DIY Fröling install

[ktm010]

Grundfos 26-99FC Was told this did not need to be the same size as the primary pump. I'am sure 1" copper and a small pump would work fine.

 

[dogwood]

Thanks. I'm trying to find a less expensive alternative to the 12v Laing Ecocirs.

Mike

 

[Chris Hoskin]

correct me if I am wrong, ktm010, but the pump you are using is a 110V AC pump connected to an inverter, right?

 

[ktm010]

Correct, 110volt pump running thru a 12dc inverter, sorry for the confusion I would hate to steer someone wrong.

 

[dogwood]

Thanks for clearing that up Chris.

Mike

 

[ktm010]

The tank got a nice coat of closed cell foam

 

[jebatty]

One thing I like about the Froling that is innovative is that it cycles the loading unit after the burn is done and the boiler has otherwise shutdown to move to storage continued heat buildup in the Froling from the remaining hot coals. That heat otherwise likely would move up the stack and be wasted. A similar control on my Tarm may be an improvement for next summer and would be quite easy to install with a differential controller which would measure boiler hot water temperature and the temperature of the middle or near bottom of the tank.

 

[ewdudley]

would be quite easy to install with a differential controller

It is straightforward and should work as intended. But there is a gotcha if any of storage is above or at same level as boiler, in which case much of the cool water pumped into boiler will fall right back into bottom of storage unless there's a check valve.

Loading units provide a (sometimes optional) low resistance check valve so no problem there. I don't know of a source for a comparable standalone low resistance flapper type check valve. I built one from a swing check by replacing the brass flapper with one machined out of HDPE that works well, but it took more time and testing than I would have liked.

 

[skfire]

One thing I like about the Froling that is innovative is that it cycles the loading unit after the burn is done and the boiler has otherwise shutdown to move to storage continued heat buildup in the Froling from the remaining hot coals. That heat otherwise likely would move up the stack and be wasted. A similar control on my Tarm may be an improvement for next summer and would be quite easy to install with a differential controller which would measure boiler hot water temperature and the temperature of the middle or near bottom of the tank.

Yes, it will cycle intermittently for hours after burn shutoff. I have observed mine loading 130 degree water into the tanks almost 10 hours after the burn. A fact which in my system is more than welcomed and usable, I run my tanks down to 105 and auto switchover at 98. I am wondering if there is a condensation preventative strategy in the procedure, gauging the variation between vessel temp and flue gasses.

 

[jebatty]

But there is a gotcha if any of storage is above or at same level as boiler, in which case much of the cool water pumped into boiler will fall right back into bottom of storage unless there's a check valve.

A U-shaped heat trap also should prevent this from happening, wouldn't it?

 

[ewdudley]

A U-shaped heat trap also should prevent this from happening, wouldn't it?

I think a trap would work if it goes up higher than the top of the boiler.

Also, how does the Fröling get water though/around the thermostatic valve when in scavenging mode?

 

[hiker88]

Yes, it will cycle intermittently for hours after burn shutoff. I have observed mine loading 130 degree water into the tanks almost 10 hours after the burn. A fact which in my system is more than welcomed and usable, I run my tanks down to 105 and auto switchover at 98. I am wondering if there is a condensation preventative strategy in the procedure, gauging the variation between vessel temp and flue gasses.

I can't prove this, but I think it also kicks on the pump occasionally, just to exercise it. There have been a couple times in the summer, where the fire has been out for a couple days, amd I will hear the pump turn on for a few seconds, then shut off again...

 

[skfire]

I think a trap would work if it goes up higher than the top of the boiler.

Also, how does the Fröling get water though/around the thermostatic valve when in scavenging mode?

scavenging mode...I like that...
Maybe Chris will have a definite answer to the thermostatic bypass question.

The loading pump gets switched on via the Froling controller, when it deems it necessary, I do not know what logarithimc variables are involved in the trigger, but I assume it has to do with vessel protection first and then scavenging for add heat, based on tank readings.

 

[__dan]

Also, how does the Fröling get water though/around the thermostatic valve when in scavenging mode?

I have the circ launch temp on the Froling set at 70 C which is just above the opening temp of the thermostatic loading unit. As described above, the boiler will shutdown, but remaining coals will relaunch the circs to scavenge heat with the boiler off and then go off again as soon as the boiler temp falls below the differential, about two degrees C. The circs wil cycle on and off for maybe three hours as the coals burn down with the boiler off. No scavenging below 69 C because the loading unit valve closes near there.

The factory setting for launching the circs was a few degrees lower and the loading unit was closed at that temp, making the oading unit circ run for hours around the boiler but no flow through the boiler with the loading unit valve closed. That's without the smart controls I have planned.

Pretty sure the circ launch parameter is just the boiler water temp setpoint, independent of the boiler firing or not.

 

[skfire]

I have the circ launch temp on the Froling set at 70 C which is just above the opening temp of the thermostatic loading unit. As described above, the boiler will shutdown, but remaining coals will relaunch the circs to scavenge heat with the boiler off and then go off again as soon as the boiler temp falls below the differential, about two degrees C. The circs wil cycle on and off for maybe three hours as the coals burn down with the boiler off. No scavenging below 69 C because the loading unit valve closes near there.

The factory setting for launching the circs was a few degrees lower and the loading unit was closed at that temp, making the oading unit circ run for hours around the boiler but no flow through the boiler with the loading unit valve closed. That's without the smart controls I have planned.

Pretty sure the circ launch parameter is just the boiler water temp setpoint, independent of the boiler firing or not.

I have seen scavenging and circ running below 69, I do not know what the setpont is in my controller is, I will chk and post, but I ahve definentely seen thew pump run in the low sixties.

I have the circ launch temp on the Froling set at 70 C which is just above the opening temp of the thermostatic loading unit. As described above, the boiler will shutdown, but remaining coals will relaunch the circs to scavenge heat with the boiler off and then go off again as soon as the boiler temp falls below the differential, about two degrees C. The circs wil cycle on and off for maybe three hours as the coals burn down with the boiler off. No scavenging below 69 C because the loading unit valve closes near there.

The factory setting for launching the circs was a few degrees lower and the loading unit was closed at that temp, making the oading unit circ run for hours around the boiler but no flow through the boiler with the loading unit valve closed. That's without the smart controls I have planned.

Pretty sure the circ launch parameter is just the boiler water temp setpoint, independent of the boiler firing or not.

Factory setting for release of pump at 149f(65C) and thermic element in LK Loading pump is also 149F.(as per LK cuts).
Do not know what the equation for triggering the mode, but I assume it is a relationship between Flue gas temp , Boiler Temp and Storage status(that one minimally, in this mode).

 

[skfire]

Here are some pix from tonight, boiler has been off since this morning's burn, LK loading pump was on when I checked(boiler was at 65C) and was running when boiler was down to 63C.
LK supply side was at 60-62C.
Top of Tanks were at 127F (50c).
System supply side was at 130(52.5c).

 

[__dan]

I have seen scavenging and circ running below 69, I do not know what the setpont is in my controller is, I will chk and post, but I ahve definentely seen thew pump run in the low sixties.




Factory setting for release of pump at 149f(65C) and thermic element in LK Loading pump is also 149F.(as per LK cuts).
Do not know what the equation for triggering the mode, but I assume it is a relationship between Flue gas temp , Boiler Temp and Storage status(that one minimally, in this mode).

I set my circ launch temp by trial and error. In the off cycle after firing, I noticed the circs were running but doing nothing. The boiler was hot but the near boiler piping was cooler, meaning the loading unit valve was closed. I have the slab load circs and reset controller piggybacked on the Froling circ launch signal, so if the load is on but no heat comes from the boiler because the loading unit is closed, the load piping runs at the basement slab temp ~ 90 F.

