vacuum relief

ice4life1417

There is a vacuum relief on the fresh air intake for my oil burner. It has a 1/8" space all the way around the damper and leaks cold air into the basement. When I get to the bottom of the stairs I can immediately feel the draft from 10 ft away when the burner is not running.



How do i weatherproof the relief valve? so that it's not just acting as a giant hole in the wall?



Could there be something missing from the fresh air intake ductwork?

icesailor

Vacuum Relief:

There is no vacuum relief valve on your oil burner. If it is a Beckett AFG, it is a draft damper. Most have been removed.

If you feel a draft coming out of your air inlet on the burner and around the damper device, you have a back drafting condition caused by air venting out of your house somewhere. It is possible that the chimney flue that the boiler is connected to, has another flue. The air is being sucked down the boiler flue and going up the other flue. If you have any other fan driven devices in the house, that could be causing it. But it is not normal to experience what you are. Only when something isn't right.

Charlie from wmass

I believe you are speaking of the barometric

damper used on the fresh air intake. it is used if the air intake becomes blocked. DO NOT block it it is a safety device. You may need to relocate it if wind is an issue.

Charlie from wmass

The damper may need to be relocated or leveled.

Can you post a picture?

ice4life1417

pic

attached is a pic. Charlie, I think your assessment is correct in that it is a safety device. Correct me if I'm wrong but if anything happens to the fresh air intake (blocked or draft conditions created by excessive winds) then the burner would be able to pull from the room air.



Field Controls Company VRV-4 Vacuum Relief Valve

It is positioned in line of the fresh air intake right before the burner. The only time it leaks is when the burner isn't on. That just happens to be a lot cuz i heat with a wood stove more often than not right now. The valve is positioned perfectly vertical and the damper appears to be in good working order and functioning properly.



I just can't get over the fact that when the boiler isn't running, it leaks cold outside air like crazy.



I haven't checked the outside intake to see if there is a damper on it, I suspect there isn't. Is that the way it would normally be designed?

icesailor

Vacuum Relief:

There, you said it. HEATING WITH A WOOD STOVE!!!

If the wood stove is on the same flue and it was a gas boiler, the house could fill up with CO and you could die. EASILY. And it happens all the time. You need make up air to feed the oxygen requirements of your home. All that money you think you are saving isn't squat to you when the saved money is used for your funeral. Or, if you survive and someone else dies.

You have a deadly situation. It MUST be fixed immediately. Good luck finding someone that really understands the problem though. And the answer isn't

A fan in a  can". That will just make your wood stove smoke like a pig.

If the wood stove is on another chimney, it is getting make up air from the boiler flue.

icesailor

Vacuum Relief:

Ice4,

Don't take this the wrong way (but I'm sure you will), but you know just enough to kill yourself.

I'm not too sure that what you have sent a picture of is what you really have. It is highly unusual to install a Field Vacuum Relief damper on an oil appliance unless it is a direct vent, sealed combustion unit and as I remember, you have a W/M WTGO-3. I've never seen that boiler connected up as a balanced flue install. You sent a picture of what you think you have from the Field Web Site. If you have a "RC", that's what should be on there. Unless it is an Effical, which most didn't use because they were junk compared to a Field RC. So, go back and look to see if you have an RC

Take a picture of what you REALLY have on your boiler. Take a picture of your boiler and post it.

If you smell oil exhaust and you have a wood stove going, you better fix your draft/make up air problem or you may not survive to enjoy it.

icesailor

Vacuum Relief/Combustion air:

My first combustion analyzer was a Dwyer. The instructions told all about combustion. I remember that it takes somewhere like 15# of air to properly burn a gallon of fuel oil. Maybe more for wood. Wood wasn't discussed. But you still need the 15# of air.

Where do you get X# of air for combustion in your wood stove?

How much does a cubic foot of air weigh? How many cubic feet of air equals 15#?

An inquiring mind is wondering?

People didn't die in old drafty houses.

