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jerry scharf

jerry scharf

Joined on May 17, 2004

Last Post on March 13, 2005

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@ February 22, 2005 12:51 PM in Leaky pipe and mold

Paul, The fact it is not visible means nothing. If they have to stay for now, I would make sure that the work odne by the landlord is being done under the supervision on a trained and certified mold abatement specialist. They will do testing now and until the unit is certified safe for inhabitation. Like I said, moving would be a cost and a pain. I seriously doubt it's impossible, My wife is immune compromized from mold allergies. Trust me, it's way more of a pain and a cost than moving. jerry

Been toying with an idea

@ February 22, 2005 12:16 AM in Energy Conservation

Geoff, You seem like the perfect person to bounce this off of. Handling the construction details of staggered stud walls has always seemed difficult to me. I came up with a slightly different idea on how to reduce the thermal bridging, but didn't have anyone to bounce it off of. My idea is that you build a standard 2x4 exterior wall, then run 2x3s horizontally and flat across those at 16" spacing. Then you foam the wall with low pern closed cell foam. The thermal bridging is only 22 square inches per stud (as compared to 144 for a standard stud.) It seems like a very simple addition to a stabdard framing job, keeps the wall thinner than a 2x6, and achieves R25+ in the field of the wall. If the bridge points are about R5, and constitute 1.5% of the wall field, this seems like a good simplification. I haven't figured out a nice way to decouple the top and bottom plates or the inner frame of windows and doors. How are these handled with staggered studs? thanks for taking the time to look at my musing. jerry

The point about capital cost neutral is a great one

@ February 22, 2005 12:01 AM in Want to make a real difference in energy consumption ?

Geoff, How successful have you been at pitching this? Can this be pitched by a sub of a bidding contractor or does it have to happen with the owner and architect. I'm really waiting to see how well my GFX waste water heat recovery setup works. If it does prove out, it seems like a slam dunk for those "lots of body jets" type of shower. thanks for posting, jerry

I think tesla was a wizzard

@ February 21, 2005 11:22 AM in World Wireless

Many saw him as a fruitcake, but this guy could imagine things no one else could and then he would doggedly set about building them. Not everything he imagined worked, but so many things we take for granted now came right from his brain. The problem with picking one of his ideas is that it didn't seem to be the way he worked. He had ideas flying around, and he would try things out. When an idea hit a block, that idea went back in the brain and he would work on other things, nothing got discarded. The difficulty of his brilliance is that those who follow can't see the problem as he did, so they can't follow the expolration path he would have. Some of his ideas have been disproven (he didn't grasp the impact of quantum mechanics on some of his work,) but most hang in that tatilizing state that Tesla held things in. I'm not sure who could take an idea like this and make it work. Also, I'm not sure it would be the best idea. The electron differential that this would exploit would almost certainly change the way solar radiation would strike the earth. Given the fact that we have already mucked things up by dumping CFCs and the like, it seems like a risky thing to do. then again, I would have been nervous when they set off the first hydrogen bomb having calculated the risk of all the hydrogen in the atmosphere flashing to be non-zero. On a side note, I would be surprised if the theoretical available bandwidth of Tesla's idea could come close to the capacity of the fiber optic fiber currently in the ground. In talking with a friend, we figured that it should be possible to put fiber in the ground such that every computer could transmit and receive and 100Mbps to any other computer in the world with no blocking. jerry

tell them to move

@ February 21, 2005 10:56 AM in Leaky pipe and mold

Paul, I am quite serious. Mold at the levels you are speaking of will erode most people's imune systems, and the older the person is the faster that happens. If they were my parents, I would have them out of there by the end of the month. Costs and hassles of moving would be dwarfed by the costs and hassles of one of them becoming immune compromised. Dehumifiers are for drying possessions, the rental needs mold remediation. Landlords are notoriously bad at paying to have this done right (not all, but many.) In the meantime, get them enough HEPA filtration that you get at least a couple ACH (air changes per hour) for the whole place. It will be noisy, but it will keep the mold spore counts in check. I can talk to you about various types of filters, there are a couple that are not "true HEPA" but can still do the job for them. jerry

dumb question

@ February 19, 2005 11:17 AM in WM ULTRA

Kal, You show the hot water coming into the bottom of the indirect coil and the return out the top. I always thought you wanted to run the hot into the top and the return out the bottom. Am I confused? jerry

do you do after hours service

@ February 19, 2005 1:01 AM in Inventory Stock,,How Much Is Enough.

