PB105 / Oil Boiler Basic Configuration Guidelines?

[luggal]

Apologies if this has been answered previously. Various searches didn't turn up what I was looking for but I may not be using the correct terminology.

I recently had a PB105 installed in series with my current oil boiler. These are the settings initially made by the installers:

OAT: yes
DHW: yes
Feed Rate: 4
Igniter Mode: Auto
PB105 Min: 165°
PB105 Max: 175°
Oil Min: 150°
Oil Max: 160°
Hot Water: 120°

What I wanted to know is if there is a guideline for the min & max settings on the oil boiler that work best in concert with those on the PB105 - something that I've seen referred to as a "head start" in another thread. In other words, is there a recommended base difference between the Min setting on the PB105 and the max setting on the oil boiler in order to ensure I'm not blowing through oil needlessly? Example: 5°? 10°? 25°?

I understand the oil boiler will run when calls for heat and hot water are made, which I want in order to exercise the unit. What I want to do is ensure that the oil boiler run time is minimal.

Thanks in advance for any recommendations/suggestions!

 

[luggal]

Weekly bump!

 

[Delta-T]

I dont think there really is a "guideline" for the optimal temp differential between the 2 units. observation and some good old fashioned trial and error is likely your best teacher. good unit.

 

[wil lanfear]

It all depends on how often that you want the OB to run, trial and error. My OB and PB are piped in parallel with each other using a circulator controlled by an aqustate in the OB to maintain equal temps in both boilers. Myself, I don't want the OB to fire unless the PB fails to. I have the PB max set at 180*, minimum set at 160*. The OB max is set at 160*, minimum set at 130*, if the PB fails to fire, the temp in the OB drops to 130*, the OB will fire.

 

[BoilerMan]

How is your hot water heated? Domestic coil in OB or indirect? I installed a PB105 for a family member and I set it at 145 185 to minimise startups which WILL build creosote and he lost the igniter in less than a year, but he said is was due to lask of cleaning in the burnpot around the igniter.

Personally, I'd have an indirect and turn run the OB with an aquastat in the BP set to 130 or something as low as possible. You say they are piped in series, I assume the PB is first? If it is then a strap-on aquastat on the supply to fire the OB if the PB runs out or is not able to maintain a minimal output water temp. I don't like to burn any oil if I don't have to. If you have a domestic coil for DHW then you are burning way more oil than needed in the summer and winter. I'd look into getting an electric water heater for the summer and using a sidearm for pellet heated water in the winter. Also a series configuration will keep both boilers hot all the time and draft heat up the chimney, this was commonly done in the past when fuel costs were not as much of a consideration because it meant the boiler not supplying the heat would always be hot and there was no lag time if they both had to fire. This being said, some oil boilers will leak is left to cool off. His setup is pellet only, and he tried to use the PB to heat hot water in the summer and it was woefully bad (burn-pot buildup), we connected an electric water heater for the summer, and he uses an indirect in the winter with the PB.

I was very impressed with the unit and it's build-quality and reliability, just don't expect the world from it, as it's not a $20,000 self cleaning European unit that never needs anything but ash removal.

TS

 

[luggal]

Thanks guys, I appreciate the replies. I'm the kind of guy that is endlessly annoyed if I think something isn't configured for optimum performance, even if I don't know what "optimum" is. My wife calls me persnickety when I think she really means a-hole hehe. I'm trying to avoid letting that OCD nature screw anything up here since I don't know what I'm doing...

My OB has a domestic hot water coil as does the PB105. I believe the OB comes first in the series and the PB105 is plumbed to preheat the water that the OB uses when the call for heat/hot water is made. Turning a few ball valves takes the PB105 out of the equation, which is what I'll do when the season is over. I discussed an electric water heater with the plumber while the installation was being done. It's probably something I should look into.

For the time being, I've lowered the temperatures on the OB to 130° Min & 140° Max. This gives me a 25° buffer between OB Max and PB105 Min, at least according to the numbers on the dials, and it seems to be firing a heck of a lot less. I need a cheap way to accurately measure the water temperature to see where I'm really at with both units. The OB gauge may or may not be accurate and the gauge on the PB105 used to work but has been stuck at 140° for the past month.

 

[luggal]

Thought I'd post a quick update. With the OB min/max settings I had previously made I burned ~24 gallons of fuel oil between 1/14 and 2/14. The month prior was 80 gallons and the month before that was 100. We're getting there!

 

[Tdiguy]

Hey another person with a pb 105. I have had my pb 105 for a while now. Its been a fun journey when they came out a few years ago after the mfg re-tooled they had tons of ignitor problems. I have had 3 different revisions of this ignitor the latest with i think 15 fins seems to be the longest lasting. They also totally ditched the fin ignitors for the boiler and now use some other style ignitor for newer pb105's.

Anyway check out my post about mods i have done to my boiler for control. The way mine is set up i only burn oil when i want / need to. I also use a hot water coil that is in my oil burner so getting an electric hot water heater is not needed as long as your oil burner is feed hot water from the peller boiler it will still heat up your hot water coil.