Heating Help

Hi Tech back when.

@ December 15, 2011 1:22 PM in Question for homeowners

Regarding surveys with technology. Time moves forward and so should we. Many will be left behind. Thirty years ago I walked in with a sling psychrometer to diagnose a humidity problem. The elderly man took offense claiming I was trying to scam him with it. I was shocked he was so ignorant about this simple instrument. No words could change his mind. Happily he was the only one in my entire life I met. Yes you may find resistance to accept your fancy tools, but not enough to worry about. Speaking of which when you tell people your tool can cost up to $2-3K you are using, they begin to appreciate your value.

reply to air in system

@ April 21, 2011 2:47 PM in Constantly purging air in hydronic system

I am thinking: In order for air to enter your system it has to be pumped in or let in. I find it unusual to suspect the utility water supply as a source containing air unless a problem exists on their system. It takes a certain amount of pressure to makes sure a leaky air vent will not allow air into the system and although a pressure gauge at the basement may read 12-15PSI, it most certainly will not be that at the top of the system. With 12 PSI on a gauge a pressure of 3 PSi could be found at the top of a system. and even though parts are new, pressure devices & gauges can lie, so it is important an accurate test gauge measure the pressure to make sure the fill valve is on and properly performing its job. The science of air in hydronics is that water under pressure will contain entrained air until its pressure is reduced and temperature increased where it will tend to change into free air bubbles you may be accumulating at high points. In order to prevent entrained air from being released into a lower pressure zone, a certain pressure must be present. Also it is known that an air cushion device such as an expansion tank can be siphoned of air in a cool down cycle to be later redistributed to a lower pressure area in the system. This is why steel expansion tanks without sealed bladders loose their air charge. New filled systems contain a lot of entrained air. So it is important that a tight properly pressured system with a bladder expansion tank be used. The older the water the better. Pressure changes can also occur with pump action, but normally are insignificant when system is properly pressurized.
Possible solutions: Verify pressures and the fill valve operation. Verify a check valve and or some type of back-flow protection exists to keep the system from draining into the supply water should pressures there drop. ( usually a code requirement). You could change the expansion tank to a bladder sealed type that keeps air and system water separate. This has proven to prevent call backs the next year from many customers. Properly pressurized and maintained if a leak occurs it should show water and not be a hidden leak sucking in air. You could also raise the pressure to 20 PSI. Just don't exceed the expansion pressures that might trip a 30 PSI relief valve which is standard. Just so you know many residential boilers used in commercial application are re-rated with no change other than adding a 50 PSI relief valve when higher pressures are required like in a four story building. Also there are superior air removing vents that handle the tiny entrained bubbles, there is however many opinions on many brands.
Hope this helps. By the way AMTROL made an extensive study of air in hydronics. Steel tanks can remain, bladders are better until they fail. some are made for potable water higher pressure and others for hydronic low pressure heat systems. They are sized on volume and btu input and summer winter v cold start.
Best regards, Lance

Water

@ April 21, 2011 2:06 PM in softened water in boilers

It is amazing to me how little we learned from our school systems even though we are on a planet largely covered with water, in bodies made up mostly of water. It is good to see learning does not stop when we graduate. Pure H2O is one thing but water in all its variations is another. Even my Master Plumber education is still expanding on the science of water. One thing I did find fascinating is that pinholes in copper piping can be caused by too much velocity. The film that forms on the inside of a clean potable water system actually protects pipe. Flush it away and pin hole city. Did you know water does not always crystallize at 32F. Boy would my science teacher get an F today. I have seen filtered water liquid at 22F at atmospheric pressure, and only when acted upon by adding energy such as heat or movement would it then start to crystallize. The science of water from ice to steam is truly a science that needs much study. One might say water as we call it is actually a solution of many different elements of which we almost never know its true identity and properties without a chemistry lab.

Expansion tank or is it another problem?