My $.02. If so, you have to consider the range and amount of parts that are consumed after hours. The supply house and JIT is great when you can predict and plan things, but in the service business you never know what the next phone call will demand. You reall yneed to stock what it will take to get the majority of the after hours problems resolved without a "wait till the supply house opens tomorrow." Ideally, this is all tied to the inventory system, but at the least you need to look through all the after hours calls for the last half year and see what gets used and in what quantities. If it doesn't move in 30 days, but does get a repeat customer back with heat, it can still be a money maker. You may need to bump the overhead fee on parts that sit, and that would be a reasonable way to keep the financials reasonable on these parts. jerry


@ February 17, 2005 12:39 AM in boiler doesnt shut off untill gauge reaches 270 water gets too h

You're absolutely right! I'll go to the corner and put the dunce cap on! jerry

indoor reset vs. outdoor reset

@ February 16, 2005 10:54 AM in The REAL Condensing Boiler is Here !!

Here's my take from a controls point of view. Outdoor reset is simple to build, simple to document, simple to set up boiler optimization. It provides improved comfort and efficiency compares to a fixed set point boiler. It still needs a full indoor control system of some type, and needs to be run sufficiently off optimal to allow the indoor control system to successfully control the interior. Indoor reset is a more complex system that allows an indoor sensor to drive the water temperature. It would normally be implemented in a completely automatic mode, with possibly some kind of adjustment. Indoor reset should be better at estimating demand and can deal much better with things like setback cycles. This allows the curve to be run much closer to optimumu. On the other hand, indoor reset is vulnerable to problems from sensor location. Some can come from transient loads (open doors...) or from transient supplies (cooking, extra people...) A major difficulty can occur with houses that have dramatic solar differentials over the day, making there be no point that is always the coolest. I like indoor reset better, but there may be certain situations where it can be difficult to get a house to optimum comfort. We will need some honest manufacturers to get any sense of how often and to what degree the potential problems of indoor reset occur. It's just too easy to blow this off as installation error when it is actually a control systems design problem. I expect them to be fairly rare, but only the field can tell this. jerry

some other entertaining pictures

@ February 16, 2005 2:01 AM in radiant surfaces

First is the foam going onto 60 year old walls. From no insulation to continuous R20 in a few seconds. The second is preparing the sleepers for the way I wanted to install the tfin. I wanted the transfer plate against the finished floor for the minimal thermal resistance into the room. The third picture is of the sleepers and fin in place and about to get tubing and stapled down. The 15 gauge stapler goes through the fin, sleeper plywood and subfloor like nothing. The auto body air hammer is nice on the floors, but just about mandatory on the walls and ceiling panels. The fin is stapled onto the crossmembers, and the whole unit is nailed into place. A strait edge is held across two framing members, the fin is pushed flush and the crossmember is nailed in. Then the tube is put into the tfin in place, which means there's no backing other than my hand as it is hammered in. The 17' ceiling in the entry area was the most fun. jerry

why choose, use them all

@ February 16, 2005 1:28 AM in radiant surfaces

With the recent talk about radiant ceilings, I got some pictures together. Well, I'm almost done with the radiant surface part of the lab I am going to live in. Given the idea of a lab, it seems smart to put several different types of radiant in the house. 4 of the 5 types are in now: warmboard floor, thermofin floor, thermofin wall and thermofin ceiling. I am working out the final details on the exposed radiant ceiling panels. Part of the premise was to use more radiation capacity and tight thermal coupling to keep the water temperatures as low as possible. With the condensing boiler, returns above ambient are lost efficiency. :) The first picture is warmboard on the first flor section. This is on TJIs with closed cell foam sprayed to the bottom. The second picture is some thermofin U on sleepers on top of plywood. The third picture is a thermofin U wall radiant secion. The last picture is of a ceiling radiant section. All have insulation to direct the heat. the ceiling insualtion is not the building envelope, there is foam sprayed to the roof deck for that. Each of these is installed to address a specific challenge in trying to get "ideal" heating. With the low target water temperatures (trying to keep the supply water at or below 100F), the radiation capabilities and controls will get a good challenge. jerry

don't rebuild, just shim it up

@ February 16, 2005 1:09 AM in Ron Jr.

