By-Pass Valve?

ChrisinMD

I believe I need to install by-pass piping in my Burnham oil-fire boiler, and the install manual lists a by-pass valve in the piping scheme. My local pumbing supply house employs a phalynx of heat-pump gurus who look at me like I have 3 heads when confronted with hydronic questions. They told me I need to order the valve from Burnham. I doubt that. I was wondering what exactly is a bypass valve(ie., gate, ball,etc.)

The system works well, but that cold water coming back into the boiler worries me enough to fix it.

Thanks for any responses.
Chris

DanHolohan

I'd recommend

an ESBE thermic mixing valve. It's simple and automatic.

http://www.danfoss.ca/catalog/heating/esbe/tv.htm

Mike T., Swampeast MO

All kinds of bypass valves.

The simplest is a manual throttling valve installed in a "bridge" pipe between supply and return. Such is commonly used in gravity conversion systems to help the boiler come up to temp more rapidly. Sometimes the throttling valve is omitted. Crude, but reasonably effective in some situations.

Thermostatic bypass valves are three-way valves designed to automatically introduce bypass based on temperature. Danfoss ESBE type TV is one example. It is a FIXED temperature bypass valve available in temperature ranges suitable for either supply or return mounting. Because they are fixed they would not be appropriate if the boiler itself is reset. The ESBE type TV is intended for systems operating at 170° or higher supply temperature.

There are also differential pressure bypass valves. These aren't intended to regulate temperature, but amount of bypass. They are installed in constantly circulating systems with proportional flow devices on the system to ensure that water continues to flow around the boiler when all of these devices are closed. Danfoss and Honeywell (possibly still under the Braukman name) are two companies I know who make them.

ChrisinMD

bridge pipe

bridge pipe is depicted in the install manual, and I have now discovered the valve is either a globe or plug type valve. I'm not sure why a mixing valve is not called for because with the bridge pipe and valve the water temp will still be fluctuating quite a bit.

The boiler is a Burnham v-8 cold start but there is no outdoor reset. There is 2 zones plus an indirect DHW loop. I have since found a piping scheme from Burnham's website that seems to fit the bill. A bridge pipe with a by-pass balancing valve that is outside the DHW loop. Not as fancy, but looks like a good foolproof way to go.

Thanks
Chris