Heating Help

PVC can work fine

@ May 24, 2012 3:08 AM in Is PVC an acceptable vent material for flue gases?

The simple answers are: 1) All appliances using a plastic vent system, and/or, an uninsulated vent system with low or zero clearance to combustibles, must include a manual reset high limit switch in the vent outlet.  2) Adopt a similar, if not parallel standard to ULC636 which clearly establish the maximum continuous and intermittent peak temps the material has to tolerate.

Our company has been installing PVC venting on warm air furnaces since 1993.  This material has worked well on furnaces.  Not surprising since the flue temps are often in the 100~120F range.  All of the old equipment I can think of had a thermal limit switch mounted in the outlet of the inducer.  Much of the newer equipment seems to have eliminated the switch (tisk tisk).  We inspect PVC closely on every service call and the odd issue we've seen appear are in joints that have no evidence of primer being used in them before cementing.

I think the room air flue temp dilution design is problematic, and the HWH manufacturers would have to walk away from the design if the were mandated to comply with the above.

Question

@ May 24, 2012 2:08 AM in Hallmark Furnace Issues. Looking for advice.

Why was the smoke pipe replaced twice in such a short period of time?

Chinese Solar Products

@ May 21, 2012 10:13 PM in US to add large tariff to Chinese solar panels

I've always thought purchasing Chinese Solar Products as an oxy-moronic choice to make.   Why are you buying solar products for in the first place?  If the environment, sustainability, or social responsibility is in the mix then shouldn't you rule them out?

It appears the issue is related to PV panels and not thermal solar.

Look for...

@ May 21, 2012 9:50 PM in yellow flames, combustion problem?

Look for...

@ May 21, 2012 9:50 PM in yellow flames, combustion problem?

The 1st thing I'd look for " waited 5 mins and noticed flame went from blue to bright yellow"  would be contamination of the comb air with exhaust.  It can be responsible for the pilot outage too.

Pilots full of crap will throw a yellow flame, but do it all the time.  Partially cloged flue passages won't usually bother the pilot when the burner isn't running.

I agree with the others who are unhappy about you leaving an appliance burning like that.  As a minimum, you should have a CO detector and able to walk away from EVERY service call knowing the appliance is not producing exhaust with elevated CO level, and there in no measurable CO spilling from the installation.

Pipe sizing is only 1/3 of you planning

@ April 19, 2012 5:38 PM in Generator Gas Pipe Sizing

With Gen sets are on LPG, you also have to keep in mind clearance requirements between, well,  everything(gensets are a source of ignition).  I usually do a 2 stage system with one 2nd stage reg for the house and one for the genset exclusively.  This usually involves either locating the 2nd more than 10 feet away, or piping away the reg vent.

The other thing you need to consider the tank size and vaporization rate.  In my mildish corner of the world a 10kw genset needs a pair of 80 gal tanks, and a 15kw gets a 500 gal tank.  See attached delightful reading material from my fav regulator supplier.

No Fan

@ April 18, 2012 1:44 AM in Homart 600 fan not working in auto

What you are describing is typical of a failed fan motor.  Could be other things too, but most common would be a dead fan motor.

The thing you have to be carefull about is many older furnaces will keep bouncing off the high limit:  this is a sequence where the furnace burner comes on, the furnace heats up, the fan is switched on but doesn't function, a small amount of hot air may gradually waft up through the vents.  The furnace continues to heat up until it hits a over-temp high limit that turns the burner off until it cools down and then it starts over again in 5 min.  If the limit switch then fails; you risk a house fire.

In a house that has been for sale for a while, the previous owner may have been reluctant to get it serviced, so it may have been limping along like this for some time.

Just googled the Homart 600.  Old.  Consider replacing.  the energy savings of new gear could exceed the interest expense of financing it making it an easy decision to make.

Gas pressures

@ March 11, 2012 1:52 AM in Gas piping outside?

The gas pressure in modern P-E street mains is often 60 psig; best not to play with that part.

All appliances are required to have low inlet pressure only (7"wc)

If your service is a 2psig service, all appliances have to have a 2psig to 7" appliance regulator.

There are 2psig BBQ outlet boxes available that have a shut off valve, a 2psig reg, and a quick connect coupler inside them.

Also note BBQ outlets must have a fusible link inside them that shuts off the gas flow when your new BBQ: gets a little old, full of grease and lights the side of your house on fire when it's imitating the Olympic cauldron.  The idiots who use the quick connects intended for air tools as BBQ couplers should be shot.

x

@ March 11, 2012 1:24 AM in Combustion air

why you sometimes need high & low air supply vents

@ March 11, 2012 1:24 AM in Combustion air

I think the rule goes something like this (plz don't do without checking 1st)

For passive vents you need 7.5 sq inches per 100 000 BTUs if there are no draft hoods (or barometric dampers) in the room.  Air supply vent usually terminates at floor level.

You double that to 15 sq inches per 100k BTUs if ANY draft hoods are present. Plus add second vent the same size located as near the ceiling as practical and must be higher than the highest draft hood.

