-standing, but perhaps you could try the hammer. We never wanted to burn with the bypass open to send all the heat straight up the flue.

We never lubricated ours, but I’ve read that you can use some sort of graphite powder. Maybe that would be a wise step when the stove is cool again.

By the way, we found that bypass damper great for using a sooteater to clean the chimney. It was easy to do from the bottom up.

Mine does the same thing. This well be the second winter we've used it. It happened within the fisrt month of using. Closed just fine any other time but if you leave it just a little to long a tap with a hammer does the trick.
 

webby3650

Master of Fire
Sep 2, 2008
11,015
Indiana
Mine does the same thing. This well be the second winter we've used it. It happened within the fisrt month of using. Closed just fine any other time but if you leave it just a little to long a tap with a hammer does the trick.
Sounds like you have water getting into the stove somehow.