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Joined on March 1, 2007

Last Post on September 16, 2014

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The reason

@ February 20, 2009 11:04 AM in hot water recirc

they use the higher head pumps is to pump the water at high velocity. Metlund has a drawing of the actual flow characteristics in the piping of the hot/cold relationship. It's pretty neat. It shows that at 1gpm you end up with a skim coat of hot water going over the cold remaining in the pipe. At 1-3gpm yo end up with what looks like a long spear point of h/c and in the 5gpm range you basicall have "plug" flow where the hot totally displaces the cold. That takes a higher head pump. Given they have the temp sensor for shut-off purposes, the high head pump is best. If you are recircing to an on-demand make sure you run your return line in 3/4" so you can get the higher flows.

Running wild

@ February 19, 2009 2:50 PM in hot water recirc

recirc is not really a solution to anyones issues and we are certainly in agreement with that. The Metlund's electronics are designed to only recognise the call for operation every 8 minutes, so it will prevent the short-cycling to which you refer. As well, because it has the thermistor on the hot side of the pump, when it sees an 8F delta t it will shut off because it knows that 2' behind that there is hot water. I think it is a pretty slick system One of the biggest issues for us here in MA is that with the Boston Harbor and Charles River clean-ups, worthwhile projects, but we are paying for them, we have the highest water rates in the US. I was reading a report (I think from Lawrence Livermore labs that said that every 3 gallons of water down the drain is equivalent to approx 1kw of energy/cost for delivery and treatment. I think we will be seeing more attention placed upon recirc. I'm looking forward to it and the further discussion. In my own home, I re-modelled two fo the three bathrooms last year and didn't install the recirc. I'm now doing the master bath and will install it there. Without it, in the morning, I have a 45second wait for hot water with the shower going. I'll report back what the time difference is when I get the Mstr Bath done...ahem, whenever that is;/

Respectfully, must disagree MArk

@ February 18, 2009 10:58 PM in hot water recirc

Time and/or temperature controlled recircs are serious energy wasters. Why would I want my aquastat running my recirc pump while I am at work or in bed? The best of the recirc systems is the demand system, imho. Go to and look over the Metlund system for comparison purposes.

For climate control

@ February 16, 2009 9:37 PM in Clamp on Multimeters

I'd look at UEI or Fluke. Fluke gets a lot of support here but UEI does a great job for climate control. Whatever you buy make sure it has a Microamp range for your ignition checks. The microamp symbol is a long nosed U. I used to have a heck of a time with Autoranging meters. I was (or am) a tad dim with meters at times and with an autoranging meter and a modulating piece of equipment that meter would scan and scan and never settle down. I figured it out but I still prefer the manual adjustment of the UEI 383. Can't beat them for the money, imho.

I'm planning

@ February 13, 2009 6:32 AM in Solar roofing material

on a solar system for the house. DHW for sure and looking into a PV system also. While I have instaled many solar system and worked on more roofs, I would not install my system without first doing a re-roof. Mine is a pretty much standard low pitch colonial roof in New England, which I would "over-collector" as necessary to compensate for the pitch. The house is a a two story with a walk out basement, so effectively three stories. This south pitch cannot be seen from the ground as the property slopes also so appearanace of the material is not a consideration. My question is, What type of roofing material do you like to work on. Cost is certainly a factor, but durability (you do have to clean panels) and ease of drainage are important also.

You can contact me

@ February 9, 2009 6:38 AM in Small 4 apartment building,best way to control heat bill

on my phone at 617 834-8751. Be happy to help!

Would your building owner

@ February 7, 2009 4:55 PM in Small 4 apartment building,best way to control heat bill

like to sub-meter and have the tenants who "like it hot" pay their own fuel bills? If so, we have done a few tens of thousand apt conversion using Rinnai DV modulating gas valve and blower wall furnaces. They work very well. I represent them and have sold about 125,000 of them in New England. They are excellent and ideal for this application.

