OWB struggling to heat the house

[Kevin in Ohio]

Is it possible that the impeller on the pump is no longer firmly attached to the shaft? It holds on enough for you to spin it by hand, but when it tries to push feet of water column, the shaft spins on the impeller without actually spinning the impeller (or only spins it at a fraction of the speed it should).

That is why it is always good to have a couple of pressure gauges in your system as well. there is still some pressure even if it is an open system and it helps to figure things out.

 

[panolo]

Did you ever measure your temp leaving the boiler and what it is entering the exhchanger?

 

[MH49]

Well the new pump is in and circulating and I believe that we have it fixed. My air temperature measured at the register was 90° and now it is up to 110°.

Some comments:

• The pump was still moving water, evidently just at a reduced rate
• The pump rotor looked to be in good shape so no visual signs of issues
• In hindsight I think the performance has been degrading for some time, even into last heating season.
• Everything else in the system looks real good.
• The pump that was removed was approximately 6 years old.

It is warm here in Ohio right now so won't know for sure until next week when we get the next cold snap but fingers crossed this is it. Thanks to the community for all the help and input!!

 

[avason]

You are making me want to change mine! How did you know it was the pump?

 

[cantoo]

Wife just picked up a new fan for mine, she said she didn't like the sound of it so replace it. Okay I'm just sitting around waiting for something to do according to her. I'm picking up a new pump soon too and switching it out. I don't like the way it sounds. It's about 5 years old and runs 24/7 so won't hurt to switch it out. I'll keep it for a spare.

 

[avason]

I’ve had the original for about 12 years now! I’m going to order one of those temp guns and start from there.

 

[blackdogon57]

Those pumps ( mine are taco 009 ) seem to crap out once every few years. I keep at least one spare cartridge on hand just in case. Might want to change the rope on your door as well. Mine went bad last year and caused my water to overheat and fried my pumps.

 

[MH49]

I circled back to the pump because I couldn't find anything else wrong in the system. When I called my dealer to see if he had a pump in stock, I asked him and he agreed it was probably the pump. Right now setting in the house with an outside temp of 24° F, the wind is howling through my drafty old farm house and I am toasty warm without the fan running all the time.

FWIW, this is my third pump since the burner was installed in fall of 2009. The first one locked up on fall startup on the 3rd season; the second one is the one I just removed seemed to fail over time.

 

[NSMaple1]

What do you have for a circ anyway? I might be off base but seems most or all times a read of a circ failure it was a Taco. And don't think I've read it being a Grundfos.

 

[MH49]

I am not 100% sure on the original, it MIGHT have been a Grundfos. The second one was a Taco 009 and that is what the replacement is.

 

[avason]

That’s great news...I wish there was more of a litmus test to find out for sure. Either way, my original pump is going on 12 years and at one point, I ran it for the first 5 years straight through all the seasons including summer for domestic hot water.

 

[crowbuster]

Good thread guys. My indoor boiler pump went out again this Christmas. 3rd and last taco 009 I will ever install. Seems they know they have a problem as well. They have replaced them with 009-35 or some such thing. Cant take the heat they say. 2nd one I have had that seem to bind up from what would seem to be lack of lube. But always had water. Grundfos for me. 13yr old and still going on the heatmor

 

[Deleted member 117362]

Taco makes a 2400 series for wood boilers. Sold my 10 year old 434 to neighbor with original taco pump and has served him 4 years and still running. I guess like saws, some good, some bad in every brand.

 

[NSMaple1]

Something else that might be a factor, from boiler to boiler, no matter what you have for a circ. Is unnoticed cavitation. Quite often in an OWB, there is not a lot of water, above the circ inlet. That can be OK most of the time, but if your boiler temps get up there, it can put it into a cavitation zone. Where that zone is would depend on head on each side of the circ (on supply side, related to water height), and the circ specs themselves - I think getting above 180 might be time to watch for it. But the certain thing is that cavitation is bad for circs.

 

[lefturnfreek]

That could happen but any boiler setup I have seen would pressurize the pump inlet just by the gravity acting on the water.

The other side of the coin is what are you circulating .... straight water? Any anti corrosion additives? Any poly antifreeze? Filters any where .... ???

I have Grunfos circ's that are getting close to 10 yo, no problems. The last one fried the start up capacitor and was handed off to a buddy who used his capacitor and that circ is still going.