Adding a second pump

[gtmci84s]

Anyone here ever added a 2nd pump to their wood boiler? I have an old central boiler I think it's a 4436. My run from the owb to the plate exchanger and back is about 200 feet if I remember correctly. The pump that came with the boiler is on the supply side at the boiler and there is no wrighting on it but I think it's a taco 009. I have an extra taco 007 laying around and was thinking of adding it to the return side thinking it might improve the recovery time when the house calls for heat. Any input would be appreciated. Thanks!

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[E Yoder]

I've done what you're describing. Ideally both pumps would be pushing (rather than pulling) as it lessens the chance of cavitation. Since it doubles the head, the flow rate will increase. The output of the boiler won't increase tho, just flow. Not sure if you need more flow or not without checking return water temps during a call for heat. The 009 is a fairly low flow pump, with high head. More info on your heating system would help give better answers.

 

[gtmci84s]

5 zone in floor heat with 6 pumps. Oil boiler closed system. I heat it with a 40 plate heat exchanger. 1 inch central boiler brand pex from the wood boiler to the oil boiler.

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[maple1]

What exactly do you mean, by 'improving recovery time'?

 

[gtmci84s]

When the house starts calling for heat I get a pretty big temp drop in the oil boiler, the wood boiler seems to struggle to keep the oil boiler up to temp when there is a high heat demand. It does the job, just thinking if it can do it a little bit better its worth it since I already have the pump.

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[maple1]

Ok, that sounds like more flow might help, which a second circ should improve.

Ideally, bigger underground pipe would be a more overall efficient setup, but replacing that would likely be a last resort. Is it their therompex type pipe or something else? If not, heat loss to the ground could be playing a part also.

EDIT: Just noticed the 40 plate HX mention. That is likely undersized also. I would likely use an 80, at least.