Taco SR502 installed nest all was good 2 days. now no power to RH message on nest , no power to common on all the other thermostats. and no power to common and 24v on sr502 board.
The Taco sr502 has no lights on at all .
fuse is good what can I do next?
Last edited by PJmax; 01-29-23 at 01:40 PM.
Reason: reoriented/enlarged pic
Heating systems status diagnostics the easy cheap way
On heating systems pilot lights (120 or 24 volt) on zone valves, pumps, aquastat, transformers, etc..
make it easy to see status and quickly trouble shoot problems, especially on multi zone systems,
When wife says no heat in some room. Can see whether that thermostat is calling for heat, zone valve open, circulator running, boiler aquastat calling for heat, burner on, etc. etc. Sometimes reason for no heat was someone forgot to turn up thermostat. Duh, Duh.
OP said none of the status lights in the SR502 are on so some status indication is provided. Green light ON means SR502 has 120 vac. I would be leery of the lights suggested in post 3. They are not UL approved and have a metal body. If the hot 120/240 vac wire makes contact with the metal body, the metal body and anything it touches becomes a shock source unless grounded or a protection device opens circuit.
Link in DH Post #3 showed many types of pilot lights, But not how to use them.
Comment in Post #4 about UL not approved does not apply to home owner system changes.
UL is used by manufactures of products. “Underwriters Laboratories UL Solutions delivers testing, inspection and certification services, together with software products and advisory offerings, that support our customers' product innovation and business growth.
National Electrical Code (NEC) is for building wiring, electrical service, not things connected to it
NFPA 70, is the benchmark for safe electrical design, installation, and inspection to protect people and property from electrical hazards.
The SR-502 has LED's on it Doug,
There is no need for additional LED's if the factory ones are not working.
EV..... welcome to the forums.
I see your SR-502. I see 2) two wire thermostat cables.
I see some kind of splice at the C/24v terminals.
How can your nests possibly be showing a common problem with no C connection ?
With two wires on the SR-502 you should be connecting to R and W on the thermostats.
That would mean no C connection and a good chance the nests will not work there.
If you have 120vac present to the unit and the fuse is good..... the transformer is blown.
It's only a 15va transformer..... not much room for connection or load errors.
Readers might note words in Opening Post#1 "The Taco sr502 has no lights on at all."
DH comment: SR502 LED’s do not have power ON light. Only LEDs that light to show which zone active.
Taco would raise costs and lower profits putting On LED light on R502. But DIY’s can add their own.
Solving DIY issues is often made more difficult s by "static" words in posts who do not read, or understand issues.
See Post.#6 "WAY TOO MUCH static here. The SR-502 has LED's on it Doug, There is no need for additional LED's if the factory ones are not working."
Yes Doug... member said no lights on at all.
That would be correct if the unit is dead as it does have a green power LED.
Most of the Taco controllers have a power LED.
Getting back to business.
Do you have 120V at INPUT 120V terminals?
If yes, pull the fuses and check for continuity on fuses.
The green light looks like it could be in trouble and why it may not be lit.
Hi all,
I found this site after the following thread came up in my search:
[url=https://www.doityourself.com/forum/boilers-home-heating-steam-hot-water-systems/332856-how-troubleshoot-internal-variable-speed-pump-burnham-revolution.html]how to troubleshoot internal variable speed pump in Burnham Revolution - DoItYourself.com Community Forums[/url]
My baseboard radiators were not heating properly topping out around 110F. The boiler itself was starting and cycling on and off at the proper set temps. I zeroed in on the circulator pump which I discovered was not operating and mixing with the heating loop. I followed the advice on the above thread and come to the conclusion that my thermistor was loose, but operational. It had a broken clamp but it was still touching the output tube. It also measured ~970 ohms at ~190 degrees.
I disconnected the thermistor, and that did not kick on the circulator as it did for the OP. That left jumping the pump wires 1 and 3 on the VS3000 mixing board, which did the trick. The circulator lit right up and my radiators came right up to temp.
So here I am with a system that is operating normally but the circulator is jumped to full speed. I don;t see how that can present an unsafe condition, but what other troubleshooting can I do before I replace the VS3000?
Thanks in advance.
This boiler has been nothing but trouble since it was installed in 2014 and I moved into the house in 2015.
I’ve had to replace the heat exchanger 2 months after the warranty expired. The pressure/temp gauge leaked and fried the control panel cleverly located under the $5 gauge.
Now the “Water Supply Piping Assembly” has rusted out where it looks like they have dissimilar metals contacting each other causing electrolysis to corrode.
I’ll attach photos.
Can I replace the piping but re-use the fittings and sensors? Or should I replace the fittings and sensors.
Also attaching a photo of the parts diagram. The pipe that is corroded is part number 8, but I’m wondering about number 10 and 11 in the image.
Thanks!
01-28-23, 06:15 AM
Taco SR502 no lights please help
