Condensing boiler vent creates HUGE ice formation on roof!

Unknown

Wall hung condensing boiler with coaxial vent termination outside. Soon after installation, a deck was added last year and this is the solution the heating guy came up with.

I'm a bit lost as to what to tell these nice people. The old heating contractor won't even pick up his phone to preform the simple anual maintenance on the unit and this is what I find outside.

2 Questions for all you gas venting experts. 1) Is this installation a hazard? 2) What would you guys do to remedy this situation? I'd appreciate a little help here as I don't know what to think of this.

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bob young

direct???

how about checking with manufacturer as to how he wants to properly vent the unit he invented.you started with a direct vent that is not so direct anymore.

Mark Eatherton1

Acid Rock...

will KILL you if it hits you in the head.

If'n it were me, I'd first defer to the manufacturers instructions. If they are of no help. I'd consider getting rid of the down turn fittings, and leave the vent terminated facing upward. HTP has some nice 3" PVC couplings with stainless steel screens in them that will keep the major winged vermin from building nests in the end of the terminus. Worse case scenario, you may get some environmental liquids (rains, snow, sleet) into the vent. No biggy.

I've seen this happen with non condensing equipment too. H.O. said when it came off the roof, he thought he'd been hit by a hijacked jet! Good thing he wasn't actually standing there at the time it came off, or he may have FELT like he'd been hit by a jet.

This IS going to become a major issue as more and more high efficiency appliances come on line. I can see a lawsuit in the making...

ME

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Unknown

Can the vent be run

out from under the deck and be terminated 12" above grade? Some equipment manufacturers make extension kits for their equipment.

Is this a condensing piece of equipment? If so I would think the condensate is running back into the unit.

Unknown

Owners claim to have almost died from CO poisoning,,,

before the new sealed combution condensing MZ25C was installed. They want that vent termination no where near their new deck where they breathe clean air. That's why I suspect we see it in it's present condition. The owners swear that they are STILL smelling the burnt gas vapors even this far above & away from any openings. Strange. I can't smell a thing even when I get in the cloud:) They claim to be oversensitized ever since their close call with death by CO. I can't argue with that.

Another thought: could this freeze closed? I like Marks idea about getting rid of the turndown 90ºs. Remember the Skylab is falling!

Don't the pipe lengths (inside & out) need to be the same length
for a ballanced flue to be "ballanced?" None of this can be found in MPI's technical Litter.

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S Ebels

I'm at a loss for words...........

What was the guy thinking?.............

If the MZ is a balanced flue type appliance, that one no longer is.

Hmmmm. Could a person extended the concentric pipes out to the edge of the deck. (Which BTW should not have been built there if no proper method of venting could be accomplished.) I realize the HO doesn't want the thing vented there but his vent system is really messed up the way it is.

Maybe Pete Caruso could give you some help or suggestions on that one.

ed wallace

condensing vent

some one should have told homeowner not to build the deck over the vent temination

Constantin

Several solutions...

One, is to pull out that drain pipe and install a new coaxial vertical stack with a vertical termination. Only then do you have a balanced intake/exhaust. Furthermore, such an arrangement would be less prone to icing up. If there is no wall to hide the stack in (it should be Cat IV, zero clearance, right?) then have them add a boxed wall section in that area to hide the flue in.

Turning the flue 90° to the right would prevent the ice formation you see. However, I would be loathe to add this hazard to my collection of "fun things to get sued for".

Or move the MZ to another site in the basement for a side-vent.

Lastly, we;ve only heard one side of the story, i.e. the H.O.'s. For all we know,
a) they were warned long ago by their installer that installing a deck next to the vent is a really bad idea
b) his/her "solution" was all they were willing to pay for
c) not to call him/her if it didn't work.

jim lockard

too much exposed pipe

In my minds eye I can see the condensate gathering and freezing in that horizontal section below the gutter, the pressure switch fails to close, signaling a blocked vent condition. I have never installed a condensing boiler only gas condensing furnaces and water heaters and most vents termiate within a foot of the wall,I have run under decks 10 or 12 feet without problem but Virginia weather is not that cold for long periods of time. Best Wishes J.Lockard

m dewolfe

Ice

> One, is to pull out that drain pipe and install a

> new vertical stack with a vertical termination.

