Pellergy install with storage

[AndrewChurchill]

I'm building a new house as we speak and I'm installing a Pellergy pellet burner on a Buderus G215/4 boiler. I have one of the Pellergy units at a duplex I own and it's been working great. The only issue is during the shoulder season it tends to short cycle since the demands for heat are less.

To combat this issue I am installing a 500 gallon storage tank. I should be up and running in about a couple of weeks.

I will post pics soon.

 

[AndrewChurchill]

As promised. Here are some pictures of my set up.

 

[Former Farmer]

Nice looking setup Andrew. How many zones are you running?

 

[AndrewChurchill]

I've got 11 zones. 6 for the main house, 1 for the mudroom, 1 for the garage, 1 for the apartment, 1 for DHW, and 1 for future plans.

 

[maple1]

Please share you experiences with the pellet head. Have you used it much yet? I think there is all kinds of potential for those things.

 

[AndrewChurchill]

I've been heating my houses with pellet boilers since 2008. The home I sold last year was heated with a Harman PB105 pellet boiler that was hooked up in parallel with a oil boiler. In the 5 years I lived in the house we only used 1 tank of oil.

What I liked about the Harman was once I got it dialed in I only had to give it a thorough cleaning once a year. I would clean the heat exchangers every night or two when I filled the hopper, clean the burn pot once a month and empty the ash pan about every two months during the heating system.

Things I didn't like was having to fill the bin every night, and the huge amounts of smoke it produced when it started.

I had been watching the Pellergy systems for a few years and last year I decided to install one in the duplex I have.

The things I like are the multiple storage options, the extremely quick ignition, easy switching back to oil and the ease of cleaning the boiler.

What I don't like is having to clean the boiler every two weeks, and the short cycling that happens if you don't have storage.

When I built the new house I decided I'd do the Pellergy system again. I went with a 5 ton bag bin this time instead of the 3 ton bin I have at the duplex. The bulk delivery people around here have a two ton minimum and since it takes anywhere from 4 to 6 weeks between when I call for pellets and when they actually deliver it makes timing when to call them tricky.

I also added storage. I bought a 500 gallon tank from New Horizons. Now when the burner comes on it will run for an hour or more before it shuts down. At the duplex a lot of times when there is a call for heat the burner starts up and as soon as the ignition cycle completes it shuts back down again. Next spring I'm going to put in a 120 storage tank and that should eliminate the short cycling up there.

At the new house the boiler is coming on maybe once a day. I suspect it will come on 2 or three times a day during the heating system vs. the 31 times p/day at the duplex.

 

[heaterman]

Being that the Buderus is an iron boiler, how is the Pellergy burner integrated or set up to protect the boiler from condensation on a cold start?

 

[AndrewChurchill]

The Buderus is designed as a cold start boiler so no extra protection is needed.

 

[heaterman]

True to a point. The Buderus control incorporates logic for the operation of the heating pump that will not allow it to run unless water temp is above a certain temperature. The gas/oil burner will fire but the pump will not run until the water temp reaches that target. Then it will cycle the pump until the temp stabilizes above that target.
I was just wondering if the buderus control was still "in the loop" or if it was replaced by whatever operates the Pellergy head.

 

[AndrewChurchill]

There is a control unit that takes care of that. I don't believe I'm using the Buderus control box but there is a unit that controls the circ pumps. There is a separate control box for the Pellergy settings such as feed rate and fan speeds.

 

[heaterman]

It would be very prudent to double check that the control has that capability in it especially with 500 gallons of storage involved.

 

[AndrewChurchill]

The Buderus boiler is designed so that it's almost impossible to shock. Buderus almost dares you to try to shock their boilers. In addition to their design I have a low limit switch that turns the boiler turns on at a predetermined temp. Also, the fact I have storage also mitigates the risk of condensation since the zones draw from the storage tank and also return the cold water to the storage tank and not the boiler.

 

[maple1]

Storage usually increases the risk of condensation, as the coldest water in the entire system is usually located at the bottom of storage, which is where the boiler typically draws from. And there can be a lot of it at times.

 

[AndrewChurchill]

My system is set up using injection so the return water goes into the bottom of the storage tank and when the tank needs to be heated up the boiler comes on and injects hot water into the storage loop so cold water from the tank doesn't come into the boiler and with the low temperature switch set at 160 the temp doesn't drop low enough for condensation to form.

 

[heaterman]

Exactly Maple. The risk is not shocking the boiler but rather that it runs below dew point of the flue gas for such an extended period of time that it rots out due to condensation. This can happen very quickly, just a season or two unless precautions are in place to keep the return temp from storage above condensation temp of the flue gas.
Not saying that the installation is done wrong or trying to point fingers at anyone Andrew.....just saying that protection against long periods of low temp water entering the boiler is very important.

 

[AndrewChurchill]

It may be an issue with someone who doesn't know what they're doing but that's not the case here.