They say they used to build castle stairs with the top stair too high. This way people sneaking in at night would trip, fall and wake up the guards. Maybe that's just a myth. Anyway, rather than rebuilding the stairs, you can just pull the finished surface of the treads off, and add plywood on top of the structural tread to keep the riser within 1/8th or proper height. That's what I do when the floor changes height, it works either way and it doesn't take too long (as long as someone else gets to put the finished tread surface back on...) jerry jerry

we're saying the same thing

@ February 16, 2005 12:44 AM in calculating solar gain, windows?

The way you described the projection and the way I did look different but turn out to be the same. I was trained as a physicist, so my brain works the way I described it. You are completely correct that ourdoor reset doesn't solve this. This is the soapbox I continue to stand on, that outsoor reset can't adress things like this or room occupancy issues, so you still need some kind of temperature sensor in the room and htat has to continue to be the "primary control" for heat into the room. You are starting to see more and more talk about "indoor reset", which makes more sense. It still is playing "behind the curve", but it's better. My experiments are about seeing how well I can be "in front of the curve" with the radiant controls. Maximum stability and minimum room overshoot are often a hard mix. jerry jerry

shut the puppy down!!

@ February 16, 2005 12:36 AM in boiler doesnt shut off untill gauge reaches 270 water gets too h

If the gauge is right (doubtful), my rough estimate is it will flash to steam if the pressure were to drop below about 27 PSI anywhere in the system at any time. Were this to happen, it is likely that you would be missing at least a couple walls. This is deadly serious, TURN IT OFF NOW! Then call a tech and see what's up. Most likely a broken gauge, but it's not worth your life or your house to bet against it.

Hill Street Blues

@ February 16, 2005 12:26 AM in Weekend movie guide

I seem to remember a couple episodes where there was hot stuff going on in the boiler room. jerry

paying the cost of repairing roads

@ February 16, 2005 12:21 AM in Gas mileage fee?

Now I know people don't like to hear details when they are ranting about taxes, but I think it's important to know you get paying the freight and who is getting off light. The best reflection of this cost is one based on miles traveled times axle load raised to some exponent. There are only a few things that kill roads. The first is improper drainage, and those are on the road builder's shoulders. The second is road cuts. Even with the saws they use now, each cut cuts the road life around half. The third thing is weight deflection cracking. I love those signs on the back of trucks complaining how much they pay in road taxes, maybe $2k. One overweight big rig can do more damage than that on a single cross country run. The taxpayers subsidize the truckers by paying far more than their share of the road repair compared to the wear inflicted. A Toyota Corolla size vehicle could run over a road thousands of times and not do the damage of one of those heavy machinery transports. If not for heavy trucks, interstate class roads would last almost as long as the Appian Way. On the old turnpikes of the horse and buggy days, they charges based on the width of the wheel. PAH, you live near a couple of the old century road historical toll booths. The wider the wheel, the less ruts produced and the lower the fee. Above a certain width, the trip was free. Now that makes sense to me! jerry

Not sure what answer you want

@ February 15, 2005 12:05 AM in calculating solar gain, windows?

Are you looking to answer "how much heat gain I will get in my house today" or "how much I will get in a theoretical building on the 7th of January 2006?" As with everying else, the later is almost impossible. Computing the gain for today is much more tractable, and here is how I plan to do it. First I compute the solar track through the sky (lots of free software that will do that), and compute the gain as a geometric function of the projected surface area of the window (the size of the window projected onto a theoretical sphere centered on the sun.) There is a bit of fudge for atmospheric loss, but that's smaller. The next thing you need to do is to calculate shading. One part of this is the local opject shading, such as walls, overhangs, and trees. This is done with simple projected object coverage. (That dip into computer graphics can pay off.) The other part of this the shading is cloud cover. One way to take on cloud cover is to build a tracker tube photosensor and an ambient sensor and look at hte differnetial. Another way is to collect NWS avaiation weather information on cloud cover for local airports. I plan to start with the later and then later see how it compares to local measurements. enjoy, jerry

