Print

[ryan4030]

I have a CB 4030 with a Taco 007 pump with insulated pex lines feeding a side arm HX on a 40 gal. water heater and then the baseboard heat of my 800 sq. ft. house. The side arm is too slow and we run out of hot water a lot and I want to go to a flatplate for on demand water. What is the best way to plumb this? Should I feed the water heater from the flat plate ,or put it on the outlet side of the heater, or eliminate the heater completely. I burn the stove all year and have no electricity to the HWH now, so eliminating it is a possibility if the plate exchanger will provide on demand with no problems. What size of flat plate will be good for any of these situations? I plan on plumbing in some tees and shut offs so I can flush out the exchanger when necessary. Any suggestions or help would be greatly appreciated                        Thanks

[yoderheating]

 I would put it o the fill side of the HWH and leave the side arm in place. That should give you the most consistent water temperature.

[hatfield]

Feed the HWH from the plate I think is the best way.. my 2 cents

[dirtryder]

I have my plate HX on the "out" line of my HWH. This gives me on demand hot water.....all day. I have a 10 plate and have had no problem at all with running out of water. Kids love the long hot showers. I turn my HWH off and it becomes a "cold" storage tank. Why would you want to heat the water going INTO the water heater.....to just sit there and get......cold? Then when you use it, you are not heating it? It makes no sense to me. I know you have a side arm....but you already know it can't keep up. If you are going to take the time to put in the HX I would put it "after" the water tank.....

[ryan4030]

Thanks for all the input. I think the easiest thing for me to do would be to  feed the HWH with the flat plate and leave the side arm there. This way I wouldn't have to plumb in a new tempering valve or relocate the one I have. Does anyone have any thoughts on having a flat plate and side arm, is it over kill or  will it  use more heating energy from the boiler water than what it will be worth?             Thank You for your ideas

[tulenutn2o]

I have yet to figure out how you guys are running out of hot water with the sidearm. I turned my lp off to a 40gal I just installed to replace a faulty 50 gal. on oct.23rd. My son takes 15min shower right after my wife takes her 15 min shower, and then I take mine. My OWB temp is 180. Thinkin..........

[willieG]

im gonna agree with yonder on this one...you allready have the sidearm in place, leave it there and put your plate exchanger before your HWH this way you will be filling your tank with hot water and the side arm is really dong nothing but keeping teh tank hot when not in use, i really don't see anything wrong with that.

if you however had no side arm or took it off then i would say after the tank but before your anti scald valve

[ryan4030]

Thank you guys very much. I think I will go with my idea of the flat plate before the heater. I need to make a list of the fittings and supplies I will need and get it together. I will let you know how it works.  This is a great site and forum for us OWB people. 

[parkinspot]

Does anyone have any thoughts on having a flat plate and side arm, is it over kill or  will it  use more heating energy from the boiler water than what it will be worth?

To answer your question, yes it is overkill IMO. 

Since the plate exchanger is capable of providing you on-demand hot water, why would you waste energy to keep the water in your HWH hot when you will never need it?  So, I would say yes, you will be using more energy than it is worth.  Especially since you run your boiler all-year.  That will add up to allot of wood.  Just my .02.

[yoderheating]

 The reason to place the heat exchanger feeding HWH is because it will give you a more consistent hot water temperature. The temperature of the domestic hot water will change depending on the amount of water flow through the plate heater.  In other words if you are taking a shower and someone starts the dishwasher and then starts the washer the water temperature would go noticeable down.  By having 40 gal. of preheated water in the HWH the inflowing temperatures can go down a little without having a noticeable effect on the outgoing temperatures.  I have found this to be very noticeable in older homes with poorly planned plumbing systems.

[parkinspot]

Well put yoder.  I guess you could even take it one step further and put a theromstat an a circ pump on the water tank to keep the water nice and toasty 

[Airgap]

A sidearm will heat the water in the WH without running a circulator...If you use a plate ex before the tank without moving water, you're tank can get cold, then you'll have to run the tank out to get HW...This is only if the tank sits without hot water being used...

[willieG]

maybe the taco 07 cant deliver teh needed GPM due to head pressure?

[ryan4030]

I don't know much about how head pressure and other factors affect flow but that is what the CB dealer installed . The circulator is mounted out on the boiler and it is about 25 feet from my house.My baseboard heat works great and the house warms up within a short time of the thermostat calling for heat so I don't think I have a water flow problem.I am thinking that a flatplate feeding the HWH with the side arm still in place will be the best setup to go with. The flatplate should feed the HWH hot water ready to be used and if I decide to sleep in and my fire goes out there should be 40 gal. of hot water to use until the boiler temp is back up for the flatplate to work. This is why I don't want to go with just the flatplate for on demand water.I think this will be nice too if I ever have to shut down the boiler.Before I moved into my house I left my fire go out and I had hot water in my HWH for a few days before it got cold again. Thank you guys for all your input .I  am just about ready to start spending money on the flatplate and fittings.

[willieG]

your pump should be fine with your stove that close to the house