variable speed pump location.

cutter

I am wanting to use a variable speed pump to supply water to the zones with zone valves. These zones will have flow control valves in them. I am thinking this pump will have to be on the supply header and pumping away from the boiler for the pump to speed up or slow down depending on load. If the pump was on the return header it would be pumping towards the boiler and little to no friction loss. Is my thinking all wet or am I on the right track?

deadmansghost

I have used a system exactly as you stated and it worked fine on the supply header.

Paul S_3

Install the pump on the supply of boiler ...pumping AWAY from the expansion tank. Connect your feed valve to the same location of your expansion tank

Jamie Hall

The pump is part of a loop, so all it cares about is the total friction loss in the loop. So far as that goes... however, as @Paul S said, it should be just downstream from the expansion tank, pumping away from it, and any feed valve should be at pretty much the same place.

cutter

Jamie Hall, / Paul S, Attached is a drawing of what I am trying to build, or think I am going to build. Unless someone can see something I overlooked or did not know enough to put in. Another member said the expansion tank could be above the boiler so I plan on hanging it from the overhead. The auto fill valve, Is it required or just used by everyone? Most if not all systems I see on here are fed with a auto fill. My current system is fed manually whenever the gauge says feed me. In the drawing the pump is on the supply header. Jamie in your post in sounds like the pump could be placed on the return header, just rotate the pump. The pump doesn't know if it is pumping from the load or towards the load???????? And the variable speed will still increase or decrease depending on load?????

Ironman

Because of the LLH, the primary loop will "see" the secondary loop and the LLH as the Point Of No Pressure Change. You should "pump away" from the PONPC as shown in your drawing.

Paul S_3

As ironman said your drawing is fine....just the infloor zones have to mixed down to a lower temp than the unit heater and the other zones....with either a thermostatic or electronic mixing valve or injection pumping...it requires a lower temp ....what type of boiler do you have?

cutter

Ironman said:

Because of the LLH, the primary loop will "see" the secondary loop and the LLH as the Point Of No Pressure Change. You should "pump away" from the PONPC as shown in your drawing.

Ironman, Thanks, that was what I was thinking but wanted to make sure. I could not find the meaning for the acronym LLH.

What are your thoughts on the auto feed valve, should I put it in or use the manual feed method? If yes do you have a recommendation for a certain brand.

I currently have a Watts back flow preventer, and I don't really like it. If pressure on the supply side is shut off the valve starts dripping out of the pipe in the center of the valve when the water is turned back on and pressure is on the supply side of the valve.. Is there a better valve?

cutter

Paul S said:

As ironman said your drawing is fine....just the infloor zones have to mixed down to a lower temp than the unit heater and the other zones....with either a thermostatic or electronic mixing valve or injection pumping...it requires a lower temp ....what type of boiler do you have?

Paul, The two in-floor and unit heater zones are a little ways out right now. I just want the initial plumbing started now. One of my in-floor zones is not being done by the book. I Dug that floor down eight inches and put in two inches of high density Styrofoam and a inch or two along the side walls. I fastened the pex to the Styrofoam and put in six inches of sand, then poured the floor on top of the sand. I can probably run the water there a little hotter than if the floor was poured right on top of the pex. I also have a small unit heater that I want to hang in a corner of that room and supply water to that before the floor. That room is only 14'x18'. and is a storage/ workshop. I have no idea how many BTU's that small unit heater puts out. Looks like I will need to find out to design that room right.
The other in-floor is right above the other one and that will have gypcrete. ( kinda misspelled that word) poured for the floor instead of concrete. That floor will need to have the water temperature reduced to 120 degrees.

I do have two boilers a 140.000 BTU Buderus, (140,000 if i am burning coal or Oak, I have no coal and very little Oak) and a BP-3W Burnham, oil fired.

Jamie Hall

Just to clarify my remark a teeny weeny bit -- so long as the intake of the pump is at, or close to, the point of no pressure change -- in an hydronic system, the expansion tank -- it's happy. A low loss header doesn't really change that, since the pressure drop in the header is very small.

One does have to pay attention to what is happening when there are two pumps which share part of, but not all of, two (or more) different loops. But the basic principle stays the same.

Paul S_3

I would still use some sort of mixing for the basement radiant....obviously you know you need boiler protection for the wood boiler and oil fired ....especially the wood

cutter

Paul S said:

I would still use some sort of mixing for the basement radiant....obviously you know you need boiler protection for the wood boiler and oil fired ....especially the wood

Paul, I have something similar in the house basement bathroom floor. The basement has one loop that supply's the entire basement the bathroom is the last room in the loop. When the water leaves the baseboard it goes into a couple of loops of 3/4 K copper in that bathroom floor that are is six inches of sand. That water is a little colder than it was at the first baseboard. but it keeps the floor warm when the boiler is fired. On a zero degree night when we go to bed with a hot boiler the morning temperature of the basement could be 65 or so but the bathroom is still 70 degrees if the bathroom door was closed. I am hoping the same principal might work in that radiant floor in the little workshop storage area.

Yes I have bought a boiler protection valve for the wood boiler (I have currently ran this boiler for 30 years without one) The Oil is that Burnham BP-3W old cast iron boiler that has just sat idle for most of the time I have had it. It has had hot water in it all those years. I am not sure if the Burnham boiler really needs that boiler protection valve. I do plan on running that oil boiler more than I did in the past.

cutter

Jamie Hall said:

Just to clarify my remark a teeny weeny bit -- so long as the intake of the pump is at, or close to, the point of no pressure change -- in an hydronic system, the expansion tank -- it's happy. A low loss header doesn't really change that, since the pressure drop in the header is very small.

One does have to pay attention to what is happening when there are two pumps which share part of, but not all of, two (or more) different loops. But the basic principle stays the same.

Jamie, Member Zman suggested using a Taco ZVC 406 -4 control to run the pumps and zone valves. So that is what I have in mind for that. That control is one zone short though.

Paul S_3

You can get a 3 and a 4 zone control to get your 7 zone valve controlled .... little bit more wiring...i know taco makes expansion relays ....but i dont know if its for zone valve control

cutter

Paul S, / Hatterasguy, After looking at that Taco ZVC404-EXP -4 zone valve control I see that it will only work on zones controlled by zone valves. The other 3 zones will have pumps on them and It looks like I will need something like a Taco SR503 switching relay. It looks like that SR503 relay will also fire the boiler so both pumps will run at the same time. Zman must not have realized that 3 of the zones would be controlled by pumps and not valves.

Paul S_3

You can use the Caleffi zone panels....i believe you can connect pump control panels with zone valve panels....control priority pumps....primary and secondary pumps etc....i believe the pic below is similar to what you have.this is what i use most of the time

hot_rod

Thanks Paul for the mention. Here are some shots of our Gen 2 relay boxes, we have added quite a few features, on both the valve and switching relay boxes, that installers asked for.

Most important zone one has a dedicated end switch, it can be priority or not.
No longer need to use pull down resistors with power stealing 2 wire stats.
Additional ground screws.
Remote enable for use with ODR functions
No limit to how many boxes can be joined

At a glance you can tell which generation you have by the 3 end switch connections at the top