Caleffi pump issue

[maple1]

Have you verified those temps with something else?

Maybe a thermometer with a probe sensor that you could periodically move around from place to place (temporarily surface mount the probe to a pipe under some insulation), or an IR temp gun? Although my IR gun is kinda suspect.

You should try to maintain 140 entering the bottom of the boiler, yes. Quite important for long boiler life. But I am still wondering about your manually controlled or constantly running circ pump. It should start when the boiler gets hot, and stop when it cools off. By itself.

 

[Boardroom]

I think my IR gun is suspect too. I will try a temp probe on my next burn to see if I can confirm the temps.
I understand what you mean about getting the boiler temp up before the pump comes on. I may have to consider rewiring it.

 

[velvetfoot]

Tor the IR gun, it's best if the surface is black

 

[Floydian]

Hello Boardroom,

I was really starting to think you had a bad thermostatic element BUT......

In the last pic you posted it sure looks like you are mixing 105 from the bottom of storage with 155 from the bypass and you are returning 120 to the boiler. IF, big IF here, you are pumping 10 gpm with a 35T through the boiler, then your boiler is putting out 175,000 BTUH. A good number for the ebw200, I think.

Now as far as the temp gauges, I have found with my LK810 Loading Unit that my mix temp usually shows 130 with "cold" storage. (low 90's or upper 80's ) I was concerned this was too low as I also have a 140 element. First I moved my temp gauges around-nothing. So I did as maple suggests here:

Maybe a thermometer with a probe sensor that you could periodically move around from place to place (temporarily surface mount the probe to a pipe under some insulation),

and I found that the LU temp gauges definitely read at least 5 lower than a sensor taped(and insulated) onto the 1.25"x6" sch. 40 pipe between my LU and my boiler. I believe if I could measure the actual fluid temp I would be very close to 140. I think with the way the temp gauges slide into the brass housing, you just can't get a very accurate reading. 10 too low would surprise me.

Noah

 

[maple1]

And on that note - I have no idea what my loading unit temp guages read. The way it's mounted, I would need to go around to the back of my boiler, get down on my hands & knees, and stick my head in a tight spot (after finding a flashlight). Don't think I've ever done that - I instead T'd in two tridicator guages on my boiler inlet & outlets & those are what I'm reading on anything temp related on my boiler ins & outs. They face me front & centre when I'm standing at the front of my boiler.

Hmm, I should actually check out my loading unit guages for once - got me curious now. Will try to remember later tonight when I'm burning...

 

[Boardroom]

Thank you for all the replies lads. I am starting to get things worked out.
I have some digital temp gauges so I mounted the small probes on the pipes coming to and from my loading unit. The input gauge on my valve was reading properly, at about 165 degrees. The mixed return back to the boiler was reading about 120 on the gauge but my probe says it was 143. If I believe the probe, which I think I do, all is well with the mixing valve. I feel a lot better now knowing that I have the proper boiler protection.
Also Maple, I think you are onto something with not starting my pump until the boiler heats. I tried it with my burn this afternoon. No pump until the boiler hit 150, then I started it with my manual switch. It only took about 35 minutes to get to 150 with smoke disappearing at the chimney even earlier. Previously it would take me about 1 1/4 hours, and enough smoke to choke a small village, to reach the same temp. I expected that the temp in the boiler would drop when I turned the pump on but it didn't. It just kept rising. Also, I was able to achieve my highest boiler output of 167. My boiler coasted at this point as I was nearing my target setting of 170.
Floydian man, you are confusing me with all that delta stuff. All I know is that I have the Caleffi valve on medium speed, 1 1/4 inch piping to and from the boiler. Here is the pump chart that I have no idea how to read.

 

[Bob Rohr]

Thank you for all the replies lads. I am starting to get things worked out.
I have some digital temp gauges so I mounted the small probes on the pipes coming to and from my loading unit. The input gauge on my valve was reading properly, at about 165 degrees. The mixed return back to the boiler was reading about 120 on the gauge but my probe says it was 143. If I believe the probe, which I think I do, all is well with the mixing valve. I feel a lot better now knowing that I have the proper boiler protection.
Also Maple, I think you are onto something with not starting my pump until the boiler heats. I tried it with my burn this afternoon. No pump until the boiler hit 150, then I started it with my manual switch. It only took about 35 minutes to get to 150 with smoke disappearing at the chimney even earlier. Previously it would take me about 1 1/4 hours, and enough smoke to choke a small village, to reach the same temp. I expected that the temp in the boiler would drop when I turned the pump on but it didn't. It just kept rising. Also, I was able to achieve my highest boiler output of 167. My boiler coasted at this point as I was nearing my target setting of 170.
Floydian man, you are confusing me with all that delta stuff. All I know is that I have the Caleffi valve on medium speed, 1 1/4 inch piping to and from the boiler. Here is the pump chart that I have no idea how to read.
View attachment 148881

Sounds like it is working, and I do agree turning on the 281 with the EKO pump connection, or any temperature control is much preferred.

