Outdoor wood boiler install

bubba

Hey guys, I have a question about the install of an outdoor boiler (central boiler). This boiler is a wood burning type and is non-pressurized.

The boiler is already in place and the supply and return piping are brought into the bldg.. I installed a primary loop with two closely spaced tee's. There is a pump on the boiler outside and a pump on the primary loop inside. The bldg. has radiant floor heat. The pump on the boiler (outside) pumps water from the boiler into the primary loop (injecting) The primary loop's pump circulates water around and around, piped off of the primary loop is another pump that I am using to "inject" water into another loop with a pump. There are three different supply manifold's off of this loop, each with their own zone valve. The idea is that when a zone valve "calls", the loop pump will come on and circulate water thru the zone. As the temp. drops in the loop supplying the zone, the injection pump will "ramp" up and "inject" warmer water into this "second" loop. I am using teckmar 361 controllers to acomplish this. Once the switch on the boiler is turned on, the pump starts to run "injecting" 180 deg. water into the large primary loop. When a zone calls for heat, the pump's inside start (loop pumps and injection pump.) I filled everything with a mixture of propylene glycol and water (50/50). The question I have is when everything was turned on, I had good flow inside but I was not circulating water thru the boiler and injecting it into the primary loop inside. Taco 009 is outside and I have 007's inside. The pump outside is on the supply and on the return is a swing check valve (recommende by the mfr.) The boiler holds approx. 390 gals. and the total amount of fluid in the system is approx. 500 gals.

Tom Blackwell_2

elevation

Is the wood boiler at a lower elevation than the loops in the house?  If so, may need a heat exchanger to separate the two.  Sounds like you have the control right, by injection off of the primary loop.

bubba

Outdoor wood boiler install

The boiler is at a lower elevation then the bldg., and the boiler overflowed a slight bit from the vent on top and I added a piece of pipe ( 5inches) and that took care of that. I still think that I have a problem with the pump outside.

lchmb

What type boiler?

I am thinking with the antifreeze (250 gallons wow) that your pump is not enough. I would get back with the manufacturer and run your design by them and see what they recommend. I would however put a plate exchanger on the system and unless needed run water in the house.

Generally with wood boiler's, if you can get away with it, they recommend against using antifreeze, unless you go away alot or have power supply issues.

TMorg

outside wood boiler

More pump- like a 0011 and less glycol. What size are the lines to the outside wood boiler? How long are they?Are they insulated or just wrapped with bubble foil crap

Mark Eatherton

N.P.S.H. = ....

Not Pumping So Hot eh... :-) (Thanks Siggy)



Actually, it stands for Net Positive Suction Head, and if the pump is not located at least 5 feet below the highest standing water level, AND it is not pumping away from that point, then you can expect problems.



ME