Tarm solo plus 40 (140K) : flue sizing & hydronic stuff

[turbotech]

The gasifier has a 6" outlet. The manual says 8" ID HT is best if the length is 20 - 30 feet. Then the manual says 6" ID HT is satisfactory for around 20'.
Suppose I need two 90* black elbows, 3' black, and 20 to 24' of class A HT. Would the 8" or 6" HT be better? Just worried too large might cause creosote, and too small will cause smoke on reload.

 

[jebatty]

Why not give Tarm Biomass a call?

 

[turbotech]

I did. They said 6" is fine. The answer came a little too quick so it had me thinking. I was wondering what others have done. I was hoping for some clarity on the confusion that is given in the manual.

 

[jebatty]

I have no experience with 8", so really can't provide much insight on any issues related to 8". I use 6", one 90 immediately off the back of the Tarm, 9' of black stove pipe from the Tarm to the ceiling, and then 11' of Class A. Works very well. Last year before I moved the Tarm to my new shop I had 19' of Class A, 5' of black stove pipe, and one 90 off the back. Also worked well.

As to smoke on reload, it is related to draft. In my old shop which was poorly insulated and sealed, smoke roll out was minimal. In my new shop, I have to open a 24" window at least 8" when the boiler is operating to provide extra combustion air. With the window open, virtually no smoke roll out; with window closed, I will get smoke some smoke roll out. My reload procedure rarely involves adding wood unless the fire has burned down to mostly coals. Adding wood during a vigorous burn is not the best procedure, and that's when some smoke roll out may occur.

The Solo 40 is a great boiler, just finishing the 4th problem-free heating season with my 40. Refractory also remains in good condition. Best wishes to you.

 

[Chris Hoskin]

6" HT is best.

 

[turbotech]

Thank you both for helping with the decision on 6" or 8" pipe.

I am trying to make this system as low power as possible. The manual lists the Automag valve for the dump zone but I can't find the "watts" or "va" rating. I was looking at the TACO V075T2A1ZB024Q4 which is a normally open valve that uses a ball valve inside and a motor instead of the normal AC sync motor. It only uses 1.44 watts in the closed position. That is a small amount of power compared to a convention valve which typically uses around 8 to 10 watts. The TACO also has a manual override switch built in to open the valve.
What are your thoughts on using this TACO valve instead of the AUTOMAG valve?

 

[Chris Hoskin]

the automag is specifically intended to allow you to set up a heat dump when the power fails. The small 24 V transformer that holds the valve closed via an electromagnet draws very little power. When the power fails, the magnet is de-energized and the valve literally falls open (horizontal mounting orientation is critical!). A motorized zone valve would have to have a spring return so that it opens when the power fails - I don't know if the Taco you mention does or not.

 

[turbotech]

The TACO valve uses a ball valve and microprocessor technology. The microprocessor charges a capacitor that works to turn the ball valve closed during operation. This takes 13 watts much like the automag would take during operation. Once the ball valve is closed it only takes 1.44 watts to keep it there where as a spring design still takes 13 watts. If power is lost then the capacitor discharges and the ball valve returns to the open position to dump the excess energy into the sink.

I need to get more info about continuous operation of the TACO valve. By design it should be fine with 100% because of the holding mechanism but I need to check with the manufacturer because the spec sheet doesn't have an info about it.

 

[sweetheat]

I've used 6" 304 stainless pipe 32 feet for the Tarm and another 5" stainless pipe 14 feet for a Jotul 118B Both inside a 12X12 lined brick chimney. Both work great, I get very little smoke roll out with the Tarm. Sweetheat

 

[ewdudley]

What are your thoughts on using this TACO valve instead of the AUTOMAG valve?

The Taco EBVs are very appealing but they have disappointingly low Cv numbers, so they might be too restrictive for a gravity-fed over-temperature circuit.

Also, even if the numbers work out and an EBV would do the trick, there would have to be some uncertainty --even if it was unjustified uncertainty -- that would weigh against using the EBV in a situation that the AutoMag is designed for.

 

[turbotech]

the automag is specifically intended to allow you to set up a heat dump when the power fails. The small 24 V transformer that holds the valve closed via an electromagnet draws very little power. When the power fails, the magnet is de-energized and the valve literally falls open (horizontal mounting orientation is critical!). A motorized zone valve would have to have a spring return so that it opens when the power fails - I don't know if the Taco you mention does or not.

The literature says that the EBV charges a capacitor to do the opening and closing. When power is lost there is still enough energy in the capacitor to open the valve. At least that is how I read it.

Could you give me a ballpark figure for the AutoMag or should I use the tarm email address?

 

[turbotech]

What are your thoughts on using this TACO valve instead of the AUTOMAG valve?

The Taco EBVs are very appealing but they have disappointingly low Cv numbers, so they might be too restrictive for a gravity-fed over-temperature circuit.

Also, even if the numbers work out and an EBV would do the trick, there would have to be some uncertainty --even if it was unjustified uncertainty -- that would weigh against using the EBV in a situation that the AutoMag is designed for.

I am new at this so I need to read up more about the flow I will need for the gravity loop. All I know right now is I need to dump 14K BTUs and it may be through some 1.5" big copper K pipe.
What are the cv numbers for the automag? All I could find is info on chosing an AutoMag for a given pressure and flow. There will be no pump so I can't really use that table listed on the website.

 

[turbotech]

I decided to go with the Selkirk DSP and Class A HT for the stove pipe.

 

[turbotech]

I did some measuring for the amount of pipe I will need. Next is making a list of the inside pipe I need.

I read about some EDPM that can handle 200* F, but I don't think I will be able to heat the storage to that anyway. What is the best online company to go with for ordering an EDPM liner. I pretty much made up my mind on unpressurized storage due to the small door way and wanting DHW and solar capability later on.