All codes aside for a moment

Unknown

that was "outlawed" awhile back,, but Ipex got certification for their own PVC.<BR><BR>Dave

Unknown

What

are you using in the U.S. for mod con venting materials?(I`m in Canada)
PVC plastic?,, SS?,, many have ABS here!
Just curious.

Dave

Todd S_8

Venting materials

I actually just heard today that Canada has banned the use of PVC and ABS for venting heating equipment, is this true?

Bob Sweet

What

the manuf. lists as acceptable venting materials.

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Unknown

Bob,

In Canada we are told only SS is acceptable,, how am I to charge $70.50(my cost) for 1-3" 90?,, ludicrous!!

Dave

Todd S_8

CPVC

Is the IPEX product CPVC?

I was discussing this today and was told that the flue gas temps in a modcon are 18f above the return water temp. Since a lot of these boilers are used in high temp applications, it appears that the temps could easily be over 200f and I believe that is out of range for most plastics.

Unknown

Todd

You have to look at the limit settings of the M/C, not your "dialed-in" stuff. It can only get the system as hot as that.
BTW-The answer to your above question is yes.

Dave

Todd S_8

dialed in

I'm not sure I know what you mean by this.

I know some modcons are limited to 167f, but there are several that the limit can be changed simply by changing max fan speed. This is a bandaid that is used when the system won't heat like the old clunker it replaced.

Bob Sweet

Oh I agree

bureacracy at its best. Although not out of line with many manuf. that only allow proprietary venting systems for their equip.

I wasnt trying to be a smart @ss just answering your question of what we (I) are using for venting material. Give it time with our fervent desire to be like others we will be following right behind you.

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Unknown

Good question Todd

and that`s a "grey area" to me also.
The M/Cons I use(not being specific), have a DHW point factory set at 194, but it can be set lower(no higher), if we override these settings(and go lower), is this now "interpreted" as the hi limit?

Dave

Todd S_8

As I understand it

Yes, I know of jobs for simple one temp radiant that we lowered the fan speed and were able to run without any additional mixing device. This in essence became the "new" high limit. What I didn't like on any of these jobs is there was never an additional high limit to prevent overheating when the control eventually dies and a new one goes in without being "dialed in".

There goes the terrazo!

Unknown

Thanks Bob

Just can`t see much use in paying more for an exhaust system than the units worth. Autos are astronomical, would a titanium or SS exhaust allow any of us to live longer?
Yes M/C boilers cut GG, and are most certainly efficient from a "consumption" point of view, however(most) manufacturers only warranty them for 10 years.Tough to tell a customer I`ll be "X" cost for the boiler, then half that again for the venting materials that terminate directly outside his home.

Dave

Todd S_8

chimney costs

How would you like to have to replace the venting system in 10 years or less? I wonder what the life expectancy of AL-29C or CPVC in these applications is?

I am following this closely as the more I learn, the more questions I have.

Unknown

Todd

Is`nt the Wall great for all perspectives?
And I wonder about your questions too,, however I would think CPVC(as you mentioned, w/temp limits) would outlast anything.

Dave

Bob Sweet

As far as I

can tell it is a crap shoot. PVC has been used on hot air for 20 + yrs,with some manuf. allowing the use of cell core. If flue gas temps are the issue than redundancy must be built into the controls (gas valve, limits, sensors etc) I question the motives behind these venting limitations, but defer to the authorities in the end. I lean towards the use of proprietary vent systems (coax, most use polypropylene combustion side) I give the benefit of doubt to the manuf.

I'm not an engineer and sometimes question the additional $$ for the venting but at a certain point you HAVE to cover your butt.

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Unknown

Thank You Bob & Todd

I respect your opinions and appreciate our exchange! This is fun!

Dave

Unknown

Missed this earlier

Todd could you not have added an external HL control to the system after the HX?

Dave

Todd S_8

venting w/ scorched air

From what I have been told, the flue gas temps are 18f above the return water temp. This being said, I would imagine that for forced air they are similarly 18f above return temp ( I don't know if this is correct though)
So if the average return air temp is 70f that would make the fluegas temp 88f. Obviously much lower than a boiler.

I hope someone with more knowledge will comment on this.

(is it forced air or forced error!)

Unknown

Just a guess

as I do no FA work, but I think it has something to do with temp-rise across the HX based on the fans CFM?
Just a guess though.

Dave

rich pickering

Dave

Ipex has the high temp venting too. Don't quote me but I think it is cpvc. Haven't got my specs here. But it does cost a lot more.

And our inspectors are looking for it.

Glen

It depends -

but look at this website. It clearly lists two types of 636 PVC for venting. And while CSA B 149.1 is clear on this requirement, you may still have local inspectors or jurisdictions require different standards. Moreover - the manufacturers specs and installation manual reign supreme. So if the mfg'r wants AL29C - then that in fact becomes the code for that installation. ABS and standard PVC are not suitable for any type of gas appliance venting.
http://www.ipexinc.com/Content/EN_CA/2_0_Products/2_4_Plumbing_Mechanical/2_4_9_System636.asp