Buffer tank

nick z.

Picked up a used H.S. Tarm wood fired boiler that I'm going to hook in to my oil boiler. I will pipe primary secondary. My question is about the buffer tank. Am I coorect in thinking that whne the boiler reaches 200 deg. I want a pump to come on and send the water from the boffer tank into the system? I'm thinking I must use a mixing valve so I don't send 70 deg. water into a 200 deg. boiler. Couold anyone recommened a control for that?
Thanx, Nick

hr

Some of Tarms

latest piping diagrams show a three way thermostatic valve piped at the boiler. They may be shipping the boilers with then now? The intent is to prevent that cold shock you mentioned, and to run the boiler temperature up to a more efficient temperature range. I see no reason to wait till you get to 200 degrees to feed the buffer, as long as the the load is being satisfied.

Personally I like the buffer piped as a secondary with a VS injection mix to sip off BTUs, blend, and protect the boiler return. This could be configured so the house "load" is met before the buffer recieves any BTUs also. It takes some creative control work to make it all happen.



The other issue Tarm is concerned with, I believe, is a dump zone or load. This would be to protect overheating should the call for heat be satisified with a full load of wood still in the boiler's belly. Personally I think the induced draft boilers shut down the fire pretty quickly when the fan shuts down.

For me building fire to match the weather, and load is something most "wood burners" learn rather quickly. Saves wood and lessens the danger of an overheat situation.

Also a power outage could be a concern. If the fire keeps burning but the pumps quit running you could overheat. It gets tricky to accomodate all these features. Draw the whole thing up first

Check with Tarm for their suggestions.

This link has some good ideas, not sure if the diagrams will show up, however.
http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,4498,00.html

hot rod

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Scott Nichols

Glad to help. Call

us at 1-800-782-9927 and we can look at your design so we can then make suggestions. We do a lot of heat storage systems with Tarm boiler customers. They work great and make using wood heat much easier and more flexible.

Lloyd