Taco SR501 wiring help

Inthewoods

I’m looking for help wiring my Taco SR501 Switching Relay for my shop. My circumstances: Outside wood boiler with circulator#1 always on that’s controlled by boiler controls. Have in-floor pex, 1-zone, with thermostat wired to R and W. Power comes into N and H (hot) and inside floor circulator#2 wired to N (neutral/white) and 4 (hot wire). There is a jumper between H and 3. Works great, and when thermostat calls for in-floor heat – floor circulator#2 starts up, shutting down as appropriate when space is hot enough.
Recently I removed the heat exchanger (it was plugged) and plumbed direct so that boiler water now directly flows thru floor and back to boiler. As part of reconfiguration, added another inside circulator#3 to return loop to boiler. Kinda works, but would work better if I could get this new recirculation pump#3 to shut off when the thermostat triggers the floor circulator#2 to go on, and then also trigger the recirculation pump#3 to turn back on when thermostat triggers floor circulator#2 off.
I’m guessing there’s a way to do this with the Taco SR501, and this is what I need help with. Any suggestions are appreciated. Thank You!!

Big Ed_4

Go back to the start of the problem ... Replace the heat exchanger .....

Ironman

You’re gonna end up with a lot of issues if you keep that wood boiler directly connected to the floor.

hot_rod

It might be better to reinstall the HX and add some flush and purge valves to blast it clean with a garden hose occasionally

A couple valves like this to isolate the HX and flow through it. A threaded version to screw right onto the HX.

EdTheHeaterMan

You have a system that was designed and worked for some time now.
Your boiler has clogged up your heat exchanger

OR

Your floor tubing has clogged up your heat exchanger
Now you want to connect the tubing directly to the boiler with no HX
Won't that make the source of the clogging end up in the other part of the system that was not clogged?

Does not sound like a good idea to me. "Hay everybody now that we clogged up the heat exchanger and the guy removed it, now we can clog this bigger thing. CHARGE!!!!"

that is the water with all the gunk in it talking

I wonder what type of HX you are using that got clogged?
I wonder if you have oxygen barrier PEX in the floor?... NO... could be the cause of the HX clogging
I wonder if the wood stove is deteriorating and that junk is getting stuck in the HX?

Find the source of the clog!

OR

Just clog up something more expensive to replace, like a boiler or a radiant floor tubing system.

Inthewoods

Well... not exactly what I was planning, but thinking about the advice here... it's pretty clear I need to go back to the heat exchanger, and will do so. I'll keep that circulator I'd installed as a spare and reconfigure pretty much back to the original with a heat exchanger. Thanks all for your help!!!!

EdTheHeaterMan

I wonder what tubing you are using in the radiant floor system? Does it have an oxygen barrier? If you have regular PEX a or PEX b used in open plumbing systems (hot and cold potable water) and there is no O2 barrier, then you can get oxygen migration through the tubing into the water inside the closed loops. that oxygen will act on any ferrous metal in there like cast iron pumps and pipe fittings and steel heat exchangers. That is the reason I asked about the tubing. That could be the source of the gunk!

If that is the case, then you fix it by using stainless steel, copper, bronze or brass pumps valves fittings and the like on the tubing side of the heat exchanger.. the Oxygen in the water will not cause those nonferrous metals to rust away like steel and iron fittings and pipes

hot_rod

I suspect you have an open type OWF? If so are you adding rust inhibitor oxygen scavengers regularly . That sludge on the OWF side could be your OWF corroding away.

GroundUp

Put the heat exchanger back in. Add flush valves and/or a Rusco high temp spin down filter to mitigate the plugging issue