New sytem not maintaing in this cold snap

ED95Pont

Here is a link to my discussion on the system I put in.
http://forum.heatinghelp.com/discussion/155179/help-me-choose-an-oil-boiler-low-mass-vs-mid-mass#latest

Today 0 outside , set point 68 actual 64.

Budarus 115/3 f3 burner.
Honeywell AQ control
Hydrystat 3250 aquastat (Just used for safety High limit)

I tried running max 160 water as suggested in the other thread it wont keep up past 20 f outside.
I keep increasing the max water temp to keep up with the cold.
As off now
Honeywell set:
max 190 , auto diff, design temp 8 at design water 185.

There is always a delta between the hydrostat (probe in well) and the honeywell (probe on insulated supply pipe)and my mechanical guage. This is usually around 10 degrees
Temp now
Honeywell 190
Hydrostat 199
Mechanical gauge 178


As of this morning I had the hydrostat set max 193, I just moved it to 202 This should allow the honeywell to satisfy. How high can I go on my safety high limit.

If I cant get there with the setup I have can I over fire my f3 ?

Ed

GW

Ed, can you share about the basics of you home and how many zones you have? What are you doing with your thermostats? Night time setback? I am always curious how people set their stats back when it's crazy cold.

Gary

ED95Pont

Gary all the details of my home are in the linked thread.
2400 square 2 story colonial
2 zones , 1 dhw
No night setback.

Hatterasguy,

1) After 1 hour at 202 I gained 1 degree then lost 2 degrees when I had a domestic call. I left for work
I am home now but the outdoor temp is now 17 and the house is satisfied. It will run fine now

2) With the 202 setting, The honeywell aq hits its high target of 190, (hydrostat around 199). The boiler shuts down with a start target of 179 (auto diff).

I understand to lower my high limit back to 190/195. I would like to get to the point where I can leave in one spot.

Can I put both my probe for my honeywell aq and the probe for the hydrostat in the well on top of my budarus? I would hope that they would both read the same then.

I wish my mechanical gauge also matched my hydrostat. It is why off. When I get a chance I will test the probe on my hydrostat,

Ed

GW

Ed what are the stats set at on both floors?

ED95Pont

Stats are set at 68

ED95Pont

Lets hope that it does not get so cold for the rest of the year and I can worry about it next year.

Some random observations:
1) I replaced a 140k btu boiler that heated the home below zero with the same radiation.
2) My first floor zone is very large split zone. It had a large circulator and the return on the old boiler was 1 1/4. the buderus return manifold is 11/4 inch but is bushed down to 1 inch. I know have an alpha pump
3) The second floor zone did not call often. When it did with the boiler at 190 it would pull it down to 160 quickly then slowly recover during the call. At this time the 1st floor circulation was running, and would never satisfy.
4) Old boiler kept the basement close to 70f, New boiler basement is closer to 50F. The lost btu's out of the boiler were keeping the floor warm. (and the outside)
5) My basement is allowing more outdoor air in than I thought. Possibley my heat loss calculation is off due to it.

Brewbeer

Is all 200 feet of the baseboard finned? Or is some of that baseboard just concealing bare piping running between rooms and finned sections?

GW

let me try that again

GW

3) The second floor zone did not call often. When it did with the boiler at 190 it would pull it down to 160 quickly then slowly recover during the call. At this time the 1st floor circulation was running, and would never satisfy.

---yes, your 1st fl heat is flying up the stairs, see point 5

5) My basement is allowing more outdoor air in than I thought. Possibley my heat loss calculation is off due to it.

---yes, what comes in cold, leave warm. Stop the air coming in and you'll reduce your heat losses quite a bit.

Ironman

A couple of things:
1. That boiler can be up fired to 105k input using a .60 60* B nozzle. Settings will have to be adjusted to Buderus specs and checked with a digital analyzer.
2. What setting are you using on the Alpha pump?

Robert_25

You say the boiler was shutting down on high limit even during the cold spell, so it shouldn't be a capacity issue. It would be nice to know what the return temperature was from that large zone during the cold spell. If that zone is piped in 1.25" and used to have a B&G Series 100 on it, the flow rate may be significantly less with the Alpha, depending on the setting.

Sounds like you are due for some air sealing between the second story ceiling and attic.

DJD775

Very well could be the setting on the Alpha pump. When I installed an Alpha on my oversized boiler it would not keep up on the coldest days when set on auto adapt.

hot_rod

Try moving the Alpha to one of the fixed speed position.