Remember all 3 temperature gauges are drilled into that brass housing. Possibly that is mis-leading as more accurate temperature would be downstream from the component with the probe into a well in the fluid stream, or a well insulated strap on temperature sensor downstream.

The 3 gauges seemed like a good idea for owners to check, but not if the accuracy is that far off, sorry.
Let me know how it works out.

 

[Boardroom]

No need to apologize Bob. The valve works exactly as advertised. As for the gauges, now that I know the temp difference, they are still a good reference.
We can always use someone with your knowledge on the forum.
Thanks again.

 

[maple1]

I did check my dials on my pump unit last night. My tridicator guages were showing 165 out & 145 in at the boiler fittings, while the outlet guage on the unit was 140 (5 degree diff) and the bypass guage was 150 (a 15 degree diff). So ya I guess they aren't super accurate.

You should get your pump control sorted. No idea what the EB has on-board for that - but I would think it would have something. I think starting it at 150 is even too low, I would try starting it at 170. You could have a lot of excitement if you forget to start it just once - and also could waste storage if you don't turn it off early enough at end of burn.

Good to hear of progress though.

 

[Clarkbug]

I agree, you should interlock the pump control with the boiler.

You shouldnt be having any real smoke if you are gasifying, so its important to get the boiler up to temp then start the pump.

 

[Boardroom]

I have been experimenting with this process and it definitely works better with heating the boiler before turning the pump on. I guess I was under the misconception that pumping around the small boiler loop was basically the same thing. Heat the small loop (small volume) along with the boiler before Caleffi valve diverts flow to storage.
Have a look below at how my connections from boiler to storage are connected. Initially I was leaving the pump off while I heated the boiler. However, this still seemed to be taking too long to get to temp. Then I realized that my Caleffi valve has a failsafe in it that allows thermosiphon flow through the pump if there is a power failure. If I turn the pump off (imitating a power failure), I am initiating the thermosiphon process which is drawing cold water directly from the bottom of my tanks through the boiler. This is worse than leaving the pump on and having mixed water return to the boiler.
My solution is to close the ball valve coming from storage (the red one in the picture) until the boiler heats up. This seems to solve the problem except that I have to reopen it manually before I turn the pump on. Even if I wire the pump up so that start and stop are controlled by the boiler, it won't work if I have to open the valve manually.
Anyone see a better way?

 

[maple1]

Yes - that can be a real catch-22 with good convection flow between the boiler & storage when using a loading unit. Such convection flow is usually a good thing. Mine isn't that good, but I still have a period of time between lighting the fire, and when the pump kicks on, during which I have cold water entering my boiler. But even with cold storage (say 120), it usually is only 20 minutes or so before my pump kicks on.

Short term, I see maybe doing something like you're doing - except I don't think I'd close the valve but maybe only partly close or throttle it. Which is kind of a pain though because you're then tending the valve with each burn - and usually manual valve operation is poor practice. The other thing would be to burn before bottom of storage gets too cold. How cold is your storage when you do a burn? Might have to find a balance between that, and when you start your pump. When are you starting your pump? 20 minutes or so after lighting seems to be right here, time-wise. Usually my boiler is hitting the 170-180 range at the top by then. Starting at 160 at boiler top might be a decent thing to shoot for, considering 140 return to boiler and generally accepted 20° delta-T through the boiler.

My boiler also uses a flue gas thermostat during normal start up. When it gets up to temp, it starts the pump. But it's also paralleled through an aquastat, so if the boiler gets too hot before the flue gas sees temp, the aquastat will take over & start it. The flue gas stat stops the pump at end of burn. No idea what the EB uses - but you could also maybe check out getting & using one of those? Mine came with my boiler but should be available separate though a dealer.

 

[Boardroom]

I turn my pump on when the boiler reaches 170. I should probably do a better job of heating my tanks all the way to the bottom as they are generally around 110 even when I heat the top to 175. If my boiler is reading 85 when I get up in the morning it takes me about 30 minutes to get to 170.
The end of my burn also creates the same issue. If I turn the pump off when the boiler cools, in order to avoid pushing cool water into storage, the valve again starts to thermosiphon cold water through the boiler and into storage unless I close the red valve mentioned above.

