Heating Help

PVC for vent systems

@ May 14, 2011 9:04 AM in Is PVC an acceptable vent material for flue gases?

Regardless of its performance over the years I think that as an unlisted product for the application, its days are numbered. Charlotte went thru some linguistic gymnastics a while back in the "Suitability of PVC for vent systems" letter. Essentially they acknowledge that it is not listed, say there isn't enough of an installed base to make a reasoned assessment of it suitability for venting (nonsnese) and then say it is up to the equip manuf to determine the best material for their system. This type thing is just blood in the water for the Trial Lawyers Assoc. This one will make polybutylene and Plexvent look minor. I hope I am wrong!

A part of this suitability discussion goes to the type of appliance. A warm air furnace that never gets its filter changed will run up on limit and cycle on and off on that limit. Once a boiler has heated and cooled its operating fluid becomes kind of an inert fluid and there is not much scaling...normally, that will take place. I have seen quite a bit of brown PVC on tank water heaters. I think this has been on mostly high duty cycle apps.

When Rinnai was designing their condensing water heaters we told them that for competitive purposes we needed a PVC vent system. Rinnai Japan Engineering took one look and said, No joy on PVC and we now have a Polyprop concentric vent. With their explanation, I have to agree with them. Every gallon of water going through a tankless water heater is fresh water. If, over time, the unit scales up you end up with an increased stack temp. A limit in the stack could be a solution, but it shows the product to be unreliable (hot/cold cycling shower) and I'm of the opinion that a limit is a safety control, not an operating control. Where PVC can take 156F the polyprop will take 250F. I'd rather take the high road on this with tankless and am pleased with the decision RJ engineering made.

I think a part of the problem PVC will have going forward is the availability of the Polyprop in the market. It is a better material and as the discussions heat up on PVC, and they are, the pressure will lead to the higher spec product...whether you need it or not.

Today, where is pvc NOT legal for use?

Before

@ May 10, 2011 6:05 AM in we wish to convert-propane to oil heat

changing anything I would strongly suggest you follow Charlie's advise and get a good guy to look at what you have. I bought a house that had a horiz lp furnace. The system had been added to an old 1400 sq ft house. In my case, the furnace wasn't the problem, other than not being able to get to it. The problem was the duct $y$tem leaked like a sieve. Air was going everywhere but to where the ducts were run. You may be in the same situation. Speak with the service manager of the gas supplier. If you don't get what you need there call the manuf of the furnace and find the local rep. Ask for his help in finding a good HVAC guy to analyze the install. Look before you leap. As well, look at your states programs for energy/system analysis. You may get some assistance there

I know you guys know this, but...

@ May 9, 2011 1:42 PM in I know you guys know this, but...

I sure don't. I have on occasion found this site useful

http://www.engineeringtoolbox.com/

Just an fyi!

Tim, remember in '92

@ May 7, 2011 8:15 AM in Help with Table 13.1

When the venting tables first cme out all the furnace manuf. Decided that they could have one furnace that would do both Cat I and Cat III. That lasted a year or two and then one by one the difficulty of using a Cat I "inducer" to handle side wall vent requirements convinced all the warm air guys to make two separate units.

I'm with you on the NAT col being correct, but what is the static capability of the Carlin...and what kind of mischief could ensue if there is any short cycling, oversizing, etc on this job?

www.gothotwater.com

@ May 2, 2011 6:18 PM in Thoughts on DHW circulation return controls for MFD settings...

Mark, check this system out. It really is excellent. Give Larry at Metlund a call and let us know what you think of this. It is head and shoulders above any other system out there...imho that is!

Great news....

@ May 2, 2011 6:11 PM in Osama Bin Laden is DEAD...

Now declare victory and get home!

If I was in your spot

@ April 25, 2011 12:16 PM in Baxi Luna 24fi motherboard issues?

I'd go back to the " rental/ owner " company and start again. I'd request the dept manager. Make sure you have model/ser # available. I'd contact Baxi directly to see if parts are in fact available for that unit prior to calling them again. Make sure you know who you are talking to for follow-up calls, if necessary. Good luck!

