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[slimjim]

I normally will put a purge port on each port from the heat exchanger and follow that with a ball valve for easy cleaning without removing the HE

[ITO]

 I do similar, use hose bibs with valves on S&R end of HX, a person can use them to flush both ways and also fill the boiler with garden hoses using house pressure from inside the house.

[CountryBoyJohn]

I am blessed with abnormally clear and pristine water in this part of the state.  If I had very hard water, I'd look at purchasing water that has been treated or purified.  You're going to have the same clogging problem with your water-air exchangers as you would with a plate exchanger.  (I guess I'm assuming you are on forced air)  I think it would be worth it to start with good water. 

[racnruss]

I agree with Countryboy.  Just fill the boiler with storebought water to start with.  I probably only ad one gallon per year.

As far as DHW heating.  I have both a sidearm and a plate exchanger.   Started with a plate exchanger and never had a problem, just added a sidearm because I could and wanted that water to be hot all the time.

Another thing that was bothering me was that here on the thread people in the know are always saying that you don't want the return water to going back to boiler very cold.   If you just use a plate exchanger, when you run your hot water at the faucet, you are seriously cooling the water returning  to your boiler.  I put my plate exchanger after my water heater so the domestic water running through the plate exchanger is preheated by the sidearm on the water heater.  Less shock to the boiler.

Just skinning the cat my way.

[Sprinter]

The DHW is only flowing a few GPM, most faucets are 2.0-2.5gpm limited now, so the occasional 5gpm laundry faucet or old style three handle bathtub faucet. That's not enough flow to pull down even 160 degree water. It would have to be seriously undersized FP, and then it would not be enough to heat up the water to 120. The boiler side is flowing double or more.

[AirForcePOL]

Sorry I should have clarified, I will be using city water to fill the boiler but I was worried about my domestic water being hard. 

[racnruss]

Oh, thanks sprinter, I was probably worried about nothing then.   I didn't have a return temp monitor when I added the sidearm.

[willieG]

unless i am doing math wrong (quite possable)  if your domestic water was entering the plate exchanger at 2 gpm at 55 degrees...and your OWB was sending water through at 8 gpm  you would lose about 17.5 degrees to heat that 2gpm at 6 gpm from the owb you would lose 23.3 and at 4 gpm  32 degrees ..these are close guesses at using water at 8 pounds per american gallon (i think)

this is figured at 2 gpm  (16 pounds) raising  water is  1 btu per pound per degree so for every degree raise you need 16 btu ...heating from 55 degrees to 120 is 70 degrees rise  so 70 x 16 pounds would be 1120 btu per minute or 67,200  btu per hour or about 7 gpm to keep your 20 degree delta?

perhaps the real btu figuring guys can straighten this out if it is wrong

[mlappin]

I agree with Countryboy.  Just fill the boiler with storebought water to start with.  I probably only ad one gallon per year.

As far as DHW heating.  I have both a sidearm and a plate exchanger.   Started with a plate exchanger and never had a problem, just added a sidearm because I could and wanted that water to be hot all the time.

Another thing that was bothering me was that here on the thread people in the know are always saying that you don't want the return water to going back to boiler very cold.   If you just use a plate exchanger, when you run your hot water at the faucet, you are seriously cooling the water returning  to your boiler.  I put my plate exchanger after my water heater so the domestic water running through the plate exchanger is preheated by the sidearm on the water heater.  Less shock to the boiler.

Just skinning the cat my way.

Great mind think alike

I'm thinking of doing the same. Normally the sidearm keeps up fine but once in awhile the wife has a damn near fatal brain fart and decides to do all the laundry in a afternoon, run the dishwasher a couple of times then she'll get a hot shower in. This always seems to happen if we have to be somewhere like a meeting or meeting another couple for dinner then I end up with the cold shower and um... shrinkage problems.

[slimjim]

WOW!!!!

[mlappin]

WOW!!!!

Well it's really cold water.

[CountryBoyJohn]

Not sure how much you were joking about, but how do you run out of hot water?  We've done all that in our house and the water in the tank just gets hotter the more you use it.  Are you serious that you run out of hot water?

[mlappin]

Not sure how much you were joking about, but how do you run out of hot water?  We've done all that in our house and the water in the tank just gets hotter the more you use it.  Are you serious that you run out of hot water?

Serious as a heart attack.

Using a side arm, power vented 40 gallon water heater, couldn't get the top of the sidearm low enough. Seen no higher than 4 inches maybe? I ended up almost six. It does work, just not as well as it could I suppose. You also haven't met my wife, she looks like a damn lobster when she gets out of the shower, how she can stand it that hot is beyond me.

I also use a LOT of hot water in the winter. We use glycerin, jam and even maple syrup in the rations for the beef cows. It gets cold enough and the solids in all of those will settle out, only way to get em mixed back up is to add a lot of HOT water and agitate, I usually run out of hot water before I'm done.  The hose is hooked right to the pop off valve at the top of the water heater.

[AirForcePOL]

lol I like my showers really hot too. 

[slimjim]

Let's work on that hot water shall we? You said your sidearm is 4 -6 inches above the relief valve, can we raise the tank and drop the sidearm down so the top of the sidearm comes directly horizontal to the relief valve.