Electroboiler Miniboiler EMB series

[thoyer]

Any users of this series of boiler can tell me what the typical boiler temperature is on gauge in the unit? Mine never seems to get above 85 deg even with the boiler set to 120 deg. Circulating pump is on the slowest setting.

Current to each heating element is about 34 amps.

I'm in contact with the boiler manufacturer as well as the supplier but want some real world feedback.

Tom

 

[fitter30]

9 kw= 31000 btu's. Is this for radiate floor system? If it is need how many loops, tubing size, lenghts, pump model and brand. If not what is it heating, and pump.

 

[thoyer]

9 kw= 31000 btu's. Is this for radiate floor system? If it is need how many loops, tubing size, lenghts, pump model and brand. If not what is it heating, and pump.

Sorry - important details left out........

Garage radiant floor, 3 loops each approx 250' of 7/8" tubing.

Pump is Grundfos UPS15-58

On initial start up I thought it was runnign properly but the more it ran the more I don't think it is. The boiler temp never gets above 80 deg even with setting the pump to the lowest setting.

Floor will get to about 57 deg but that is with the boiler running pretty much all the time.

Spent about an hour on the phone today with boiler mfg (very helpful) and based on his calculations (18amps per element, 238VAC and the 10 deg temp rise across the boiler) he comes up with a flow rate of about 5.8gpm.

From our discussions it seems like that needs to slow a bit in order to get the boiler outlet temp up.

Tom

More details, 2" foam under slab, 1" foam around perimeter. 5" slab

 

[fitter30]

7 /8" tubing with 20 * temp difference is 50 btu's per foot = 37500 normal design. So for i haven't found pressure drop info on 7/8". So right now pump is moving to much water for your boiler. Looking at the pump curve by closing a valve on the discharge of the pump will raise the head loss thus lowering the flow (a globe valve or circuit setter will have the best control gate and ball valve don't) but try it with your valve first. Just take baby steps when closing the valve close it a little look at temps in a few hours the slab as alot of mass

 

[brewchief]

How much space are you heating and is it insulated yet?

Sent from my SM-G965U using Tapatalk

 

[thoyer]

How much space are you heating and is it insulated yet?

Sent from my SM-G965U using Tapatalk

Approx 950 sq feet. Not fully insulated - yet. I'm working on that and should have it complete by the end of the month.

I'm not too worried about the air inside the building being heated until I get the insulation done. My main concern right now is the boiler temp.

 

[thoyer]

7 /8" tubing with 20 * temp difference is 50 btu's per foot = 37500 normal design. So for i haven't found pressure drop info on 7/8". So right now pump is moving to much water for your boiler. Looking at the pump curve by closing a valve on the discharge of the pump will raise the head loss thus lowering the flow (a globe valve or circuit setter will have the best control gate and ball valve don't) but try it with your valve first. Just take baby steps when closing the valve close it a little look at temps in a few hours the slab as alot of mass

Thanks. Last night I did just what you suggested but used the three return valves to limit the flow. I had to close each one about 70% before I could get the boiler outout temp to move higher then it had been. By adjusting the return valves and having the pump on the slowest setting, I was able to get the boiler output temp up to about 95 deg.

Points to a flow issue - right? Even with the pump at the lowest setting it is still flowing too much?

Tom

PS: Thermostat is set to control the floor temp - not the ambient temp. I have a floor sensor located in the approx middle of the slab