Best Of
Re: 2 thermostats on one input on a TACO SR504??
You will need two of these: https://www.supplyhouse.com/Taco-SR501-4-1-Zone-Switching-RelayThe relay you mentioned has only one set of contacts to operate the fan on the Unit Heater. there are no extra contacts that will operate the TACO SR504 zone
The TACO SR 501 has the needed 24 VAC R, W and C terminals you need and it has the necessary contacts to turn on the 120 VAC fan motor and to operate the 24 VAC Taco SR 504
Re: steam boiler
The second feature is that there is a built-in backup system if one of the boilers has a failure. I could keep the place protected from a freeze up by switching the operating boiler to be the lead boiler until I had time to repair the boiler that was down.
There are some less expensive control systems now available that can automatically do the auto lead-lag boiler switching and also have automatic second boiler operation based on demand as opposed to just an arbitrary outdoor temperature. But at the time those controls were more expensive with more features than I required for the job of this particular church. So with these new controls systems are another reason to choose two smaller boilers over one large boiler.
Steam boilers, maybe not so much. But the choice to offer two steamers to this particular church was easy because there were three zone valves on the old boiler. Two 4” valves feed the large Church wing and the large auditorium wing. A third 2” valve feeds a smaller Chapel. Finally, there was the bathrooms and two business offices that were on one of the large zones, so when the Pastor or the Secretarywas there working during the week, the large auditorium zone needed to be heated in order to heat those two offices.
The 2 boiler system would work out great because I could size one of the boilers for the largest zone EDR, the other boiler could handle the balance of the system if all 4 (yea, I added a loop of base board for the offices) Zones were calling for heat at once. This was the church that selected the one commercial boiler job, so I never needed to design a control system for 2 boilers. I did however install the optional water baseboard loop to heat the offices and bathrooms. This was a big savings, because they were able to set back the temperature on the three large steam zones. The baseboard heat was piped off of a tankless coil on the steamer. That worked great with a L4006A limit control set at 170°F in the coil aquastat tapping.
Re: Weil Mclean EG/PEG 504 Steam Boiler not working
I can see the water level in the gauge glass looks about 7/8 full. The circulator pump is for a hot water heating zone or an indirect water heater.
Re: How Do I Connect This Wire?
HydroStat recovery software will increase temperature every 30 minutes
Some think that is too long for their needs
This is the one that started the idea for this discussion, HydroStat has several controls that have optional outdoor reset. This works great when maintaining a given set point temperature. If, However, you wish to lower the temperature at night for sleeping in a lower temperature room, the recovery time in the morning can be over 2 hours with the pre-programed boiler temperature boost after 30 minutes. @TerrS wanted that timing to be faster, so this is the two stage thermostat idea I offered"
Here is the latest diagram based on the 4200a control:
1. The concept is to fool the HydroStat control to get a higher boiler temperature during setback recovery. (at 6:00AM and 3:00PM)
2. The HydroStat will provide a higher boiler temperature if there is a call for DHW. (so we will use that feature at 6:00AM and 3:00PM)
3. The thermostat you have has the capability for 2 stage heat operation.
4. Your thermostat will automatically select stage 2 operation whenever the set-point (the desired temperature) is more than 1° higher than the room temperature.
5. This happens whenever there is a change from set back to normal set point (desired temperature). For example changing from 64° to 68° is more than 1° higher
6. By operating a RIB relay with stage 2 from one of the thermostats, the relay contacts can tell the boiler to make DHW with higher temperature water. (but we will operate the CH circulator pump)
7. Once the room temperature reaches 67° (or the DHW demand reaches 45 minutes) the stage 2 relay will drop out and the boiler will automatically revert to ODR mode.
8. You must program your 4200a to accept the stage 2 as DHW demand for this to work. (it should come that way from the factory)
9. You must connect the DHW/Zone 2 circulator wire to your existing circulator with a jumper or wire nut at the 4200a control (see triangle note 5)
Re: Help diagnose radiator noise
Re: Should low limit aquastat switch trigger circulation pump?
C1 should not be powered just because the boiler is making the low limit differential if there's no heat demand.
Is it possible the circulator isn't running while making differential, but the check valve in the circulator is bad.
Easy enough to replace if it's in the flange. Can't see the volute in the pics but if it's old enough, it could be in the volute.
Is there any flow check on the supply side. Post some pics from 10 feet away if possible. Floor to ceiling.
Even if it is a faulty check valve, there are better aquastats out there that offer cold start and condensate protection.
HVACNUT
How Do I Connect This Wire?
I have made several wiring diagrams in the recent past in order to help others solve a problem they encounter. Some are simple, others are more complex. Digital electronics and technology are built into just about everything from our cars, to our front door locks and cameras, to the thermostats that we use to keep us comfortable. I think that stuff is great, but I would not know the first thing about a chip or a diode or a triac or transistor or any other pieces of these electronic wonders, gets put together. I am strictly an analogue relay and switch kind of guy. So when it comes to HVAC controls and how to make them work, I break it down to the simplest common denominator. What gets turned on and what gets turned off based on what you are asking the equipment to do for you.
The NEST thermostat is one of those marvelous pieces of technology that has no contacts, switches or relays inside it, but somehow it opens and closes circuits on analogue type HVAC equipment just like a conventional set of contacts on the older thermostats, in order to turn a gas valve on and off, or a compressor contactor to energize and close a set of contacts or to de-energize when we get to the proper comfort level.
A fellow wallie
@MikeAmann, gave me this great idea to post a discussion with some of my wiring diagrams after one of my ideas helped solve an issue for him. So here it is,
As I post different solutions to common problems and maybe some rare occurrences too, I will copy and paste them here. And I am going to start with one of
@pecmsg's favorite subjects, the one that seem to come up more often over and over The Dreaded C wire for the NEST thermostat and other smart thermostats.
Re: How Do I Connect This Wire?
When the Nest first was introduced (Before google acquired NEST) I found that there were some problems on some devices. The first one was a Taco Zone Valve 570 series. Without going into details this is how I fixed it.
Before Nest Thermostat
After Nest Thermostat showed E72 error
I added this isolation relay with a separate transformer. (Green) See how the contacts on the relay do the job of the old T87F thermostat contacts. It is the simplest fix for all kinds of incompatibility issues with any smart thermostat.
Here is a comment made by a Taco Tech Support guy years later. It seems that they fixed the Nest or upgraded the software over the internet.
Re: Radiant Purge Viega Manifold
Until the actuator is powered up.
When the pin is up, that valve is open. Depress the pin to close off that valve.
Or leave the actuators on and power them up, to open them, one at a time.
I generally do all the purging before I install actuators.
hot_rod
Re: oil furnace sooting extensively
When i say dripping i meant i saw a drop on nozzle semi dried there and once i removed nozzle i couldn't see thru it.You can't see thru a nozzle. There are some finely machined parts inside that nozzle and they will block the orifice from letting light thru the cindered filter. If however you went to the trouble of disassembling the nozzle to look thru the orifice, then throw those nozzle parts away. You will never get it back together with the proper torque and cleanliness needed for proper flow and pattern.
Here is a look at the inside of the nozzle:
