Munchkin 50 control issues

MikeOBrien

So I recently installed a Munchkin 50 w/ a 925 controller and when I have a call for my indirect fired tank, the supply sensor water shot up to 200* and flashed to steam.  So I discovered that my boiler pump conected to the brown and orange wires labeled central heating pump on the boiler was dead.  Traced it back to the boiler and the brown and orange wires read 0.0 on the multimeter.  So temporarily, I hot wired that circ pump to run 24/7 and the system is purring again.  I disconnected the wires into the 925 controller and found some oxidation but wasn't sure if that would cause this.  Also when the aquastat on the IFWH calls for heat, it should override the spaceheating pump and prioritize.  But that doesn't happen, both pumps, the indirect pump wired to the boiler and the zone circulator wired to the Taco ZRC both run.  The wires on the boiler are connected to the same wiring harness on the 925 controller.  I suspect a bad connection on that harness.  Any Ideas?

Mark Eatherton

Purple and Pink....

Mike, The prioritized DHW pump is supposed to be connected to the Purple and Pink wires. I didn't see you mention that.



The DHW priority is activated when the 925 sees a control signal closure between the two light blue leads (DHW sensor per instructions at http://htproducts.com/literature/lp-185.pdf page 53)



If you do not have two light blue wires, and a purple and pink wire, then you do not have a complete Vision 1 control package. The DHW priority will disable the space heat output and enable the DHW output, hence DHW priority.



Better yet, I found a copy of the original Vision 1 wiring instructions on line. THey are at http://www.scribd.com/doc/933449/Hvac-Munchkin-Vision-1-Manual-07127-Lp102



If you do not have the necessary wire colors and leads as called out in the instructions, let me know and I will look around to see if I have some laying around.



ME

Steve Whitbeck

Munchkin

Do you have three pumps ( boiler, system and indirect pumps )

The boiler and system pumps should run only with a call for heat.

The Indirect pump only runs with a call for hot water. ( the boiler pump doesn't run with a call for hot water )

MikeOBrien

Still troublshooting

Yes Tinkerer, I have a boiler loop (primary) circulator (Taco 007), An Indirect (parallel)circulator ( Grundfos Brute 3-speed)) and I have 2 space heat zones (secondary) zoning w/ circulators (Taco 007's).

The Space heat zone circulators are controlled w/ a Taco 502 ZRC, (shoulda bought the 503)

The Indirect Tank sensor goes to the Munchkin and when there is a domestic call, the 925 controller is supposed to send 110v to the pink and purple wires for the indirect circulator.  Which in turn is supposed to kill the orange and brown wires to the primary circulator, so as to concentrate all efforts to make sure your wife is in hot water!  This is not happening which makes me think something in the 925 is fouled up.

Talked to the rep here in Denver and he also pointed out that my boiler has no way of telling my ZRC that the Domestic has priority.  Which I'm kicking myself for not getting the 3 zone controller. See if I have a spaceheat call and a domestic call, all circulators are running.  So his suggestion was that I install a double pole double throw relay, which would only energize the 502 ZRC and boiler pump when there isn't  a domestic call.  Still with me? 

Done and done, got the relay installed and still no 110v at my brown and orange or at my pink and purple. 

I can run through my (d-1,2,3,4,) codes and the code for the indirect circulator is on and not for the boiler circulator.  But there isn't any power to that circ.

The only way I can get the boiler circulator code to say it is working, and it does have power is to override the fanspeed and kick it up a notch.  Could the fan speed have anything to do with it as I have it programmed?

Hope this info is clear enough, any thoughts would help.

I suspect that the wiring harness is glitching. 

Steve Whitbeck

Munchkin

Have you checked the fuse on the 925 controler?

If your boiler is piped primary /secondary with check valves then let the boiler control the indirect and boiler pump and let the zone control do the zone pumps.

If your pumps are on the supply side of the boiler or the supply side is heat trapped then you don't have to shut down the zone pumps when the indirect is calling for heat.

If you can't get power out of the 925 control and the fuse is good then I would say the control is bad.