A/H with modcon questions

Unknown

This customer(my brother), wants <em>constant low-speed air movement</em>  throughout his house ductwork. So last fall I installed an Ecologix A/H with ECM blower motor, included in the factory coil is a 3 speed 15-58. The boiler is a TT Solo 60, with a Smart 40 indirect. Piping for the Solo & A/H is <em>straight-through </em>, no buffer-tank.



Anyway,, when the stat calls, the blower kicks to a higher speed(to satisfy it),,, then reduces back to low after and stops the boiler,,,, fine right.

But then after a time, <em>before the stat calls again</em>,  the low-speed air movement <em>feels</em> cool

and he`s uncomfortable.



So, we tried a constant heat-demand(Par 45=01) for the boiler & wired the A/H circ to run continuously from the boiler. When the stat calls this is fine,,, but once satisfied the blower returns to its low-speed OK,,,, but after a time the house temp over-drifts,,, the stat <em>never calls</em>  he`s too hot,,, & the boiler short cycles, ( the MCBA has an unmovable 6° pre-set variance.)



I`m thinking,,, adding a buffer tank & VS circ,  combined with adjusting Par 40(CH call blocking time) should cure this.



What say y`all?







 

  

Unknown

No opinions yet?

As to this query?

I would think a small modcon should be able to take-on any A/H @ design without over-shooting.

bob_46

opinion

I don't think your problem is with the water side. If the duct work and more importantly

the number of, type and location of the registers have not been engineered to provide

a draft free environment you have a problem. ASHRAE's handbook has a whole chapter

on physiological principles. Bottom line if you have air moving at 15 to 20 FPM at less than 85ºF it will feel like a draft. From my experience most residential air handling systems are designed by rule of thumb. The boiler can't change the air side.

joel_19

hvac

No way to stop overheating without stopping the water flow. Why doe he want the air always moving???? Almost impossanbe to not have drafts with that.