WoodGun E140 installation questions

[ALL4GLH]

Hello everyone.

I've had my WG installed for about 2 weeks now. I have some questions on the installation and was wondering if you could all give me a hand with some things.

A few things. My WG is installed in an insulated room in my pole shed that is 100ft from my house. The water goes through 1" thermopex into the basement where all the other HVAC items are. I'm heating my 2600sqft home on one zone (I'll be dividing this up this summer, it was trial an error on my part), and also heating my 1000sqft garage. I think the E140 is a little overkill, but, I'll be finishing my basement in the next few years and didn't want a possibility of needing a larger wood boiler.

What is supposed to happen is the hot water from the WG is supposed to flow through my Weil Mclain GV90 so that the GV90 doesn't fire when a zone calls for heat (because it should see hot water already). Then it goes to my manifold and from there a pump is activated when a zone calls for heat. The way the installer hooked it is that the WG hot water is going into the boiler through a "T" fitting that is just below the PRV and the return water is coming from a T at the return from the GV90. I want it set up in a way so that in the event the wood/fire goes out that the GV will automatically pick up the slack.

The problem is that the water at the WG is 180-190 and I'm only seeing ~150 just before the manifold. I don't think things are hooked up so I'm getting the most efficiency. What I think is happening is that the pressure from the GV boiler is pushing the water back through the supply line on the WG, thus keeping most of the 180-190 hot water from getting to the manifold.

What I think needs to happen:
1. install Danfoss valve on the boiler side, before the thermopex for boiler side protection (right now there is no way of knowing the return water temp).
2. Install a backflow preventer where the thermopex comes into my basement (before it enters the GV).
3. Install a "T" before the GV but after the backflow preventer so some of the hot water goes into the GV but some also bypasses and goes into the manifold.

My schematic may suck, I did it hastily in PowerPoint. This is how it is currently hooked up.

Here is a schematic on how I think I should hook it up to improve my manifold temperatures and also to include the return water protection valve (Danfoss).

 

[maple1]

What do you have for a pump moving water from the WG to the GV? Might just need a bigger one, or bump up the speed on it. 1" pipe presents quite a bit of head over 200'.

Might get an IR gun for checking temps - checking temps in various places is essential for figuring things out.

You might benefit from the Danfoss, but the other two things won't help much if any. There should be no pressure differential in the system - and adding a backflow preventer won't reduce the head the pump sees. And if hot water is coming in the top of your other boiler, that should also be what is going to your manifold.

 

[ALL4GLH]

I had a Central Boiler E-1400 in the same spot in the pole shed at one point. I'm using the same pump, a Taco 007-F5.

What if it were something like this? Would this make sense?

I'm obviously not an HVAC guy. I am looking for second opinions on my setup to see if it's the most efficient way to have it. The GV has two circulator pumps on top of it, One mixes the return with what's in the tank and the other pumps it to the manifold. I wasn't sure if my 007 on the WG was fighting against the other two OR if the 20lbs of pressure that I currently have in the system was holding the supply from the WG at a standstill because it wants to week out of the PRV. Moreover, where the WG goes into the GV was originally just the PRV that the installer put a "T" on for the WG supply to hook up to.

 

[maple1]

The CB was plumbed through the WM same way as the WG is now? Things worked better then? Any other changes beside just the CB swap?

The WG should make as much heat as the CB did, I would think.

More temp info might help - like WG water where it enters the WM, and return temps at the pipe before it heads underground. Maybe more?

That last diagram wouldn't be very good for heating with the WM when the WG fire is out.

 

[ALL4GLH]

When the house was first built I only had the CB without the WM. Zoning overlay district against OWB's made me take the CB out and explore other options. I had the WM installed until I could find a indoor wood boiler that I liked. The WM was in operation for 3 months before I added the WG. I'll have to get some more temps.

 

[maple1]

Your Taco pump should certainly be up to the task, from a quick look at pump curves & pex head loss.

I'm a bit over my head with your WM though - no experience here with a unit like that & the pumps inside it & flows through it. Some of your WG flow could be short circuiting through it somehow & not getting out to your manifold, with the way it's piped in now.

 

[avc8130]

I think you need to run the REAL calculations on that 007 for your pump.

1" pex for 100' each way seems like a bit of a stretch for an 007 trying to carry all the btus for a whole house.

ac

 

[ALL4GLH]

That's where I'm stuck, I want to make sure that it's plumbed correctly to make it work the way I want.

Something I just noticed after getting an IR thermometer.
1. The line that comes into the GV from the WG the temp is 170-190 depending on load.
2. Thermometer on GV was reading 140*, thermometer just before the manifold was 140*.
3. Return water temp was 105-110*

After there was no zone calling for heat, it took about 5-10 minutes for the temp gauge on the manifold to read 180*.

Here is where the WG goes into the GV90 at the T on the PRV.

