Joined on November 14, 2009
Last Post on December 4, 2013
@ February 25, 2010 3:07 PM in Temperature-based cut-in for a Vaporstat?despite all the mechanical complexity, the vaporstat is just a switch. It will handle 24V just as well as it does 120V. The only downside is that I still have to keep the pressuretrol on the line voltage burner circuit. I'm breaking a few rules by having the p-trol, v-stat, 0-30in, and low pressure gauges all on the same pigtail. Not sure what else to do as there's only one tapping. But that's a problem for a different day.
The relay came yesterday, now I just need to get the right sized electrical box and find a couple of hours to wire it up.
I did get to test the relay yesterday. My Honeywell R7184 burner control has some extra terminals for an "EnviraCOM" feature. The thermostat ties in to terminals 3 and 4 on the control. Terminals 2 and 3 provide a constant 24VAC for whatever the EnviraCOM is supposed to do. Since I don't have any EnviraCOM devices, I tested the relay on those terminals yesterday and it worked fine, so now I have my 24 V power source. Small steps.
@ February 23, 2010 3:08 PM in why do Honeywell vaporstats suck so badly?The gauge I used is only 0 - 30 inH2O (17.3 oz), and I could easily peg it.
Here's a pic of the test setup. The lung power comes in thru the black tube on the right. Here I've set the v-stat cut-out at around 7 inH2O.
Incidentally, the reason I'm using an inH2O pressure gauge instead of ounces is because this is the same gauge that I've used to check the playing pressure and adjust the reeds for bellows-blown bagpipes.
@ February 23, 2010 11:27 AM in Temperature-based cut-in for a Vaporstat?Here are two solutions and wiring digrams for adding a time delay to a vaporstat cut-in.
Thermostat Interrupt (Low Voltage)
In this setup, the vaporstat and time delay relay are used to interrupt the thermostat call-for-heat signal to the burner control. The pressuretrol remains in use along with the LWCO in the burner line voltage circuit.
In normal operation, the upper set of relay contacts is closed and the thermostat controls the call for heat as usual. When the vaporstat cuts out on pressure, R-B breaks and R-W makes, energizing the relay coil. The lower set of contacts on the relay serve as a seal-in circuit to keep the coil energized after the vaporstat cuts in, breaking R-W. While the relay is energized, the upper set of contacts breaks the thermostat circuit. After the configured time delay, the relay drops out, breaking the seal-in and de-energizing the coil, and closing the contacts to the thermostat circuit.
Burner Circuit Interrupt (Line Voltage)
In this setup, the vaporstat and relay contacts are wired in series into the line voltage burner circuit. In normal operation, the upper set of relay contacts are closed and the burner controls work as usual. When the vaporstat cuts out on pressure, R-B breaks and R-W makes, energizing the relay coil. The lower set of contacts on the relay serve as a seal-in circuit to keep the coil energized after the vaporstat cuts in, breaking R-W. While the relay is energized, the upper set of contacts breaks the burner circuit. After the configured time delay, the relay drops out, breaking the seal-in and de-energizing the coil, and closing the contacts to the burner circuit.
In both cases, there's no power draw until the vaporstat cuts out. The contacts on the circuit to be interrupted are normally closed unless the relay is energized, so the risk of failure and a no-heat situation should be low.
I've decided to go with the low voltage solution, partly because its low voltage and partly because I still have the pressuretrol. I've selected a Magnecraft TDRSOXP On Delay/Interval Time Delay relay, available from FactoryMation.com.
@ February 23, 2010 8:42 AM in Air vents: what would you do?I replaced all the vents on my system in January with Gortons, to the tune of around $600 including one spare for each size vent. I have 14 radiators on five main legs I have two Gorton #2's and 11 #1s on the mains, and an assortment of #5, #6, and #C on the rads. All of the #1s work fine. One #2 either failed within the first week, or was DOA and I didn't catch it right away. I had one bad #5 on the rads. Everything else was fine. If I were to do it over again, I might have substituted all #1s for the #2s
@ February 22, 2010 9:39 PM in Temperature-based cut-in for a Vaporstat?so there will be more data collection opportunities if I don't get everything I want this season.