I put that out there

@ April 2, 2011 7:19 AM in Need Help figuring out gallons needed for water heater

to prompt the thought that getting out of the mechanical room is not a bad thing. The water heater has tradtitionally been installed in the mechanical room because that is where the chimney was. Then it was because that was where the boiler was. I could care less about a chimney and the tankless doesn't require the boiler. Given that, why is the water heater in the mechanical room when it may not lend itself to the best comfort of those living there or the efficiency. I bring this up to all arches and GC's I talk to. I also tell them that they are wasting money on masonry chimneys. Why use 11th century technology to vent 21st century appliances. Save the money on the mason and pay the plumber more;)

the best way to recirc any hot water system from an energy, water waste and time issue is to use the Metlund Design system with the motion sensors. Check it out at www.gothotwater.com I don't sell them. Practical, sensible recirc design.

Another option

@ April 1, 2011 6:08 AM in Need Help figuring out gallons needed for water heater

A few years ago I visited a 10,000 sq ft'er that had 3 Rinnai water heaters. Had they plumbed it traditionally there would have been a million miles of copper throughout the building and recirc would have been necessary. They built a small insulated "dog house" in the attic at each vent stack and put one Rinnai in each spot. A short vent thru the roof and they downfed that stack. Minimal amount of labor and piping and excellent response at the tap. They punched a small register up thru the second floor ceiling for some heating and it worked great. It was an excellent solution.

For this size house breaking the hot water system up into areas is best for tankless. Traditional piping and recirc can consume more energy in heat loss off the piping than the actual hot water demand costs. I am stunned at how few people insulate hot water lines.

For the big showers storing hundreds of gallons makes no sense either...imho, but I am biased;). If I can put in 5 tankless water heaters delivering 25-30gpm, or whatever the required number is, you will have unlimited hot water for the 40 min shower ( as long as you have gas, elec, water & septic capacity, and I have a story about that too). Then, when you shut the shower off, to get out of it to go pay for it, you consume zero energy. Due to the ability to control all of the Rinnai's together you have modulation from 9500 btu -1,000,000btu. We can manifold up to 25 units. How big is the shower flow rate?

De-centralize the big systems. Yes, you have to run significant gas lines, but the systems performance is better.

There are bathrooms...

@ March 28, 2011 6:41 AM in Need Help figuring out gallons needed for water heater

And then there are BATHROOMS! Do you have any high flow or body sprays in the place?

Don't change...add

@ March 25, 2011 6:30 AM in To convert from oil to gas or not?

Look at a mini-split heat pump. First, you get AC/dehu. With the 410A inverter systems the heating performance is excellent. You run the HP in the shoulder seasons and you decide what the balance point is for you to bring on the oil. You will save money.

Another angle

@ March 22, 2011 5:52 AM in To upgrade or not?

The way to make oil more efficient is to burn less of it. Look at adding a mini-split heat pump system to the house. You get cooling and dehu as well as excellent cost effective heating. Keep your old system in good running order. You pick the point where you turn on the oil. Depending upon the lay-out of the house, it can offer excellent zone control.

Given that you have gas in the house ou could also add a Rinnai direct vent wall furnace. either of these gives you a hybrid system. It offers choices in heating. My normal disclaimer is due here. I represent Rinnai as well as a Fujitsu on the mini-split side, so bias noted, but both systems are happily in my home.

I think you can get most

@ March 18, 2011 6:05 AM in Converting from steam to Geothermal??

Of what you want by adding mini-split heat pumps to the house. They are pushing the efficiencies of geothermal and offer the best zone control for far less than geothermal. Keep your steam system maintained and you choose your balance point. Perhaps best of all, you can do mini-splits in stages.

pellet stoves are

@ March 2, 2011 6:40 PM in venting oil and pellets

not negative pressure appliances. They have a positive pressure vent system. A chimney for your oil appliance is a negative pressure system. You cannot combine the two. As well NFPA 31 specifically prohibits solid fuel and oil venting into the same flue.

Get two 1/8" brazing rods,

@ February 28, 2011 11:28 AM in locating underground pipes

Bend a 90 6" from an end. Hold them loosely in your hands pointing straight ahead of you and SLOWLY walk across the area. As you go over the pipes they will spread to parallel the pipeas you go over it. I cannot witch a well, but can find pipes accurately this way.

Just saw this post...

@ February 26, 2011 6:51 PM in At what outdoor temp is a heat pump

I'll see if i an get some info.