All vents must be above highest anticipated snow level.  If the air supply vents are ducted, they also have to be separated by at least 36" on the exterior

The intent of the requirement is to recognize that many installations will spill through the draft hood for a brief period of time on cold start up while the vent is warming up and developing adequate draft.  This creates a need to have a path for the spillage to exit the mechanical room and avoid recirculating back to the burner and making it barf out very high CO.

Replace the igniter

@ March 9, 2012 9:37 PM in GlowPlug lights - but no flame

If it's giving up only 5 secconds after it starts to glow, replace the igniter.

Yes, it's toast

@ March 9, 2012 12:20 AM in Gas Vent Condensation

The B vent has to be replaced.  B vents have aluminum on the inside that corroded to make the white dust, now the exhaust is corroding away the outer jacket. 

This vent has failed and needs to be taken out of service immediately.  The corrosion will be worse in your attic where the vent was colder, there is risk it could fall apart and start venting the exhaust into your attic instead of outside.

Bvents are only expected to tolerate very brief wet times, unfortunately a lot of furnaces with no draft hoods and designs with very little excess air will have exhaust that is completely saturated with water.  So the sweat fiercely and for long times which kills the vent.  When it's replaced the new vent should be the minimum size allowed per the venting tables, the connector  should be B vent as well, and, if allowed in your area, the length in the un-heated attic should be insulated.

The irony is; if you looked at the economics, replacing the furnace with a 96% unit would have likely saved you a lot more money and netted you a better return on your investment than the HWH.  
  

Old 'A' vent

@ February 28, 2012 10:36 PM in flue pipe mystery

It is an older style of A vent, originally designed for venting oil appliances, the uppert tee looks like an old Selkirk Metalbestos style and the lower tee is a subsequent replacment, much newer, different brand.  Certification was toasted when the tee was changed.

A lot of these old vents had corrosion issues due to the stainless inner liner and galv coupler and outer jacket.  It should be viewed as suspect due to it's age.

I've slowly changed my mind on this one

@ February 25, 2012 5:38 PM in Is this vent pipe installed incorrectly and the source of my problems?

I think there is a strong likely-hood the moisture is coming from the vent.

Everyone in the heating business has dealt with issues perceived to be caused by our work in their house.  The nature of these claims are widely varied and often border on bazaar.  I had a customer once who phoned the day after we did an install in his house and was quite upset because his car wouldn't start and wanted to know what we did to it (we walked by it several times!).  Invariably, our work seldom has anything to do with the problem.  So I admit I started off being a bit skeptical when I read your initial post.

With no building paper under the siding (in my area its always present, even in old homes), you can see daylight getting in near the junction of the upper wall and roof, and the prevailing air movement appears to push the exhaust towards the wall.  It's easy to see how at least some exhaust is getting into the attic.

As far as remediation.  I think you need to get rid of the moisture, to stop the mold and rot.  After that; why go to the expense of removing it when its in the attic?  It'd be different if the mold was in a living area of the house.   In most houses leakage between the habitable part of the house and the attic is one way only from the house int the attic (google "stack effect").  You most likely won't be exposed to the mold spoors.  So why have it removed when it will just go dormant and eventually die off from low humidity and high temps in the summer?

more info

@ February 23, 2012 3:30 PM in carrier furnace lock-out

Post an e-mail address, and I'll send you the lengthy heat exchanger failure evaluation bulletin from Carrier.

Condesate trap?

@ February 23, 2012 11:22 AM in carrier furnace lock-out

Did you take the condensate trap out & clean it out?  These can get full of crud that settles and clogs the lower port to the secondary hx, and then the hx runs 1/2 full of water with similar results.  There's a little 3/8" hose that's only 1 1/2" long (when it's set up for up-flow config) be ready to see a quart of water gushing out when you disconnect it.

The 200 ppm was from an old Carrier/Bryant service bulletin for diagnosing for failed hx issue.  When I've run run into failed 2nd hx in the past they pushed over the 2500 ppm max of my Bacharach.  So I'm still a little doubtful it's the 2nd hx.

If it does indeed turn out to be a failed hx, it'd be worth repairing.  They were otherwise very good furnaces.

Changing the vent location

@ February 22, 2012 10:11 PM in Is this vent pipe installed incorrectly and the source of my problems?

The video does show the gently prevailing air movement in the area pushing the exhaust towards the wall.

What is in the room on the upper level near the vent?

I'm thinking maybe the vent could be run from the lower attic sideways into the room (hopefully a closet) below the problem attic and then up and out the the upper roof.

If you have a look at the installation instructions, they usually have an allowable combination of: Furnace size, vent length, vent size, and number of elbows allowed.  So by example; you could work out that your 80 000 BTU furnace with 2" vent can have 50' of vent length with 4 of the 90 degree elbows, or 35' length with 6 elbows.  Measure carefully every single inch of  existing vent length and count elbows along the way.  You may find it necessary switch it to 3" vent to allow a longer total length and more elbows.  Yes, it is a bit convoluted.  Have the company who installed the furnace do this, or, hire another qualified dealer for the same brand of furnace you have do it.

Maybe, but have a closer look

@ February 21, 2012 2:40 AM in Is this vent pipe installed incorrectly and the source of my problems?

