PB105 Feed Rate Question

[AndrewChurchill]

I fired up my PB105 boiler this week and I have been using it to heat my hot water. My first setting was max temperature at 160 and a feed rate of 4 (out of 6). I put two bags in and marked that level with some tape. After 48 hours I filled the hopper up to the mark and determined I had used 1 and 1/2 bags of pellets.

I have lowered the max temp to 140 and the feed rate to 2. I'm hoping to get down to 1/2 a bag a day or less.

My question is will a higher feed rate build a bigger fire and take less time to heat the hot water and thus use less pellets?

 

[AndrewChurchill]

So with a little experimenting I've answered my own question. I set the feed rate to 6 and now instead of using 3/4 a bag of pellets per day I'm now under 1/2 a bag per day.

Now I have another question. If the PB105 determines the feed rate based on the heating demand coming from the heat zones and Outdoor Temperature Sensor why wouldn't I just leave the feed rate at its highest setting (in this case 6) and let the control board determine the feed rate? It would seem to me if I set the rate at a setting lower than the maximum setting and there was a large call for heat it's possible the boiler couldn't keep up.

 

[AndrewChurchill]

Explain your reasoning.

 

[Delta-T]

Andrew, view the feed adjuster as a limiter. At a feed of 6 the control board will allow the auger to turn for all 60 seconds of each minute anytime the auquastat says the water is not hot enough. In theory this allows you to generate more heat faster. By turning the feed adjuster down you reduce the auger turn time by 10 seconds for every whole number( ie 5 will allow the aiger to turn for 50 seconds, 4=40sec). If you were at say 2 you are telling the machine it can only feed pellets for 20 seconds of every minute. Then it must wait for 40 seconds before it can feed any more. I'm sure you can see how having a very low setting will not allow the machine to get the water to the temp you desire very quickly or at all if you have a high demand. I beleive that 4 is the default recommended # but you cant go wrong with 5 or 6 in my opinion. BTW this is all information I learned from Harman's Factory Techs.

 

[AndrewChurchill]

Delta,

Thanks for the info. My question is since the PB105 is capable of adjusting the feed rate depending on how much heat is needed why would I want to limit it since the control board should determine the feed rate?

I did a little test last week. I am using my boiler to heat my domestic hot water with an indirect water heater. I set the feed rate at 2 for a week and determined I was using 3/4 of a bag of pellets per day. Then I set the feed rate to 6 for the next week and my usage dropped to 1/2 a bag per day.

This is why I'm wondering if I should just leave it at 6 and let the boiler do all the adjusting.

Thanks,
Andy

 

[Sting]

Andy

a 1/2 of a bag per day --- thats very frugal

I never tried to heat DHW in the summer - but on really low degree days it still took 2 bags min to idle and produce DHW in my load.

Congrats - I should insulate Baby Boiler with modern materials -- but then there a lot of things I should do around the place -- its job security!

Why do you think CO went quiet in this thread????

 

[Nofossil]

Andy

Why do you think CO went quiet in this thread????

Perhaps CO is having an identity crisis. As far as I can determine, CO has also been Pook, Koop, Enord, and at least one other name in the last year. Must get tiring.

 

[AndrewChurchill]

I think he went quiet because he didn't have any facts to back up his theory. I've noticed that he does a lot of posting but a lot of his data or suggestions are suspect.

 

[AndrewChurchill]

Sting, I suspect the reason my usage is so low is because the PB105 has auto ignition and thus goes out when there's no call. Also, I have my DHW tank on a timer so it only calls for heat in the morning about 1/2 hour before we need to take our showers and then it turns off after we have left for work. The tank is insulated well enough so when we come home in the afternoon we have enough hot water to do our dishes, and other evening chores without turning the tank back on to heat it up again.

 

[alaz]

How did you get your PB105 so soon, when did you order?
What is the gpm that can be pulled out of the pb105 at 180 degrees? How about from the Traeger? I know it is early, but how do you like the boiler? Does anyone know of a forum specific to the PB105 and has there been any negative reviews?


Thanks.

 

[AndrewChurchill]

Alaz,

I got lucky. I went to my local dealer in May and asked if he had a PB105 in stock. He only had the floor model. He said he could order one but he didn't know when it would come in. I said I didn't need it until June so I asked him to order one, but I also asked him if he'd be willing to sell me the floor model if mine didn't come in before I needed it.

He said yes. Needless to say the one I ordered didn't come in so I got the floor model.

I like to boiler so far. My only complaint is it doesn't have a TT connection so the boiler maintains a minimum temperature even when there's no call for heat. Since my water heater is on a timer it only comes on twice a day, but my boiler comes on several times a day just to maintain boiler temp. I've since put a timer on the boiler as well so it only comes on twice a day as well.

Before the boiler timer I'd use a 1/2 bag of pellets a day to heat my water. After the timer install I'm using about 1/4 a bag of pellets a day to heat my hot water.