What to do ? New stove DHW problem

[tiswood]

I bought a new stove ( in basement)and had a plumber friend hook all the DHW connections. There's a main 50 gal water heater and a 50 gal water heater used as a buffer tank. I thought all was good so I fired up the stove yesterday after hook up. Well today the 210 degree blow off valve is dumping water in buffer tank? This is after a morning shower. So I started turning on spigots to dump some water and it's still draining some. There's a mixing valve between tanks set at 130 so it doesn't ruin main tank (was told to hot of water will ruin elements in main tank ) . I didn't expect a wood fire to overheat 50 gallon so easily? I need some direction in what to do now ? After about $1000 invested in material , tank and plumber . I would hate to have to unhook it all??

 

[tiswood]

Just to add. This is a gravity system . 1st tank is about 3 feet from stove. 2nd is about 5 feet from stove. What I don't understand is the cold on the buffer tank going to stove coil is still cold. If it's getting to hot to blow off the 210 degree valve wouldn't the whole tank be hot 1st? Seems kind it's not circulating enough to me ? But I'm no plumber .

 

[maple1]

Think more info is needed to try to come up with advice.

Pictures of the entire setup would be quite helpful.

Do you have pressure guages? Maybe it's pressure & not temp that is blowing it? Bad relief?

Plus - exactly what stove?

My electric water heater is also heated with wood via an HX, and it has seen temps in the 160 range on occasion. The elements still work after 3 years - but that's not necessarily saying it's not bad for the elements. I just hadn't heard that before - and I think the dial on the tank element stats goes up to 140 or so.

 

[tiswood]

It's a ds160 stove fitted with a coil for DHW. I called the stove co and he talked me through it and thinks there was air trapped at the top of the tank stoping circulation. ( that's why the bottom pipe on tank was still cold). It stopped blowing off water now but I'm not sure if it's because air excaped or I let the stove cool down. The bottom (cold) pipe is warm now making me think circulation is working.im having trouble loading a pic. Tells me it's to large. I will try again

 

[tiswood]

Ok ,hope this helps.

 

[maple1]

That sounds possible.

 

[tiswood]

added a couple small pieces of wood just to keep some coals until bedtime and the water temp coming out is around 170. About 100 on cold side. So it sounds to me like it's circulating . But I can't have it over heating all the time.

 

[Steaming Pile]

I don't see a circulator?

 

[Steaming Pile]

You should be moving water continuously with that setup. Does the stove heat your entire home or just domestic hot water?

 

[Steaming Pile]

I've found that gravity hot water flow (thermo siphoning)usually works best when you don't want it to.

 

[Wisneaky]

You should have an automatic float type air vent installed and I don't see one in your pictures.

 

[Wisneaky]

The auto air vent works by venting the air out while the water is circulating.

Read page 3 section C about the auto air vent. (broken link removed to http://www.hilkoil.com/domesticcoil-install.pdf)

I believe this is the vent you would need. http://www.zoro.com/watts-automatic...m_source=Bing&utm_medium=cpc&utm_campaign=PLA

 

[Wisneaky]

Also can you post a closer picture of your second tank so I can see how the pipes are run?

 

[maple1]

Took me a few minutes to figure out the piping from the pics. I think I would try upping the temp of the water coming out of the mixing valve into tank 2, assuming its adjustable. Might also still be a chance there's a partial air blockage still in that pipe? The airvent mentioned above would prevent that.

 

[Wisneaky]

Took me a few minutes to figure out the piping from the pics. I think I would try upping the temp of the water coming out of the mixing valve into tank 2, assuming its adjustable. Might also still be a chance there's a partial air blockage still in that pipe? The airvent mentioned above would prevent that.

That thing isn't installed right. That mixing valve shouldn't dump into the second tank it should go right out to the hot water lines.

 

[maple1]

I think he wanted to temper the hot coming into the second tank for concern of element damage. I would also have put it on the outlet of tank 2, I think.

 

[Wisneaky]

This is how it should be plumbed.

 

[Wisneaky]

I think he wanted to temper the hot coming into the second tank for concern of element damage. I would also have put it on the outlet of tank 2, I think.

I doubt that it would ruin the elements.