> Only then do you have a balanced intake/exhaust.

> Furthermore, such an arrangement would be less

> prone to icing up. If there is no wall to hide

> the stack in (it should be Cat IV, zero

> clearance, right?) then have them add a boxed

> wall section in that area to hide the flue

> in.

>

> Turning the flue 90° to the right

> would prevent the ice formation you see. However,

> I would be loathe to add this hazard to my

> collection of "fun things to get sued for".

>

> Or

> move the MZ to another site in the basement for a

> side-vent.

>

> Lastly, we;ve only heard one side

> of the story, i.e. the H.O.'s. For all we know,

> a) they were warned long ago by their installer

> that installing a deck next to the vent is a

> really bad idea b) his/her "solution" was all

> they were willing to pay for c) not to call

> him/her if it didn't work.

joel_21

No Way!!!!!

You can't do that!!!!!!!!! that is not approved that would be an instant fail on any codes in Mass!!! If I was the contractor I don't see how it would be my problem if my client biult a deck over it after the fact. Up here that sucker would freeze solid, block the flue and you'd have no heat. I can see he was trying to help them with a cheap solution, he was trying to be the good guy. There is only 2 solutions for that remove the deck or move the boiler. If they don't like those ideas then just run away or it will be your nightmare, not the last guys.

m dewolfe

Ice

Several years ago befor the age of CO detectors I went on a fire call in the middle of the night {volunteer}. homeowners were "smelling somthing bad that was making them ill" after a long search in the cold winter night I found the top of the chiminey completely blocked with frozen condinsate and a hole about the size of a quarter for flue gas to escape. CO in the house was so high we had to wear air packs. New gas furnace had been installed just a few months earlier. This was an old brick chiminey with a high eff boiler just piped up to it with a reducer. I said my prayers for them that night!

tom_49

gary

I'd be concerned w/ flue gas getting back into the house if there is drip edge attic vent above the gutter. I'd cut those 90o's off for now and contact man. or local inspector for guidance, dont just guess. Good luck Tom

Constantin

FYI...

...Gary Wallace is based out of MA. I would be highly surprised if the unit under scrutiny was not in MA.

Constantin

That's why type IV coaxial vents were invented...

... keep the appliance sealed, no interaction between the indoor and the combustion/exhaust air possible. If the bad air can't make it into the house, then it'll have a much harder time poisoning you... Hence, I was pretty miffed to discover that my Vitola does not allow sealed combustion.

hr

I'd look

for a better route inside the home. Must be a closet corner somewher. If not, build a chase.

Then take the vent as close as possible to the peak of the roof.

I agree with others, lose that 90 and try it, that's an easy first step.

hot rod

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Sweet

vent

I agree 90 at top of vent should vent unobstucted vertically.Also at C.T. adapter connection should have some type of drainage tee installed to alleviate condensate from draining back into horizontal line.Get rid of 90s at eve, consider going straight through eve.Most of all read manufacturers installation manual.

Grumpy_2

Harruummmp!

Nice color coordinated paint job! Do people in Mass sit out on an open deck when it is cold enough for a furnace to be running? Seems like extending the vent under the deck would have been more aesthetically and mechanically acceptable.

Dave Bush

Ten too many 90's, IMO.

Someone seems to be more knowledgeable than the manufcaturer of the equipment, yet again!

ed wallace

bad vent

reminds me of the guy in maynard mass who wanted a sealed combustion boiler in stalled and wanted the balanced flue exhaust pipe run under ground 10 ft from the house and to terminate inside a phoney wishing well

Weezbo

wow! That sure don seem like the Plan:)

here is a guess...a long drop T at the first 90 would allow the condensate to sail straight down the pipe ouside to some drainage catch lose the trap on the lid...

ScottMP

Not only is

the flue not balanced but the condesate Will freeze and couse problems. Thats why this Can Not be extended under the deck.

I agree, once Gary touch's this, it HIS !

I see moving the vent terminal as the ONLY solution here.