You should have the vent moved if the wall stays wet, but that's not nesesairly what's causing the problem in your attic.

The siding should be able to stay wet for long periods of time without harming the building.  The building paper under the siding is supposed to be providing the barrier keeping water from penetrating the wall.  See the attached picture.  Note the flashing they show at the bottom .  On the junction between your lower roof and the wall you should be able to see about 2" of flashing, but your siding is coming right down and touching the roof.  So that tight junction could be packed with dirt that could be letting water wick up into the sheathing behind the flashing.  I mention this because in your picture of the roof the siding looks like it has mildew lower down the roof.

There could be other problems as well.  Like if you have constant warm air from the house leaking into the attic.  Humid air from the house looses it's capacity to hold water as it cools down so it can condense in the attic.  So have a look at draft proofing in the attic, leaking bath fan vents, If you have added insulation to the attic both the size and qty of vents near the peak and at the soffits (as well, the 'trays' between the soffit and attic should not be clogged with blown insulation).

Have you added insulation to you attic in the last few years?  I've seen some issues with mold in attics as a result of just adding insulation and not considering draft proofing, and attic venting. The good news is you don't really need to remove mold from attics since you are not normally exposed to the air in your attic.  Just stop what ever is making it wet enough for it to grow. 

It's now a common practice to install gas appliances with side wall venting.  I've had very few issues (and never with a roof terminal location), but it does sometimes happen.  Usually due to the prevailing gentle breezes that may push the exhaust back towards the house.  I'd suggest asking the company to have a look at the instructions for the furnace and see if they can add more elbows and length the the vent system.  If they can,  have them move the vent further away from the wall by offsetting the vent where its inside the lower attic.

If it's not too late, I'd skip the liability/legal part of the discussion.  If the installing company becomes concerned you are going to sue them, they may not want to move the vent since it could be taken as an admission they did something wrong.  

It'll still condense

@ February 19, 2012 2:53 AM in Buderus- Chimney Condensation problems

I still think the best option will be switching to a stainless vent system designed for continuous condensing.  You have a non-condensing boiler, but you definitely have a condensing vent system.  Even if the boiler gets set up for longer run times, the vent damper is going to shut off the chimney when it's not running and it will cool right off again.  There so little heat going into the chimney for its size and being exposed.  Eliminating or clipping off part of the vent damper would help by keeping the vent flowing and warm, but a significant efficiency loss will be incurred ( you did buy the  thing to reduce heating costs,.. right?).  

Since it does have a draft hood, the vent has to be bigger, at least a 5", and maybe back to 6" (according to Can. Code) if they have to use a corrugated flex liner (used if the flue isn't straight).

Using B vent for vent connector might help, but I don't recommend it since there is always corrosion potential between the stainless liner and the aluminum inner jacket of the B vent.

I also hear you are frustrated by this issue and want it solved.  I don't think anyone here would say that any of the other alternatives would work with 100% certainty.

One other alternative would be installing a Teerlund power venter and convert the boiler to side wall venting.  The down side is the cloud of steam/exhaust that you will then have coming from the area of the terminal.  This would cost a lot less.

....uh oh

@ February 16, 2012 12:07 AM in Test Holes

Wool socks don't work.?...?

Condensate in the vent

@ February 15, 2012 11:52 PM in Buderus- Chimney Condensation problems

The condensate coming out of the chimney could be an indication of an incorrect vent lining system being installed that won't last.  Might be.  Defiantly warrants a close look.

Have a look at the venting section of the installation instructions provided with the boiler.  I think this is a unit that typically requires a smaller (3" or 4") vent made of a high tech stainless alloy.  the Joints in the pipe lengths should have gaskets in them making the vent system water tight.  Usually near the boiler there is a tee with a condensate drain built in to it.

Like this stuff:   http://www.novaflex.com/productcart/pc/viewcategories.asp?pageStyle=p&ProdSort=19&page=3&idCategory=39&viewAll=yes

If the chimney is an exterior one, insulation becomes important to avoid the possibility of the exhaust icing up and choking off the vent in extreme cold weather.

Its very doubtful you have leaks.  Newer higher efficiency equipment generally have exhaust that is completely saturated with water vapor.   This is due to very low excess air in the burner design and the absence of a draft hood or draft regulator that allowed additional air to enter the vent.  That additional excess air and dilution air has a benefit helping dry the vent out, but it did so at the expense of overall efficiency. So your new boiler should have a vent system designed for continuous condensation without harm.

Please post your outcome.

intermitent carrier

@ February 13, 2012 5:07 PM in carrier furnace lock-out

The MXA was, I think, a 2 stage, condensing furnace, sealed combustion.

If code 31 is somthing along the line of 'pressure switch fails to make', then fire it up and after 5 min sample with your CO tester exhaust.  If it's over 200 PPM, (usually waaaay over) then suspect cloged/failing seccondary heat exchanger.

Carrier had some issues with the laminating material they were using for thier seccondary heat exchangers during that era.  Carrier has a warranty that covers this failure with customer option for repair or credit towards new replacment furnace.

If it passes the breathilizer test, don't bother tearing it apart just to look at the 2nd hx, it will be fine.

Let us know.