 

[maple1]

Me as well. Although it might trip the overheat breaker. Mine has done that.

 

[tiswood]

Thanks for all the replies. Yes the stove also heats the whole house. (About to much so far still learning the new stove) There's no circulator do to the gravity setup. Yes I believe the air vent would be the right thing to install, I will have to call plumber back for that one lol. Yes the reason there's a mixing valve going into 2nd tank to protect it from damage from to hot of water ( per stove co ). I was thinking the same thing but they said it has a good chance of not working with elect again if you use it for the stove hot water. Also in my mind what's the need for a buffer tank if you use the main tank for the stove hottest water ? Either way you are only using 1 tank for the hottest water?The mixing valve going into main tank is set @130 and main tank exit is at 120. Wife already saying to water is hotter than normal.. I guess it's not cooling much in the main tank. She swears to me she smells smoke when the hot water is on? I can't smell it but I also load the stove so prob just don't notice it. This morning I had no blow off and cold pipe going into stove was cool. I was expecting it to be warm after sitting all night. The fire was kept as low as poss with biometric damper . 3/4 load @9 pm and its little over 10 hrs later and there's still 2-3 hrs of glowing logs in there. I have never had a fire start this easy with that below the fire air. If there's a coal and you put on some wood , open the bottom air and it's like a torch. I don't know if I can add a video but I will try later.

 

[tiswood]

This is how it should be plumbed.

View attachment 164484

That is how it's plumbed except for mixing valve placement. I was just lining at that air valve lol. I see a brass fitting is known to California to cause cancer and birth defects??? I am going to have to drain the water and get plumber to install 2 of those . 1 above relief valve on buffer tank and 1 between tanks due to the high pipe and a spot for air to get trapped. Actually want a way to bypass buffer tank if the problem persist that way I can at least drain it and use stove for house heat.

 

[Wisneaky]

Thanks for all the replies. Yes the stove also heats the whole house. (About to much so far still learning the new stove) There's no circulator do to the gravity setup. Yes I believe the air vent would be the right thing to install, I will have to call plumber back for that one lol. Yes the reason there's a mixing valve going into 2nd tank to protect it from damage from to hot of water ( per stove co ). I was thinking the same thing but they said it has a good chance of not working with elect again if you use it for the stove hot water. Also in my mind what's the need for a buffer tank if you use the main tank for the stove hottest water ? Either way you are only using 1 tank for the hottest water?The mixing valve going into main tank is set @130 and main tank exit is at 120. Wife already saying to water is hotter than normal.. I guess it's not cooling much in the main tank. She swears to me she smells smoke when the hot water is on? I can't smell it but I also load the stove so prob just don't notice it. This morning I had no blow off and cold pipe going into stove was cool. I was expecting it to be warm after sitting all night. The fire was kept as low as poss with biometric damper . 3/4 load @9 pm and its little over 10 hrs later and there's still 2-3 hrs of glowing logs in there. I have never had a fire start this easy with that below the fire air. If there's a coal and you put on some wood , open the bottom air and it's like a torch. I don't know if I can add a video but I will try later.

The buffer tank effectively doubles the available hot water.

 

[maple1]

I would likely round up some temp guages, so you can monitor the actual temps in the first tank. I've got a bunch of them I got on Ebay. I taped the probes to the side of the tank, one under each element cover. So I always know the temps of my water. That will give you a better idea on what's going on than pipe temps, and some peace of mind.

 

[tiswood]

The buffer tank effectively doubles the available hot water.

I guess. It really only preheats the water going into main tank . There's no circulation between main tank and stove. That's why I was thinking the stove is still only heating 50 gal. If the water sits in main tank long enough the elect still has to reheat it in main tank. The only other way would be to have the very hot water in main tank?

 

[tiswood]

I would likely round up some temp guages, so you can monitor the actual temps in the first tank. I've got a bunch of them I got on Ebay. I taped the probes to the side of the tank, one under each element cover. So I always know the temps of my water. That will give you a better idea on what's going on than pipe temps, and some peace of mind.

Good ideal .yesterday I ordered some strap on pipe temp gauges to monitor it. If you tape a deep frying type to tank near heating element will that work?