greenwood 100 Hot water

[docgogo]

I recently asked the question about my greenwood 100 boiler and a sidearm hot water heater.
i read in the installation material that a sidearm only assist in the hot water production is this true.
also the material said not to turn off the hot water heater? why would this be if i keep my boiler at 170-190 is that not enough temperature to keep dhw for a home.
are there alternative solutions for hydronic heat. (another kind of water heater fired from the boiler)
i do appreciate everyones help. thanks doc

 

[DKerley]

Hi Doc,

I don't know about the side arm installation, but I do have my greenwood heating my DHW through a 10 plate heat exchanger and have no shortages of hot water. The heat exchanger heats a loop (?) of DHW using a taco 007 bronze pump, 2 aquastats and the 10 plate HX. The two aquastats are for running the bronze pump. One aquastat is on my main line that goes to my manifold. This stat is set at 150 deg. and allows the pump to have power as long as the main water temp is >150. The second stat is on the side of the hot water tank and turns the pump on and off to keep the water at 140deg. The reason for the first stat is so that the hot water tank does not try to heat my main line should my main line drop below 150deg. The DHW tank that I have is propane unit that I keep running but with the thermostat set very low. If I shut down the boiler for servicing, etc. I just turn up the thermostat and we have propane heated hot water. I hope that this helps.

 

[sixroses]

In my system, the side arm will allow for constant thermal siphoning. Mine does not keep up with water demand while taking a shower but does keep the tank hot between uses. The sidearm simply does not have enough surface area to heat DMH as it passes through the 2.5 inch pipe. I am thinking of plumbing in a second tank, not connected to power, that will run throug a second side arm that will act as a hot water supply to the main tank. A flat plate HX would provide more "instant" hot water though, I think...

 

[atlarge54]

I've got a sidearm on a 50 gal elec. with the breaker turned off. Haven't run out of hot water in 3 years and my boiler temp is 130-140 deg. F. I run it year round.

 

[docgogo]

so does anyone know how i would plumb a flat plate heat exchanger and tie it in with my side arm ?

 

[antos_ketcham]

I recently asked the question about my greenwood 100 boiler and a sidearm hot water heater.
i read in the installation material that a sidearm only assist in the hot water production is this true.
also the material said not to turn off the hot water heater? why would this be if i keep my boiler at 170-190 is that not enough temperature to keep dhw for a home.
are there alternative solutions for hydronic heat. (another kind of water heater fired from the boiler)
i do appreciate everyones help. thanks doc

I have a sidearm hooked up to my old electric hot water heater (40 gal.) The electric is off. My Greenwood 100 provides more hot water than we can use. Works great. The sidearm was purchased from Central Boiler.

I also have a plate exchanger at my furnace so I can keep antifreeze in my system - my system is outdoors in a shed off of my woodshed.

Pete

 

[antos_ketcham]

I've got a sidearm on a 50 gal elec. with the breaker turned off. Haven't run out of hot water in 3 years and my boiler temp is 130-140 deg. F. I run it year round.

Do you have a Greenwood? I'd like to run my system year round but was told by Greenwood that it wouldn't work.

Pete

 

[atlarge54]

I've got a sidearm on a 50 gal elec. with the breaker turned off. Haven't run out of hot water in 3 years and my boiler temp is 130-140 deg. F. I run it year round.

Do you have a Greenwood? I'd like to run my system year round but was told by Greenwood that it wouldn't work.

Pete

* I don't have a Greenwood, you'd need storage for year round hot water. With your boiler I see no reason a sidearm couldn't provide all your DHW during heating season.

 

[Eric Johnson]

For truly instant hot water, I think you need a tankless coil immersed in a boiler. And even then, you don't get an endless supply.

The sidearm-mated-to-a-hotwater-heater approach is probably the most economical, and it runs on gravity. It's like any other kind of heat storage in that the sidearm captures heat and stores it in the tank for use later. If you can keep it from thermosiphoning, it will remain stored in the hot water heater tank until it's needed. The only time you run out of hot water is when the boiler is out and you use up all the hot water in the tank. Then you need to either fire up the boiler or turn the electric elements in the hot water heater back on. Leave them off normally, however, or you could wind up trying to heat your house with your hot water heater.

I'm sure there's a way around that, too--I just haven't taken the time to figure it out.

 

[docgogo]

I turned off the breaker on my 40 gal electric water heater today
about 4hrs. later 101 deg . water
gw 100 running at 200 deg
temp taken at water heater 190 deg.
why don't i have hotter water.
mixing valve is set as high as it will go usually with electric on i get 135 deg. water
could something be hooked up wrong?
thanks in advance. crazy in ky.

 

[steam man]

I turned off the breaker on my 40 gal electric water heater today
about 4hrs. later 101 deg . water
gw 100 running at 200 deg
temp taken at water heater 190 deg.
why don't i have hotter water.
mixing valve is set as high as it will go usually with electric on i get 135 deg. water
could something be hooked up wrong?
thanks in advance. crazy in ky.

