# central boiler-domestic hot water question.



## ant (Nov 25, 2010)

i seem to be running out of hot water. (40 gal hot water heater unit) i have a side arm heat exchanger. my boiler is set at 170 deg. if i set it to 180 would the hot water in my hot water heater recover quicker?


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## lopegod (Nov 25, 2010)

I am not to familiar with the side arm i was always under the impression that they will not keep up to heavy demands. I am useing a 30plate exchanger hooked up to my hawken and it heats the water up as it goes into the hot water tank.


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## blackdogon57 (Nov 25, 2010)

I had similar problem with mine. The sidearm became filled with sediment from well water. I added filter and water softener. Also replaced tank with 60 gallon electric because it too was filled with crap. Breaker on tank is shut off and I have limitless hot water. 

You could also try bleeding air and adjusting mixing valve as an easy fix. Increasing boiler temp will make little difference. I run my boiler temp as low as 150 in the summer and the tap water is very hot.


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## coppersnowblue (Nov 25, 2010)

I wasn't happy with the performance of mine so I put a small brass circulation pump on a timer on my side arm exchanger works great. I am able to turn off the gas on my water heater all winter. If or when I replace mine it will be a brazed plate exchanger I feel they perform better.


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## Alan Smith (Nov 25, 2010)

MINE WORKS FINE IF YOU DON'T MIND FLUSHING IT EVERY 6 MOUTH it get full of white flakes


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## wayno12 (Dec 2, 2010)

*Sidearm poor performance*

Ant, I too am the owner of a CB OWB. It is an E-Classic 2400. Performance of the stove is rated so far at a 10 based on about 2 months use since install. I have a 185k HE in a plenum and a sidearm on 40 gal HW heater that CB rates at 25K-30K BTU. My propane HW heater is 34K BTU when in operation. My household is a family of 4: my wife, 10 yr old son, 9 yr old daughter, and myself. My daughter loves to take a 20 to 25 min shower if you aren't monitoring her. My son therefore would always get stuck finishing with a cold shower. Talking to CB, they told me usage was considered "excessive". 
The sidearm is meant to "build" up the temperature over time; actually it will take the sidearm longer to recover the temperature than it would if the tank was being heated with propane because the sidearm delivers fewer BTU’s than if the propane were firing. I found it that when my son finished with his cold shower, it would take nearly 2 hours before the water was warm enough to be comfortable for me to get in and shower, and you notice I said warm, not hot! The sidearm is a very passive means to heat water. My CB dealer could not believe I could run out of hot water. I was the first case he heard of in 14 years of selling CB units. He said he and his wife could both take showers and he has never run out of hot water. However, he is a 2 person household, both adults, using a 80 gal electric HW heater, taking about 10 minute showers each. No wonder! That is not comparing apples to apples! 
Now for the truth: If you are a "normal" size household, performing "normal" daily activities such as laundry, showers, dishes, etc., and you don't have all day to do it, you may, out of sheer luck and by practicing some major conservation practices, get by with a sidearm only, but don't bank on it. Here is what you must do if you need to get 4 people to church on Sunday before the closing hymn at the end of the sermon. Get a plate exchanger big enough to supply you about 140 degree hot water at your estimated gallons per minute usage while performing several functions at the same time, for instance, doing a load of laundry while taking shower and the dishwasher is in operation. Run your cold supply line from your water softener, hopefully you have one if you water is bad enough to be a concern for a plate exchanger, into the plate exchanger. If your boiler operates in the range of 185 degrees the water should exit the plate exchanger ideally around 140-160 degrees and dump into you hot water heater. By doing this, you are not diluting your water heater that was already heated to 165-170 deg by the sidearm before you started using water for your duties, with water straight from the well which is 45-50 deg. Now your water will flow from the water heater through a mixing valve, don't leave this little contraption out, and to your faucets. Basically, the plate exchanger will work like a hot water on demand water heater and your 40 gal HW heater is preheated stored water just waiting for you to enjoy it. The water in your HW heater will never get colder than the water exiting the plate exchanger, and even if you used so much water that the water heater was full of 140 degree water, as soon as your water usage subsides, the sidearm will begin bringing up the water temp until it reaches say 165-170 degrees over the next couple hours waiting for you to tap into it and enjoying even more hot water. The biggest problem in most cases is that the dealers are always dealing with customers who want to get out as cheap as possible so I feel they are hesitant to suggest any additional equipment in fears of scaring you away from even the most basic of options. 
Word of advice: Don’t buy a boiler that “might” heat the sq. footage that you want to heat, buy the next size up; install a larger heat exchanger than you think you will need to heat your house and you will never have a cold feet; install the proper equipment to meet your demand for your hot water heater, and you won’t be the unfortunate last person in the shower wishing you had been first!


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## blakey (Dec 2, 2010)

No shortage of hot water here, family of 5, long showers, baths, dishwasher, tons of laundry etc. I have a 60 gal electric water heater with the breaker off and a sidearm I put together from a kit from CB. Most people I see on here with issues have a 40 gal water heater and likely a smaller sidearm to go with it. My outer tube is about 5 1/2 ft long. 

My lines go to the sidearm before the furnace heat exchanger which will make a difference as well. I am on well water but luckily never had a problem with sediment in 10yrs of usage. Not bragging but just to let you know they do work.


