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[Scott7m]

I heated my water one whole winter with a 10, I never worry about which way the water is flowing.

I wanted to switch to a 20, it was a little hotter, but not a huge difference I could tell

How many feet of pex on the boiler side and what pump were you running?
It you have a pump that can do 30 or 40' of head you can get by with a 10 plate

That was the case, it was one of the nc pumps that came on the stove.  Do they do around 30 on high?

[RSI]

I believe they do 39'

[gandgracing]

Ok so I'm gonna switch the domestic water on the exchanger and then hook it up on the hot water side of the water heater. Do I also need to make a bypass to go around the heat exchanger for the summer months when the boiler isn't being used or do you guys just keep going through it?

[HandyMark]

I am using a 5x12 ten plate off a taco 0011 pump dumping in to my water heater. Boiler is at 170 and my water is over 140 at the tap even after not being used all day. I do have mine plumbed with water flowing in opposite directions.

[Scott7m]

Ok so I'm gonna switch the domestic water on the exchanger and then hook it up on the hot water side of the water heater. Do I also need to make a bypass to go around the heat exchanger for the summer months when the boiler isn't being used or do you guys just keep going through it?

That won't work......   It needs to be in the cold side so that you have all that hot water in storage.  Your hot water will vary a lot doing it like that

You would be much better off to get a 1" 20 plate and do it right..

[Scott7m]

If you do it correctly on the cold side you'll never have valves to turn or make bypasses as the water will flow through it the same in the summer as it does now, it just won't be preheated

You likely have to slow of a flow of water for a 10 plate to work properly, 10 plates really restrict flow, that's why I recommended the 20, your gpm would increase and your make everything work better

[gandgracing]

Ok I guess I do need a 20 or 30 plate. My wife took a long hot shower today and I went to check out the heat exchanger and the line going to the water heater was nice and cold. Boiler lines were real hot though.

[RSI]

Both boiler lines were hot?

I didn't expect to hear that. A normal 5x10 10 plate will usually make plenty of DHW if it can get enough boiler flow to keep up.

Which way is the boiler water flowing?

[Scott7m]

This isn't making any sense at all.... 

[willieG]

i agree with RSI IF the boiler water going into your exchanger is hot AND the boiler water leaving your exchanger is hot and the domestic water lines are both cold it would seem that the domestic water is not moving through your exchanger if things were truly working properly and your exchanger were not big enough then i would think that the water leaving the exchanger and returning to yoru OWB and the domestic water leaving the exchanger would be the same temp (warm but not hot)

bottom line is (if i am thinking correct) if there is no change in boiler water temp in and out...there is no heat exchange taking place.

[gandgracing]

Yeah this is really confusing and it seemed so simple. Something must be way off.

[willieG]

are you certain 100 percent of your domestic water is going through the exchanger.(no other way for your domestic water to enter the tank?)

i would make a guess that domestic water going through a 1/2 inch pipe at normal house hold pressure would not be surpassing about 3 gpm and i would further guess that your OWB is doing at least that. heat transfer of some kind would have to be taking place in the exchanger if it is working at all. your owb pipes being hot on both sides means the boiler water must be moving, you say when you use the domestic hot water that the tank is eventually cold. That means yor domestic water is moving also. That is why i ask if there is a nother domestic cold water line delivering water to the tank and by passing the exchanger. I cant for the life of me figure out how water could be moving through both sides of your exchanger and not be transferring heat from one medium to another?

even if we said your boiler water was going through at 1 gpm and your domestic was traveling at 10 gpm there should be some noticable temp changes on the OWB return line. also if your OWB was going at 10 gpm and your domestic was at  1 gpm there should be a noticable difference on the domestic lines. if they were both going at 10 gpm (even though the exchanger was too small) there should be a difference of some sort in both lines from the feed to the return on the OWB side and the domestic in and out??

[muffin]

Yeah this is really confusing and it seemed so simple. Something must be way off.

Is the plate exchanger clogged?  Something is very wrong.

[gandgracing]

Ok so I switched the domestic water lines around and shut off the water heater. The water to the shower was nice and hot but I had to have the cold water about off. And it seems that it will blow cold air thru the registers in the house. The boiler outlet line coming out of the exchanger was pretty cool when the water heater was using. Should I try replacing the pump first?  Taco 0011?? And does it need to be a bronze pump??  Or do I keep my pump and get a 20 or 30 plate exchanger. Probably will only be able to do one or the other for now.

[RSI]

on the boiler side, is the water going in the top fitting or in the bottom fitting?