Best Of
Re: Air to Water Heat Pumps
it is always about the application. Starting from scratch on a new build is a nice option. Or retrofitting low temperature emitters
Pairing to the millions of fin tube, cast rads or dry, mid temperature radiant in the US will take more attention.
I always thought radiant surfaces provided the lowest SWT requirements? Massive amounts of surface area in floors, walls and ceilings. Radiant slabs can work with 95 SWT, what other type of emitters are an option. Jaga forced convectors possibly?
Does a 60C dhw function drive down the SCOP number? It seems that temperature is mandated by legionella codes, across the pond?
Panel rads tend to get large and $$ when you are looking at sub 120 SWT. If the home needs to be retrofit with radiators to get the high SCOP, the system may be cost prohibitive. Are there any cost examples with the systems Heat Geeks promote?
Leaning on our European colleagues we are already exploring options, crunching numbers for systems that exist in the US of A
I’m all for the A2WHP movement, with caution about over promising, under delivering on performance, cost and ROI.
If it is a system just for the 1%ers, do they even care?
Good on you for taking the plunge, keep us informed
hot_rod
Re: Radiators versus convectors -- optimum use and placement
if used on the same zone. This is because cast-iron holds its heat whereas fin-tube or steel panels cool down instantly when the circulator stops.
My first choice here would be cast-iron baseboard. It will behave the same as the old radiators. If you must use something else, give it its own zone.
Whatever you use, size it according to the same water temperature the radiators use now. This was usually 180 degrees on the coldest day of the year when these old houses were built, and may be as low as 150 now if the house has had insulation, storm windows or other such improvements added.
Optimum placement is still on outside walls under windows, since this is the coldest part of the room.
To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
Re: Boiler Zone 2 won't ignite boiler
Kudos to HVACNUT! He does it again!
Now, why does it only happen when a second zone calls for heat?
Is there something weird going on with the Taco end switch?
Is something in the flue damper circuitry preventing enough power to close the boiler relays?
Re: Boiler Zone 2 won't ignite boiler
Hello Dean60068,
So when the system had the RA832As the behavior was exactly the same as it is now with the Taco SR502 switching relay ?
Can you take off the cover of the SR502 and take a picture of everything inside ?
What thermostats do you have ?
The zone 2 LED does come on with a zone 2 call ? I don't see it on in the picture.
Red arrows, Priority off and jumper installed ?
109A_5
Re: Boiler Zone 2 won't ignite boiler
" Yes, it is acting the same way it did when I had the RA832As . "
This makes it very puzzling that so much was replaced and yet a strange problem persists. By the symptoms it seems like it was a relay issue or now a SR502 issue. With the Isolated End switch controlling the boiler the boiler should not be sensitive to which zone is calling.
I guess if I were there I would verify all the power supply voltages when it acts up, 120 VAC and the 24 VAC in the SR502 and the boiler.
I also would verify the voltage across the thermostat zone terminals, that they (both zones) go close to zero volts and the voltage across the Isolated End switch terminals also goes to zero with either zone calling.
When either or both zones calling the Isolated End switch terminals should have 0 voltage across them, and 24 VAC with no call. The voltage across the non active Isolated End switch terminals comes from the boiler (or an aquastat).
I would also use jumper wires as a test instead of the thermostats.
With zone 1 off and zone 2 calling (if the boiler does not start) I would jumper the Isolated End switch terminals and see if the boiler starts.
109A_5
Re: (Updated with pictures.) Likely gas leak after installing new thermocouple?
according to the first photo attached at the beginning of the thread. There looks like plenty of slack on the tubing to reshape it under the pilot assembly to soften that bend. Here’s a nice video clip I found that shows what many are explaining about the loose nut under the pilot light. If you’re not comfortable maybe a neighbor can help with the video assist.
PeteA
Re: Underperforming system in cold temps
Just looking at the control module, multiple knobs, this boiler probably has ODR outdoor reset function. Is that being used, a sensor mounted outside on a north wall, for example? That would explain the varying SWT temperature
That control display screen or info screen should tell you boiler supply, boiler return, and maybe boiler target, the temperature it is trying to get to? The operation manual would tell you how to access that info. Those would be the most accurate measurements as they are usually probes into the fluid stream, not strap on.
In my mind if the 3 way valve has 110 or whatever in the H port, the mix port, or AB port should be able to see 110. There should be no blending if the valve closes off the cold, or B port?
If the thermostat satisfies before the boiler reaches the setpoint temperature, you may not see the target temperature being reached. The load is satisfied, the boiler should ramp down.
At days end, are you warm and comfortable now and at the coldest days? If so you may not need to screw with it?
hot_rod
Re: Circulator wiring with Taco SR504 switching relay
Just an update. Using the ZR terminal did the job. So much better than before. I believe I will save a lot on wood this way. Again thanks for everyone's support.
Re: Simple Steam Heat Thermostat Recommendations
I too have single pipe steam system and was able to get a mercury Honeywell T87 just before mercury was banned years ago. It has performed flawlessly for a few decades - set it and forget it for the most part. Its possible these thermostats can still be had on Ebay etc.
All the Best,
RTW
RTW