Basics of System Bypass

Jeff W

Basic question on system bypass--When piping a FHW boiler (CI rads) with pumping away setup (2 zones w/ circulators) should I take the bypass line off before the shut-off valve from the feed or right after it? Thanks...

Unknown

Bypasses

PJ,
What you are referring to is in actuality a "Boiler Bypass" because you are trying to bypass the boiler with the system return water. This will account for proper system flow while reducing the flow through the boiler. Depending on where your pump(s) is, there are two piping methods as shown below. A System Bypass takes heated boiler water and diverts it back to the boiler return to keep the boiler warmer while reducing the flow to the system somewhat. We would most always call for a boiler bypass. Hope this helps!

Unknown

Bypasses

PJ,

What you really are referring to is a boiler bypass and not a system bypass. A boiler bypass is used to take a quantity of cooler boiler return water and divert it back to the system supply instead of through the boiler. Thus bypassing the boiler and devoting all of the system supply flow through the system where it should be. This will reduce the flow of cooler water through the boiler and will allow it to stay warmer.

A system bypass takes heated boiler supply water and sends a portion of it across the bypass to the boiler return to help keep the boiler warmer. A considerable reduction of flow may result through the system this way though. We would most always recommend using a boiler bypass as per the drawings below. Pump(s) location will change the way you pipe the boiler bypass. Hope this helps!

Glenn Stanton

Manager of Training

Burnham Corp.

Mark J Strawcutter

system bypass more appropriate

Since he has cast iron radiators (gravity conversion?) might not a system bypass be more appropriate?

Mark

j_4

no bypass required with a Revolution, right?

some boilers, like the burnham revolution, have their own boiler circ pump and it acts like a built-in bypass

Unknown

Test

of Archive

Unknown

Radiators

do not neccessarily have to always be on a gravity conversion system. There are many radiator jobs installed with Venturi system layouts. If in fact his radiators are installed on a gravity conversion system with big old pipes, then a system bypass like the one below would be appropriate, otherwise stay with the boiler bypass. Hope this helps.

Glenn

Unknown

The Revolution

does not require a bypass because one is already incorporated into the boiler. This bypass in conjunction with a variable speed pump performing reverse injection keeps the boiler safe with return water as low as 55°F. Hope this helps.

Glenn