How To Unstick Fields Auto Gas Vent Damper

D107

Fields GVD-5 Auto Vent Damper. Last night noticed on a call for heat the damper was clicking repeatedly as it tried to open. Finally made it after 10-15 clicks, and burner ignited. But by this morning heat had been off for hours, and I came down and found it clicking again. I started to turn it myself, and it immediately turned into position automatically. Then I lockd it in manual. The motor seems fine, no horrible noise coming from unit, but these things look kind of flimsy and I wonder could some gear or friction within cause this? Anything to lubricate?

Big Ed_4

Best repair is replacing the motor assembly

D107

@Big Ed_4 Thanks. Is that much cheaper than just buying a new unit? Maybe less labor, eh?

SuperTech

I'd just leave it in the open position. Those flue dampers aren't worth it. They aren't reliable enough to risk losing heat over. And they tend to sound like fingernails across a chalkboard when opening and closing.

Tim McElwain

Make sure the flue pipe is not out of round and causing friction when trying to open.

D107

@Tim McElwain Thanks good tip; can't say it looks out of round; however it is slightly pitched forward towards the chimney instead of vertical. perhaps that's the issue. I've heard that these can save up to 5% fuel a year and obviously keep the basement warmer--how much I don't know. see photos.

Jamie Hall

I'm with @SuperTech this one, no question. Maybe they do save some fuel. However... when they fail to open, which all the ones I have had to deal with do from time to time, you have no heat. Not so bad if it's your own place and you wake up cold. Not so good if it is a place you are maintaining for others...

Big Ed_4

Yes , It's cheaper and easier to just replace the motorassembly .I keep one on my truck.

Tim McElwain

@d107 I would make sure the flue pipe is perfectly vertical. With all the height in the photos it is possible to create some binding on the damper. Dampers can be fussy. The typical listed efficiency with a damper is 2% to maybe 3%.

Motorapido

When I bought my house four years ago and started learning about steam from this site and Dan's books, I discovered that the prior home owner shut off the automatic damper and left it in the open position, because it had failed. When I replaced the automatic damper
, I noticed a significant increase in basement temperature and faster times for steam to reach the main vents on colder days since the damper prevented lots of boiler heat from going up the chimney between calls for heat. The damper assembly isn't expensive and I found it a breeze to install. After installing it, I showed my Commander In Chief how to disable the damper using the on/off switch and how to manually open the damper in case the damper motor would fail closed during a time when I might be out of town. If I owned a rental property and the tenant paid the gas bill, maybe I would delete the automatic damper to prevent angry tenant calls if the damper failed and the house got cold. But if it's your home, why send BTUs that you paid for up the chimney between calls for heat?

Jamie Hall

Agreed, @Motorapido . If it's your home, and someone is always there -- or there at not more than a few hours intervals -- the automatic damper is a good way to go. If you are a landlord you do have the problem of getting up at oh dark hundred on a snowy morning to fix it when they call. Or, if you are like me, taking care of unoccupied but open properties in the winter you simply can't afford to have something which is doubtful out there. It's a balance.

D107

@Motorapido Agreed and that's one piece I might keep a backup unit or unit motor in the house. And if I was going away in the winter I'd keep it locked open. From the photos I agree with Tim the vertical flue pipe should be straightened.

D107

@Tim McElwain I think your advice was on target. I have temporarily 'fixed' it by moving some of the movable flue pipe rotating pieces ––not sure what you call them––that hopefully took a little pressure off the one side of the flue and made it slightly more vertical. must be a matter of fractions of an inch. It's now worked for a few cycles. Have to keep my eye on it. When I get the installer over, he can open it and make some more permanent adjustments.

D107

@Tim McElwain So the only remaining question is what is the best gauge thickness to use for the vertical galvanized flue pipe to keep the pipe true? The current is marked 5-26 which I believe is diameter and gauge. The breach piping is 304 -18, which would be thicker. I'm guessing 26 is ok for that horizontal galvanized but for the sake of the damper perhaps we need thicker gauge for that vertical piece? (Chimney Liner is 316 L).

Tim McElwain

The 26 gauge is fine unless you want to go stainless steel all the way then 304 or 316 stainless is okay.

D107

@Tim McElwain one more thing. Instead of dragging the installer out to do this, can't I unscrew the three screws at the bottom of the flue where it meets the damper housing, try to straighten it out by pushing in the part that leaves the crimping exposed, then screw it back?

Tim McElwain

What ever it takes to make it work.