Caleffi pump issue

[Boardroom]

Hi Gang.
I took advantage of the mild weather we are having here and filled my 1000 gallon storage tanks. The first burn on my new Econoburn EBW200 was today. I have to make sure I get the tanks heated up before it turns cold again
My first burn was only about half a load as I was a little nervous. The boiler only reached a156 degrees. I initiated another burn soon after the first with a larger load of wood. This time it got up to 163. The tops of my storage tanks are at about 140, but much less at the bottom. I thought it would get hotter as I had the boiler target set at 170. The wood I was using was seasoned two seasons and my manometer was reading perfect draft at .03.
I am suspecting that my problem is with my Caleffi 281 mixing/boiler protection valve. Even when I had the boiler up to 160 and the input in the top of the valve was reading 160, the water going back to my boiler only ever reached 105. I have attached a poor picture but you get the idea. I think the valve is suppose to recycle all water back to the boiler until the return water reaches 140. Only then will it pump to storage. In the picture my boiler is to the right and storage to the left.
I removed the small packing screw from inside the pump before I installed it so that is not the problem. If anyone else is using this pump can you tell me if I am missing something.
Boardroom.

 

[leon]

I think you should plan on removing
the valve and you will find dirt/scale in it
affecting the mixing valve and causing
it to bypass.

DO you have unions where the valve is???? I hope so.

 

[Boardroom]

Yes. Isolation valves all round so removing it is not a problem. Should this be an issue when it is brand new though?

 

[maple1]

Are you sure the pump is actually pumping? If not, and if the caleffi is anything like the lk810, it is designed to convect fully to storage and bypass the thermostat until the pump kicks in - for overheat protection in a power outage situation.

 

[Boardroom]

Pretty sure it is pumping. I can hear the motor and the rotor is turning according to my little magnet tool that you hold on the end of it.

 

[Boardroom]

Should the rotor turn clockwise or counterclockwise? Is it possible to wire it backwards?

 

[maple1]

Shouldn't be. I paralleled an indicator light with mine so I know when juice is being sent to it. Can you find power at the pump connections with a meter? If pump is indeed running might be some dirt in the stat. Might try lowering your pump launch temp & see what happens, say to maybe 150 or so, before taking things apart.

 

[Boardroom]

I think there is definitely power to the pump as I have it wired with an on/off switch and I can hear it come on when I flip the switch. I don't have a meter.
Sorry Maple but I don't understand what you mean when you say to lower the pump launch temperature. The Caleffi comes with insertable thermostatic sensor cartridges. Mine is set for 140 and is not adjustable. The 140 refers to the mixed temperature lower limit back to the boiler.

 

[Boardroom]

I think there is definitely power to the pump as I have it wired with an on/off switch and I can hear it come on when I flip the switch. I don't have a meter.
Sorry Maple but I don't understand what you mean when you say to lower the pump launch temperature. The Caleffi comes with insertable thermostatic sensor cartridges. Mine is set for 140 and is not adjustable. The 140 refers to the mixed temperature lower limit back to the boiler.

I should add that the pump is set up to run continuously unless I turn off the switch.

 

[maple1]

I think there is definitely power to the pump as I have it wired with an on/off switch and I can hear it come on when I flip the switch. I don't have a meter.
Sorry Maple but I don't understand what you mean when you say to lower the pump launch temperature. The Caleffi comes with insertable thermostatic sensor cartridges. Mine is set for 140 and is not adjustable. The 140 refers to the mixed temperature lower limit back to the boiler.

I thought the 170 you referred to above was what you had your circ set to start at - 'launch temp'. So it might not get that high to start your circ pump. So lowering it would make your pump start earlier therefore use the thermostat. I have no experience with either caleffi or econoburn so might be speaking over my head here.

 

[Bob Rohr]

try moving the gauges, they just pull out of the block. It could be a bad gauge.

What temperature sensor do you have? The bypass line will be 100% shut down when you reach the sensor temperature plus 18. So if you have a 130 sensor + 18 = 148 for complete shut down.

It will allow some flow to the system as the boiler heats up.

A large slotted bolt in the motor can be removed to see if the shaft is spinning, carefully as hot water may spray out.

Also if it was dropped sometimes the ceramic shaft can break, so the shaft my be spinning, when you remove that screw. but the impeller not.

Two allan head cap screws remove the motor from the housing, run it with the motor out to see if the impeller spins.

Isolate all the valve before you remove, of course.

 

[Boardroom]

Thanks Bob. I have already removed the unit from the system so I will check the shaft after lunch. I think my sensor is 140.

 

[Boardroom]

Thanks Bob. I have already removed the unit from the system so I will check the shaft after lunch. I think my sensor is 140.

OK Bob. I took the large slotted bolt out of the end of the motor and could see the shaft spinning.
I then removed the motor and turned the power back on. I could see nothing moving. Is the impeller the big white thing with the black stripes in the middle?

 

[Boardroom]

OK Bob. I took the large slotted bolt out of the end of the motor and could see the shaft spinning.
I then removed the motor and turned the power back on. I could see nothing moving. Is the impeller the big white thing with the black stripes in the middle?