Check Appendix E in 31

@ February 7, 2009 4:39 PM in chimney liner and insulation - oil boiler

for some sizing guidelines. Sweeps with whom I've spoken find the sizings to be spot on. Is this an interior or exterior chimney. It makes a significant difference in performance. Answer those questions all ready asked and consider an insulated vent coneector. I've posted this before, but when John Strasser and Rich Krajewski did their vent modeling they said the thing that had the greatest impact on performance was an insulated chimney liner. Depending upon the size, you can get DS from Selkirk or DVL from Duravent.

@ February 3, 2009 6:03 AM in Combustion Air Intake Efficiency

You will find equipment that is either single stage or variable speed for combustion air.

Just saw at ASHRAE

@ January 29, 2009 6:58 AM in best ductless mini split with heat

the new (March availability) 12 RLS unit from Fujitsu. 26seer/HSPF 12. Cooling capacity 3,800-14,500 Heating capacity 3,100-24,000 btu I represent them, so my bias is acknowledged, but it is an excellent line.

Saw the originals

@ January 29, 2009 6:48 AM in Another Lynyrd Skynyrd Tragedy

in Tempe in 74. Jas Cotton Blues Band, MArshall Tucker, LS, Boz Scaggs, Steve Miller, and Elton John came up out of the crowd to play. MT and LS just blew the place away. Ronnie Van Sant had a huge shiner and a bandage on his head, but it didn't seem to affect him, but then again, ho would you have known. There were some bizarre stories surrounding that event, but I can't talk about them in polite company;/

Tim Dwyer

@ January 19, 2009 1:53 PM in Tjernland Power Venters

Tim is at 800 255-4208 X 132.

I have done many of these,

@ January 16, 2009 7:00 AM in Instantaneous Water Heater

but with Rinnai's, as I represent them. You still need the booster at the dishwasher. That way you can run the water heater at 140 and supply the rest of the kitchen with hot water temps. The booster will then peak the temp the last 40 degrees. Everyone likes to try to eliminate the booster, but with a good pre-heat you can minimize the size and cost of operation of the booster. The reason yu need the booster is that if the water heater is 10' away from the dw, if the unit produces 180f water, by the time it gets to the dw it will no longer be 180...Period! The rinse cycle is where the "rubber meets the road" with on-demand. Never call it instantaneous, it isn't. Satisfactory rinse operation requires water at both the correct temperature, but also the correct pressure. You will find that if the unit is making hot water for the kitchen faucets and the rinse cycle calls, the unit will respond without issue. If however the unit is in stand-by mode and the rinse cycle calls the unit will see high flow instantaneously, recognize that water is getting thruough at the wrong temp, slow the flow down de-pressurinzing the rinse cycle, it gets control of the flow immediately, re-opens the flow valve and by the time the water heater is happy the rinse cycle is almost done. Ka-boom! I have had very satisfactory results, but I had a pretty rough apprenticeship in these applications. Rinnai engineering likes to be involved in these designs. How many one/two/three bay sinks, spray systems, lavs, dishwasher make and model (imperative that you understand the flow characteristics). In other words, what is your total load.

JIm, what is plugging the screen?

@ January 12, 2009 7:08 PM in rinnai call backs

If the screen gets plugged it limits flow to the unit and stresses the flow control valve which over time in this situation will cause it to moan and groan prior to failure. That component with good clean flow is very reliable and operates quietly. I'd suggest replacing the flow control valve and see if it quiets it down. Are you in the New England area? If so, I'm your rep. I'd be happy to help. Give me a call if you'd like 617 834-8751.

Bob pretty much has it....

@ January 9, 2009 6:42 AM in Chimney size

but a couple other things to consider. Basic physics, when a gas expands, it cools. Do not oversize. A masonry chimney follows the old adobe principal. Masonry never saw a btu it wasn't willing to absorb, which exacerbates the first point. Essentially, in todays world, for todays equipment, a masonry chimney is an excellent architectural device but a very, very poor mechanical device. Personally, I would never pay to build a masonry chimney.

Variable speed

@ December 30, 2008 3:59 PM in New furnace advice

Assuming the air can move the through the ductwork at the proper static pressure, the variable speed unit will deliver better comfort and less temp swing in the home. When you say variable speed, are you talking a "manually adjustable" speed or an "automatically modulating" fan? If it is going in my house it will have a modulating gas valve with a modulating fan. That is the best comfort and best long term economy. Has an actual inspection of the underground duct been done to confirm its integrity. There are companies that can run a scope through the duct to determine its condition. I'd make certain that everything is ok before I put nickel one into the system. Now that you are adding the ductwork, and the system will be able to operate at a proper static you can now put on a high quality filter and humidifier as well. Good luck and Happy New Year!