Here is the actual supply lines for the GV90 if it were operating on it's own.

This is the supply line for the boiler before the two pumps. The wire in the supply line is the thermometer.

 

[ALL4GLH]

I think you need to run the REAL calculations on that 007 for your pump.

1" pex for 100' each way seems like a bit of a stretch for an 007 trying to carry all the btus for a whole house.

ac

How do I go about getting REAL calculations?

 

[avc8130]

How do I go about getting REAL calculations?

(broken link removed to http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf)

Follow that.

 

[maple1]

Well, 'real' calcs would start with a heat loss calc on the house, which would determine BTU/hr you need to pump. Then it goes on from there, through temp drop (delta T) in vs. out, then gpm, then to head loss for that flow based on 1" pex (there are charts for that). Then you look at the pump curve to see if it's capable of overcoming the head loss.

But I just looked at a chart, estimated/guessed/randomly picked a 5gpm flow (somewhat typical I think), and came up with under 2ft. head loss. Even doubling to 10gpm is still under 5ft. Looking at the pump curve, even at 5 ft of head, it will pump over 10gpm. So I deduced the 007 is good. That doesn't take into account other fittings or restrictions or flow through the other boiler though.

 

[ALL4GLH]

Maybe I should start from square 1. Part of me doesn't think it's the pump. I think it's how it's plumbed on the WM.

What has me wondering is that my temp from the WG on the barn side is 180*, in my basement is 176*. From there it goes into the WM where that temp reads 140-150. Now where the water from the WG comes in is on the opposite side from the actual feed on the WM, the one that passes through the thermometer.

I believe that the supply from the WG isn't going into the correct spot on the WM and that's why I'm getting such skewed temp readings. Is it normal to remove the PRV on the WM, install a "T" and have my WG feed into that (which would be the top of the heat exchanger)? Or should I remove the boiler drain on the WM, put a "T" on that fitting and feed through that (which would be the bottom of the heat exchanger)? If it feeds through where the drain is at least the WG supply will pass through the thermometer on the WM and maybe start reading right.

 

[avc8130]

Well, 'real' calcs would start with a heat loss calc on the house, which would determine BTU/hr you need to pump. Then it goes on from there, through temp drop (delta T) in vs. out, then gpm, then to head loss for that flow based on 1" pex (there are charts for that). Then you look at the pump curve to see if it's capable of overcoming the head loss.

But I just looked at a chart, estimated/guessed/randomly picked a 5gpm flow (somewhat typical I think), and came up with under 2ft. head loss. Even doubling to 10gpm is still under 5ft. Looking at the pump curve, even at 5 ft of head, it will pump over 10gpm. So I deduced the 007 is good. That doesn't take into account other fittings or restrictions or flow through the other boiler though.

That's only partially true.

Let's take this for example: he bought a 100k btu boiler. Why would he only want to transfer 30k btu? That would keep his boiler short cycling.

f= 100,000/(500X20)

He needs to flow 10gpm to transfer the capability of his boiler.

Using standard design rules, that is over the suggested max flow rate for 1" pex, unless it is Pex-Al-Pex. So let's just assume he has Pex-Al-Pex.

Let's calculate the head loss:

HL = k x c x L x (f1.75)

Hl = .0012*.933*200*56.234 (you can find those values in the referenced document. I assumed NO fitting loss.

Hl = 12. 6 feet

A 007 is NOT going to like this at all.

ac

 

[ALL4GLH]

This shows all of the pumps within the system. All of which are 007's.

 

[maple1]

That's only partially true.

Let's take this for example: he bought a 100k btu boiler. Why would he only want to transfer 30k btu? That would keep his boiler short cycling.

f= 100,000/(500X20)

He needs to flow 10gpm to transfer the capability of his boiler.

Using standard design rules, that is over the suggested max flow rate for 1" pex, unless it is Pex-Al-Pex. So let's just assume he has Pex-Al-Pex.

Let's calculate the head loss:

HL = k x c x L x (f1.75)

Hl = .0012*.933*200*56.234 (you can find those values in the referenced document. I assumed NO fitting loss.

Hl = 12. 6 feet

A 007 is NOT going to like this at all.

ac

But, he can't transfer more than his heat load will absorb, no matter how much heat he wants to move from his boiler. If there is no place for it to go , there is no place for it to go, and the boiler will short cycle no matter how much water is pumped. Which is why I put heat loss calc first. Can't transfer it from the boiler if the house isn't taking it.

It is possible the 007 isn't enough - but can't say for sure without knowing the heat load. Figuring the pump sizing should start with heat load, not size of boiler. You would then also size the boiler for the heat load, ideally.

EDIT: Also, I didn't run through your calcs, but looking at two tables from pex manufacturers, I found figures of 5 & 6.6 psi/100 ft. for 10gpm of flow for pex-al-pex. Which I think figures to about 4.5 & 5.7' for 200 ft. Way less than 12.6.

