Did I gain anything?

[jfriesner]

So this morning I threw in a second Taco 007 pump on my system. A quick run down of the system is it leaves the back of the boiler and goes directly into the first pump, the original pump. It then goes 65' into the house and to the first appliance, 24" tubular style sidearm, then it goes into a 40 plate exchanger for on demand hot water, then it goes 45' out to our hot tub, another 24" tubular style sidearm, and then it comes back to the house and goes through the 16x20" heat exchanger in the furnace. Then back the the boiler. When nothing in the system is calling for heat I have a supply/return temp difference of 4degrees +-1.

When hooked the system up i knew little about hydronics and wanted to system to look neat and not take up much room in my furnace room since it is really small so I put in a lot of fittings. I hooked pex up more like copper. There are a total of 42 fittings in the whole system. Quite a few elbows, a few couples, and quite a few ball valves so i can bypass and isolate every part of the system for draining/maintenance. There are also a few T's in the system for hose hookups for system draining/bleeding.

I added the second pump on the return line right before it leaves the house. I did not add the pump because there was a problem. The spa is always 104, the house is always 72, and we have endless hot water 24/7 with 7 people in the house. I mainly added it as a safety measure if the primary were to fail I don't want to wake up to a frozen system when its -30 out.

Main question is does adding that second pump help with moving the water through the system? Did I gain any GPM? Just curious thanks!

 

[DoHomerSimpson]

As far as I know putting 2 pumps in series allow you to combine their effect on either flow rate or on head height while they are both in operation. However if only one of the pumps is in operation at any one time, the other one may act to restrict the flow depending on its design.

 

[NSMaple1]

Likely answers are yes & yes.

But whether it improved performance is likely debatable since it seems it was working good before.

If you upped your FPS speed to beyond what the fitting & piping & HX manufacturers recommend, you might shorten their life - but by how much, who knows. You'll also be spending more $$ on electricity - whether enough to matter or not is hard to say.

 

[jfriesner]

With as high of a head loss as I have i kind of doubt i'm pushing water too fast. But I really don' t know. I've been making it up as I go for sure. As far as electricity goes prior to OWB hookup an average winter month was $350-$500 utility bill. Now that we are all hooked up we are averaging $80--$100. So i'm not too concerned about running to 1/25hp pumps. But I would be curious how much they cost to run a month.

 

[Ikeholt]

I've thought about an "insurance" pump as well. Can you turn one pump off and get an idea of how well you can push through a non-running pump? Pumps always seem to go out at the worst time.

 

[Erik B]

If you plumbed in a bypass around each pump, wouldn't that eliminate any problems with one pump restricting flow? You would only be using one pump at a time.

 

[rancher2]

I installed my system 10 years ago. I have two feed lines and two return lines from my Garn to my house. I installed two pumps one in the Garn barn one in the basement my run is 450 ft so I felt like I need two pumps. It has saved my twice as one failed and the other kept the system going. It seems to work on one pump with no problem. I don't think the added cost to run the pump is a big thing. One is out right now on my up stairs furnace I just found it out as I was checking the system before I went to the hospital to get some heart surgery. I didn't have time to change it before the surgery so it will run on one pump for a while. It may had been out for a while I hadn't give the system a good check over in a while it was running fine. I run my year around as we heat our water also with it.

 

[jfriesner]

If you plumbed in a bypass around each pump, wouldn't that eliminate any problems with one pump restricting flow? You would only be using one pump at a time.

I'm thinking that may the added elbows and other fittings would restrict flow as much as a shut off/broken pump. But I don't know that for sure.