Aquastat wiring question redux

OK, it's time to take some action, well, more action.

Trooper suggested and I want to incorporate the 504 and the Ranco. Could you give me more specifics on how to wire the Ranco? What about one of those strap on Honeywells'?

Whichever, I'm putty in your hands.

I put in a pair of those Azels and am still working on the HX issue. BTW, in case anyone couldn't tell, I move at glacial speed.

Original post http://www.doityourself.com/forum/bo...ml#post1932173

Thanks much

 

Hi Gary!

I just took the time to read through that epic post... I thought of merging this one into that one, but decided against it for now since it was so long. If we can keep this one on track and just talk about the wiring of the 504 and the Ranco, it shouldn't be that long.

Before we get to that though, and this might tend to 'drift' the topic a bit, near the end of the epic you had swapped the 36 and the 14 pumps and that seemed to 'fix' the HX issue so I'm surprised to hear you say you are still working on "...the HX issue."

One on supply and return on each side of the HX I guess? (for readers that didn't go back to the old thread, Azel DS-60P Digital Temperature Gauge, Digital Temperature Gauge Radiant )

You don't want to know how many years it took me to replace my old boiler... you are in Kindred Company here! And BTW, I used one of those Ranco controllers in a fuel oil preheater I built for the new system.

The 504 is straight forward. There are thermostat inputs across the top, pump connections across the bottom. Pull all the 89s, and wire all four thermostats to the 504 (moving the one that is currently wired to the T T in the 8182). Wire all four pumps to the 504 (moving the one that is currently on the 8182 C1 and C2 terminals). Wire a source of 120VAC to the 504 power input.

C1 and C2 on the 8182 will remain unused.

The ENDSWITCH on the 504 will be wired to the T T with your choice of either the Ranco or a strap on Honeywell wired in series.


image courtesy pexsupply.com

ETC-111000-000 - Ranco ETC-111000-000 - Single Stage ETC Temperature Control w/ Sensor, 120/240V Input (Includes 8' Cord)

You certainly could use a strap on if you wish. I personally like the convenience of a digital setpoint and display but electromechanical is just as functional.

You would need to use the contacts on the Honeywell that BREAK on temperature RISE. On the Ranco you have choice of Normally Open, and Normally Closed, and also a switch to choose Heating or Cooling mode (basically selects break or make on rise, and 'direction' of the differential). See install manual for more info on this.

http://s3.pexsupply.com/product_file...structions.pdf

This switch would be wired in series with the wires to the T T on the 8182 control on the burner.

 

Sorry for the delayed response, things have been a little crazy around here.

Thanks much for the wiring instruct, seems simple enough....famous last words.

As for the HX, I'm still not certain that this system has the correctly matched components for; the volume of water that can be pumped from the WFB (I've figured it several different ways and have a consistent 7-7.5 gpm max), the existing HX, the pump on the house side, and the square footage of the house.

Here are some operational temperatures for water entering and leaving the HX. Two of four zones calling for heat, water temperatures having reached steady-state after the initial call for heat.

At -5 F (outside): House side, in = 135, out = 150; WFB side, in = 167, out = 158 (last year's numbers)

At ~37 F: House, in = 143, out = 156; WFB, in = 172, out = 163.

When it's cold (very) outside, the house side "in" water temp drops to ~115, then warms up. The living room/kitchen/dining room/foyer has ~100 feet of radiator on three levels. It's an open floor plan with cathedral ceilings.

I think the house side should pick up more heat, maybe. Or, do those temps look reasonable? Now, one might ask "is the house warm?" and I would have to honestly answer, "toasty." Then the next question might be "then why screw with it?" Because....I'm a rocket scientist (really) and can complicate the crap out of anything....

That was an epic post. Lots of information....a clinic.

Thanks,

G

 

That's funny! I've worked with my share of scientists... so, don't I know what you are saying is true! I could tellya some stories, but I bet you've heard them all! Heck, you may have even been IN some of them!

Just today as a matter of fact... I was consulting with a guy at one of the national research facilities who is doing plasma research. Imagine a controlled plasma stream... a METER in diameter! Yikes! All the while I was talking to him on the phone, my mind was wondering how much water we could boil with THAT!

If we were to guess at the flow rate, we could come up with BTUH being transferred.

But yeah, if house is nice and toasty, it's only theoretical banter, which I personally enjoy!

 

So, a year later I have the 504 installed. Works like a charm. Neatened things up considerably.

Now to the Ranco. Just so I understand, looking at the Ranco instructions, Figure 6, line voltage to the upper terminals and the thermostat wires through the load terminals....yes? Or alternatively, could I use the line voltage feed to the 8182 and wire it as shown in Figure 4?

We're gett'in there.

 

I'm going to call you GGG for GratefulGlacialGary!

I've totally forgotten the purpose of the Ranco controller... I guess I have to go back and read the 'novel' again.

I'll be back... someday!

 

In a nutshell....when the outside wood fired boiler (OWB) is heating the water on the house side through the heat exchanger (HX), I don't want the oil burner to fire upon a call for heat. So the Ranco would prevent the boiler from firing if the water being heated by the OWB was above some temperature I decide upon.

So maybe I use 130 F, Normally Open, and heating with a 10 F differential. So if the water dips to 120 the boiler can fire on a call for heat and will continue until the water is 130, or the thermostat is satisfied. That is, if I have interpreted the instructions correctly.

This way, if for some reason the OWB isn't heating the house side sufficiently, I'll still have heat. I have another Ranco that I intend on using with the pump on the house side that circulates the radiator water (that would also be heated by the oil burner) through the HX. Set that to stop the pump if the water from the OWB falls below, let's say, 115. That way the oil burner will not then be heating the water from the OWB. I would wire that one as in Figure 4.

My wife made some crack yesterday about glaciers melting with regard to painting this room.....two years later. Of course, she meant glacial speed but rather than correct her I mentioned, in the alternative....the end of the world....

But at least we'll have heat!

 

It think you have it almost correct...

You want the sensor for the Ranco on the supply pipe from the wood boiler. It should sense only whether or not the woody is providing the hot water.

When the temp drops below setpoint, you want to enable the oil burner, but allow it to fire to whatever it needs to fire to... not the setpoint of the Ranco.

I think I understand what you are saying about the second Ranco, but you could also use one Ranco and drive a double pole relay with it. One pole enabling/disabling the oil burner, and the other the pump through the HX.

 

And just how should I go about doing that?

I already have two Ranco's, although I'm sure I could find another use for one of them.

This could be above my pay grade...

 

Probe placement...

By putting the probe on the tubing from the wood boiler.

Naahhhh...

 

Do you mean that I would use a higher set point on the Ranco since the probe is on a tube that carries hotter water? I don't think that would work since the water from the boiler can drop to ~135 if it's really cold and I'm not Johnny-on-the-spot putting more wood in.

Otherwise, I still don't see how the oil burner can reach a temperature higher than the Ranco setpoint.

 

Never mind, I get it....Duh

My wife explained it to me. OK, that's a lie...

Thanks much, as always.

G