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[Sawdust]

    Hello,  I am trying to decide on what type of water to water heat exchanger to purchase, what is the pros or cons of flat plate versus side-arm.  Thanks for any info.  Sawdust

[juddspaintballs]

I tossed this around for a while.

Flatplate:
Has the ability to transfer more heat more quickly
May need a circulator if you want to heat an entire water tank instead of heating just on demand
Can clog quickly from hard water and mineral deposits (plumb it up so you can flush and clean it yearly)

Sidearm:
Can circulate via convection to heat an entire water tank in about 15 minutes
Usually not quick enough for on demand heating
Rarely clogs from hard water or mineral deposits
You can build your own or buy several different types of pre-made ones


From that, I chose to purchase a sidearm with a rolled interior tube from freeheat4u on ebay.  I figure if that doesn't work well enough, I'll build a second one myself and run them in parallel.  I have hard water, which was the main reason I went with it.  Once I'm done installing everything, I might look into a flatplate for on-demand heating later on. 

[jackel440]

juddspaintballs
   Nice little bit of info there.I had not considered the hard waters effects on the plate exchanger.I hope to go the plate route my self,but might build my own sidearm for now till a later date.

[yoderheating]

 Side arms can also become clogged although normally not as quickly. I have used both a side arm and a flat plate with my furnace. I have also installed furnaces for a number of years. The only time I would go with a side arm is if you use very little hot water. The problem I ran into with my side arm was when we started using a lot of hot water we had to stop and wait for the tank to reheat. The main problem I have encountered with flat plates is when folks have limestone in the water. I have customers who flush the flat plate 6 or 8 times a year to keep the water flowing properly.

[tulenutn2o]

Side arms can also become clogged although normally not as quickly. I have used both a side arm and a flat plate with my furnace. I have also installed furnaces for a number of years. The only time I would go with a side arm is if you use very little hot water. The problem I ran into with my side arm was when we started using a lot of hot water we had to stop and wait for the tank to reheat. The main problem I have encountered with flat plates is when folks have limestone in the water. I have customers who flush the flat plate 6 or 8 times a year to keep the water flowing properly.

Don't you have to stop and wait for water heater to catch up if you wasn't hooked to the boiler anyway.

[boyland]

IMO plate style is also a lot easier to install for the average home owner.

The sidearms are great I disagree on not having enough hot water, I am guess they where undersized to start with.

But if you have a sidearm the install is more complicated and you run the risk of not getting the valve out of the bottom I have seen where they just will not move. 

The plate style cut the line put a couple of sharkbits and you are good to go.

Just my 2 cents worth.

[Sawdust]

Thanks to all for the helpful info.