Check out

@ February 15, 2011 7:40 PM in Recirculator for a hot water tank system.

www.gothotwater.com Excellent system

you can try

@ February 15, 2011 6:59 AM in 5" double wall DSP like oil flue pipe (not low temp)

Dura-vents DVL and Metal-fab. Not sure if it is 5" though. These pipes are L-vent which of course meets our NFPA 31 venting requirement for oil. Pellet vent is L-vent also in 3 & 4". The 4" has come in handy at times. Look over Appendix E in 31 for sizing "guidelines". I say guidelines because we were never able to get that part into the code. From the people I've spoken with who have used E the sizing were spot on. I think you will find 4 & 6.

According to Rich Krajewski from Brookhaven, who did the work with John Strasser on the Appendix E, the best thing you could do to improve your vent performance, with metal chimney, lined or unlined masonry was to use an insulated vent connector.

I wouldn't put a nickel

@ February 13, 2011 9:33 AM in RINNAI 2532 C

into this unit until the internals are squared away. Rust on the burners? If they have had condensation coming back onto this unit the biggest problem is that the moisture boils off the finned hx and seals up the fins. That causes hot spots and ultimately leads to hx failure. On the burners, if you have had condensation getting back on them it is best to remove the burner tray, remove the strap that holds the burners in the rack (4 screws) and individually clean them with water/compressed air. I will take each burner and tap it, gently, face down on a horizontal surface to get that white precipitant out of the burner. Make sure you identify the 3 low fire burners by the flame rod and sparker. Set them aside and when reassembling the rack put those three on the far left so they become high fire only burners and you put the 3 from the far left in the FR/sparker position. On the "clear tube", we have a problem. If you look at how that equalizing tube connects to the burner tray and gas valve you will see that in the burner area the sensing port is elevated about 3/8". That is to prevent minor debris/moisture from being able to get into the tube. If you call Rinnai tech and tell them you have signs of moisture at the bottom of the tube at the gas valve they will insist/demand/require a new gas valve, and correctly so. One other thing I have found when improperly vented and no drain tubes present the moisture goes down the fins, then the burners and if there is a great deal of it, it passed down to the air diffusing plate between the inducer and the bottom of the burners. The air difussion holes heal up and now we have the full monty. You can't get air to it, the gas valve is toast, the hx is compromised, but not leaking...yet.

Due to improper installation, this unit may likely be compromised beyond reasonable repair. The question is, how much in parts and labor to save a unit that even when repaired is not "like new" as the customer would expect. If you want to talk this over, give me a call at 617 834-8751. That is my cell

An alternative is...

@ February 13, 2011 8:49 AM in Direct Vent distance between inlet and vent

to suggest other side wall locations. such as an exterior wall closet and then box the piping in. As well, I've had guys run some of our DV equipment vents up behind the lazy susan in the kitchen. That is the deadest of dead space and gains quite a lot of height above grade. To paint PVC I've always wiped it with hite vinegar to strip it and then painted it out to match.

In my house

@ February 12, 2011 9:21 PM in Cold sandwich

The other day I took the second shower of the morning, I had the existing hot water in the piping. Given that the water flow had stopped, the burner must shut off. When I started the water flowing for my shower it was still a hot shower so I entered and began, well, showering. A few moments later I felt the water begin to cool as that slug of "cold water sandwich effect" start-up water get to my shower. Recognizing what was happening, I stepped aside for about 5-7 seconds and the cooler water passed and I had a nice hot shower. That is it!

that is a nice looking job, Scott

@ February 12, 2011 8:52 AM in Install pictures of four on demand HWH for Rest.

And I am sure it will please the owner both in performance and economy.

As to the pp discussion, well, I was in the last apprenticeship class that had to wipe lead in our local. I did a lot of lead and oakum CI and then we had the great advancement to no-hub. Terrific, I spent all my time drilling 3/4" red-heads as you had to put about a million hangers in to support it. Then on to PVC/ABS. For the iron pipe the Victaulic was a great advancement except for the mechanic who had to butter up the gasket, the fitting halves, the pipe and then try to hold it together with greasy hands while trying to place the bolts.
There are all kinds of "advancements" in the technology of piping, making it easier for about anyone to do the work. What will not be replaced by that technology is the eye and the heart of the mechanic who knows what he is about and can lay it out so it looks like it is supposed to be there. I get to see a lot of jobs, and it is such a pleasure to walk into a guys, or gals job and see a really nicely laid out job. Personally, I think we should heli-arc everything 2" and above;)