cold start or maintain temp?

bp1980

Hello I wanted some info on what is best in my situation. I have a biasi b-10 4 oil boiler with a indirect water heater set to 120 degrees, a hydrolevel aquastate set to 160 low limit, 180 high limit, and the purge set on. Before I had it at low limit off and high limit at 180. Its a 2 zone house and wanted to know what is best setup for this boiler during the winter and summer months? Is it better to maintain or to set it up as a cold start ?. The boiler is also 6 months old. Am I gonna save more money on oil having it maintain or having it cold start? Thanks

russiand

Cold start

Those are designed to run cold, turn off the low limit and save fuel.

earl burnermann

cold start

My Biasi is heating three zones; Two are for heat and the third is for the indirect. My system is cold start.

agropoli44

My B4 was installed 2 weeks ago, 2 zones B Board & an indirect =3 zones. The installer set the low limit to 140 & high to 180, not a cold start. I was not getting any heat. Today I wired for cold start, hi limit 180, economy on 2. Time will tell if heat is sufficient. I hear a whining noise from the B & G nrf 25's. Any thoughts on the noise?

jjette

3 pass boilers designed for cold start. Maintaining boiler temp is the reason you will save fuel in the off season. I would also recommend setting indirect at 140 and mix down to 120-125. Circulator noise could be a few issues. I would start with location. IFC? is the circ rubbing against something? low boiler psi?

Marz

I prefer "warm start" 110-120. After many years I believe warm start is the way to go

Jason_13

Boilers have been designed for cold start for more than 2 decades. No advantage to warm start other than fuel usage. When the boiler water levels dropped so low warm boilers should have gone away. When they had more water volume it was more of an argument.

icesailor

Jason said:

Boilers have been designed for cold start for more than 2 decades. No advantage to warm start other than fuel usage. When the boiler water levels dropped so low warm boilers should have gone away. When they had more water volume it was more of an argument.

What was done 20 years ago to oil boilers that changed the design to be able to work better as a cold start system?

Many of us who have worked and cleaned cold start boilers consider the idea a bad one and a total failure as far as application goes. Just because someone says it is better and will work, doesn't mean it is so.

The Cheapsters don't like to pay for any service. A cold start oil boiler needs to be cleaned thoroughly, every year. Or it will cost you. A warm start run at 140 degrees and set up properly with a quality modern burner will go 3+ years without serious cleaning. A serious cleaning isn't a "Brush & Buff". Cold start boilers, including "triple pass" fail 5 to 10 years earlier than warm start boilers. Factor in premature failures into the annual cost.

There must have been a reason that all the boiler manufacturers started putting swing out front doors on oil boilers. Because no one wanted to take the fronts off to clean all the crud brushed down into the chamber, where it was left to pile up. They've been putting doors on boilers since the 1990's. Its still not uncommon for a quality soot sucker to find a failed 10 year old boiler that the holding bolts have never been off for cleaning and the boiler has 6+" of kibbles and bits in the bottom. If the bolt doesn't have Never-Seize on it and/or won't come out, it probably has never been out.

agropoli44

Referring to my April 17 post , A rep from the co. came by and informed me that the NRF 25 is too powerful for the job & said he believed that was the cause of the high pitched sound heard in all the rooms. He told me I could try installing a flow check valve in each zone & that might cut out the noise or purchase smaller circulator. My old system had the circulators on the return feeding into the boiler, no noise then using the NRF 25. Also since I went to cold start, the target increases on the hydrostat 3250 & now it's much warmer with the high set to 180, economy on 2, low limit off.

On another note, the check valves on the NRF 25 are not up to par. Convection is heating my second fl. room which is the first room on that zone. Have to decide on how to tackle all the issues. install a check valve & assess the results or replace the circulator one zone at a time.

icesailor

agropoli44 said:

Referring to my April 17 post , A rep from the co. came by and informed me that the NRF 25 is too powerful for the job & said he believed that was the cause of the high pitched sound heard in all the rooms. He told me I could try installing a flow check valve in each zone & that might cut out the noise or purchase smaller circulator. My old system had the circulators on the return feeding into the boiler, no noise then using the NRF 25. Also since I went to cold start, the target increases on the hydrostat 3250 & now it's much warmer with the high set to 180, economy on 2, low limit off.

On another note, the check valves on the NRF 25 are not up to par. Convection is heating my second fl. room which is the first room on that zone. Have to decide on how to tackle all the issues. install a check valve & assess the results or replace the circulator one zone at a time.

Those are 3 speed pumps. Are you running the noisy pumps at #1 speed?

Set the operating/Low temperature to 140 degrees and the high limit to 160 degrees.

The Baxi was a replacement to an old system? Did they use a hydraulic separator between the new boiler and the old system? Wonderful things happen to old systems and new boilers when they are piped through a hydraulic separators.

Do the B&G NRF 25's have internal checks? They must have because the rep said to try putting check valves in the system. Does the sound get better when the speed is on #1 as opposed to #3?

A NRF 25 on #1 speed is slightly greater than a Taco 007 and would have worked fine.

IMUO.

agropoli44

I've operated on speed 1 to 3. The whining is always evident although at a lower pitch. I'm in cold start mode. Low limit is off. Why use the 140-160 arrangement when I'm on cold start with a 32 gal Buderus (set at 140) & mixing valve. The internal checks are in all 3 nrf 25's & they all don't do the job. I would have been better off with flow control valves. The Nrf 25 at speed is comparable to the taco 007. I just might take the check valve out of one nrf 25 & see if that solves the whining noise problem.