condensing boiler on large pipe system

billygoat22

Thanks guys,
I was concerned about the required flow rate for the boiler vs what would work through the system.

A flow of hot water putting along slowly from the boiler could cause serious balancing issues.
Already recommened odr, try to get everyone to put one on when I work on a (hot water) boiler.

billygoat22

Was told by salesman today a customer wants price for condensing boiler to replace old coal boiler.

Old beast is about 6' long or so with oil burner conversion. Used 2000 or so gallons last year.

The old pipes are 2 or 3" and have 23 rads on the system. I know new boiler wouldn't like a blast of cold water hitting them from such a volumous system, but will the new boiler?
I'm thinking of perhaps a primary secondary setup. It doesn't make sense to run 2 or 3" down to the size of boiler connection and back up again. I'm afraid that you'd have an imbalance in the system if the water moved too slow directly through the boiler.
Would circulating a larger volume of water through the system and injecting the boiler's output into thast flow be an advantage?
Haven't done any condensing boilers yet so wary of any pitfalls.

Norm Harvey

Yeah Id do the primary secondary that you suggested with ODR, and constant circulation of the large volume loop.

Robert O'Brien

Condensing

boilers love cold return water!Most condensers need P/S to assure flow rate through the boiler or even better a LLH. But don't worry about cold return water,that's the goal!

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Tom Kane

old to new.............

don't know if you are using gas or oil. if it is gas and you have a large volume system may i suggest a a popular mod con for your area, (service and parts after the fact.....i am particular to buderus) the a low loss header such as Sinus, because of your imbalances between the 2 sides, then an ecm system pump such as the wilo stratos eco and non-electric thermostatic radiator valves such as Danfoss to zone your system. This will give you high efficiency on the fuel burning side, outdoor reset(standard with the Buderus GB), high efficiency on the delivery side with the wilo stratos eco and you can easily run zones as you see fit with the danfoss non- electrics. The Sinus low loss header will balance you boiler side vs. your system side as far as water flow is concerned. Lot to think about, ther are a lot of smart contractors on this site to help.........good luck! If it is oil, let me know, ther is another alternative available to you

billygoat22

Its going to be on propane, which already eliminates some of the manufacturers we can get. Some don't make propane, only nat gas burning. Been looking at some of my hydronic books for loop setups,too.

I mentioned thermostatics, but it seems they're trying to keep the price down on the install. They wanted a/c, but the house won't allow the install of duct (that they'd accept) or the price of minisplits.

After they see the price for an upgraded system might think different, but compared to 2000 gal/yr oil use now?

Kal Row

Lochinvar Knights comes with the propane orifice…

right in the box - and you can do multiple of them in a mini network also right out the box – a multiple boiler setup seems like the best fit for you application - do use a Caleffi Hydro Separator as with such a large volume of water you are going to have to get lots of air and dirt out – also with two boilers you effectively get a 10 to 1 turndown as each boiler gives you 5 to 1 and continually matching the fire to the load is the key saving, plus you will have plenty of extra when you need it of for making domestic hot water via an indirect – for which I recommend triangle tube’s plus line of indirect tanks – and if you have two boilers you don’t have all you eggs in one basket if one fails

billygoat22

Locknivar is one of our options.

Another call for estimate came in today- guy wants radiant heat put in an old house-off an outdoor wood boiler

What's the third one to be I wonder?

billygoat22

Locknivar is one of our options.

Another call for estimate came in today- guy wants radiant heat put in an old house-off an outdoor wood boiler

What's the third one to be I wonder?