People die in modern, tight and sealed houses. Lack of fresh air, CO

I once read an article on CO when it first became a big issue. The article stated that if a room would hold 10,000 ping pong balls and four of the balls were CO balls, the CO balls would kill you. That got my attention. I carry a CO detector in my pocket when I go into houses to work. I've been surprised on more than one occasion.

ice4life1417

another pic

three pics



the "vacuum relief valve" as the manufacturer named it



3 distinct flue



the termination of the fresh air intake, i looked into it and only see a screen to keep the big stuff out, did not see a damper.

icesailor

Vacuum Relief:

I don't know the orientation of your chimney but one flue is for the boiler. The others are for fireplaces, usually. If the wind can blow across the three flues, and the first/windward flue is connected to a fire place, and it is running, and the second flue is for another fireplace, and the house is tight, it will suck smoke down the chimney and fill the house with smoke. If the wind is the opposite, the exhaust gas will be sucked down the chimney as make up air for the boiler/burner. If you don't have a fire or whatever going, it will be doing this all the time. Even if you have closed dampers in your fireplaces, they will still suck. Back in early December, we had a storm and the power went out. I lit up my vent less fireplace log set. It is behind a set of glass fireplace doors that are very tight. There is a glass door and a screen. When I opened it up, I was surprised at all the cat dander behind the doors and on the screen from normal draft in the house.

The draft you are feeling is draft coming down the flue, trying to balance the air pressure in the house.  That outside air intake system is somewhat controversial now. I put a few on but they never took off. When the outside air is really cold, it changes the air/fuel ratios. The draft breaker was intended to open up if the intake air from outside became blocked. Beckett to my knowledge didn't really like them used. Carlin made a special adapter kit do do it with. I solved some draft problems with them. But Carlin never required the draft breaker on them.

The biggest problem with them as far as I am concerned is the location of the inlet as opposed to where the wind is blowing on the structure. The pressure differentials can really be different and cause problems. If you are feeling hot exhaust air coming out of the air box, it may be more from the air blowing from the exhaust. Which doesn't appear to be much more than a dryer with the flapper removed. Is there a screen on it to keep squirrels out? Rodents will find their way.

This house could easily have a bad case of environmental emphysema.

It also looks like the exhaust gasses are backing uo in the boiler and the burfner is overheating when the burner isn't running. The back where the Beckett label looks like it has heat damage. Does the burner ever feel very hot in this area after it has been running on windy days? I once burned my fingers on a nozzle assembly taking one out that had this problem. Lack of draft was the cause.

ice4life1417

seal it?

can i just seal off the vacuum relief valve??

there is a screen on the intake outside.



u r prolly right about the heat damage, the tech last week pulled out about a solid foot worth of debris from the chimney. previous owners apparently did not take care of it.



this house is the farthest thing from tight...haha. i'm working on that though, it def needs to be tightened up quite a bit. it's like swiss cheese.

billtwocase

Never seal it

It is just that. A vacuum relief valve for the air intake. Should the outside vent hood plug or something, which I have seen happen, The vacuum relief will open and allow necessary combustion air to enter the burner, otherwise it will soot up nicely

icesailor

Oh dear:

That means that the flue may not have a liner in it and may be falling apart. It may need a SS liner. Those old dogs didn't use flue liners back when and would lay the wydths up with bricks and parge the flues. With age and acidic flue gasses, the mortar comes apart and the sand falls down and blocks the flue inlet. Or there's the later breed who decided that the fastest, cheapest way to build fireplace chimneys was out of block and tile. They were clueless about keeping the flues tight and sealed from each other so the draft would go back and forth between the flues. Fun. I once did a new house where the draft between a concrete block that was part of the fireplace base at the sill, had more draft (according to my Bachrach) than the flue vent pipe that the boiler connected to. How do you fix that? One burner will NOT be happy, firing against fluctuating, positive pressure. Another brand doesn't give it a thought. I changed the burner to that one, 25 years ago and it still goes strong.

I was a mason, before I was a carpenter, before I became a plumber and heater. The experience serves me well.

