Bypass with circulators on supply?

Timco

This setup works VERY well...

Tim

Jnash

Bypass with circulators on supply?

We have installed some larger boilers with Thermostatic mixing valve as a bypass , however they seem to restrict return flow. Has anyone piped a bypass not using a thermostatic valve on a system with circulators on the supply side. Where is takeoff on supply After circ. or after expansion tank , or from 1 zone. Any opinions welcome thanks

Timco

When installed in P/S setup, I have never had a problem with a properly sized TV as boiler protection. You can do a system bypass, but it mixes supply water to the return at all times...not really boiler protection.

Tim

Radman

What happens....

when the thermostatic mixing valve closes? I always pipe a bypass into every system, and set it during commissioning. Usually downstream of the circ, pumping away from the ex tank and towards the bypass. Some of our systems incorporate the bypass directly into the dist. manifold. This is on our smaller systems. I'm not familiar with using a thermostatic mixing valve for a bypass. Seems you'd need to pull through the valve with your system pump, so if it closes down you lose the bypass?

Radman

What is that valve?

What brand/type of valve is that on your primary? Is is a thermostatic or just a paddle? I see the primary pump pulling though the valve, but where is it set? I think I misunderstood your question, I thought you were looking for pressure bypass.

Radman

Ah!

I see, bypass for low mass boiler protection. Is that a thermostatic valve or a simple 3 way paddle? Sorry, thought we were talking pressure bypass.

Timco

Danfoss TV. EBBS I think they call it.