question about international code regarding recirculation lines

[kevlon]

in the 2003 Michigan boca code, section 607.2.3 states where a thermostatic mixing valve is used in a system with a hot water recirculatiing pump, the hot or tempered water return line shall be routed to the cold water inlet pipe of the water heater and the cold water inlet pipe or the hot water return connection of the thermostatic mixing valve.

What I am asking is,

1. is a pressure balanced shower valve considered a thermostatic mixing valve, requiring the recirc line to be connected to the hot water inlet for the shower instead of a hot water lav line or the furthest downstream hot connection?

2.can you no longer connect the recirc line down where the hot water heater drain is connected? because that is how i've seen it done in past applications.

3.If you have two bathrooms on opposite sides of a house, can you run two separate recirc return lines that join together at the water heater and then are operated by one recirculation pump?

Any and all information is most appreciated, with Thanks in Advance.

Kevin

[kevlon]

Well I looked it up myself and found out a thermostatic mixing valve and a pressure balanced are two different type of approaches to solving the same problem, so that one is answered. As far as the other questions go I am disapointed that they did not generate more interest and discussion. Even if someone thought they were stupid questions I figured someone would call me on it. I've been a long time lurker and occasional poster for quite some time now and I almost miss the days of HOTH204U2, aweisinheimer and others going straight for the jugular whenever they smelled weakness. It would still be helpfull if anyone can tell me if the hot water return for the recirculation line is still acceptable to be connected at the bottom of the HWH at the tank drain outlet, as long as the drain is still present.

[Ned Flanders]

I have done that. Wind the boiler drain out and replace with nipple and tee. You can run your recirc lines wherever you like. They all meet back at a manifold near water tank with balance valves (at least that's how mine is). As far as putting a thermostatic mixing valve in line goes, if the recirc came back into the hot feed then you could get over heated water in your lines. (IE: when you keep storage tanks at 140 and use the mixer to drop it to 120). You want water to be able to circulate without passing through the tanks when it gets hot enough. Like a bypass.

no and no.

I have not seen code but sounds like a no. You could do it if the storage tank was kept at a safe temp. They say "with a mixing valve" because it means you most likely have very hot water. You could only protect your recirc line from veryheating with an aquastat or something (not feasable).

yes.

Sorry for not answering sooner.

[kevlon]

Hey, thanks for the helpfull info, Mr Flanders, The homeowner is going to use a regular pressure balanced shower valve. in that bathroom the shower is last in line in the fixures so I ran the recirc line to just before the hot inlet on the valve to complete the loop.