Boiler sizing by fin tube

rm762

Hi all, I have a pensotti dk2-4 oil boiler with 4 zones, 2049 square feet cape style home. I totaled all the fin tube baseboard which came to 86,500 btus, the 4 section boiler puts out 106,000 and it short cycles all the time, should I have went with the 3 section boiler that puts out 74000??? I did not do a heat loss because house is drafty and in the middle of replacing Windows and doors, thanks for the help

STEAM DOCTOR

Heat loss. Only way to go.

rm762

So the amount of fin tube baseboard doesn't have any meaning? If I do heat loss now then after Reno won't it be off?

STEAM DOCTOR

Take stock of any upgrades that you make. Factor them into the heat loss calculations

rm762

Is there a heat loss program u recommend?

STEAM DOCTOR

Slant Fin has one. You can go on Taco website. They have something called the "flo pro university". There is a course dedicated to explaining the what's and why's of heat loss. The courses are super short and supper easy to understand. You should be able to complete by the time you go to bed tonight.

rm762

I will def check both of those thanks! So correct me if I wrong on this but regardless of fin tube in the home it has nothing to do with what the boiler puts out for btus? Even if all zones are calling?

rm762

That sounds good to me! Could a still use outdoor reset with the smaller boiler? The boiler is used for heat only, is there a way to make this boiler work out or should I sell and get the 3 section? Also NG is being installed on my road next month thinking if I should make the switch and go the condensing route

rm762

What is swt? Awt? The boiler will not produce condensation w return water possibly getting down to 130-120? I'm in Rhode Island, u?

rm762

Either I go with 3 section or I I go with gas I'd liked to go with a condensing unit, navien combi, alpine?

rm762

Is primary secondary preferred with these oil boilers? The original boiler had just a supply run that branched off to the zones and zone valves on the returns

rm762

Ok. Should I want slower or faster flow? Currently with the short cycling of the oversized boiler the baseboard doesn't throw out slot of heat

rm762

U obviously know your stuff because my differential is just that, 10f. I have 1 taco 007 circ on the supply I was actually thinking of switching to a 0010 taco? Your thoughts?

rm762

Ok, so I measured all zones and my 2nd floor is the longest at 160 feet , it has prob 18 90's in the loop. Is this too long of a circuit? I als forgot to tell u my boiler has a bypass loop installed between the supply and return, should that be there?

rm762

Could I just repipe the supply and return pipes and do away with the bypass loop all together? When I called pensotti they said I didn't need it , it's only used for high volumn systems. Does all this still apply if I sell the 4 section and buy a 3 section? Would the short cycling go away and would I actually get heat out of my baseboard? Sorry if I'm all over the place but I know this boiler is oversized now and should've went with the 3 section just trying to see if I could get this boiler to work out or replace, thanks

rm762

The boiler only runs for 3-4 minutes til it reaches high limit then shuts off I can still feel/hear the circulator running but when I feel the baseboard it is only warm and doesn't stay that way for a while. I replaced the boiler 2 years ago when I bought the house, first heating season was brutal some mornings I would go down to the first floor and check thermostat which was set for 68 and it read 64? Wasn't even keeping up just short cycling all night. All the elements have been vacuumed and cleaned, maybe I should flush the system too?

rm762

All 3/4, old boiler heated the house good but was rusted out and leaking that's y I replaced it, that's the reason I was thinking of going with a bigger circulator

rm762

I could actually feel the warmth from the baseboard and the house was nice and warm with the old boiler

Paul48

Was the 007 a replacement with the new boiler, and, if so, what did it replace? Series 100?

rm762

Yes 007 was replacement, I don't know what it replaced? I have winters temp guages on supply and return. I will be doing away with the bypass loop in a couple of weeks, there is a ball valve between the loop that I had closed during operation and boiler still did the same thing

rm762

This is the bypass loop let me know if u need a better pic

rm762

If I remember correctly they read 170 and 160, even though the boiler shut off on high limit of 180 the guage never read 180 on supply. Here are some more pics

rm762

The boiler also has a .65 nozzle from the factory and they do not recommend downfiring

