piping question

Richard D.

Wouldnt a 3 piece cirulatoer be better the the 00 series?? IE: High temp of the wood boiler!!!!I know you ve been around a while so thought i would ask you.. and Yea its been awhile since I posted lol... Thanks for the helpin the past..and off thread check out my 1 pipe steam post...? Rich

jim post

wood burner tie-in

I want to connect a tarm wood boiler in parallel with our existing lp-boiler. The tarm manual calls for 1-1/4 inch piping between the boilers. The installers want to use 1" piping...they say they see no benefit in using the larger piping. I see that the existing lp boiler has 1-1/4 inch supply and return piping and serves 3 zones of 3/4 inch baseboard. What size piping should I use between the boilers? Thanks for your help.

Al Letellier

piping tween boiler

there is only one way to do this....FOLLOW THE MANUFACTURERS INSTRUCTIONS. Pipe size has to do the the load and flow required to insure proper circulation. do what he manufacturer says to do......anything else leads to the L word in case of a problem....LIABILITY !!!

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bob young

the 1 1/4 \" method

if the mechanic refuses to follow the piping layout take a hunk of 1 1/4 " pipe and beat him over the skull until he agrees.

hr

Pipe gets sized

by the flow rate they need to handle, and the delta t allowed. If the manufacture gives you a "needed" flow rate, and the acceptable delta T the HX can see, then a sizing table will give you the correct answer.

Sometimes they ask you oversize piping to allow gravity flow should the power go down, circ stops, and the boiler still has some heat to "shed" Wood fired boilers do not stop on a dime.

I'm not sure you want to pipe in paralel. This usually allows heat to flow through unfired "off line" boilers and basically turns them into cooling towers.

You certianly don't want to run your gas or oil fired boiler through and unfired wood boiler. Unless you have fuel dollars to waste.

Look into a primary secondary. This allows one or both boilers to feed into the circuit, together or alone. It can offer return protection to both, and really helps a gasification boiler run most efficiently, as well as the back up boiler. Unless the back up is electric or condensing.

A Calleffi HydroLink is another way to pipe multiple boilers and or loads, if you don't want to pipe a PS loop.

hot rod

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Andrew Hagen (ALH)

Check

page 15 of the Tekmar 363 Brochure.

-Andrew

jim post

primary/secondary question

I was thinking primary/secondary would be a good piping option but the parallel arrangement in TARM manual looked a little simpler and less costly to implement.

My existing LP boiler serves 3 zones of baseboard with a B&G100 series pump on the return. If I piped primary/secondary would I need to replace the existing zone valves with circulators?

I have read Dan's books "Primary/Secondary made Easy" and "Pumping Away" so I am getting familiar with these concepts but I'm still contemplating the best way to proceed. Fortunately, with a high of 94 here yesterday it should be awhile before I have a need for heat. :-)

Thanks for any/all advice.

hr

Sounds like

you are balancing the best way against the least expensive, easiest way?

Yes, the PS would be much more involved and component intensive. Adding a buffer tank makes it even more complicated.

There are a number of ways to pipe this, basically the more you invest in time and pieces, the better control and more efficiency you stand to gain.

In my mind all the components get seperated by PS. The wood boiler is #1. It runs until it meets the load. Then any excess charges the buffer tank. The back up boiler only feeds the primary loop. No reason to warm the buffer via the fuel fired boiler, as it is most efficient to keep your energy, in high grade form, in the fuel (oil, lp, etc) than in a tank of water

Differential controls could make all this happen automaticlly. The buffer would charge based on the available heat, the back up would fire when the loop fell below a certain setpoint. Both boilers could be protect againts low return temperatures, via these pumps and controls.

Heck even the distribution side could be run on a reset control, which would modulate the supply temperature and get you near constant circulation. You are probably talking 5 or 6 circs and a few tekmar controls to get to this end. Lots of fittings and piping also.

Get a budget number in mind and build around that. Just be sure to protect that boiler (both boilers)investment and not send your LP, gas, or oil fuel dollars up the flue via an unfired boiler. That would quickly offset the savings of having a wood fired boiler to begin with

hot rod

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jim post

Primary/Secondary question

Is it necessary to have small circulators on the secondary circuits?... Or with closely spaced Tee's would zone valves opening be enough to encourage flow from the primary circuit? I was hoping I could reuse my b&g100 pump on the primary loop....and connect to the existing zone valves for heat distribution to the baseboard radiators. Would that work?

Thanks.

hr

Yes and no

Yes you will need circulators on the secondary loops. You may be able to use that pump on the primary loop, as long as if meets the flow requirements.

No you could not zone valve off the primary loop. It needs circs to establish the flow. You could pump the supply side and zone valve the return as a check protection if you REALLY want to reuse the ZV's. Also the ZVs could still be used in the secondary loops for your zoning, once a circ is installed.

The main concept behind PS is that all the secondary branches are seperated from the primary loop, hydraulicly. The primary loop and take offs, properly designed and installed will act a seperate systems seeing only the same fluid.

hot rod

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jim post

Bought a brick to boot

Thanks for the advice. The installers supplied a copper sidearm heat exchanger for preheating my domestic hot water tank. It seems to me I would pipe the sidearm heater in the primary loop so that whenever the TARM is running it heats the domestic hot water. Or would it be better to put the sidearm in a secondary loop with a circulator. I guess I am not sure of the control strategy for having it in a secondary loop. Any advice?

One other question, Has anyone seen a digital thermometer with a probe that could withstand the temps in a wood fired chimney pipe? I would like to monitor the chimney temps to try to minimize creosote deposition.

I really appreciate the wall...I bought a brick today.

hr

You

should really control those sidearm HX with an aquastat controlled circ or zone valve. I have seen them heat water heaters to over 180° F! For sure install a 3 way thermostatic scald valve on any tank with those side arms connected.

Stove shops sell small magnetic flue temperature gauges. stick it right on the flue piping near the heater, instead of drilling the flue. Probably find one via a web search.

hot rod

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hr

By all means

reuse the B&G if it is in good shape and fits the requirement. They do need periodic maintenance (oiling) and probably cost a bit more electricity to run. Properly applied, and maintained they last for decades

hot rod

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jim post

Primary/Secondary Question

My existing lp boiler has a 1 inch supply and return with 3 zones valves that control the flow to 3 loops of 3/4 inch copper fin tube. Would it be better to treat that as one secondary loop? Or should I break each zone into it's own secondary loop? My thinking is that since they all use the same high temp water there isn't much to be gained by seperating each zone and the pump that currently serves those zones could be reused. Does that make sense?