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Re: Trying to understand wiring for heating system
Looks like you have a multimeter, good. It looks like there is 4 voltages in use with your system.
3 VDC the thermostat batteries.
The pilot generated millivolt system nominally about 0.750 Volts DC no load. Will be less under load of the gas valve.
120 VAC, for the Circulator Pump and the primary side of the transformers used to produce the 24 VAC.
24 VAC, thermostat control wiring and Zone Valves and parts of the R8845U relay.
Basically when the thermostat(s) call for heat (contacts close) it should provide power to the Zone Valve motor. (the 24 VAC is provided by the transformer near the Red cover plate safety switch).
When the zone valve motor fully opens the zone valve the zone valve's End Switch closes.
The closed End Switch then activated the respective R8845U relay.
The R8845U relays do two things, switches the circulator pump on and switches on the Gas Valve powered by the millivolt Powepile. They should be wired so either thermostat call for heat energizes the circulator and the boiler's burner (the Gas Valve).
When the thermostat is satisfied and opens its switch everything releases.
BTW you really only needed one R8845U relay. Since the Zone Valve End Switches could be paralleled to control one R8845U relay. Either way will work. The logical 'OR' that is needed (two zones and one boiler & circulator) can happen at either of two places on the input to one R8845U relay or the output of two R845U relays.
109A_5
Re: Trying to understand wiring for heating system
The powerpile/milivolt gas valve system is its own power source — the power pile itself (sort of a takeoff on a thermocouple) generates a very small voltage proportional to its temperature — which is sufficient,, if it's warm enough — to open the gas valve. So… the powerpile is heated by the pilot flame, and when the circuit through the gas valve is closed the gas valve opens and the burner operates.
No outside transformer needed!
However. It's pretty weak. So any problems in the wiring — or the switch calling for heat — can defeat it.
Therefore… use the X1 and X2 contacts, which are intended for very low voltage and very low current (there is a reason that Taco notes they are for powerpile/millivolt use!) rahter than A and B terminals which are intended for switching literally hundreds of times the voltage and current (120 volts at several amperes) of the X1 and X2. but which may have much too much resistance to switch the millivolt power.
Re: pls help me id "epoxy" substance
Hi, Can I hazard a guess that this is a drain line? If so, A good fix would be to cut out the cracked part and use no-hubs to replace the pipe. Some Band-aids like stretchy silicon rubber tape can last a very long time, but are still considered a patch. As the cast iron loses integrity, other problems like sagging can crop up, which is a reason to go with the most durable fix. In the long run, this will save you time.
Yours, Larry
Re: Cleaning HVAC Ductwork?
Unless they run a camera thru the entire ductwork, live, to prove to you that it's actually ALL clean and sanitized. Which they won't, because it won't be.
Re: Cleaning HVAC Ductwork?
Your right but it wasn't always that way. With modern burners and boilers, I don't consider oil boilers dirty but they have to be set up properly.
I agree that a lot of boilers can go maybe 4-5 years without being cleaned. But they are still thing that need to be done during a proper tune up. Nozzle, filter, electrodes check combustion and oil pressure and test safety controls as a minimum. In fact the nozzle can go many years with clean oil.
Re: Adding a radiant manifold to existing single zone loop
I would purchase a Taco SR 502 (or 503) to operate the zone one and the zone 2 circulators separately using separate thermostats. Here is that diagram
Any Questions?
Re: Need help with Radiant How to go laying panels over existing floor
Thank you everyone for the input, I agree abandon redoing the floor especially having to modify the rest of the house for the new height. @PC7060 The boiler is going to have to have re-piping done regardless of which way I choose to go. Which I'm looking at going towards the Ceiling heat option.
@hot_rod Can you refer me to any training for radiant installation? for the future? any suggestions would be great, or books/ literature . Thank you for your time
Re: Help with screw nut
Be advised we can be more powerful than the metal, it may fail when you succeed.
Lance
Re: Where's the capacitor?
I can tell you since those motors first came out, I've never replaced a capacitor. Can't even remember replacing a psc burner motor in the last 8 years.
What problem are you having?
Re: Cost to clean a heat exchanger?
@dandub1960 @mattmia2 @HVACNUT @EdTheHeaterMan @Alan (California Radiant) Forbes @captainco
I wanted to follow up on original post because I appreciate everyone's help and wanted to thank you. I had the original installer of the boiler come out and ran another combustion test (results in image). Tech took the sample from under the draft hood. We also discovered a little nozzle looking piece on the ground next to boiler. I believe he said it was an orifice that goes over the pilot burner, and without that orifice on there the pilot would be burning unrestrained and could give some crazy numbers in a combustion test. So basically the tech who took the original test sampled from wrong location and did not reassemble all the parts!
![IMG_4981[1].JPG](https://us.v-cdn.net/5021738/uploads/9VAXSHCMQS8F/img-4981-5b1-5d-jpg.jpg)
Evan0307