Paul48

Are those monoflow tees? In the 3rd picture down on the left, there is two tees.....are those 2 zones? If so, we know your problem.

rm762

There are 4 zone valves for 4 zones, I don't know what to look for

Paul48

Look at the picture I called out. Are those 2 zones tee'd off a main?

rm762

This pic?

rm762

Bottom left pipe is return, 4 zone manifold up top, only a ball valve and draw off is on the pipe

Paul48

Hat.........I think he's running an un-balanced split-loop. The zones need to run to a proper manifold, with a means of balancing. The installers forgot to put arrows on the pipes.

rm762

The only convectors I have is in bothe first floor bath and 2ndfloor bath all piping is 3/4 copper no 1/2. Everything else is 3/4 fin tube baseboard. One circulator is on the main supply run which runs across the ceiling of the basement , each zone branches off the line, all zones return to the 4 zone manifold , I have traced all zones to make sure they r not crossed, as far as flow, do u mean all zones have to run is same direction? How I explained my system does that mean I have s monoflow system? I hope this helps, as far as testing temps I will have to wait till winter for more accurate testing

rm762

What would be the 100 dollar solution? Everything is piped the same as the old boiler. The pic shows the first 2 zones to branch off the main supply, basement and breezeway zones. Breezeway baseboard never feels hot at all basement is a littlebetter

rm762

Lol ok , out of all the zones I would say my upstairs (2nd) floor provides the best heat and is the furthest one out on the supply line, so u want to put the heat on in the worst zone right now? And it should be really hot? Ok I'll try it

rm762

Ok so I started the boiler, my breezeway zone which is the smallest zone and put out very little heat in the winter was really cranking out a lot of heat, at high limit of 180 the supply read 140 and return was 173 even after the boiler shutoff the high limit kept climbing up to 190 as the supply always stayed st 140... I think it's installed wrong I'll provide a closeup pic. I waited a few minutes and checked the temps again supply 140 return 170 control 180, next was check was 140 supply 165 return 173 control next check 140, 160, 170, and the whole time the the baseboard was putting out a lot of heat

rm762

First pic is supply and 2nd pic return I'm thinking the supply temp guage should've been installed on the black pipe portion close to the boiler, it seems like the bottom half of the guage isn't submersed in water

Paul48

The picture of the gauge, up by the ceiling is your supply.

rm762

Sorry it downloaded the pics wrong

Paul48

I would imagine you can run any "one" zone with no problems. The problem you have is, water is lazy. It will take the path of least resistance. As 2, 3 or 4 zones open, the water takes the easiest path and some zones don't heat properly. You need to have someone, or yourself, set up a proper supply manifold.

rm762

Ok that makes sense and I actually wanted to do that during the install but was told I didn't need too lol, what would a proper manifold be? 4 circs? Get rid of the zone valves?

rm762

The temps weren't mixed up , I think the supply gauge wasn't accurate in that location do u think it should be installed on the black pipe portion? I'm assuming that when using the globe valves when setting each zone it would be easier if all zones are calling? As far as the caleffi valves they look hi tech but expensive thry also install near the zone valves?

rm762

Winters gauges, do u think once I get them adjusted right I will get better run times and stop the short cycling? I appreciate all the help thanks for taking the time to help me understand how these systems work

rm762

The boiler came with hydrostat 3250 plus, there was no setting for a differential just hi temp lo temp and economy but with the outdoor reset hooked up it was short cycling at its worst so I went out and bought a hydrostat 3150 which has a differential setting so I set it at its max of 30 degrees which helps a lot, I'm hoping that getting more heat out of my baseboard will satisfy the t stat quicker and prevent the boiler from kicking on and off multiple times before its satified