 

[Deering]

I had a similar problem with my Caleffi circulator. Return water to boiler was lower then the 130F the valve was set at. I finally installed two therm wells, one upstream and the other downstream of the pump on the return line. Mystery solved. The Caleffi thermometers were totally uncalibrated. The Caleffi is working perfectly - boiler always gets 130 regardless of the incoming temp. So I don't even use them now but rather rely on the thermos that are directly in the flow. But there is a small screw head at the end of the Caleffi thermo probe end for calibration - I didn't bother.

Happy I solved it. I was suspecting a faulty cartridge. Good luck finding one. Every supply place I contacted had a hard time even locating a part number. Sounds like they had to order it direct from Italy. Crack your wallet and bend over.

One other note: The pump curve chart accompanying my Caleffi shows the three curves for the three pump settings...it's wrong. The curve labeled #1 actually corresponds to pump setting #3 and vice versa. Maybe they switched the pump labels at some point and forget to update the curve chart...whatever the case - sloppy. You might check yours as well - perhaps it's been updated. You'll be able to hear the pump change speeds when you switch the settings.

 

[Bob Rohr]

I had a similar problem with my Caleffi circulator. Return water to boiler was lower then the 130F the valve was set at. I finally installed two therm wells, one upstream and the other downstream of the pump on the return line. Mystery solved. The Caleffi thermometers were totally uncalibrated. The Caleffi is working perfectly - boiler always gets 130 regardless of the incoming temp. So I don't even use them now but rather rely on the thermos that are directly in the flow. But there is a small screw head at the end of the Caleffi thermo probe end for calibration - I didn't bother.

Happy I solved it. I was suspecting a faulty cartridge. Good luck finding one. Every supply place I contacted had a hard time even locating a part number. Sounds like they had to order it direct from Italy. Crack your wallet and bend over.

One other note: The pump curve chart accompanying my Caleffi shows the three curves for the three pump settings...it's wrong. The curve labeled #1 actually corresponds to pump setting #3 and vice versa. Maybe they switched the pump labels at some point and forget to update the curve chart...whatever the case - sloppy. You might check yours as well - perhaps it's been updated. You'll be able to hear the pump change speeds when you switch the settings.

Got a pic of the switch on your pump? Speed 1 has always been the low speed on any circ I have worked with? Possibly the label on the Wilo is incorrect.

Either way we need to get it right, thanks for catching that.

 

[Deering]

I stand corrected, Bob. Switch one does correspond to the low curve.

My pump is oriented so I can't see the switch due to piping and my boiler preventing my fat punkin from getting back there. Ended up laying on my belly like a reptile and reading it with a mirror. After a half hour of twisting my neck and squinting and swearing, I was pretty sure I was reading the numbers right.

Tried photographing it with my iphone but it couldn't macro-focus that tight. But last week I cleaned up my phone sparkly clean and now it works a lot better. The cleaning process involved leaving it in my pants pocket and throwing the pants in the wash machine. The new version of the iphone has a better camera...

So I just went and photographed it again per your request, and lo and behold the numbers match the curve! The paint coating over the number stamp is pretty thick which makes it impossible to distinguish from an angle.

Ignore what I said about the pump curves in my previous post...

 

[Boardroom]

My valve is labeled correctly. 1 low, 3 high. I found the same thing as you Deering. The pump works just like it is suppose to, although the temp dials take a little negotiation.
If you and Bob are using the same pump, can I ask you to describe how you use it? Run continuously or start when boiler reaches temp? I think you said you start yours at temp Bob. How do you handle thermosiphon through the valve if you turn it off after the burn?

 

[maple1]

I'm thinking there shouldn't really be that much thermosiphon at end of burn. What drives that is heating of water, and once the fire is out that ends that. The lighter hotter water will want to rise to the top, and as long as the top is top of storage, and hotter water isn't being generated in the boiler, there shouldn't be movement.

 

[Deering]

Mine runs when the boiler is running. My pellet boiler controls the pump, so when it shuts off, the pump shuts off. I've inserted a bit of time delay so the pump runs for an additional 10 minutes after the boiler shuts off, in an attempt to suck the last little bit of heat out of it. At startup the boiler delays starting the pump until it reaches 130 degrees.

The pump has a built in flapper valve that prevents siphoning short-circuiting through the pump. It lets the boiler to siphon naturally through the storage tank, but I think that will achieve equilibrium as long as the boiler and tank are at the same level. If one or the other were on a different level, then you'd need to add a check valve between the boiler and the tank.

