Taco Control loses power then comes back
#1
01-15-10, 11:22 PM
Taco Control loses power then comes back
I have a Weil-Mclain boiler oil/hot water with a honeywell aquastat l8148a. 5 taco zone valves 571-2 connected through taco control ZVC-406- with seperate relay and circulator for hot water. My issue is everything works perfectly- then the control (zvc-406) shuts down (green light goes out)- after about 15 minutes the control comes back and everything is good again. I bought the house 6 months ago but have noticed the control doing this since christmas eve. Which is when I also realized I didn't have heat in my basement. I diagnosed the aquastat was bad (or the C1 connection wasn't getting power to run the circulator) so my house was being heated by gravity feed. I replaced the aquastat today and everythng runs as it's suppose to (circulator is working correctly and heat in basement!). Then the control goes out.- 10-15 minutes later it comes back on. I'm assuming all zones close when this happens and the circulator will continue to run if a thermostat was calling for heat for the control went down. Again, ASSUMING this is why the aquastat went bad as circulator was pushing water into closed zones.... Any ideas why the control goes out at random times??? HELP!
#2
01-16-10, 06:56 AM
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I would check all wire conections. Undo all wire nuts, and screw conections, and check. One at a time though.
#3
01-16-10, 08:18 AM
I wonder... if that separate relay for the hot water (and I'm assuming that you mean it's an indirect water heater?) is cutting the power to the Taco panel as a way to gain 'priority' for the water heater?...
Follow the 120 VAC wiring into the Taco back to it's source, and look to see if the BLACK wire is possibly being switched by the extra relay.
If the power to the Taco IS going down, the zone valves should all close, and the heat demand signal from the Taco to the boiler should 'go away'...
Are you certain that the main boiler pump still runs when the Taco powers down?
Can you tell by looking at the water heater circ running if the Taco is powering down during a demand from the water heater?
Follow the 120 VAC wiring into the Taco back to it's source, and look to see if the BLACK wire is possibly being switched by the extra relay.
If the power to the Taco IS going down, the zone valves should all close, and the heat demand signal from the Taco to the boiler should 'go away'...
Are you certain that the main boiler pump still runs when the Taco powers down?
Can you tell by looking at the water heater circ running if the Taco is powering down during a demand from the water heater?
#4
01-16-10, 02:18 PM
I have found that the power to the control is wired into the SR501 relay at 4N/C. This causes the control to shut down on a demand for hot water which is fine but since the thermo starts wires from both boxes go into the aquastat TT both circulators run. Thoughts???
#6
01-16-10, 03:09 PM
Here are the pictures. I forgot the water heater- SuperStor Ultra with a honeywell stat but that runs off the green taco pump on the left in the pics. It does not have a zone valve.
Boiler pictures by obsmoney - Photobucket
Boiler pictures by obsmoney - Photobucket
#7
01-16-10, 03:46 PM
thermo starts wires from both boxes go into the aquastat TT both circulators run. Thoughts???
#8
01-16-10, 03:56 PM
The green circ is for the water heater from what I can see... and the return from the water heater is going back into the return manifold along with the rest of the zones, correct?
Yeah... you probably could have saved the money on the aquastat... wish we had known the full story when you first told us about the problem!
See the three screws on the terminal block in the lower left corner of the Taco panel? Those should have been used to run the space heating circulator... no... that's wrong... those are the "zone 6 relay"... the ones you would use would be the 'second endswitch' terminals.
Do you have the documentation for the 406 panel? There's a diagram in there that shows how to wire it.
Yeah... you probably could have saved the money on the aquastat... wish we had known the full story when you first told us about the problem!
See the three screws on the terminal block in the lower left corner of the Taco panel? Those should have been used to run the space heating circulator... no... that's wrong... those are the "zone 6 relay"... the ones you would use would be the 'second endswitch' terminals.
Do you have the documentation for the 406 panel? There's a diagram in there that shows how to wire it.
Last edited by NJT; 01-16-10 at 06:55 PM.
#9
01-16-10, 07:34 PM
Thanks Trooper- you are correct about the circ pump and about saving the money on the aquastat- oh well, live and learn. Just got done doing a little rewire abut I'm still using the 501 relay but jumping it over to the taco control extra end switch. I have the water heater pump on 4 n/o and conneced a lead from 4 n/c to the extra end switch on control. I wired the heat pump to the other side of the extra end switch and power to the control direct to service switch. Control stays on even when calling for hot water and pumps shut off when they are suppose to. I think I've got it done... unless you see were I might have went wrong. Let me know. Think I could probably lose the 501 relay all together couldn't I... not sure why it was wired with it. You guys rock- thanks again!!!
#10
01-16-10, 07:51 PM
Yanno, if it had been wired thusly, you would not have even needed the other relay box at all...
The indirect aquastat would wire to the Zone 6 (T T) terminals, a jumper from 3 to 4 on the zone 6 valve terminals, and the switch to 'priority'.
The indirect aquastat would wire to the Zone 6 (T T) terminals, a jumper from 3 to 4 on the zone 6 valve terminals, and the switch to 'priority'.
#12
01-16-10, 08:49 PM
Almost what I did. Only difference is I got the hot extra end switch going to the 4 n/c on the relay (which is hot) but cuts out when the indirect calls for hot water which was the goal (to get the system pump to stop working when indirect calls)- you see any problems with that?
#13
01-16-10, 09:11 PM
you see any problems with that?