Another angle

@ December 19, 2008 6:20 AM in Condensing vs. Traditional

to this. You could install a Rinnai Energysaver Direct Vent wall furnace in each apt, 83% AFUE, modualating gas valve and blower. Cool to the touch. Nice! Sub meter the load to the tenants. Hot water with an R50LSi Rinnai direct vent water heater. Everything will be new. To assist in moving air from one room to another check out the Tjernlund Airshare. I have done several tens of thousand Rinnais over the years and they work exceedingly well. My normal disclaimer applies here. I, fortunately, represent Rinnai in New England! Happy Holidays!

Ummm, Tim...

@ December 12, 2008 6:03 PM in Power Vent Boilers

a "power venter" is not a positive pressure device. It is why they are located at the terminus so the suction side of the venter (the vent connector)is negative. Are we talking the induced vent that we were poking around a while back vs a power vent?

I did a few of these

@ December 11, 2008 6:18 PM in GEOTHERMAL

in 78-82. It was in the Napa Valley and the heating and cooling degree days were about a push. The pools were not indoors. We would use a glazed solar system to heat the pool and use a good pool cover for the pool. Collector efficiency was very high with the low temps and we would supply the pool water to either a water to water or water to air HP. For cooling we would reject heat to the pool and not cover it at night so the temp would radiate to atmosphere. The engineering spec gets a bit tighter with an indoor pool of course but I like the idea of the cusotmer putting the money into an indoor pool rather than a couple wells. I'd be interested to hear how it goes for you.

You can run....

@ December 2, 2008 6:48 AM in good ductless split system

The Fujitsu's heat effectively down to 20F. They will work below that but outputs diminish. For output info on each model and low temp limits, which vary by model, go to Careful here, as the low temp limits vary by model (0, 5, 14F). Also, if you register in the contractor section, the username and password are "installer" and "1ton12kbtu" you can find output temps by model at temps dwon to I think it is 5f. Prior to the introduction of the inverter units and the 410A equipment, if you told me you were buying a heat pump I would have said, "what are you, nuts?" Today, if you don't buy the heat pump I have to ask, "what are you, nuts?" There has been that big a gain in performance and technology. If you are in New England you can go to and run some numbers. I represent Fujitsu in New England. If I can help you, let me know.


@ November 15, 2008 8:26 AM in Common Venting of Condensing Boilers

You state, "Now we know I will certainly not get a blessing from Viessmann on this one, there is nothing in there literature that but I am thinking that says I can do this, but..." This is the perfect nightmare scenario. Maybe it will work, but is it right, long term? Build it to the manuf specs and you have their support. Do otherwise and the problems may go up and down the line. My suggestion would be to follow the manuf specs, make your profit on the job and leave with a system that you have confidence in and can defend your decisions. Common venting is almost always a compromise even when allowed. You end up with reversion issues that may have subtle effects but long term can impact the gear. I'm assuming that the reason you want to put in two units is to stage them. If so, and the 2" is the right size for the one unit you are going to pump it into 3" which has almost 3X the cross sectional area of the approved 2". Is the single unit operating alone 80% of the time going to be happy with this? If it works well, then good for you, but this is also how you create PITA jobs for yourself, the manuf and your client. Ask me how I know;)

Step one

@ November 15, 2008 7:47 AM in Large Scale domestic hot water

IN my opinion is to deal with the water quality issue. You state that you think the current equipment problems are in large part water quality related. Regardless of the type of material used in the newer system, poor water will rapidly deteriorate performance of high quality materials through scaling, etc and while you will be happy for a while, it won't last and it will end up costing more, sooner than you thought. Listing the equipment types in no way provides the information needed to size your system properly. How many apts in the building? What type fixtures and flow rates from those fixtures? In any hot water design you want to look at water conservation steps as a part of the design. Can you do that? It can have profound affect on the system design. Can you provide that information?
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