I presume you have a sidearm heat exchanger (according to the threads)? I'd say that though I think sidearms will underperform an active type heat exchange I think you have a problem if in 4 hours you're actually losing ground. Do the simple stuff first. It sounds like there is a flow through the boiler loop of the exchanger, i.e. both inlet and outlet are hot-is there a temperature drop? Probably not the way things sound. How about the tanks side-does the bottom pipe of the sidearm feel relatively cool compared to the top pipe? I would guess not. My first thought is that there is a possibility there is a plug with sediment or something in the bottom of your hot water heater that may be blocking the naturally convective flow through the sidearm. You may have to blow down the tank to check (making sure you are blowing from the bottom of the tank). I haven't seen a picture of your piping but I am wondering if you have some piping restriction or if the incoming cold water can partially bypass the stored hot water. Post us some detailed pictures. I am sure we can figued that one out.

There's nothing time and money can't solve.

 

[ISeeDeadBTUs]

My GW100 heats the oil boiler through a 20-Plate HX. The oil boiler then heats the DHW tank with an internal HX. On paper it sounds inefficient, but I always have a tank of DHW with a minimum of 135*.

Since I have no storage, I don't run the GW during the summer, though I have run a small load at late evening during spring/fall - just enough to max the DHW at night so there is shower water in the AM.

 

[BrownianHeatingTech]

For truly instant hot water, I think you need a tankless coil immersed in a boiler. And even then, you don't get an endless supply.

A flat plate and tank, or an indirect water heater can keep up with all the hot water you could ever need - if it's sized to provide the quantity of water needed by the number and type of fixtures.

Of course, most aren't sized that way due to cost, and because most people don't turn on all the hot water fixtures at the same time, but if someone wants that capability, and doesn't mine paying a premium (which may end up being substantial, if it requires a second boiler and a staging control in order to supply the amount of water that they could use), we can certainly design for it!

Joe

 

[leaddog]

read thru this post as it sounds like a simular problem. https://www.hearth.com/talk/threads/12552/

leaddog

 

[docgogo]

Here are some pics of my sidearm
Also just got off the phone with my dealer (who hooked up the sidearm)
when he plumbed the sidearm the literature said to plumb hot from boiler into the top and then onto the next appliance since then he has learned to plumb the hot into the bottom and then onto the next appliance from the top.
any ideas and suggestions would really help thanks doc.

 

[BrownianHeatingTech]

Also just got off the phone with my dealer (who hooked up the sidearm)
when he plumbed the sidearm the literature said to plumb hot from boiler into the top and then onto the next appliance since then he has learned to plumb the hot into the bottom and then onto the next appliance from the top.

No, it is correctly piped. You want "counter-flow" - the boiler water flows down, and the domestic water flows up.

Joe

 

[docgogo]

i was looking at central boiler literature and the contradict that. they say to plumb it the opposite way.

 

[BrownianHeatingTech]

i was looking at central boiler literature and the contradict that. they say to plumb it the opposite way.

I've not read the Central Boiler literature, but that is definitely incorrect. Heat exchangers should always be piped counterflow for best performance.

Joe

 

[atlarge54]

i was looking at central boiler literature and the contradict that. they say to plumb it the opposite way.

I've not read the Central Boiler literature, but that is definitely incorrect. Heat exchangers should always be piped counterflow for best performance.

Joe

I find it difficult to believe a 3/4" siphon loop sidearm could put enough load on a system to even matter. Seems to me it should be plumbed using fewest fitting thus providing least resistance to flow.

 

[docgogo]

Today read every post i could find ran across a post about sediment in the tank
tried to run water out of my drain on the water heater was full of sediment
ran about 30 gal of water off ( never was warm )
waited about an hr. water temp about 105 -110 only lasted for about 5-10 gal.
boiler temp is at 200+ damper is closed
temps at the water heater are 185-190
looks like i will have to turn the electric back on again.
thanks doc

 

[steam man]

I am thinking that the the sidearm had no flow due to the sediment. It may be even up in the sidearm itself. You'll just have to make sure everything is cleaned out.

 

[docgogo]

how do i have to take everything apart?

 

[steam man]

I haven't seen pictures of your connections. I would say go the easy route first. Maybe remove the drain valve and poke a rod of some kind (preferably one that won't scratch your tank) in through the line and bottom of the tank. I have used a heavy bass guitar string to clean out small tubes since it can bend around a corner. If you can get a small water hose inside you may be able to flush the tank bottom out until it is clear. Compressed air would work especially if you adapt a piece of copper tubing on the end. Hopefully you only half to dismantle a minimum number of fittings. Do what you can to be sure it is all flush out. Let us know what you do.

 

[docgogo]

can i hook up a taco 007 pump on the loop at the hot water heater?

 

[steam man]

Not being familiar with how well a sidearm operates with just using convective flow I wouldn't be able to say for sure that you need a pump. One thing to consider is that any sediment will end up going through the pump so cleaning everything would be prudent. An extra pump will cost electricity to run but then the efficiency of the sidearm comes into question. There doesn't seem to be much surface area for heat exchange compared to a flat plate exchanger. I would think it would improve the sidearm performance at the expense of defeating its principle advantage. If it helps, then you could consider a properly sized flat plate exchanger. You would never run out of hot water with that setup. If there are any sidearm advocates here please speak up.