Your flues may all be cut so that they sit nice and proud up there. Like soldiers standing at attention. But, that is an unusual band at the top, It has a funny bond. We/I always put a small piece in the two courses of band to keep the bond correct. And we always returned back to the start with two courses. Nothing wrong with it, it's just the way it was done. Unless it is a fake chimney. All the even shadows on the brick. It almost looks like wall paper.

rlaggren

could find which duct the air leak comes from

Ie. from the burner or from the air inlet. Either stick you hand all the way into the vacuum relief tee or if you can't do that, remove the bottom el from the burner; turn off the burner first, of course. If you remove the el, first check that the duct from the air inlet is supported, hung, so that it doesn't just drop in your lap (sometimes duct work isn't supported by much of anything) - you want it to pretty much not move anywhere, only swing a little when you free it from the burner. If you need to add support use some perforated tape or bailing wire and loop around the top el, or the lateral duct close to the top el,above the vacuum relief tee.



Could also find out if the leak still occurs with the boiler OFF and the fireplace NOT in use. No air leak w/out the fireplace = your fireplace is causing the leak. If that's the case you might consider whether you could seal the boiler space from the living space (where the fireplace is) - maybe by just closing a door and/or weather stripping the door? But sounds like you have an old leaky house so that might not work. But assuming you can get your boiler space tight enough vis a vis your living space, the fireplace will just draw it's combustion air from somewhere else... And also, that closed door then becomes part of your burner's drafting system because it's protecting the burner from the suction of the fireplace so you need to put a door closer on it and maybe a sign saying it's got to be closed during heating season..



More info gives you a much a better chance of figuring out your actual problem and fixing _that_.  But sometimes when you fix one problem you find a couple more hiding behind the first one - so perservere.



Happy New Year.



Rufus

disclaimer - I'm a plumber, not a heating pro. I have professional experience with large and small

gas water heater and small forced air heating flues. I have maintained

hydronic heating systems on of my families houses for 10+ years.

icesailor

Seals in the flues:

And if the flue is blocked, it gives the exhause gasses a place to go. Right back into the house.

Be sure to put a CO/smoke detector over that boiler too.

ice4life1417

air infiltration

so i disconnected the vent just before the burner. it appears that cold air was more than happy to rush in from the intake side. also, on the burner side, a small volume of air could be felt but i was unable to judge whether it was cool air coming in down the flue or a little bit of wind chill from air passing into and up the flue.



i suspect if the updraft was at the point that it needed to be then the air would be pulled up the flue instead of passing through the relief valve into the home. prolly cuz i am heating with the wood stove and have a fireplace next to the boiler room. if that flue was pulling better then it would create a negative pressure situation in the basement. does this sound accurate? the flue is closed but it is by no means a tight seal, i plan on weatherproofing it today since it will be unused for the winter.



so the vacuum relief valve probably doesn't do much good when there's a fireplace next to it with it's own natural draft and the wood stove (granted it's on the next floor up) pulling against the draft of the boiler flue. right?

rlaggren

Say what? WARNING!

> "flue is closed but ...."..... "... plan on weather proofing it..."



Whatever you do, DON'T PLUG THAT FLUE OR AIR INTAKE or vacuum relief!



You have a boiler in there that needs them properly installed and functioning to avoid dangerous combustion gases getting into your home. You change or alter that flue at risk of serious injury and death to yourself or others. Saying now that that boiler will be unused won't prevent it happening later and you may cause a tragedy if the flue is not connected and functioning properly.



Be warned! There is a reason that the owner of this site felt it necessary to provide a separate forum devoted to the dangers of CO and combustion gases. Read through that forum. Think very carefully before making ANY changes to your combustion appliances.



I and others try to provide advice to help you learn more and make sound decisions but NOBODY can make specific recommendations to your particular problems without visiting your site.  It _sounds_ like your fireplace and wood stove are depressurizing your boiler room and that is a BAD thing. But it will not be fixed by "weather proofing" your flue, whatever you mean by that.



I see a red flag here. Again:



DO NOT CHANGE, PLUG, ALTER OR IN ANY WAY INTERFERE WITH THE PROPER WORKING OF THE FLUE FOR YOUR BOILER! DOING SO CARRIES A SERIOUS HEALTH RISK, UP TO AND INCLUDING DEATH!



Be smart and safe this new year.



Rufus

ice4life1417

misunderstanding...

I meant i was going to weatherproof the fireplace in the basement because i do not plan on using it. the fireplace seems to pull air even though the flue is closed cuz it's not a good seal.