It was me

@ February 14, 2005 11:35 PM in Too Hot, Too Cold - Part II

Susan, I just warned you that you were going to want them everywhere once you install them. How close was I? Thanks for reporting back with the success. jerry

It's a V1 not a V2

@ February 14, 2005 2:08 AM in Hydrotherm Hydropulse

Guys, You just don't know your aviation history. The pulse jet "buzz bomb" was the V1. The V2 was a true rocket and was silent after the inital burn. V2 was much more effective and accurate thanks to Dr. Von Braum, who went on to lead the NASA rocket propulsion group. The Saturn 5 used to launch the moon shots was their grand achievement. A house just down the street from me has a new hydropulse installed less than a year ago. Within a week after they moved in they were complaining about the noise. I just shut up and nodded. jerry jerry

Donation from across the pond

@ February 13, 2005 4:38 PM in PLEASE HELP MY DAUGHTER FIGHT CANCER (Dan H.)

Folks, Kelly's been doing her training, and we haven't been donating since the first couple days. We're not doing near as well as we could. I wanted a couple items that are available from the UK, so I contacted Jimmie and Aidan to ask for help. They came through and you will see the result soon. When I talked about paying them, they said rather than bother with money exchange, please make a donation for them. What great folks!! So I went in too and this is a joint donation. We talked about it and Jimmie had a friend who's son battled Leukemia and beat it for now. So supporting Kelly and her run seemed perfect. So even though this is only a couple cents per step, please take it with our wishes for a good race and a great cause. Surely others can put up a penny a step! jerry

Pass on the cooling tower

@ February 13, 2005 2:39 PM in Indirect versus gas fired WH

Ed, The killer for a standard hot water heater is that it has a chimney right through the water chamber. When they have no electric connection, they have to depend on natural draft. When the water heater turns off, you get a nice constant air flow through the water heater cooling the water. With flow checks, the loss from the boiler piping to the indirect will be much less. One test would be to heat an indirect and a water heater to 140F, shut them off and let them sit for 24 hours. The final temp will give you the standby heat loss. The indirect people say that it should only lose a few degrees. Efficiencies will be all over the map for indirects, depending on the boiler and piping. You can mess up the piping and take a nice collection of high efficiency gear and still lose a lot of heat. jerry

two things

@ February 13, 2005 1:27 PM in I'm looking for a test..............(SE)

Title: Please Understand Me Authors: David Keirsey and Marilyn Bates This is a good book on Briggs Meyers testing. I found it entertaining and the test takes about 10 minutes. I don't know how much it will tell about talents, but I do think it can help shed light on team interactions. I would hate to use anything like this for hiring, way to imprecise and open to fudging. It's more useful for finding ways help people on your team work together better. I went through a class 20 years ago on "behavioral interviewing." It was the best thing I have ever encountered for fitting people into jobs. My wife used it for 10+ years as a high tech hiring manager. The first step is to spend a couple hours working through exactly what you think the job needs. Then you develop some questions that you will ask you candidates (all of them.) The questions are formed as "Tell me about a case in the past where you had to handle a difficult customer. What did you do and how did you resolve it." Then "Tell me about a case where you felt like you could have done it better." You really have to be patient when you do these kinds of interviews, it often takes people a minute or two and a couple "I can't think of anything"s before they can answer the questions. Questions about how they worked with the team, how they introduced a new idea to the company, how they handles a new situation or type of equipment, handling hard customers, etc. They stressed that once you form an opinion, always ask a question to try and disprove your opinion. Your questions could be forming people into an of answer that isn't a good reflection of them. These interviews are more work for you, longer and exhausing for the candidates. The cost of a bad hire is way more. I always figured in the high tech world that we lost 6-12 months of salary for each bad hire! With the amount of customer contact, your numbers could well be higher. To this day, I still do all serious hires (with me for more than 6 months) this way. jerry
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