Print

[moparevers]

Hey guys,

I was originally just going to run a water to air HX in the furnace - about 150' total through 1" pex... I was going to use a grundfos 15-58... ordered it with the stove...

Since ordering, I've "been inspired" to add a 20 plate HX for the DHW, and a 4' baseboard in my mudroom....

This brings my total loop length (1" pex) to:
 --------210'
 + ___120' (figured for the 20 plate)

--------330' total

 plus 40' of 3/4" pex for the basebard - which I was just going to tee it off and back into the closest part of the loop to it... not sure on the calc for this...

I'm heating about 1400 SF... Was hoping to be delivering water at 7-8 GPM....

I've been running calculations... and I think 1 grundfos 15-58 is going to be way over worked... if it works at all...

Can I just add another 15-58 in series... math looks OK - or should I move up to a bigger pump? Next level up looks to be a little more than I need...

Suggestions please?

[Scott7m]

Take that 15-8 and put it on that 3/4 loop going to your baseboard using a close t system.  You can't put t in and not do something to send the water over there, but of you had that baseboard on a stat it could send signal to the 15-58 on a close t, and work that

On the main loop then you'd be getting close to what you were wanting, but probably closer to 6 gpm

[moparevers]

Well, I said "tee off" and "tee in" - but, I meant add to the loop, but do so with tees and valves so I could shut that part of the loop off/on ... which would mean I'd be effectively adding the 40' to the loop...

I wanted to do it this way, so that I could just heat this mudroom during the coldest parts of the year...

I could do this with 40 ' of 1" pex, instead of 3/4 to the baseboard - was just thinking of using 3/4 since it has 3/4 fittings... but i guess that I'd be bottlenecking the whole system... ?

[Scott7m]

Unless u plan to manually adjust the t's by varying weather im not sure

id rather put small pump on that particular loop so it wont affect the flow at all by using a close t system

if you do it the other way ur gonna have to much load on that loop anyway. ..  so putting the pump there aint costing more and youd never have to touch it

[RSI]

I agree with Scott. Don't try to make your main pump push through the baseboard loop, especially if it is not always used.

With the close tees like he suggested, you just re-direct some of the water through the baseboard heaters when the pump comes on. Otherwise it is just bypassing it completely.

[moparevers]

I haven't seen these "close tees" - any suggestion where I get them?

Also, Is a 15-58 big enough for my main loop? seems like I need little more... but the 26-99 seems a little much... any suggestions? kinda seems like my head/gpm is right in between the little pumps and the medium ones...

[RSI]

Just use standard pipe fittings and thread or solder or whatever type of fitting you prefer.
The 15-58 will be close to the right size. There are in between sizes but the price probably won't be much lower. Something like a 26-96 might be a few dollars less. Those are 3 speed pumps so if it is too big you can run on a lower setting.

[moparevers]

so, in the main loop, just put in 2 regular Tees: http://www.pexsupply.com/HydroPEX-H051175-1-PEX-x-1-PEX-x-3-4-PEX-Brass-Tee-3735000-p

connect my radiator to that...

and have a pump in that loop - and when it comes on, it will pull what it needs from the main loop?... no need to have something opening & closing? It won't disrupt the flow? I don't need check valves or anything?

[RSI]

Those would work. I like to use threaded or copper tees because they would have a little less restriction and you could put valves on it too right away so you completely turn off the baseboard loop if you ever had a leak or wanted to change something.

[moparevers]

OK - thanks for all the advice RSI & Scott...I think I'll get the bigger 3 spd pump for the main loop -  and use the 15-58 i have for this loop... I just don't think it'll be pushing quite the gpm I need for the main loop...

15-58 on low should push more than enough for the baseboard loop - right?

With 330' for the main loop - plus the tees, valves, etc - I think I'll be close to 20' head... if I'm calculating right...

[Scott7m]

The 15-58 will be fine on low if u do it like we're saying for the baseboard loop

[moparevers]

I realized last night that you guys were saying "close tee" as in "tees near each other"- but I was reading it as in "tees that close" as in close the door... so I was thinking you guys were talking about tees with valves in them or something... I look back at my posts and boy do I sound dumb!