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This is my heating design

I want to heat a basement room. It's a bit under 600 sq ft. The old heating system was a propane direct vent heater putting out 20,700 BTU/hour and struggled to keep up on the coldest days.


3/4 pex Total run would be under 200ft

(4) 8 foot baseboard elements
(1) 6 foot baseboard
22,040 BTU

Simple loop design.
I don't think I can do monoflow because this is a basement slab and returns need to travel within the baseboard enclosure on the way back to boiler.

I'd like to run 3 zones each with its own circulator. I haven't worked out the other 2 applications yet, just seeing how this looks.


Any thoughts? Does this look ok so far? If so, is there enough info for pump size? Thanks
 

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I don't know if I'm too late but...

PEX is not a good choice for Forced Hot Water baseboards because it lets in oxygen, it will rust out your boiler in a pretty short time (about a decade) in my experience but that depends. If your boiler is stainless you're good but, FHW is almost always cast iron.

You need something that doesn't allow oxygen which is either copper, PEX-AL-PEX, or use a heat exchanger. PEX-AL-PEX is special type of PEX with an oxygen barrier, it's a layer of PEX wrapped in Aluminum (which stops oxygen from leaching in) protected by another layer of PEX. The fittings also must be PEX-AL-PEX fittings, normal ones won't do.

When you fill your loop for the first time there's going to be some oxygen in the water, it attacks the iron in your boiler a bit but that uses up the oxygen. From then on there's no more oxygen in the water to attack the boiler and it can last 50+ years. This is not true if only using PEX since it breathes.

When I looked at how much it would cost to do PEX-AL-PEX, the tools, fittings, and I was only doing a small area it was going to cost less to do it with copper (I already had all the tools too) so that's what I used. Looking back, I probably should've done PEX-AL-PEX it was more time and hassle than I expected.


As for the bathroom, I agree with everyone else it is probably the most important room to have heat. When I remodeled my basement bathroom the heating for it was coming two weeks late, putting it in conflict with my wife's plan to tile (it was to go under her tile). I told her she needs to start tiling a day later that's all, but she wouldn't have that. So she tiles the bathroom, I return the heating system since it would destroy her tiling and it's been nothing but frustration since. All our guests (it's a guest area) complain how cold the bathroom is, if I have to use it I hate getting out of the shower into a cold room, I hate using the toilet it's always cold, my wife hates using it. I'm pretty sure the bathroom not being heated in the basement is the #1 thing my wife and I argue about with our house and it's been going 10 years. Every time, and I do mean every time one of us has to use that bathroom we cringe knowing it's cold. My bathroom upstairs is on the other side of the chimney to our wood stove (which we run constantly) and the warmest room in the house. It's like the best bathroom I've ever used :) so nice and warm...
 

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I don't know if I'm too late but...

PEX is not a good choice for Forced Hot Water baseboards because it lets in oxygen, it will rust out your boiler in a pretty short time (about a decade) in my experience but that depends. If your boiler is stainless you're good but, FHW is almost always cast iron.

You need something that doesn't allow oxygen which is either copper, PEX-AL-PEX, or use a heat exchanger. PEX-AL-PEX is special type of PEX with an oxygen barrier, it's a layer of PEX wrapped in Aluminum (which stops oxygen from leaching in) protected by another layer of PEX. The fittings also must be PEX-AL-PEX fittings, normal ones won't do.

When you fill your loop for the first time there's going to be some oxygen in the water, it attacks the iron in your boiler a bit but that uses up the oxygen. From then on there's no more oxygen in the water to attack the boiler and it can last 50+ years. This is not true if only using PEX since it breathes.

When I looked at how much it would cost to do PEX-AL-PEX, the tools, fittings, and I was only doing a small area it was going to cost less to do it with copper (I already had all the tools too) so that's what I used. Looking back, I probably should've done PEX-AL-PEX it was more time and hassle than I expected.


As for the bathroom, I agree with everyone else it is probably the most important room to have heat. When I remodeled my basement bathroom the heating for it was coming two weeks late, putting it in conflict with my wife's plan to tile (it was to go under her tile). I told her she needs to start tiling a day later that's all, but she wouldn't have that. So she tiles the bathroom, I return the heating system since it would destroy her tiling and it's been nothing but frustration since. All our guests (it's a guest area) complain how cold the bathroom is, if I have to use it I hate getting out of the shower into a cold room, I hate using the toilet it's always cold, my wife hates using it. I'm pretty sure the bathroom not being heated in the basement is the #1 thing my wife and I argue about with our house and it's been going 10 years. Every time, and I do mean every time one of us has to use that bathroom we cringe knowing it's cold. My bathroom upstairs is on the other side of the chimney to our wood stove (which we run constantly) and the warmest room in the house. It's like the best bathroom I've ever used :) so nice and warm...
you have no idea what your talking about, there is pex made for domestic hot water and there is pex made for heating with an oxygen barrier that is more than safe for heating systems....that is no more money than standard pex..lots cheaper than copper..no special tools needed..
 
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