Washington pole building radiant floors

[austinfender]

First post here, been a member a long time.
finally built my dream shop, 48 by 52 with 14ft tall doors. right before pouring concrete i got talked into putting tube into the slab. after spending a fortune on 2inch pink foam. I installed 3000 ft of pex tube, 10 loops to a stainless manifold with the intention of figuring out the rest later. well now later has come and in the process i have came across 20 different ways to do it.

The boiler will be propane and a combo unit for hot water later, i have decided to go with a 125,000 btu unit. when it comes to plumbing all the diy kits and designs are different. my question go why do some use two pumps and have two loops, and some have one pump and just push all the fluid thru the heater. i have installed hydranic heat on boats for years but those systems were designed by others so i am alittle lost. my goal is just to keep shop warm all year not hot by any means.

one pump vs two?
primary and secondary loop?

my design idea is just one pump to push thru the heater then a air separator with expansion tank and then back to the manifold.

too basic? i cant have a auto filler valve because there is no water in shop so its gonna be a completely closed system.

 

[austinfender]

here are some systems ive been comparing to and looking at the layout and differences. photos taken from this site or google

 

[19D2P]

This might help explain some:

 

[yeldogt]

This might help explain some:

That is just showing the same setup w/ different pumps. Only #1 is worth doing. For most utility setups the manifold is just a distribution spot vs a control. Most people lay out the zones so each loop is about the same length and they run all the time -- so normally not much need to balance. I often double loop some areas in my jobs -- so some areas have more pipe and by opening those areas you can warm a given area more than another depending on load and spacing.

 

[yeldogt]

First post here, been a member a long time.
finally built my dream shop, 48 by 52 with 14ft tall doors. right before pouring concrete i got talked into putting tube into the slab. after spending a fortune on 2inch pink foam. I installed 3000 ft of pex tube, 10 loops to a stainless manifold with the intention of figuring out the rest later. well now later has come and in the process i have came across 20 different ways to do it.

The boiler will be propane and a combo unit for hot water later, i have decided to go with a 125,000 btu unit. when it comes to plumbing all the diy kits and designs are different. my question go why do some use two pumps and have two loops, and some have one pump and just push all the fluid thru the heater. i have installed hydranic heat on boats for years but those systems were designed by others so i am alittle lost. my goal is just to keep shop warm all year not hot by any means.

one pump vs two?
primary and secondary loop?

my design idea is just one pump to push thru the heater then a air separator with expansion tank and then back to the manifold.

too basic? i cant have a auto filler valve because there is no water in shop so its gonna be a completely closed system.

Primary/ secondary is hydraulic separation. On small systems with low flow needs you can do the close spaced "T" as systems get larger you have to go with a low loss heater set up. Too much flow and resistance for the close T.

With radiant you have two things going on. It may not seem logical -- but a big house with all kids of radiators and a big old cast boiler is very easy to move water around. There is very little resistance in the system. This is not the case with Radiant using PEX tube -- you are pushing water through 1" CU pipe or maybe 1.25 pipe and sending it out through very long 1/2 loops -- lots of resistance. Same thing with the boiler -- cast boilers hold lots of water and big pipes. Wall boilers -- small amount and small passageways .. resistance.

Boilers also have flow and temp requirements -- they want (need) a minimum flow and most want some return temp (especially cast).

So primary/ secondary gives the boiler what it wants by pumping water around just for the boiler and secondary gives the radiant or whatever you are using to deliver the heat what it needs. If you tried to use one pump -- it may work on a small system ... but as the system grows in size the one pump just can't over come the head or resistance. Often people have systems that are working -- but, the flow is not really ideal and the system would worked better if they had piped differently. Radiant is forgiving and will often work -- with 20 years of cheap natural gas people don't really care sometimes. A system too big with one pump is often the reason on-demand water heaters don't work well as they have a lot of resistance.

