Thread: outdoor wood boiler pump question

k so i got this outdoor boiler all hooked up, started filling with watter and started the water pump to circlate the water into the exchanger, well, its humming, but i aint getting nothing out my return line, now my only issue is that i had to run my water pipes up into my attic were my furnace is, suck i know,, so the pipes are going 12-16 ft up will this pump not push the water that far, i only have like 40 ft of pipe each way , the pump says on it 140 psi do i need to prim the pump or get something to suck on the return untill i get water then mabe the pump will push or get some sort of bigger pump or mount another somewere between the ecchanger and stove so i have two pumps?? any ideas, thoughts or what u would do??? also what do u all use to add to the water,, i bought the stuff for it but kinda lost it all due to open drain valve... stupid me

Well what I was told to do was put a T in the line with a valve on it after the pump. A short piece of hose coming off the valve. You open the valve and water should flow from gravity from the tank, once the pump is primed good, start the pump . When all the bubbles and air pockets have blown through close the valve. I am pumping 75' with my heat ex about mid level with my stove, and I have two small pumps in series. ( cheaper than a big pump). Hope this helps.

I like to vent a system from both sides to the top vent. Then the pump is only circulating water, not trying to push it uphill.

Originally Posted by tawilson

I like to vent a system from both sides to the top vent. Then the pump is only circulating water, not trying to push it uphill.

Exactly, in a closed loop system the only loss the pump has to overcome is the friction loss of the tubing. There is no head differential to overcome. I suspect the 140psi is the max system operating pressure. Is there a curve supplied with the pump? If the pump is capable of 140psi then it could lift water 294 feet high at some given volume.

Check for being air bound and vent the system at a high point to be sure you are trying to pump water. Pumps don't like air. Also, centrifugal pumps do not actually develop suction, they must have some suction head to drive the water into the pump, so if there is an air bubble there at the suction it will not pump.

my pump is on the rear of the stove, so its got water feeding it at all times, i had the return open at the stove, thainking the air would blead out on its way back but i just dont thain im getting the water up the 12-16 ft straight up, mabe i will try using the hose to fill the pipe and when i get water coming back out hook it to the pump, thats all i can thaink, or wire another pump up in the attic by the furnace, rilly dont wanna do that any other options guys or ways to get it primed?

Shouldn't the highest point in an open system be below the boilers overflow?

What size pump do you have?

You should have a place to hook a hose, then fill it to the top, first on the return line then on the supply.

Originally Posted by atlarge54

Shouldn't the highest point in an open system be below the boilers overflow?

What size pump do you have?

He said he's hooking it to a heat exchanger so I'm assuming it's pressurized and isolated from the outdoor boiler. I may have misunderstood that part after rereading the op. You are right, either way.

Originally Posted by atlarge54

Shouldn't the highest point in an open system be below the boilers overflow?

What size pump do you have?

I believe this is a closed loop system. One should have a vent(s) at the highest point in the system and fill until all air is forced out. I have an oil fired boiler for hot water heat that is used if we go away for an extended time. The boiler is in the basement, most of the baseboard radiators are upstairs. I have a vent on each baseboard radiator. There is a pressure controlled fill valve plumbed up to the potable water in the house. This assures that the system fills properly and stays filled incase of a leak (safety feature). The hardest part of starting that system up was bleeding the air out of it (air makes a lot of noise and won't circulate properly). Anyhoo, not having seen the system layout, I am probably speaking out of the wrong orifice, but venting the air out seems to be the first order of business. Hope this helps.

You're pump cannot push the air that high and through the heat exchanger.

Here's how I would do it.

-Remove the return pipe from the heat exchanger
-Fill the supply line from the boiler, using a garden hose.
-Vent the supply line, through the exchanger, while filling. Your supply line should be hooked to the bottom nipple.
-Fill the return line from the boiler, using a garden hose.
-Vent the return line at the exchanger while filling.
-Hook everything up and you should be good to go.

If this doesn't work PM me and I'll send you my phone # and we will get you going.

ok ill try that when i get home tonight at five, if its not raining out..

works great now, but i decovered a drip leak in my fire box in the seem, dang..

Originally Posted by troy21

works great now, but i decovered a drip leak in my fire box in the seem, dang..

now that sucks!!!!