A couple more EKO questions

[James Ascherl]

Here I am again. After abandoning my boiler project for the better part of ten months, the colder weather has forced me to now abandon my outdoor projects and focus on my EKO 40. I am hoping that the good folks on the BB can help me out on a few basic questions. I have attached a sketch of my system just to spur some criticism.
1: What is the recommend piping size for my return line from the boiler to the Danfoss bypass valve? The valve has 1-1/4" openings. Can I reduce it to 3/4"?
2: Will my zone circulator "draw" the hot water out of the top of my storage when the EKO is idle and storage is hot? The storage tank is approximately 6' away from the circulator.
3: I have an extra pressure relief valve. I already have one on my EKO as well as my electric boiler. Should I install another one? Where would one recommend I put it?

 

[ewdudley]

1: What is the recommend piping size for my return line from the boiler to the Danfoss bypass valve? The valve has 1-1/4" openings. Can I reduce it to 3/4"?

If you mean the bypass line from boiler supply to mixing valve 'H' port, it seems like that should be fine since there's supposed to be a balancing valve in that line to increase resistance as necessary anyways. Full flow from a Taco 007 or similar pump through a short section 0.75" line could get up over 10 feet per second, but that isn't really fast enough to wear out pipe elbows and whatnot very quickly.

2: Will my zone circulator "draw" the hot water out of the top of my storage when the EKO is idle and storage is hot? The storage tank is approximately 6' away from the circulator.

There's those parallel paths through the mixer 'C' port and then through the boiler or through the mixer 'H' port, but your ace in the hole as that the mixer should shut down the 'C' port completely any time it sees water colder than the mixer valve setpoint.

3: I have an extra pressure relief valve. I already have one on my EKO as well as my electric boiler. Should I install another one?

Seems pointless, but couldn't hurt as long as you put it somewhere where a dribbling failure won't make a big mess.

When electric boiler circ runs there's no zone valve control of flow though loads, that looks like a nice simple way of preventing unwanted flow through the electric boiler when it is off line.

--ewd

 

[Hunderliggur]

You might want to add a T/P gauge on the Eko. The only thing you are saving going to 3/4" on the mixing is about 6 feet of pipe, a union, and a ball valve. You are going to have a T anyway. I would not reduce the pipe to 3/4 after spending $$$$ on the rest.