Pump Sanity Check and Sensor wire in Trench

[Tennman]

Using the VERY helpful document from TACO below, it looks like I need a Taco 0013. I'm running 1.25 PEX about 180' from boiler to heat exchanger. I have a Biomass 60, 200kbtu boiler. It looks like my head loss is in the 22-24 feet range and it looks like I need about 17 gpm to get 170kbtu to the house. I'd like to order the pump today and I'm wondering if this passes the sniff test to you guys.

(broken link removed to http://www.taco-hvac.com/tmp/SelectingCirculators.pdf)

Also, I thought I posted a question yesterday about why some of you talk about putting a sensor line in the trench. I'll be covering up my trench and if that is something I useful I'll get one. But I don't know what it would be used for. The boiler works off the return water temp so why would I need sensor data from the house??

I'd really appreciate input from you experts if the pump sounds right. Per the tables it does, but I'd feel better to hear from an experienced user. Thanks

 

[in hot water]

Add a 3/4 or 1" PVC or pex that wire could be fished through later. it's nice to have some sensors in the house to read what is going on out at the boiler, or data logging, or etc.

For the cost of the condiut why not allow yourself the option.

The pump size looks fine for those specs, 17 gpm is on the high side of what 1-1/4 should carry, and it drives your head pretty high, but do-able with that circ.

 

[Tennman]

I get it. it's for in-house monitoring. Thanks. Unless I get some negative feedback this weekend, I'm going with the 0013.

 

[rkusek]

I get it. it's for in-house monitoring. Thanks. Unless I get some negative feedback this weekend, I'm going with the 0013.

Will you have storage? Will it be in house or in shed where your boiler is? It's highly unlikely you would need all 170K to heat your house and unless the storage tank were in your home you should be able to get by with a much smaller (and more economical) circulator. Your heat loss calc would tell you how much your home loses on a "cold" day in winter. My 2200 sq ft ranch loses about 30kBTU on the main floor and about 30kBTU on the basement level on a -10 degree day (Nebraska) for example. Heaterman helped me size my pex (1.5") and pump (Grundfos 15-58) to handle about 85-90 kBTU on the 350' distance to give me some excess BTUs for DHW and possible hot tub down the road. My storage (future) will be in the same shed as the boiler so I only needed to size for the needs of the home not the output of the boiler.

 

[jebatty]

I think you are wise to size for 170K on a 200K output boiler. In my experience maximum output is reached usually only with very high delta-T's or briefly during very high burn periods. And even if the boiler idles, at that rate of flow it will re-fire quickly.

 

[in hot water]

it's true you may never need the max. output of the boiler. You do need to size the circulator to move the amount of BTU the boiler will produce at full fire, to prevent short cycling. regardless of weather the building uses the output or it is going to a buffer tank.

So the pump needs to be sized to more the load through the boiler and piping to wherever the load or storage is.

hr

 

[taxidermist]

I get it. it's for in-house monitoring. Thanks. Unless I get some negative feedback this weekend, I'm going with the 0013.

I use a 013 on mine

 

[Tennman]

thanks guys. Hello taxi. Yep went with the 0013. Our home is a very old, inefficient almost 4800 sq ft. So we need all the boiler can put out. May get the storage in this year but planning that for next year. I confess i didn't do the heat loss calcs since our current propane furnace was doing the job fine, just costing me a bundle. Fortunately for us our home is where the winters are pretty mild here in southern Tennessee. Nothing like most of you guys deal with. Thanks again.