FINAL UPDATE - Wednesday 12/09/09
It turns out that the problem was not with the incorrectly hooked up inlets and outlets. There was a 1" gap between the edge of the heat exchanger and the plenum wall that was allowing unheated air into the ductwork on that side of the plenum. The installer stuffed the air gap with insulation and we now have heat coming out in all the right places. Just in time as it got down to 9 degrees last night.
UPDATE - Saturday 11/21/09
It's a week later and the inlets and outlets are now properly hooked up. My question is how to ensure that any air pockets in the heat exchanger are gone. I spoke with a CB technician last week and he was very reluctant to get into a discussion of how the heat exchanger actually works.
I'm assuming that the heat exchanger does not consist of one continuous length of copper tubing. Otherwise an air pocket would obstruct the entire flow of water. There must be multiple paths for the water to take and the air pockets are trapped behind the flow of water. The user manual talks about using pressurized domestic water to force any air in the exchanger out. Why would this be any different than the water pressure exerted by the system water pumps? If the water is already flowing past the air pockets, how would changing the water flow from the boiler system to the domestic water system make any difference?
It seems to me like I need to get all the water out of the exchanger first. And then let it fill up from bottom to top with the boiler system water. First shut off the intake and outlet valves from the boiler and open the bypass valve and let the boiler system circulate outside the heat exchanger. Then open the drain valve on the intake side of the exchanger (the bottom fitting) and let all the water drain from the exchanger. Then close the drain and open the boiler valves again to let the exchanger fill up properly this time from the bottom up. I should hear the air bubbling out through the outlet side and when the bubbling is gone the heat exchanger should be totally filled with hot water with no air pockets anywhere,ready to heat all sides of the plenum equally hot.
Does this sound logical or have I missed something here?
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It's Saturday and no one's home at CB out in Minnesota so I'm coming to you guys for some help today. The boiler's been operating for a month now. No real problems keeping boiler temp up. We're learning day by day how to keep the fire going in the firebox.
The problem is inside. The 140kBtu heat exchanger coil in the plenum of the forced air heating system only gets hot on one side, the side where the inlet and outlets are. The duct work on this side of the plenum is hot to the touch. I measured 105 degrees coming out of the bathroom register this morning. The duct work on the right hand side of the plenum is barely warm. 87 degrees inside the duct about 12 inches out from the plenum.
So this morning I'm looking at the diagram of the heat exchanger in the CB Heating Accessories and Parts Catalog and I see where it says "Correct Installation the outlet fitting must be located above the inlet fitting". I go downstairs to check it out and sure enough it's backwards. The input coming from the boiler, through the hot water system heat exchanger is hooked up to the top fitting !?!?!?
I'll be talking to my installer as soon as he picks up his phone today but I'd like to know if anyone has had this happen to them and what were the consequences? Would a backwards hookup only heat up one side of the exchanger like is happeing here?
