woodburner into heat store

[Michael5]

we have recently installed a woodburner to supplement our oil boiler and solar system. It has been installed as instructed with the flow going into the top of the tank and the return exits 2/3rds of the way down our 277 litre tank, but when the log burner has been alight for a very short time the water at the top of the heat store starts to boil and the temperature at the bottom of the bottom of the heat store does not change. At the moment the system is gravity feed from the log burner, the return gets hot as does the leak radiator.
How can we get the hot water down the tank, would it be a problem if we change the flow and return round so the hot goes in the bottom and the return would come from the top of the tank

 

[DeltaT2]

For gravity circulation of that nature the Flow should go into a connection 2/3 of the way up the tank, and the Return connected at the bottom.

Questions should be asked of the installer or tank supplier.

 

[big-all]

what did the hetas engineer say or building control say when you informed them off your plans ???

 

[DeltaT2]

what did the hetas engineer say or building control say when you informed them off your plans ???

HETAS's main concern is Building Regs, chimneys & ventilation big-all.
Technically, you'd be better speaking to the Milk Marketing Board or the wee wifey behind the till down the Co-Op!!!

 

[Michael5]

we spoke to the technical dept at the tank manufacturers and everything is installed correctly, it is circulating properly because the leak radiator is getting hot but it may not be circulating quickly enough the only suggestion they have is to install a low pressure pump to the return

 

[DeltaT2]

we spoke to the technical dept at the tank manufacturers and everything is installed correctly, it is circulating properly because the leak radiator is getting hot but it may not be circulating quickly enough the only suggestion they have is to install a low pressure pump to the return

Eh??!! But surely they must be talking rubbish?? The gravity circulation can't be working or you'd not require a circulation pump & the whole tank would get hot. You're only get the top of the tank hot because the Return connection is too high.

 

[Onetap]

we spoke to the technical dept at the tank manufacturers and everything is installed correctly, it is circulating properly because the leak radiator is getting hot but it may not be circulating quickly enough the only suggestion they have is to install a low pressure pump to the return

Eh??!! But surely they must be talking rubbish?? The gravity circulation can't be working or you'd not require a circulation pump & the whole tank would get hot. You're only get the top of the tank hot because the Return connection is too high.

That could happen if the circuit were air-locked or if there was excessive hydraulic resistance in the circuit for the head available from the gravity circulation system. The installer could have worked out whether it would work before installing it. It is his problem. You should not need a pump.

It's a bit like buying a car with a 100 mph top speed and finding it will only do 5 mph unless you install extra bits. Doesn't do what it's meant to do? Return to vendor.

 

[DeltaT2]

Cetainly sounds like the gravity circulation is working, the only problem is the lack of heat at the bottom of the tank. Of course I'm making a lot of assumptions; The log burner gravity connects directly to the tank, the heat-leak is not too large, the pipe gradiants & installation is correctly fitted.

From whom did you buy the tank Michael?