I would also provide the HO with a Good CO detector. Have you carried one with you to check whats going on in the house ? These people may be more a problem then you know. You have only heard one side of the problem.

Scott

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Marty_2

Hot rod has the right idea build a chase somewhere and exit as high up the roof as possible. even run the way it is now its going to collect water inside and freeze up.

Lurker_2

re

Seems to me the 'condensate' should be draining, so it should never go 'up' am I wrong? here at work my condensing furnace has a separate drain, small diameter. Used to run outside but the 15 foot tall ice dam kept freezing the pipe, so no it goes down the drain[landlords fix]

This is not going to work when the real weather comes-

Weezbo

And He was trying to get You to do it ))

The things homeowners come up with are bound to amaze even the best of minds:) you were wise to escape before You were Wishing and throwing money down the well:))

tim smith

no can do

If it's a balanced flue I would not touch it the way it is, tell the HO that unit must be moved to where it can be properly vented, that's it!!! IMHO

Tundra

one disagreement

A lot of good ideas. the only one I really have a problem with is the screen on the end of the flue. When the moisture hits this cold metal you have an instant ice block.

Unknown

How to correct?

I've decided that the two (turndown elbows) should be cut off. I'm convinced that by using a coupling/screen such as HTP offers for their venting system of the Munchkin will help. Help. That's what this forum is about right?

Am I taking full responsability for this venting nightmare by doing so? I'm not licensed in the state that this installation took place. This service call came to me from MPI. All I did was the anual service to keep the equipment under warranty. (it was dirty) Then,,, I find the potentially dangerous venting assembally.

What would you do? Still waiting to hear from MPI.

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Mark Eatherton1

The screen

is required by the manufacturer...

ME

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ed wallace

venting

Gary either walk away from it or redo the vent so that it meets the manufacturers specs there are to many lawyers out there

Unknown

Ed Wallace (no relation)

Ed,

It's easy to walk away. I could do that easily. That's not what I stand for.

The MFG specs don't cover this type of venting. I CAN'T move the boiler either. I'll show why & when I go back to take pictures. TIGHT INSTALLATION. I must also add that whoever installed this MZ was an expert. A FINE craftsman. Hat's off to the contractor who installed this MZ.

Not sure why the combustion/intake terminations are so screwed up.

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ed wallace

vent

gary ask the customer when the deck went in i bet it was installed after the MZ was

Unknown

Yup

oops

Unknown

Yup

Ed,

Read the thread.The deck went in after the MZ. They will not move the deck. Any GOOD ideas?

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joel_22

well

I guess they put you between a rock and a hard place. Maybe you can chase it up inside, as long as you don't go past the max length? You can't extend past the deck it will freeze and I don't think that's approved either. You may not want to walk away but you mave have to sounds like the customer is giving you no choice.

jim lockard

deck

Should running under the deck be the only way out you may be able to insulate the vent pipe.

Jason Horner

Liability Warning Will Robinson

Whatever you do....get the manufacturer to approve any non-standard proposed venting in writing, and maybe the local inspection authority too. Otherwise stick with the manufacturer's spec for venting.

Unknown

I'll need the approval from MPI in writing,,,

before I reccomend or do anything. MPI has been awesome so far. some of the nicest people work there.



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Dale

Pretty straightforward

This is a catagory 4 appliance, it MUST be vented per mfg. instructions that come with it. Lay out the options like the other posts suggest and let them pick one that will comply. If "non of the above" it's time to get another type of heat source or someone else. Without insulation I'm amazed this pipe isn't ice choked internally.

Dave Kliman

can't be outside like that

if you go to weil-mclain's website, they have a vent suppliment to their ultra boilers.

http://www.weil-mclain.com/FTP/Ultra 310/5501012350903Vent.pdf

the manual clearly states that these vents must not have very much pipe outside whatsoever. either the vents terminate right at the wall from the basement a foot above the snow line or they terminate pointing straight up out of the roof. this huge icemaker pipe that goes all those feet outside is a deathtrap waiting to happen.

beeper

Easy fix, remove the fittings back to the gutter and install a

45 degree fitting facing upward so the condensate rolls back in to the trap at the appliance. Done deal