 

[maple1]

This shows all of the pumps within the system. All of which are 007's.

That sure looks like a lot of pumping going on. Especially for only one zone. What exactly does that zone consist of? What are the temps at the zone return, before the return hits the WM stuff? i.e, what is the temp difference between start & end of zone? I suspect it is quite large. Again, I don't know anything about your WM, but it also looks like potential for some short circuiting of the WG water thru it, or mixing of the zone return water with the incoming WG water before it reaches the zone supply manifold.

 

[ALL4GLH]

I'm starting to think I'm in over my head and should get someone else to take a look at my system and give me a second opinion on the install.

 

[avc8130]

But, he can't transfer more than his heat load will absorb, no matter how much heat he wants to move from his boiler. If there is no place for it to go , there is no place for it to go, and the boiler will short cycle no matter how much water is pumped. Which is why I put heat loss calc first. Can't transfer it from the boiler if the house isn't taking it.

It is possible the 007 isn't enough - but can't say for sure without knowing the heat load. Figuring the pump sizing should start with heat load, not size of boiler. You would then also size the boiler for the heat load, ideally.

EDIT: Also, I didn't run through your calcs, but looking at two tables from pex manufacturers, I found figures of 5 & 6.6 psi/100 ft. for 10gpm of flow for pex-al-pex. Which I think figures to about 4.5 & 5.7' for 200 ft. Way less than 12.6.

I agree with you that a head load calc would help....but without one he might as well plan to move the heat the boiler can make. He's in Northern NY heating 2600 sq ft. He's gonna need some BTUs.

I highly doubt his 140 is "oversized" for the application. I know plenty of guys with E100s who aren't making it 8 hours between reloads with this cold snap we are seeing in the Northeast.

Don't Google it, do the calcs.

If he wants to transfer 50k btu, he would need 5 gpm (slightly BELOW the minimum flow rate suggested for 1" P-A-P).

At 5gpm, with the same assumptions, he'd be at 3.75' of head.

That WOULD be well within the 007 capability.

ac

PS: Another option would be to replace the 007 pumping from the WG to the Fossil with a Taco Bumble Bee. Set that to Delta T mode and let it do its magic. Then he can skip the heat load calc.

 

[avc8130]

I'm starting to think I'm in over my head and should get someone else to take a look at my system and give me a second opinion on the install.

PERSONALLY, I don't like the "T" method used.

I think you should run your boilers in series. Create a loop that is pumped constantly to keep the fossil boiler warm enough that it doesn't fire.

Then pull off this loop to feed and return your zones.

This is referred to as a primary/secondary setup and it works very well generally.

ac

 

[ALL4GLH]

Similar to one of these setups?
http://www.ecoheatsolutions.com/PDF/Schematics.pdf

It sounds like you're describing the first picture. Where the supply from the WG goes into the return of the WM (so the WM always sees warm water) and the return from the manifold goes to the WG. Like its creating one big loop.

 

[avc8130]

Yes. Page 1.

I like that because it is simple on all fronts. Plumbing is simple. Controls are simple. Operation is simple.

ac

 

[infinitymike]

Whew, we got a little off track there chasing the pump size, but I'm glad we're back.
I'm not HVAC guy but piping the WG supply into the PRV piping with a T just doesn't sound right.
I think the way you drew it in your second post and the way it is drawn on that other site is the way to go.
You may lose some heat through the WM as it travels from the return and passes through to the supply, but I can't see it being as much as you have now.

 

[ALL4GLH]

I had a friend that works for Siemens come by and take a look. He was confused why it's plumbed the way it is. He almost thinks that the 007 on the WG and the 007 on the WM are working against each other (keeping the WG hot water at a spot where it won't be used and is instead mixed with cold water within the WM) and that's why the hot water from the WG isn't flowing through the WM the way it's intended, and why the temps on the WM are so low. And the "T" on the return side has him even more confused.

He's going to come up with a schematic for me. In the mean time, I'm posting this up for you guys to take a look at. I know there is quite a few ball valves. I want to be able to isolate things. As it is right now there isn't much isolation. I'm going to have to temp/psi gauges on the supply and return piping on the house side of the thermopex for better ideas of what's going on within the system.

My system has been trying to recover from the -18* we had here last night. Been trying to get the house up to 70* (was at 66* when I woke up) all day because I refuse to turn the propane boiler up all the way. We are supposed to get 3-4ft of snow tomorrow, so I'm anticipating my job being closed for the day. I may be able to get this plumbed tomorrow, if not this weekend.

 

[infinitymike]

Looks good, and again, not be a plumber, but why the circ pump pumping warm water back into the WM where you have the hot water of the WG entering the return of the WM

 

[infinitymike]

Wait a second, did you say 3 to 4 FEET of snow??? Where in northern NY do you live?
is that lake effect?