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## Alan Smith (Dec 2, 2010)

blakey said:


> No shortage of hot water here, family of 5, long showers, baths, dishwasher, tons of laundry etc. I have a 60 gal electric water heater with the breaker off and a sidearm I put together from a kit from CB. Most people I see on here with issues have a 40 gal water heater and likely a smaller sidearm to go with it. My outer tube is about 5 1/2 ft long.
> 
> My lines go to the sidearm before the furnace heat exchanger which will make a difference as well. I am on well water but luckily never had a problem with sediment in 10yrs of usage. Not bragging but just to let you know they do work.


 i have two water a 60 gal in house 40 gal in apartment and i have sediment problem them i am on city water i have to FLush them EVERY 6 months it get full of white flakes the 60 gal suppy washer for 7 and showers for 4 we have good supply of hot water untill they stop up


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## wayno12 (Dec 2, 2010)

*Good article from a Dept of Energy Rep on Sidearms*

I am not suggesting that everyone try to build a sidearm, but Michael Lamb with the DOE makes some good points about the expectations from a Sidearm in this article. 

www.homeenergy.org/archive/hem.dis.anl.gov/eehem/99/991107.html


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## pwl (Dec 3, 2010)

I have a CB 5648 and a side arm on a 50 gallon hot water tank. The electric to the tank is off when the boiler is in operation. I have a mixing valve prior to the side arm to lower the temperature to 135 degrees from 175. Never, ever have I had anything but a very hot shower. Even with the wash, dish washer and 3 people taking showers. I open the flush valve a couple times a year to get the crud out. Even at 135 degrees you can still get scalded.


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## ant (Dec 3, 2010)

pwl said:


> I have a CB 5648 and a side arm on a 50 gallon hot water tank. The electric to the tank is off when the boiler is in operation. I have a mixing valve prior to the side arm to lower the temperature to 135 degrees from 175. Never, ever have I had anything but a very hot shower. Even with the wash, dish washer and 3 people taking showers. I open the flush valve a couple times a year to get the crud out. Even at 135 degrees you can still get scalded.



When I say the flush valve. Are u refering to the domestic water or the side are boiler water?


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## wayno12 (Dec 3, 2010)

PWL, can you explain the mixing valve prior to the sidearm. How did you plumb it in? I have a mixing valve in the hot water line out on the HW heater.


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## wayno12 (Dec 3, 2010)

*Mixed reviews!*

This is all very interesting, because I am reading more and more even from manufacturers web sites not to depend on a sidearm for continuous or higher useage. Yet, some are having what sounds like fantastic luck with the sidearm to supply all their hot water. I definitely don't consider myself a high usage family. There is no doubt though, the larger your HW heater, the better luck you are going to have. If I had an 80 gal HW heater instead of a 40, there is not doubt my problem would have been solved, but it makes no sense money wise to dispose of a perfectly good HW heater and buy another one. The whole purpose of installing the sidearm is to save the $ of propane. If you already have a very large tank, excellent, you're probably going to have good luck with it.


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## atlarge54 (Dec 3, 2010)

I'm going into my 7th year of using a sidearm both winter and summer. I plumbed it using the central boiler instructions (I don't have a Central Boiler though). I've never come close to running out of HOT water and never flushed anything. My well water goes through a whole house string wound filter before the softener, I change the filter once a year. The electric heater is 50 gal and the breaker has always been off. A front load washer can really cut your hot water consumption.


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## Alan Smith (Dec 3, 2010)

ant said:


> When I say the flush valve. Are u refering to the domestic water or the side are boiler water?


 http://www.arboristsite.com/attachment.php?attachmentid=159971&d=1291066448 domestic water put water hose on the Brass Hose Bib run outside if you cant run out side put in bucket or sink then open the red handle


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## ant (Dec 4, 2010)

well thank you all. i flushed it out 2.5 gal worth and it did not seem that it had any sediment..
if i would consider a plate H/E to be installed what would it intail? see pic of my unit.
http://groups.yahoo.com/group/Centr...ode=tn&order=ordinal&start=1&count=20&dir=asc


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## Alan Smith (Dec 5, 2010)

did you get any thing out i get a cup full out then it works good for about 6 months


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## rob206 (Dec 5, 2010)

Ant,
Cant you take your system apart to look at the inside of the copper pipes AND the inside of the sidearm itself? You may find that everything is coated with calcified lime, and that will really reduce the efficiency. On my system I have unions in place so that I can take apart the piping from the top of the sidearm to the inlet in the HW. With that, I can inspect and clean the pipes with vinegar. My sidearm right now has a nice coating of lime build up inside and it is reducing the efficiency, but it is still at an acceptable level. This spring/summer I will be installing valves on the supply/return lines to the sidearm so that I can remove it and soak it in vinegar.


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## Holdstihl (Dec 5, 2010)

*suggestion*

My Shaver has a seperate loop that circulates DHW from the top of the hot water tank, out to the boiler, through a coil, and back into the bottom of the tank. The circulation is done with a small taco pump, controlled by a cheap little thermostat glued to the outside wall of the hot water tank (you have to cut through the outer cover and insulation). I think you could use a setup like this if you installed a brazed plate heat exchanger in series with your existing heating loop and ran the DHW through it. Some of the advantages would be - no sidearm, no mixing valve, and no scalding water. I run my boiler water temp at 170 and DHW at 135. Endless hot water with a 40 gal. tank.


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## avason (Dec 5, 2010)

I run my water at 195 to heat my house up faster. The hot water line runs directly into my airhandler and my water tank. Wish I could keep my water at 170. That would be the balls. I do keep it at 170 during october though.


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## CesKrin (Jan 28, 2011)

*I agree!*

I have checked your given link wayno12 and I totally agree on Michael's idea..


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