Lochinvar WHN055 Panel Rad Install, First Fire Qs

Gordy

bmwpowere36m3 said:

Why? Probably because my house is less than 10k btu/hr loss when its 50* out.

You could always go back to your heat loss, and plug in 50 to see what it spits out. But I would hope it's less Than 10k

Paul48

Went back to 2 zones? Why? Because it was applying to much heat for the conditions.

bmwpowere36m3

Whole house according to SF tool at 50* is 10k... still planning 400 sqft addition.

Only 1 zone right now for whole house.

Gordy

So knock 20% off that.......at least.

bmwpowere36m3

Hence the very short cycles at that temp, right?

bmwpowere36m3

I think I was pretty aggressive with the SF tool, actual window/door u values, had a blower door test done by utility, etc... but yeah seems the tool is still somewhat conservative.

And they (installers I talked to, even the supply house who sold me the boiler) thought a 50k boiler on my 1300 shaft house was too small.

Gordy

OF course they dont want phone calls. No one complains when they are warm.

Heat_n_CT

I stretched my ramps to 20min each and seem to have cut my cycles nearly in half while achieving and maintaining the same 67-68 house temps. By the time the first 20 is up I'm nearly at set point, but not shutting off the t-stat...my differential is +20*. Real test will be when winter comes.

bmwpowere36m3

Here's another run… differences: slightly slower system pump speed (delta P III vs. constant III), boiler pump slightly de-throttled (due to high delta when boiler modulates up) and ODR curve raised 2*.

Gordy

Now let's see what happens when it's 5* OA. No touching.

bmwpowere36m3

That'll be interesting... was modulating up to 50% to reach setpoint, two or three times during the call. The boiler delta peaked near 36-38* for a few seconds during that period. We'll see when it gets colder if it modulates higher and forces a high delta shutdown.

Gordy

How is your ramp delay settings?

bmwpowere36m3

• 20% (3 min)
  
• 30% (2 min)
  
• 40% (1 min)
  
• 55% (1 min)
  
• 75% (1 min)
  
• 100% (1 min)
  

I'll double check at when I'm home

Gordy

ahh the Belimo CCV no touching required.

Gordy

Hmm I don't know if the ramp delay settings can be tweaked a little more to curb that jump in delta. Time, speed, and distance.....

bmwpowere36m3

Hatterasguy said:

Gordy said:

Now let's see what happens when it's 5* OA. No touching.

Not fair.

He's going to have to "touch" it to maintain the DT. At the moment, he surely doesn't have enough flow for 5°F.

In fact, he's got to be a bit careful that it doesn't shut down on excessive DT.

Yup

Gordy said:

ahh the Belimo CCV no touching required.

This is why I commented in that thread… a modulating pump or use the existing delta p pump I have and install a CCV would eliminate that (theoretically). The question becomes whether it's a worthy endeavor or just set the pump to maintain a 35-40* delta at 100% fire.

All I can say, it was I definitely WON'T be throttling the valve throughout the season. Not only is it very sensitive to adjustment, it requires a good bit of time to make sure the delta has stabilized over a few heat calls.

The system is new to me and I'm still in the "young love" phase… i.e., spending too much time and trying to understand it. However at some point I want to set and forget.

bmwpowere36m3

Gordy said:

Hmm I don't know if the ramp delay settings can be tweaked a little more to curb that jump in delta. Time, speed, and distance.....

Hmmmm, based on that previous run the boiler modulated up to 50-60% 2-3x during the call. So for it to really work, I think, I would have to set the ramp to last the entire length of the call. After is goes thru ramp, the boiler is free to modulated up/down as it pleases.

Either I set the ramp for a LONG period of time, say 15-20 min (total) or I limit the final step to say 50-70% (the boiler will not modulate above the final ramp step for the rest of a heat call).

Theoretically if I make the assumption of design day heatloss, in my case 38k, I could limit the boiler to say 75% fire and have it run all day long at those temps.

There's so many ways to skin a cat… I'll also disclaim that my "system" is finished either. I still need to install 3 emitters (panel in kitchen, panel and radiant floor tubing in bath). So the "adjoining" open areas are carrying the load for now. That's why my reset curve is higher than predicted. 183* @ 7* ODT and 73* @ 70*. My initial calculations said 150-160* would be sufficient at 7*.

Gordy

You'll never be done.....your hooked.