@ March 31, 2011 10:50 AM in Expansion Tank

Expansion tanks are a critical component to prevent damage and high pressures created from expansion of a liquid in a closed environment. While tankless heaters minimize this effect, it is the manufacture specs that must be followed. We are warranty tech reps for water heater companies and often disallow warranties or fail commercial startups when expansion tanks are not present. Many times I have seen tankless heaters undersized, because the specs weren't really understood, or the btu input was not present or changed to accommodate a large enough heater. Just to get 3 GPM flow out of a tankless requires at least 150,000 BTUH input. Also some heaters have flow restrictors designed in them to try and maintain a temp set point when flow rate is exceeds it set point. Or the heater could be malfunctioning. Good luck.

How much is enough?

@ March 31, 2011 10:39 AM in Need Help figuring out gallons needed for water heater

When it comes to sizing residential water heaters, I always compare my notes to the old rule that to supply an unlimited amount of hot water at 3 GPM, I need at least 150 MBH to supply it. As this energy input is not always available, storage is required. My best advice is to check with the manufactures like A O Smith or Bradford White. And in large places with long runs on pipe, use a recirculating pipe system and make it low velocity, well insulated pipe and properly controlled or you may end up with even lower storage reserves.

Response

@ March 31, 2011 10:29 AM in Condensing oil hot water heater?

I have found that often in homes of an elderly couple or single person that an electric water heater is more economical than oil fired natural draft flue or even the newer high efficiency direct vent units. And has a significantly cheaper life cost as there is a smaller build cost and little or no maintenance and no fumes or leaks from fuel to worry about. Consider that tanks do not last as long as they used to, replacement costs an be a huge factor. Also technology being what it is limits who can service the equipment.

Opps again.

@ December 20, 2010 8:41 AM in Venting hot water heater

From the picture the vent looks fine. The key question is does the heater pass the vent test and meet the code for your area. If it does it is OK.
Drafting flue vents can go wrong even when piped in right. It must pass the test or be modified. The code is a minimum standard and must be exceeded when needed.
Lance

OOPS! Did I hear a shortcut error?

@ December 20, 2010 8:35 AM in Venting hot water heater

Never ever remove a draft hood that the manufacturer provides.
1) To get the engineering ratings it has to be there. It is part of the heaters design.
2) It is also a safety control. In a downdraft situation it diverts the draft to keep from interfering with the burner or pilot. When operating normal, a burner makes carbon dioxide, vents up chimney, in a downdraft it makes CO and vents into the house. This is science and engineering and a highly technical business and requires the people that do the work be learned, trained and most of all experienced if we are going to keep our customers alive and their property safe. 
3) If your house burns down and the draft diverter is not there, the survivors will not be compensated for insurance loss and it will invalidate the manufactuers warranty.
Fix the problem do the right solution it's cost is cheaper than your life and home.
Your installer was wrong to alter the vent connector. Especially if it fails the NFPA 54 gas code.
Lance
AOSmith warrranty tech rep and Master Plumber, Gasfitter and HVAC contractor.

Clue

@ September 2, 2010 9:21 AM in Anybody see a boiler do this sitting idle?

I believe from the fuzzy pictures that your answer may be in the color of the metal.
It may have been cracked and weeping for years. The inside of the crack surface should indicate that.
Metal can be installed under stress, pressure and torque on bolts and pipes will created expansion and contraction over time, eventually molecular bond fails and snap, tension is relieved and all stress is transfered from the metal to the owner to deal with. Tension can even start in the casting and uneven curing of the metal.

Best way

@ February 4, 2010 3:21 PM in what is the best way to geothermal a cottage floor

Ahh to build to create, it is what we were meant for.
So many choices, what to do? Build the ultimate or spare no expense or build to my budget, what ever it be.
Principles seem the answer here. Insulation is a slowing of heat transfer. As long as heat applied exceeds heat lost your pipes will not freeze. Access to make repairs is a good thing. All things fail and like you said it gets cold. Anytime you can bring plumbing into an area that can protect it, yet not make too much of a mess when it fails should be considered. Your original plan to spray depends on which transfer of heat wins. Heat loss from the pipes,(freeze) or to the pipes, (thawed). And since heat rises, conductivity is important. Proper building of your thermal sandwich is important.
Your floor temp design may not be warm enough to put enough heat below to keep pipe freeze away.