Checking the output of the loading unit into the boiler return with an IR temp sensor, the loading unit would not let the return temp fall below ~ 155 F, which was higher than the listed opening temp. To stop the circs running unnecessarily, I bumped up the circ launch temp to the point where the circs would only run if the boiler was hot enough to open the loading unit valve and remove the heat, which was 70 C. That works perfectly. I have one noisy relay that I can hear snap on and off from upstairs. The Froling goes off but has a thick coal bed that continues to burn. I will hear the load relay cycle on and off a few times over three hours or so as the coals heat the boiler above the launch temp, with the boiler off.

The only problem I have with the boiler off, the slab will come on with the DHW indirect tank sometimes and robs the stored heat from the indirect tank as well as the boiler. I have a simple solution for this using an AB micro 800 smart relay and some temp sensor inputs to prove availability of heat before allowing the DHW circ, but it's not implemented. The relay is sitting here. It's for the future, I have a system that works and the DHW is unlimited when I need it, so it's not a priority. There are a lot more inputs to the micro 800 planned, some manual switches for oil auto / off, and an indicator lamp that says "make a fire".

When I put in the buffer storage tank, the smart relay will only load the DHW on the storage tank. Heat storage and ride through from the slabs alone is plenty.

The Froling fire control, Lambda, flue gas temp sensor, fan speed, and motorized air controls are the fancy, smart part. Pretty sure the circ launch is just one parameter, the boiler water temp.

 

[__dan]

Here are some pix from tonight, boiler has been off since this morning's burn, LK loading pump was on when I checked(boiler was at 65C) and was running when boiler was down to 63C.
LK supply side was at 60-62C.
Top of Tanks were at 127F (50c).
System supply side was at 130(52.5c).

Right, the circ is running, but if the loading unit was open and allowing the cooler return water into the boiler (and removing the heat), the boiler would cool a lot faster with no fire. Supply temp at 52 C but the boiler is 65 C means the loading unit valve is closed and not allowing flow through the boiler. If the loading unit was open, it would only be ten or twenty minutes to cool the boiler below the circ launch temp and turn the circs off. The circ could be running but not moving heat with the valve closed. That's what I saw.

 

[skfire]

Right, the circ is running, but if the loading unit was open and allowing the cooler return water into the boiler (and removing the heat), the boiler would cool a lot faster with no fire. Supply temp at 52 C but the boiler is 65 C means the loading unit valve is closed and not allowing flow through the boiler. If the loading unit was open, it would only be ten or twenty minutes to cool the boiler below the circ launch temp and turn the circs off. The circ could be running but not moving heat with the valve closed. That's what I saw.

Yes naturally, but the question I posed was regarding the controller running the pump BELOW 65C...what is the purpose and how?(the setting is clearly at 65c but it runs at lower temps...)
I see it running at 63C and this morning at 58C.

I also re checked the specs on the LK and one reason to the lower temp pump circulation may be the ability to use lower temp thermostatic elements, (safely within boiler capacity allowances)(see pix). This controller is typical to most froling eqpt in europe, so there may be a setting related to a different functioning boiler/system utilizing lower temps(in the off mode..not firing).

Either way, the "scavenging mode" could be moved down to a lower setpoint by using the 131F thermostatic element, since the pump will only be released at 65c upon firing the boiler, but it does scavenge during the "afterburn off" mode(still want to know how and when).

I have to investigate this function and see if replacing the element in the pump is a worthy endeavor since I utilize very low system operating temps...(probably not enough gain/time)


Scott

 

[ktm010]

I have a question on circulator placement, when I was tying into the oil boiler pipes I was told my choice of tying in might not be the best. It was the simplest way so I went for it. It sounds like the water is turbulating and making noise which gets amplified in the pipes, and can be heard up in the house. My question is rerouting and coming around the other side and under the oil burner is possible, would this be a better choice