I am then going to do my best to seal he basement from the first and second floors so that the wood stove(on the first floor) pulls it's makeup air from the leaks on the first floor and not the boiler intake in the basement.



i have no intention of sealing off the flue to the boiler. that's a death waiting to happen.



so, if i sealed off the fireplace and the first floor, there would not exist a negative pressure situation in the basement and the flue for the boiler would be able to maintain it's natural draft, thus keeping the relief valve from "leaking" into the basement. does this sound accurate?

rlaggren

Glad to hear your clarification

That makes sense. Sorry to yell at you, but folks use different words and phrasing to mean different things and there seemed a chance you were talking about closing off the boiler flue or the combustion air inlet which would have been very bad.



Have the Happy New Year.



Cheers, Rufus

 

Mark Eatherton

Relief is just a bucket away....

Infiltration is the one factor that comfort contractors have little to no control over, and it can make the occupants miserable.



Why not give the wood stove its own source of outside air? It would make a world of difference in the comfort in areas that are not near the wood stove.



As for the air leaking into the mechanical room, you could add a short section of pipe and a 90 degree elbow to the relief branch of the combustion air intake and put it down near the bottom of the inside of a 5 gallon bucket. Leave it just high enough to equal the effective opening of the pipe it is serving. This will act as a cold air trap. Cold, dense air will settle in the bottom of the bucket and will keep it from spilling freely (due to gravity) into the mechanical rooms warmer air...



ME

ice4life1417

air intake

i don't know how to do a fresh air intake for this stove. the inlets are on the door. i'll investigate that for next year... really though, i'd like to replace it with a newer, more efficient wood stove designed for a fresh air intake rather than trying to engineer one that'll work. this one is 30 yrs old.



love the idea of a cold air trap.



thank you for all your help everyone.

Eric_32

So to summarize...

So the original poster has a wood stove in the basement and an oil fired boiler with a Fields air boot kit on the burner.



When the boiler is off, he feels air being pulled into the basement from the air kit on the burner. Basement is at a negative pressure, obviously, due to the wood stove pulling out a ton of air from the space. It is trying to pull air in from wherever it can, the Beckett air boot kit, Fireplace flue, upstairs?  While the boiler is being supplied with fresh air from outside, not the space.



As mentioned earlier hopefully the boiler and stove are on different flues, but the fireplace flue having cold air coming in from it is not good at all. Sealing it up is not fixing the problem.



Now if the fresh air boot on the boiler wasn't there to provide some combustion air, as it is doing now, who knows what the case would be.

In sizing a room for a combustion air the space needs to have 50 cu ft for every 1,000 btu's or it is a confined space. Cu Ft, not Sq Ft. You have to add all appliances that have combustion that use the space for combustion air, eg-boiler, wood stove, dryer, water heater, to get the total btu load. Then add the total space, NOT including bedrooms and bathrooms. There can not be any door to an adjacent space either or it doesn't count unless an opening is installed (louvered grilles). Say the basement room the boiler and wood stove is 20' x 20' with 7' ceiling. total cu ft is 2800. divide by 50, you get only 56 which is  56,000 btu's that room can supply. Louvered grilles supply 1,000 btu's per sq inch of opening, (minumum size of 100 sq inches) minus 25% for the metal louvers and 75% for wood louvers. So to size the space properly for the wood stove alone because the boiler is not using the space for combustion air, that is the formula you use.



I do believe a CO/smoke detector in the basement would be a necessity in this case, and try to figure out a way to supply combustion air for that wood stove.  



You could always start looking for a newer stove that has the ablilty to bolt on a fresh air kit on it. "Most" new stoves offer it today due to the tight construction of today, and many building departments require it on new construction.  Best place for the make up air is directly to the stove.

I have a wood stove in my living room and it has a make up air kit bolted to the air intake of the stove, it and pulls fresh air directly from outside for combustion. The stove is a Vermont Castings "Encore".



I have seen this senairo in a commercial restaurant many times when the exhaust hood and make up air are not matched correctly, store is at a negative pressure and the pulls air down the water heater flue in the back of the restaurant, causing flame rollout down the bottom of the tank, You can feel the ice cold air at the draft hood being sucked in. Then the tank tries to light against that negative draft and it pours right into the store.

Good Luck and be safe,

Eric