KHN install second update heating.

keyote

decided it couldnt hurt to try the heating on the cellar finn tube loop.
As a reminder I installed a thermostat in each apt which are both on the sam manifold to get an idea of if one was a cooler space[one is a bit] and I brought both the tstats eim signals into the taco zone valve panel on the same tstat terminal with the hope that either could call for heat and that the cvall wouldnt end until both were satisfied. [dont know if this will work yet]
Also some of you will never forget their was concern even the entire floor [both apts] might not be enough of a load shoulder seasons.So I got the bright idea to put an old abandoned finntube loop in the cellar an the zone valve I piped for the eventual cellar radiant loop.My hope was this would act as ballast mass a buffer, that would run whenever the apts called for heat. to make this happen i put both the apts and the cellar zone valves on the same terminal corresponding to the tstat terminal the apts two stats are on. [this at least works]
So although a bit apprehensive about my programming abilities and not wanting to put to hot water in the radiant loop somehow inadvertently I decided i couldn't hurt the finn tube and so un plugged the zone valve to the apts manifolds and raised the setpoint above the room temp.The zone valve for the cellar opened but nothing seemed to happen for a few minutes with the boiler and I thought i had a problem.But then it started up.
It modulated up to about 65% to get the water temp up to 102 then it began modulating down, I went and set the DT pump to DT10 and checked the pump boilers and flowchecks gauges and readouts and they were all at 102 out 92 in actually the pumps was a bit lower but its sensor is not insulated.However, it was holding delta 9-10 steady at 8-9 volts. The boiler got down to 10 % modulation and held 102 degrees output without moving been doing it for an hour now.
Oh I forgot after a few minutes I worked up the courage and went ahead and plugged in the top floor apts zone valve and it opened and began to flow.Interestingly as the cold return water from the loops entered the boiler and the pumps things remained calm, the pump barely registered what was happening on the DT it remained steady at 10.Both temps showed on the pump and a couple watts changed in speed. On the boiler it simply modulated up I think as high as 100 for a second then settled back down at the old temps of 102/92.This boiler is so quiet you cant even tell its running standing next to it. and seems so precise. I get the feeling it would handle micro zones well. yes you have the issue of a small area can only take so many btus and that itself could mean the call would only last a short period. But that sort of assumes pretty efficient delivery and probably pretty high water temps, I have a feeling if i want i could make this machine give me steady 75 degree water. However thats not tonights problem. tonights problem is the apts are not warming after almost an hour.up.So my swt setpoint is too low.
So a couple questions. Today i went back into the thermostats and made some changes on advice from one of you guys. I told the tstat 2 calls per hour. does 1-2 calls per hour seem right? and as I adjust my swt is there a time to satisfy that is ideal? i mean obviously I will also be worry about the surface temp, and the odr, but Id like to know what it ought to be expected say on a warm board which is what i tried for so would like to measure against. One thing thats leading to the not warming is i havnt insulated the underside of floor yet and its actually exposed beams right now and not well heated below.But mainly i just plugged som low water temp parameters in which ive forgotten guess 102 degrees. I dont really know how to set up the ODR to match the loop cade design days. Do i simply make the ODR curve the design outdoor temp and the swt temp that loopcad gave me? like what makes the boiler give me 127 degree water on design day and a curve from that on other days?

Leon82

That is a huge wall of text but, if it feels like it takes too long why not raise the odr 5 degrees and retest it.

It sounds like you have enough mass that cph is not needed. My tstat is set for a 2 degree differential. It takes my whn about 3 hours to turn off. When it gets real cold it has run for 12 hours at a time.

Leon82

You tstat setup will work. I did that too

Leon82

I think I took my fuel use and found my btu per hour for design day and divided by my baseboard length. A math wiz on another forum helped me and it is currently within 5 degrees of that number.

keyote

that top floor was only 16 kbtu on design day and like less than half that on a day like today so below the minimum modulation-in theory.I did just take the cellar finntube off the loop and it had no problem but i had increased swt quite a bit by then. on fact iim all the way up to design day swt and it 50 degrees out and the room temp hasn't budged in two hours. I know not being insulated under is huge, but still would think I could move the needle with design swt. Two tstats cant be wrong though. the stupid tenants have their 4 air conditioners in still so theres some oa infiltration. The delta t is right, the supply manifold is much hotter than return, and the flow setters, pump, and boiler all concur on DT. so im dumping BTUs somewhere.the rooms below dont feel particularly warm. so im beginning to worry panel sucks. I have a hard time believing its that bad, and if it sucked i wouldnt be dumping btus would I? tomorrow i will buy some spray foam and do the undersides. and insulate the riser

keyote

Running the heating again this evening. DT Pump and Boiler are both ocilating. Didnt really seem like one or other were at fault They both seemed like they would over then under shoot but not really so much because they were antagonizing each other semed more like because they couldnt learn a lesson and so the swings got really predictable and you would be saying dont go so high this time. It felt like if you could adjust them to do what they were doing but tighten their range you could get it eailly dialed in. Anyway it seemed to me like a waste of energy. So I tried the pump on the lowest constant speed which is what I estimated it should have settled.Obviously that settled the pump, the boiler settled as well at least within 3 degrees and about 5% modulation range.
When I first turned the stat up to run heat tonight I was upstairs and when I got down to the boiler it read setpoint met which was not true and it did once before it seems to be a lockout of sorts and I havnt figured out how to get rid of it without turning the machine on and off. I noticed the DHW was 148 so it had just done a dhw run, I wonder if when it tried toi do the heat call next and the supply water temp was hotter than the limit on the heating parameter it shut down this could be a problem with radiant. Hmmm

Leon82

The DT pump and the boiler will fight each other unless you have a PS loop.

I would keep it on the constant setting until the variable voltage ecm pumps are available that are cheaper than the current ones

keyote

LOL
yeah we had a mile long thread about that while i was designing this. others have said they succeeded and some say they have not.Ill say this the failures were due to this issue leading to lockout mine has not nor did it look like it ever would, its just seemed kind of pointless. I will try and tweak controls to see if I can resolve it. I wanted only one ecm pump but I also wanted to maintain DT in the loops, it looks like I may actually be able to get the boiler to do that for me its maintaing dt20 now i am going to see if i can programm it to do dt10.
Yes youre right when they have 0-10v ecms in the states that will be the holy grail