Sorry Bob. That was silly. The silver part stayed in the valve when I took the motor off. I pulled the silver shaft out of the valve can now see the impeller. When I turn the power on both of the shaft and the impeller spin.

 

[Bob Rohr]

pumps okay, reassemble, move the gauges around, fire and let run a few hours. it sounds like it should be fine.

 

[Boardroom]

pumps okay, reassemble, move the gauges around, fire and let run a few hours. it sounds like it should be fine.

I put it all back together and lit the fire, moved the gauges around and got the same result no matter where the gauges were. The top gauge was reading 160 and the right hand gauge (back to boiler) was only 105. The left side gauge (from storage) was about 90. It took about 1.5 hours to get up to 160.

 

[Bob Rohr]

It takes some time to get thousands of gallons up to 180F. The cooler water at start up heats quickly due to the large delta T. as the tanks warm it a slower heat transfer into the tank. If the boiler is running 160 supply, and in fact 90 is the return temperature from the load, then the valve will be bypassing quite a bit.

The gauges are all inserted into the brass body, not into the fluid, so there may be a little error. If you are sure it is circulation, keep running.

Did you remove the shipping lock screw as shown in the installation manual?

 

[Boardroom]

Thank you for all your help with this Bob.
Correct me if I am wrong but I thought that the valve functioned so that as long as the input from the boiler (top port) was less than 140 (my sensor) then all of the flow will be put back into the boiler so that the output port (bottom right in my case) and the top port will be close to the same temperature. If my bypass line into the top of the valve goes to 160, the outlet port to the boiler would still read 140 due to the mixing with the cold from the storage.
In my mind, it should make no difference what temperature my storage is at. If storage is cold the bypass will take care to send the hot water back to the boiler. What am I missing?
The packing screw was removed before the initial install.

 

[maple1]

That's how my LK810 works. 810 output to boiler return goes right to 140 as soon as the pump turns on - doesn't matter how cold storage is. Well, actually it goes to about 150 right at first then creeps back to 140.

EDIT: I'll add for what it's worth that it sounds like yours is acting like mine does at start up before the pump kicks on. The convection flow will return cold water from storage through the mixing valve to the boiler - until the pump kicks in, that is.

 

[Boardroom]

My pump actually pumps continuously and the Caleffi valve just diverts the water to where it is suppose to go. If the return water is less than 140, the valve is bypassing storage. Once return temps of 140 are reached it starts diverting to storage.
It seems like mine is bypassing OK until it gets to 140 but once it starts mixing It drops the return temps down to 105. I wonder if something is wrong with the sensor in my valve.
My concern is that at 105 I am getting no boiler protection.

 

[maple1]

Your pump isn't controlled by boiler temps? Is that just a temporary arrangement?

Have you been burning steady? Or just once in a while? Wondering what would happen if you don't start the pump until the boiler gets hotter up top - like 180. It seems a bit tricky to not have the boiler temps play a part in controlling the pump starts & stops. But again not familiar with an EB at all.

 

[velvetfoot]

This is just from memory, but I recall on my more basic Caleffi Thermomix 280 (I think) it could be hooked to for either supply or return temperature control. Could you possibly have it piped up so it's controlling supply and not return temperature? Just a thought.

 

[Boardroom]

It is pretty clear on the valve which way everything is suppose to point so I think I have it plumbed properly. Here is the setup.

 

[Bob Rohr]

It is pretty clear on the valve which way everything is suppose to point so I think I have it plumbed properly. Here is the setup.
View attachment 148833

here is a look at mine as it is running after start up. I installed a pilot light to show when it is powered.

I also wired it to the EKO pump output, so it doesn't fire until the boiler is up to temperature.

It can be running and bypassing and still showing 105 on that return when it is just ready to close bypass. In my example the EKO pump sensor just hit 140, so the pump is powered, it takes a few minutes for the temperatures to stabilize.

Mine has been running for over 1 year now, i did change to a lower temperature sensor as the boiler would sometimes reach 170, and the fan started raving down before the bypass was completely shut.

I used the 115 sensor add the 18 differential for a 133F control temperature, works fine with dry wood, no creosote build up.

 

[Boardroom]

So there is no flow through your boiler until boiler water temp reaches 140? Perhaps I should try turning my pump off manually until I get up to that also, then turn it on. Right now it is taking almost an hour to reach 140 with lots of smoke out the chimney. That leaves me with a very short burn period at peak temperature.
My Econoburn manual states I should have minimum 140 back to the boiler for boiler protection. Mine stays at the 105 for the whole burn. My max temp reached so far on the boiler is 164. With the bypass not shutting until 158 it doesn't leave much room. You are saying that I can get away with less than 140 back to the boiler or is that just specific to the EKO?
Here is where I am confused. If my sensor is 140, should my return temps not stay above that once the top port has reached 140+? I don't understand why it is 105. Seems like I just keep pushing cold water back into my boiler.
Sorry for all the questions but I am new at this. Here is how mine looks after burning for almost 2.5 hours.