Inter boiler pipe size does it matter

[mpilihp]

I started going over what I needed for piping to connected my wood boiler into my existing system. I intend on adding extra Ts and ball valves so I can add a boiler mate and storage, maybe the garage off of it and so on in the future.

I notice on the input to my oil boiler the pipe size is 1 1/4" while on the output side of it the pipe size is 1" Does this really matter? It would be cheaper for me to do the additional plumbing in 1 in piping and valves, id leave the 1 1/4" stuff thats on the input to the oil boiler and do everything else in 1".

Is it ok that one side is larger than the other? all the heat zones are 3/4" and each zone has a seperate pump instead of zone valves.

Thanks

~ Phil

 

[Nofossil]

The 1 1/4" plumbing produces a slower fluid velocity and allows more opportunity for bubbles to float to the top for easy venting. It also ensures that there's no significant pressure drop between zone tees. I suspect that you could get by with 1" and be fine, unless you have a very large system and a very high flow rate.

As far as I know, those are the only considerations. I hope some of the plumbing folks jump in and comment.

 

[Bob Rohr]

It depends on how much energy, or flow you are trying to move. Some general rules of thumb

3/4" 4 gpm or 40,000 BTU/hr
1" 8 gpm or 80,000
1-1/4" 14 gpm or 140,000
1-1/2" 22 gpm or 220,000
2" 45 gpm or 450,000

If you oversize too much, velocity drops and it gets harder to remove any air in the system. Too small, velocity increases and you may have noise, inadequate heat, and possibly wear fittings and pipe from erosion. Like a stream bed.

When they build boilers they typically put in enough port size to move the energy that device can generate. It is possible to use an increaser to get all the piping the same size.

Many of the Euro boiler brand gasification boilers I have installed came with huge 2" connections. Possibly for gravity flow systems, or cut down on nipple inventory at the factory

hr

 

[mpilihp]

Thanks guys, My oil boiler is rated for 80K and the woodboiler is rated for 70K so it sounds like 1" would be fine, Id compare the cost of all the widgets I need and see what the diff is.

THanks

 

[pybyr]

a question for HR relating to the rules of thumb-- let's say I want to use Wirsbo hepex between boiler and storage, and I already have the expander tool with expander heads up to and including 1", and additional expander heads in bigger sizes are pricey as heck. Would it be a bad idea to use a parallel pair of equal length 1" PEX lines between boiler and storage- instead of a single line of 1 and 1/4 or 1 and 1/2 (this will be with an Econoburn 150- 150kbtu)

 

[Bob Rohr]

keep in mind pex id is smaller then the id of copper tube. It doesn't flow as much, and the pex manufacturers have flow and pressure drop charts.

I have heard of folks using multiple runs of 1" and just manifold them together. This is basically what you do with a radiant floor heat system to move a large load through multiple small diameter tubes, when you think about it. Keep them exactly the same length.

I always throw a few extra lines in the trench, for other jobs like fishing control wires or running water out to the boiler location. Or a H&C;to generate DHW at the boiler location.

I put 5 tubes in my trench. S&R;for the boiler, one for 24V wiring condiut. The other two I used after I installed a solar panel on the boiler building. It was nice to have options for the small cost of pex tube. the spared for water or condiut don't need to bee barrier pex, really.

I wish I had another one or two for a rainwater collection system I will be installing.

hr

 

[chuck172]

My TarmSolo40 is piped parallell to my oil boiler. 40' apart. I used all 1 1/4 copper. When I add 500 gallon pressurized storage should I stay with 1 1/4" or can I drop down to 1"?