MBfreak
MEMBER EMERITUS
Hi from mid Sweden, aka as 60 degrees North ( same as Anchorage
)
I have a house built 1975 where the heating supply is district heating that works great. It feeds to a plate heat exchanger with a 3 sensor inputs ( ambient, forwrd and room temps) The house has three // circuits with several radiators in each.
When we bought the house there was one circulation pump and manual valves to balance.
That did not work well, the most loaded branch was always too cold.
Two years ago I put in one circulation pump in each branch and things improved very much. When it gets real cold ( below -25 C) the heat distribution becomes uneven and return temperatures differs. Two branches are equal, the third is almost 15 C colder. Switching that pump to a higher speed fixes the situation, but has to be done manually.
I know there are speed controlled self contained closed temp loop pumps , but they cost in excess of $800 each. Has fancy ctrl and monitor , but ...
I am pretty good at electronics and have plans to make a PIC that can regulate the speed of the pumps to give best balance in the // paths.
However, I do need three small ( < 75 W) VFD to control the individual pumps. I can design and build that myself too, but would like to know if anybody here has a good supplier of small VFDs for a 220 single phase motor ( two windings, one thru a run capacitor continuosly connected)
Best regards ,
Ola
)I have a house built 1975 where the heating supply is district heating that works great. It feeds to a plate heat exchanger with a 3 sensor inputs ( ambient, forwrd and room temps) The house has three // circuits with several radiators in each.
When we bought the house there was one circulation pump and manual valves to balance.
That did not work well, the most loaded branch was always too cold.
Two years ago I put in one circulation pump in each branch and things improved very much. When it gets real cold ( below -25 C) the heat distribution becomes uneven and return temperatures differs. Two branches are equal, the third is almost 15 C colder. Switching that pump to a higher speed fixes the situation, but has to be done manually.
I know there are speed controlled self contained closed temp loop pumps , but they cost in excess of $800 each. Has fancy ctrl and monitor , but ...
I am pretty good at electronics and have plans to make a PIC that can regulate the speed of the pumps to give best balance in the // paths.
However, I do need three small ( < 75 W) VFD to control the individual pumps. I can design and build that myself too, but would like to know if anybody here has a good supplier of small VFDs for a 220 single phase motor ( two windings, one thru a run capacitor continuosly connected)
Best regards ,
Ola