Piping question

icy78

Can someone explain to me what this way of piping is called. (No dedicated boiler pumps.) Does it simply work by a lower suction pressure closest to the pump thus pulling water thru the boiler? Is there an orifice between the boiler/ return inlet and outlet? Both boilers have triple duty valves, and 1 cycles o.k. I'm going to change the '0' ring on one valve and then balance them. (There is no 'feel' of flow when closing the supply side butterfly valve on either boiler.) My drawing skills are pathetic sorry.

Paul S_3

What type of boilers? Do they have pumps inside the boilers?....lts a primary secondary setup with closely spaced tees....boilers should have pumps.... where are these valves? Located at the system connections? Then i can understand no boiler pump

EBEBRATT-Ed

What is in the main pipe between the two tees where you have the drawing marked "orfice"? Is it some sort of balancing valves?

Unless the "orfice" is throttled you will get no flow through the Boiler(s).

The way to set this up is to install a flow meter on the triple duty valves you have on the boilers.

based on each boilers btu output you want 1gpm of flow for every 10,000 btu/hour of boiler output. Example a boiler with an output of 200,000 btu/hour output requires 200,000/10,000=20gpm.

This is for a normal boiler TD od 20 degrees. Depending on the type of boiler you have your TD design may be higher.



You want to start with the orfice valve and the triple duty valves wide open. Close the orfice valve until the flow through both triple duty valves added togeather = the btu output of both boilers added togeather.

once this is done adjust the triple duty valves to balance the flow between the boilers. You may have to go back and tweak the orfice valve and the triple dutys a couple of times to get it right

Ironman

I think he was asking IF there was an orifice between the Tees.

As Paul said, it's p/s piping which provides hydraulic separation between the boiler loop(s) and the system loops so that each can maintain its own flow rate. There has to be a pump in each boiler for it to work.




Get this book from the store on this site:

icy78

Laars boilers. 1.5mbtu I think. I saw no pumps except building loop pump. I was just walking thru as I will be working on them at time's. I saw the leaking triple duty stem so ordered parts. Looked at piping while there. All fiberglass insulated so I am asking if there may be an orifice where I indicated.

I will balance them as recommmended

Paul S_3

I may be wrong but i think those 1.5 million btu Laars boiler have tbere own pump....it has a cover hiding the pump....do you have the Laars model #?mighty therm 2?

icy78

I didnt even think of that cause the inlet and outlet connections are exposed......or maybe I'm thinking of Lockinvar? Also that there was no noticeable flow. I just remembered I threw the submittal book on my van. O.K. So it's called the Pennant and I see on the OTHER end is shown a pump. However the wiring schematic shows it as optional and primary/secondary pumping is listed as recommended but not mandatory. So I guess I'll learn more when my parts arrive and I can go back and look seriously☺.