Two indirect water heaters

[maple1]

On that, will natural thermosiphon movement be strong enough to open a swing check on its own? Going through the check the right way, that is. I haven't gotten one yet, but trying one in the store it seemed to take a bit of a push to get it to open.

 

[mikefrommaine]

On that, will natural thermosiphon movement be strong enough to open a swing check on its own? Going through the check the right way, that is. I haven't gotten one yet, but trying one in the store it seemed to take a bit of a push to get it to open.

I am going to try a heat trap first since its cheap. I actually had ordered a swing check but ended up using it for the tempering valves cold water inlet,so that I wouldn't draw hot water backwards through the valve whenever I opened the cold tap.

If the heat trap doesn't work I could replace the pump with a zone valve and take advantage of the thermosiphonong.

 

[BoilerMan]

On that, will natural thermosiphon movement be strong enough to open a swing check on its own? Going through the check the right way, that is. I haven't gotten one yet, but trying one in the store it seemed to take a bit of a push to get it to open.

No. The idea is to stop thermosyphon with the least amount or restriction to the pump. Were you looking at a brass swing, or a check valve? W/O this check valve on the Oil Miser (highly recomended by the way) the Watts tempering valve would let all the hot water go into the cold side giving you quite a jump opening the cold faucet getting 180 degree water.

I am going to try a heat trap first since its cheap. I actually had ordered a swing check but ended up using it for the tempering valves cold water inlet,so that I wouldn't draw hot water backwards through the valve whenever I opened the cold tap.

If the heat trap doesn't work I could replace the pump with a zone valve and take advantage of the thermosiphonong.

What do you mean by heat trap? Those galvinized nipples with a little rubber thing in them? Generally a heat trap is a loop of copper pipe with sufficient drop to not allow hot water to rise causing thermosiphon. You want circulation between the tanks during charging, and not during use. Connect the "shuttle pump" (with the swing check) to the zone circulator so they both run at the same time giving you 240 gallons of hot water with only one tank shell exchanger used. Then during use, the SC would stop thermosiphoning and allot the first tank to cool as well water flowed in and out to the second tank which would still be hot, esentially making a 240 gal verticle tank with good statification.

TS

 

[maple1]

I think it was a brass swing check.

I'd like to install one on a 1in. line that would allow thermosiphon one way, but prevent it going the other way (on the hot supply side of a sidearm exchanger).

 

[Bob Rohr]

Water felt a little cool this morning so I checked the temps. Water temp was down to 105 after 3.5 days. Was a little disappointed, but I did notice that both tanks were at exactly same temp. So it looks like there is some thermosiphonong happening between the two tanks. I will have to add a heat trap after the shuttle pump and try again.

Any way to replace that shuttle pump with a type that has an integral spring check? I'd also add a check on the other line. Hot tries to go to cold always and it can cause bi-directional flow in a pipe.

Use a spring check or weighted flow check device, swing check can clatter on pumped systems if the pump doesn't create enough flow to hold them wide open. Piped thermal trap loops need to be about 6 foot deep to overcome the bouyancy of hot water, if you try that method.

 

[jebatty]

The copper pipe heat traps I made and installed on my dhw heater are 3/4" x 12" drop and no noticeable thermosiphon. The riser from the dhw heater is insulated, the trap itself (drop and riser) is not, and the pipe after the trap is insulated. Maybe larger pipe requires greater drop.

 

[mikefrommaine]

The copper pipe heat traps I made and installed on my dhw heater are 3/4" x 12" drop and no noticeable thermosiphon. The riser from the dhw heater is insulated, the trap itself (drop and riser) is not, and the pipe after the trap is insulated. Maybe larger pipe requires greater drop.

That is what I had in mind when I mentioned a heat trap. Currently I have ball valves before and after the pump so that I can manually stop the thermosiphonong.

I'm thinking that since the tanks were able to equalize there temps with the pump off that a nc zone valve might be the simplest solution. I could take the pump completely out and reuse for solar. I would use less electricity and completely stop the thermosiphonong.

 

[BoilerMan]

I like the zone valve idea. Get a Caleffi, or Grundfoss as they have little restriction when open, and are much more reliable than other brands/types.

TS

 

[infinitymike]

I turned on the 'shuttle' pump. Its a stainless pump that goes between the two 120 dhw tanks. It allows me flexibility in charging the tanks. I can charge one or both tanks with either the boilers or future solar collectors.

For now I just attached a cord to the shuttle pump that I plug into the wall when charging both tanks from the wood boiler. I think I will use the aquastat on the future solar tank and a RIB relay to turn on the shuttle pump when the tank hits 140-150.


I've attached a pdf of how I currently have it setup.

If I wanted to pipe it in series and didn't want to use a shuttle pump what would that look like?

 

[Bob Rohr]

If I wanted to pipe it in series and didn't want to use a shuttle pump what would that look like?

Be careful with the hot water extender valve. Best I can tell it is not an ASME listed valve and may not regulate the outlet temperature accurately. Here is the info from the installation sheet and a link to the Watts site explaining the various listings. Check with your local plumbing code, that may not be an approved device?

www.watts.com/pages/learnAbout/temperingValves.asp?catId=64

 

[infinitymike]

Would series piping look like this?

Which design would work better?

 

[jebatty]

I will have to add a heat trap after the shuttle pump and try again.