 

[Boardroom]

My boiler is usually hotter than the bottom of storage when I shut it down so I think I still get the thermosiphoning, no? As you know I have just starting learning this burning process last week when I lit my boiler for the first time. I have burned wood stoves for 30 years but this is a whole new game. Should I leave the boiler and pump on as long as the boiler is hotter than the bottom of storage or turn it off if it is less than the top of storage.
Deering, you can see from my avatar that the top of my tanks is quite a bit higher than my boiler. On Maple's suggestion some time ago, I moved my supply pipes to the top of the tanks. From what you can see, Is my biggest thermosiphon concern going to be from the bottom of the tanks through the boiler or from the top of the tanks circulating back down to the bottom? I ask because I can always add a check valve in the top line to prevent flow back out the top of storage when the pump is off but I cannot add one anywhere on the bottom.

 

[maple1]

If your boiler isn't hotter than top of storage I don't think you'll get much thermosiphoning. And if bottom of storage is colder than the boiler, that cold water will want to stay where it is, at the lowest point. Unless it is being pushed out by water coming in the top.

 

[Bob Rohr]

I stand corrected, Bob. Switch one does correspond to the low curve.

My pump is oriented so I can't see the switch due to piping and my boiler preventing my fat punkin from getting back there. Ended up laying on my belly like a reptile and reading it with a mirror. After a half hour of twisting my neck and squinting and swearing, I was pretty sure I was reading the numbers right.

Tried photographing it with my iphone but it couldn't macro-focus that tight. But last week I cleaned up my phone sparkly clean and now it works a lot better. The cleaning process involved leaving it in my pants pocket and throwing the pants in the wash machine. The new version of the iphone has a better camera...

So I just went and photographed it again per your request, and lo and behold the numbers match the curve! The paint coating over the number stamp is pretty thick which makes it impossible to distinguish from an angle.

Ignore what I said about the pump curves in my previous post...

Thanks for checking, I'll sleep better without wondering.

 

[heaterman]

Tried photographing it with my iphone but it couldn't macro-focus that tight. But last week I cleaned up my phone sparkly clean and now it works a lot better. The cleaning process involved leaving it in my pants pocket and throwing the pants in the wash machine. The new version of the iphone has a better camera..

Like, Can't begin to tell you how many gadgets I've gotten to work better using the same method. Glad I'm not the only one.. lol

PS......gauges. don't even get me started. The 4" square Weiss we installed on the main piping of a recent project reads 20-25* low. AAAAARRGGH
That's a $65.00 gauge AAAA AAAAAAARGH !

 

[Deering]

From what you can see, Is my biggest thermosiphon concern going to be from the bottom of the tanks through the boiler or from the top of the tanks circulating back down to the bottom?

Those are fair questions, Boardroom. And I'm not entirely sure about the answers.

As maple says, the hot water in the tank isn't going to want to flow downhill. And the cold water in the bottom of the tank won't run uphill. So no problem, right? Maybe not.

Here's the dynamic I see that could change things. Your storage tanks are much better insulated than your boiler, if for no other reason than because your boiler has a big flue pipe running through it. So your boiler will cool off faster than your tanks. Assuming everything is idle, no circulators running, the boiler will soon be colder than the bottom of your tank. So the boiler water will want to run downhill into the tank. But water doesn't compress, so the displaced tank water has to go somewhere, and that's from the top of the tank down into your boiler.

This can only occur if the downward forces of the denser cold boiler water is greater than the buoyant forces of the hot tank water. At some point the temperature differential may make that possible. It also depends on the relative heights of the tank and boiler. All of this requires math that is beyond me on a Saturday night (or any other time since I graduated college 100 years ago...).

A simpler solution is to add a swing (not spring controlled!) check valve in upper line that will prevent reverse flow from the tank to the boiler. You want to make sure the boiler can freely release hot water through the check to the tank to prevent trapping combustion heat in the event of a power outage shutting off circulation.

 

[Bob Rohr]

My valve is labeled correctly. 1 low, 3 high. I found the same thing as you Deering. The pump works just like it is suppose to, although the temp dials take a little negotiation.
If you and Bob are using the same pump, can I ask you to describe how you use it? Run continuously or start when boiler reaches temp? I think you said you start yours at temp Bob. How do you handle thermosiphon through the valve if you turn it off after the burn?

Every system behaves differently, just try and see, but I doubt thermosiphoning will be an issue.

You could lock the "gravity gate" check valve closed with the shipping screw that came with it, not every application wants, or needs thermosiphon feature as an over-heat safety option. As long as you have some other over-heat mechanism.

Mine is controlled by a differential controller (solar control) on when the boiler is 10° warmer than the tank, but a min. 140. off when it is within 5° of the tank. I also ran it with the EKO pump output, the solar controller gives me more adjustability and also has a second function for buffer to system on/ off.