Heat from geography? Solar heating by radiation?
Thermal storage banks? Backup systems. And it should be a fool proof easy to do system. like Light that fire.
Keep what you want warm near the flame, all else put barriers between hot and cold. Do not insulate from heat what needs heat to maintain. All failing radiant floor systems had one weakness, tubing material degradation. If it is to be buried make it good. Pex Aluminum pex composition seems to me to be the best today. Proper installation is a must.
Make a good plan and follow it. Find a good mentor in your area. Learn all you can.

Another thought

@ February 4, 2010 2:57 PM in radiator reconfigure

Add an outdoor temperature reset control. It will help offset sizing differences, improve savings, and prevent overheating. And if someone forgets and leaves the t-stat on or too high and if the outdoor temp tells the boiler not to run. It will not.
Too much radiation is a sign of wealth, a low temp design or insulating a building after a system was installed. Either way you can keep lower temps and acheive more from a condensing boiler. I recommend a Slantfin Bobcat. And with the domestic hot water unit, you will achieve +90% effiecency on heating that too.
A direct vent product will achieve about 17% more in savings when outdoor air is used for combustion. It also cuts down on drafts.

Migration of heat

@ February 4, 2010 2:46 PM in one small detail could make big results

You got it right. No insulation barrier to slow heat transfer.
Heat energy always seeks to migrate from a high state to a lower state.  Insulation can slow the transfer but not stop it. All will continue until equlibrium occurs.
To create the effect of a wall to slow this heat transfer a trench or slot can be cut in the concrete and an insulation slab of foam or a thermal resistance material be placed in this area. This will achieve savings and the desired results. And if it is cold enough the snow will remain. There will always be a temp difference but not as great.
This is why we install thermal edge insulation with radiant floor. And since insulation is very dependent on thickness to get a good R rating you may need more than 1". An air gap of even a 1/4" in the slab will at least stop the slab conductivity. My first choice would be cut the slab. Caulk just the surface and see how it goes. It must remain water free or it will not work. Good luck.
In the future, snow melt near the edge does not need a lot of heat, perhaps the temp could be lowered. It will still do the job but lessen the waste. You only need maybe 33F after figuring for design loop loss?
In building wall construction wood is not condsidered a thermal break, the air space is. Wood has poor resistance to heat transfer and may not be enough.

Seems to me

@ February 4, 2010 2:22 PM in Boiler pressure gets very high. Water temp is low...

Seems to me you have two problems, one the control and two the pressure. The pressure is now looked at because you have a problem. The pressure fix is to make sure the expansion tank is properly charged and you start with 12 PSI for a two story home.  You should be able to reach 200-240F without going above 20PSI with a properly sized expansion system. Your hi limit can be set as low as possible as long as it is enough for the sized radiation. 150F would be the lowest I'd go. Most systems set at 190F and are designed for this. Ignore the pipes are hot when you get home you never know when if it
Two, the thermostat wiring is critical to match what you have.
Sizing and capacity are concerned with set back temps, not just controls. The greater the setback, the lower the outdoor temp,(the higher the heat demand), and the quicker you want a response means the larger the system has to be. And often too large means no savings. Some setback can save money, but a perfect sized system is designed to maintain a single point temperature and unless the demand is low, return to setpoint may take longer. Good luck.

overpressure

@ February 4, 2010 1:46 PM in high temp / high pressure

When you installed the new tank did you pressureize it to matching pressure before putting it on the system? 12-PSI. Is it big enough? They come in different sizes. Extrol 30 should be more than good enough. 12 psi should be enough to start with unless you are over 3 stories high. Sometimes new products can be defective. I once had a tank that had correct pressure, correct size, but the bladder was glued to the pipe opening and could not receive water to allow for expansion. Turns out there was a slew of them after I was told that was impossible. Another tank fixed the problem. It is hard enough to figure out problems, it's worse when you are betrayed by defects.
PS. Pressure will climb faster than temps normally without expansion. That is the key. Water will not condense. the quickest way to test for a leak is to eliminate all air, and as a few drops leave the pressure will plummet to zero fast indicating a leak or lack of an air cushion.