Really important on any dhw tank. Thermo-siphoning occurs on both inlet and outlets pipes, so heat traps on both. And insulate those dhw pipes. I don't use indirect because with our off-peak electric dhw cost/month is right around $4. U-shaped heat traps, insulated lines and added 6" fiberglass around the tanks cut electric usage by 50%, so that might be a guide as to what you might expect.

 

[Bob Rohr]

Would series piping look like this?

Which design would work better?

View attachment 71162

Reverse return piping would assure both tanks get equal flow. If the goal is to heat both tanks at the same time. If one needs to be on priority a 3 way zone valve could load the primary tank first, then the second tank.

The new solar controls allow you to load tanks together, one first to setpoint temperature, or load in steps so one tank goes to 105F, then the second to 105F, then back to the first. that way the solar, or boiler is always running at the lowest, most efficient temperature. It really depends on how the tanks are used, and how complicated you want to pipe and control them to maximize their performance.

Keep them below 160F if possible above that they really percipitate the minerals out of the water, and the life expectancy is shortened.

 

[mikefrommaine]

If I wanted to pipe it in series and didn't want to use a shuttle pump what would that look like?

Here is a link to tt owners manual. Look on pages 13 and 14 for some suggested diagrams.

http://www.triangletube.com/documents/2/Smart-PhaseIII-TR-Manual.pdf

 

[mikefrommaine]

Be careful with the hot water extender valve. Best I can tell it is not an ASME listed valve and may not regulate the outlet temperature accurately. Here is the info from the installation sheet and a link to the Watts site explaining the various listings. Check with your local plumbing code, that may not be an approved device?

www.watts.com/pages/learnAbout/temperingValves.asp?catId=64

I used a Honeywell am-1 tempering valve. It's been great always -- always the right temp, no more constantly adjusting the water temp when taking long showers.

 

[kopeck]

So I'm way late to the conversation BUT call Vaughn (http://www.vaughncorp.com) about your tank. They know they have a problem and will fix it. From what I hear a lot of them leak on the side, which it looks like yours does. Mine leaked around the top. I had to pay for the part from FW Webb but got my money back when I returned the fault coil unit. The don't pay for installation though, still better then nothing.

K

 

[kopeck]

The VAST majority of indirects I see are Amtrol (boiler mate) as well, or the afromentioned "TOP PERFORMER" from F.W. Webb which have the same makup as Amtrol. Finned copper heat exchangers, and steel tanks are just not good for the long haul. Mike, I'm from "The County" and I'm headed downstate this weekend, I'll wave to your wife on the interstate........LOL My wife is from Waldoboro and we're going to a family reunion.

Taylor

I just had to reply to this one, my wife is from Caribou and I'm from Washington which abuts Waldoboro to the north. Small world.

I work in Waldoboro primarily.

K

 

[BoilerMan]

I just had to reply to this one, my wife is from Caribou and I'm from Washington which abuts Waldoboro to the north. Small world.

I work in Waldoboro primarily.

K

I'm from Caribou as well.......... Graduated HS there too, built a house in Mapleton two towns away. Small world indeed.

TS

 

[kopeck]

I'm from Caribou as well.......... Graduated HS there too, built a house in Mapleton two towns away. Small world indeed.

TS

So...you wouldn't have had Mrs. Souther while you were in HS?

K

 

[BoilerMan]

So...you wouldn't have had Mrs. Souther while you were in HS?

K

Actually yes I did, english........ This is getting wierd. LOL
TS

 

[kopeck]

Actually yes I did, english........ This is getting wierd. LOL
TS

I've really derailed this thread haven't I? Sorry about that.

None the less, just to make it less weird, she's my Mother In Law. So yeah, I'm not stalking you or anything.

K

 

[BoilerMan]

I've really derailed this thread haven't I? Sorry about that.

None the less, just to make it less weird, she's my Mother In Law. So yeah, I'm not stalking you or anything.

K

Well now I did it, told you where I live................. LOL, Don't tell me you eat @ Moody's diner either, my in-laws own that...........
TS

Ok, no more de-railing.

 

[mikefrommaine]

My wife is from Ashland, small world.

 

[mikefrommaine]

So I'm way late to the conversation BUT call Vaughn (http://www.vaughncorp.com) about your tank. They know they have a problem and will fix it. From what I hear a lot of them leak on the side, which it looks like yours does. Mine leaked around the top. I had to pay for the part from FW Webb but got my money back when I returned the fault coil unit. The don't pay for installation though, still better then nothing.

K

Just called them. Would have to pay a plumber to come say its leaking. And since I'm not the original purchaser it isn't covered under warranty anyways.

 

[kopeck]

Just called them. Would have to pay a plumber to come say its leaking. And since I'm not the original purchaser it isn't covered under warranty anyways.

That's to bad. I've heard that they can be really cranky about warranty work, the only run around they gave me was the plumber inspection. I ended up having a friend who's a plumber come over and make the call. They really didn't ask for proof though, I could have just told them I was licensed.

Ultimately I want to replace mine with a heat pump hot water heater then the dang oil boiler can stay quite all summer. I figure I could stick a coil in my storage tank that would feed the heat pump so in the winter when the wood boiler is doing it's thing then the heat pump would just be a backup for DHW.

I have a friend who live just a few miles down the road that's form Ashland. So you "imported" a county girl as well.

K