Circ speed / blower fan speed optimization

[twitch]

I have a very simple setup, basically my Tarm Solo 30 (no storage), and an air handler ducted into the house. I have a Grundfos 15-58 3 speed pump and the air handler has 3 speeds for the blower, currently hardwired to high. I haven't experimented much with the pump and blower speed settings, but wanted to know if anyone could give me an idea what the optimum settings would be: pump low, blower high; pump high, blower low, that type of thing. I'm not sure what the head ft is in my system or how to calculate it, but I guess Google would be my friend

The pics are info on my air handler (FWA60-HW) and pump

 

[twitch]

A little more info about the piping. The supply and return are about the same total length, each is about 6 ft of 1 1/4 inch black iron, 45 ft of 1 inch pex, and the water to air heat exchanger is 3/4 inch.

 

[Nofossil]

I'll take a crack at this. I think you want the lowest speed for both the circulator and the fan that will provide adequate heat delivery. That may vary depending on the outside temperature.

Since you have no storage, you'll want to try and reduce the output of the Tarm during all but the coldest days. I don't know how that's done on a Tarm, but I'll bet there are people here who do know. Basically, you want the Tarm to idle as little as possible.

At lower outputs, you won't need to flow as much water through the Tarm to carry away the heat, so lower circ speeds should be fine.

As far as the blower, I'd slow it down until it can just keep up with the heat loss.

You'll need faster speeds on colder days.

This is my best guess, based on no experience at all with this kind of setup. Let's see how long it takes to get shot full of holes.

 

[heppm01]

Remember, you have a big honkin' restriction in your plenum now. A rule of thumb that I have seen (and follow myself) is to set your blower one speed higher than it would normally run at (without the HX in the plenum).

 

[pybyr]

Remember, you have a big honkin' restriction in your plenum now. A rule of thumb that I have seen (and follow myself) is to set your blower one speed higher than it would normally run at (without the HX in the plenum).

I get the basic point that you are making-- but it sounds as if the original poster has an air handler which included the HX as part of an integrated unit-- so the HX, fan, etc., were presumably designed to work together.

 

[Tony H]

In my case it acts like Nofossil suggested the lowest setting produces the least heat the manual adjusting is not really practical on a continued basis and since I do not have an automated adjustment system I only change the pump a couple times a season and leave the fan alone.
The fan is set on medium all the time when controlled by the boiler thermostat. The pump I set on medium until it gets to November 1 or so and kick it up to high then lower it back to med when it starts to warm up in March.