Pascal's law.

Lance

Limit

@ February 4, 2010 12:22 PM in Fan Limit Switch Tripping Open

Good try, as I just fixed a lennox furnace with a bad hi limit.
The cause of limit tripping is either a bad limit or it is doing its job. If you are referring to a hi limit it may be doing its job and protecting against overtemperature. Look at cause of lack of air flow or too much fuel. Check the combustion,  make sure it is not overfired. Check airflow, blockages due to clogged coils are a common cause, especially with poor filter situations. Is the blower wheel dirty? If so the coil can be matted. The most difficult job to clean is the indoor coil since it may have to be removed and duct cut to access. So it generally gets no attention. It will cost more money to ignore it so it must be cleaned. Possible blower speed problem?
Temperature difference between return air and supply air should not exceed 60-70F.  70F in 140F out. 
If you measure the temps you can make sure the new part is not bad. Sometimes even new parts are no good and are the last thing we want to verify.

Noise

@ February 4, 2010 12:02 PM in Hydronic system noise

I am not familiar with this product, but it sounds like a combustion problem. You may be out of adjustment, or a leak is in the burner area, or the burner has deteriorated.
To eliminate this as a cause, try shutting off the gas valve while running & making the noise to see if you get a quick response. If silenced immediately look at a burner combustion problem. Combustion testing may be in order.
Gas pressure regulator?
Is your pressure gauge validated? Will it go to zero if you drain pressure off?
Hope this helps.

If not too late

@ February 4, 2010 11:52 AM in Elite v. Munchkin

We just finished installing a Slantfin Bobcat 200KBTU with a combi cat DWH and mixing valve. One of the best & easiest installations I ever had. No water tank was needed. Space requirements very little. Guranteed owner at least 5-6GPM on hot water demand.
Check it out.

Concentric vent

@ February 4, 2010 11:46 AM in Concentric Venting

Contrary to popular thinking fuel combustion does not care how cold or hot the O2 is unless it involves vaporation of a fuel and that may not be affected unless extreme conditions apply. The only disadvantage I see in concentric venting is repairing leaks or clogs as some concentric assemblies do not allow for maintenance. Usually my concern is will I be able to fit a larger hole vs a rectangle or two smaller holes in my application.

Pressuretrol reattach

@ February 4, 2010 11:36 AM in 0-3psi #33020

If your pressure trol has a mercury bulb, make sure the bulb travel is perpendicular to the pigtail movement. Otherwise it makes no difference.  Some gauges are internal trapped and may not need a pigtail trap to protect them. Follow the mfg instructions on the pipe dope container, brass to iron should not be a problem.

Chimney concerns

@ February 4, 2010 11:20 AM in Gas and Oil Flue Piping

Your information is lacking specifics. You must check vent compatability.
It is recommended that all components meet or exceed current codes.
Assuming both appliance vent connectors can use a common chimney, "they both use a natural draft flue", it is advisable to have the gas enter above the oil connection to the chimney breaching.Your oil vent connector should have a barometric draft diverter. Your gas unit a draft diverter.
The code involved should be NFPA 54 with any changes adopted by your local authorities. Each appliance installation instructions must be followed.
Your best first step is with the manufactueres instructions. They also can provide apllication support.

Good Luck, Lance

Reply

@ February 4, 2010 10:44 AM in instructional aids

NFPA 54 Gas code

Other thoughts

@ January 7, 2010 8:52 AM in Problem with Mercury Switch/Pressuretrol.. HELP!

Mercury is no longer allowed, if you replace it you will also eliminate problems caused by mercury by incorrect placement on pigtails which move when heated and cooled. Always make sure the pigtail pipe will not rock the mercury back and forth. Good luck

Ps. If the Mercury gets gray and contaminated, it will be sluggish and must be replaced.