Need advice re priority zone

FredCapo

I have a newly installed 4 zone (3 heat, 1 one priority-set indirect tank) hwbb system on Weill ng cgi 6 boiler. I realize the boiler is oversized for the present installation. It is an older Victorian style house in NJ. The temp has been in 20's and teens, and house heats well, though kitchen has cold spots due to no toekick instlled yet, though overall not likely efficient, since still under renovation. This morning was zero degrees outside. Wife was taking a long shower and then doing some cleaning with hot water when I realized the temp in the 3 zones,,set at 67, 66 and 63 was down to appx 59 and the priority zone was hogging the system.

I am looking for an explanation of why with an somewhat oversized boiler, things got cold so fast or why the inditect tank was far behind in supplying a single shower. Thanks.

Robert O'Connor_12

The design temperature in NJ is 14 degrees. If your system was correctly sized even if no domestic water is being used it probably won't maintain the desired thermostat setting anyway. Combine this with extremely cold incoming domestic temperature and it just won't keep up. Just because the boiler is oversized doesn't mean the emitters are going to put out. It's all in the sizing of the size pipe, flow rate and radiation. I personally have an indirect in my own house but don't use priority.

FredCapo

Thanks for your comment. In thinking about it I am pleased as to how relatively comfortable the house is...

Re priority, I did disable priority, leaving the hw tank dial at mid. Would you adjust the tank dial anyway to compensate for no priority? Thanks.

Robert O'Connor_12

I prefer to run my tank over 120 & use a mixing valve to control temp coming out of faucets or tub. This will give you more reserve of domestic hot water & kill any Legionella bugs that may be growing in water at 120 degrees.

Tinman

Not sure which control you're using but many allow for a 1 hour max DHW priority. I challenge people to run out of hot water when I install indirects and it hasn't happened yet. Something else is wrong. Can you post a picture showing all the near boiler and DHW piping?

FredCapo

Thanks will post pix over weekend.

Snowmelt

If the boiler is oversized they may have sized it for both the indirect and the heat load of house. Where are you from in nj, I'm in linden.

FredCapo

They is me. I, non-pro, did a calculation based on room size, uninsulated walls. Installed december with all new baseboard. Moved in jan. Heats well but Getting some short cycles, boiler has no provision to change 20 degree diff. Still plan to add extra fins in basement, attic, kitchen someday. Likely will come up with plan to fix for next season. In Rockaway NJ. Thanks.

hot_rod

Short cycling and not maintaining temperature? Something does not add up. Could be a piping or installation snafu.

Snowmelt

That's what I'm thinking, do you have pic of boiler set up.

Zman

What model indirect?
Picture of the piping would help.

FredCapo

Weill Aqua plus 40. Boiler return and supply correct (return at bottom, 1 inch copper into manifold). The temp here has been minus 5 to single digits and only heating prob has been first floor with no heating elements in kitchen, and was able to maintain 60 at minus 5 outside overnight. The boiler cycling is the issue that needs addressing. It is safe to say the boiler is oversized...by how much don't know, and dont know if whatever additional load that needs to be added to the house will mitigate the oversize situation. Thanks. May bring in someone though not decided yet.

icesailor

This obsession with boilers cycling.

If the burner shuts off, and the circulator(s) keep running, and the house is cold, either the water is too cold, or there isn't enough radiation. If the burner shuts off and the circulator(s) also stop, there's a control issue.

Especially if the SWT is too cold. Worried about a 20 degree differential? As I understood it, with a 20 degree differential and the High set to 180 degrees, the "High" can go as high as 190 degrees and as low as 170 degrees. Is the "High" set too low? Turn that sucker up to where it was designed by the manufacturer designed it to go. If you set the HIGH at 140 degrees, then the high can be as high as 150 degrees and as low as 130 degrees. If a system has a 20 degree differential, and is set for 140 degrees, and the burner is about to come on. the SWT can be 130 degrees, and the last emitter might be seeing 110 degree water entering temperature with less RWT's. Heat that house with 110 degree water.

Then there's all those Internets Expert sales person promoting undersized PEX with super long runs of over radiated loops. Its hard to tell what goes on from all the BS that a lot of people have been fed by others before they get here.

If you are going yachting, you should own your own PFD. If you weigh 250#, don't buy one that is rated for a maximum of 250#. You need to add for your clothes and what's in your pocket. You better buy a bigger one and pay the difference. When you're going down, that savings on the PFD that was big enough, isn't, you have no excuses. Looking back on HH.com, there were no discussions 5 years ago about all these cold houses. Now, in the last two years, that's all that is being talked about. And the Internets Experts are advocating smaller boilers and less radiation and piping.

The only cold houses I ever saw were the ones I was fixing to make them warmer.

When moving a long chain, I prefer to drag it. Some others seem to want to push it.

FredCapo

The high is set at 185. Agreed that there is not enough baseboard as per kitchen.

As per the cycling, the room thermostat is calling, the boiler fires and water temperature comes up quickly, circulator continues running till it comes down 20 degrees, boiler fires again, repeat.

Is there any way that measuring the return water temperature will provide some diagnostic info.

FredCapo

I have identified some deficiencies in my system,,thanks to info in this and other threads, and will make the changes. Thanks.