There is a guy with a video out using a tank water heater and a few loops and a pump -- this works because a tank has very little resistance and the pump he is using is large enough to do what he wants .... copy and make larger and it will not work. size matters

 

[Brly]

I got a complete package from Blueridge. They were great to work with. Sent my floor plan and other details, they worked up everything I needed and sent a quote. The only thing I will have to supply is power and water/glycol. Wanted to get it fired up before winter but garage door lead time is killing me. Can't wait to get it going.

 

[tdkkart]

I'd like

here are some systems ive been comparing to and looking at the layout and differences. photos taken from this site or google

I too would like a clear explanation of the theory of why primary/secondary boiler plumbing is used. I think I know the reasoning for it, and it makes sense, however in real life practical situations it doesn't work as the theory suggests.
After many years of using a 2 pump zoned system without primary/secondary I switched to a boiler whos manufacturer required primary secondary plumbing, however in actual operation there's very little difference in the way it works, and it seems like it's actually less efficient.

 

[yeldogt]

I'd like

I too would like a clear explanation of the theory of why primary/secondary boiler plumbing is used. I think I know the reasoning for it, and it makes sense, however in real life practical situations it doesn't work as the theory suggests.
After many years of using a 2 pump zoned system without primary/secondary I switched to a boiler whos manufacturer required primary secondary plumbing, however in actual operation there's very little difference in the way it works, and it seems like it's actually less efficient.

My guess is that was cast boiler and each pump was able to run the zones .... high temp -- so each zone came back with high temp.

Smart pumps can eliminate the multi pumps -- they use zone valves. This is cheaper to install and with only one pump running it's lower cost. Even those small pumps are 90watts .... many much more. I have seen systems with a wall of pumps where one would do.

I have around 40 loops of radiant doing 4000+ sf of my current house build .... all on one secondary smart pump

 

[PoorUB]

Primary/secondary generally depends on the boiler, but in most cases there is no harm with going with a primary/secondary loop system. It adds a pump and a couple fitting and a few feet of pipe, plus the boiler will be happier in every case.

The biggest reason with primary secondary is one pump will not satisfy the flow of the floor and the boiler. Most high efficiency boilers have a fairly high pressure drop. Also floor loops have a fairly high pressure drop. Add the two together and in most cases one pump will not meet the pressure demands required to get the flow needed for the system and the boiler suffers.

Read the installation manuals on high efficiancy boilers and most will require a boier pump to ensure proper water flow for the boiler.

 

[austinfender]

thanks for the info, it was a huge help! looks like I will be going for a primary/secondary system.
this makes the most sense to me design wise, now the question becomes to buy it or try to build it from supply house parts.
Ive reached out to blueridge and am waiting to here back because the nearest menards would be back east

https://www.menards.com/main/plumbi...56-c-8521.htm?tid=-4678659266504983084&ipos=3

 

[yeldogt]

thanks for the info, it was a huge help! looks like I will be going for a primary/secondary system.
this makes the most sense to me design wise, now the question becomes to buy it or try to build it from supply house parts.
Ive reached out to blueridge and am waiting to here back because the nearest menards would be back east

https://www.menards.com/main/plumbi...56-c-8521.htm?tid=-4678659266504983084&ipos=3

Decide on the heater -- that will determine the piping (you follow the manual) . I have never seen a gas wall boiler with a factory layout not using primary/secondary. Can't comment on electric as I have only been around a few installs -- they had as well.

The pre-made panel you reference is made by a company that also makes boilers -- so one has to believe they will work and are approved. It's not going to be a layout that follows the recommended for boilers I have come across. One I item that is confusing -- It has a valve in the close space "T" that makes little sense .... but -- the panel is not set up to pump towards the boiler as typical. Maybe you restrict the primary to force the flow ....

That panel has items to make a dumb boiler -- smarter. But it's still not going to graduate to a smart system. You would be better off putting the money into a smarter boiler and making the unit yourself. Also -- the pumps are not modern low energy pumps.

Pump is always bad -- I should say circulators. Closed systems are not pumping

 

[78SC4X4]

Your first post suggests you will eventually want a combi system. Make sure you let Blueridge know your eventual plans. If you want a direct system, you'll need a different level of materials. An indirect system will require a heat exchanger.