I'm very interested in the outdoor reset control offerings. I've looked at the Heat-Timer but it's way out of my price range. The Tekmar 279 is tempting but still pricey (and even then it doesn't really solve my vaporstat problem). The Tekmar folks tell me that you could see up to 15% savings over indoor-only thermostats, which for me is a 3 to 4 year payback with today's fuel prices, sooner if the price goes up.
I did contact Honeywell about the 3600 and they weren't much help. Best they could do is direct me to the current crop of thermostats. So maybe I'll just bite the bullet and get an new t-stat and an hour meter. It just bugs me that now I need two things to do what one used to.
Should have diagrams and descriptions ready to post tomorrow. Stay tuned.
@ February 22, 2010 8:21 PM in Temperature-based cut-in for a Vaporstat?reading that thread a while back, as well as the one where your flue temp data set clearly showed end-of-cycle short cycling. I've also seen a few other older threads asking similar questions, but I haven't read that anyone implemented a solution.
I thought about the t-stat anticipator. It's not quite the same problem though; the v-stat could still cycle on pressure even with an anticipator, though in my case I think it's unlikely.
I installed a Honeywell CT3600 t-stat twhen we bought the house 11 years ago. It has the "adaptive recovery" option, but according to my data it hasn't "un-learned" ten years worth of adaptation from the old, undersized boiler, and I haven't found a way to reset it. Tried turning the feature off and then on again, pulled the batteries, with no luck. It must store the adaptive recovery data in non-volatile memory. It pretty consistently starts a recovery burn about 1/2 hour earlier than it needs to, so I have to set the target time about 1/2 hour ahead of what I really want.
I've been thinking about replacing it, but the 3600 has a really nice "Usage" feature where it will display the call-for-heat elapsed time for today, yesterday, and from when it was last reset. I haven't found a new t-stat with that feature, and I really hate to lose it, as I use the time-since-last-reset along with fuel delivery info for consumption calcs.
BTW, I used to run an 11 degree setback (56 deg) at night on the old boiler (we like it cold, that's what blankets are for). The new one too, until I went into the basement one morning and found the pressure up around 12 oz! This is what prompted the vaporstat install, which in turn prompted the musings about an end-of-cycle short cycling solution.
JP, I seem to recall that your logger data was pretty conclusive on maintain vs setback. Mine doesn't point to a clear choice yet, so I'm still running the data loggers. I need a couple more cold snaps of three or four days each to try a few of the options. Once we get into the swing season, I don't think I'll be cutting out on pressure very much.
At any rate, I'm going to give this time delay solution a shot. I'll sketch up and post the wiring diagram I'm planning to use.
@ February 21, 2010 3:10 PM in Temperature-based cut-in for a Vaporstat?Thanks for the explanation, Charlie, it's pretty clear. And your first sentence exactly describes the problem I'm trying to solve.
When my vaporstat cuts out, it's always near the end of a heating cycle. I'm running at such a low pressure that it only takes a minute or so for the vaporstat to cut back in. But at that point the burner doesn't need to run any more; latent heat in the rads will eventually satisfy the thermostat.
Using the bucket analogy, bucket one fills bucket two when bucket three is, say, 90 percent full. The vaporstat cuts out and stops the flow from bucket one. Bucket two only drains into bucket three for a short time before the vaporstat cuts in and bucket one starts re-filling bucket two, which fills again in short order. This short-filling cycle repeats until bucket three is full.
But when bucket three is 90% full, I know that there's enough in bucket two to finish filling bucket three. I don't need to add any more from bucket one, even though the vaporstat says I can do so.
So when bucket two fills, I want to delay bucket one from refilling it for some period of time, even if the vaporstat says "go". I was thinking of using condensate temperature as the delay variable, but data I've collected over the last week suggests that a timing relay would work just as well.
Bottom line is, I figure if I can eliminate 10 minutes of this end-of-heating-cycle short cycling twice a day (morning and afternoon recovery from thermostat setback), over a 3 month period that could be 28 hours of fuel saved.
@ February 21, 2010 8:26 AM in Temperature-based cut-in for a Vaporstat?Charlie, I must be missing something. Why do I want to cut out on pressure, and then have a series of 1 minute off and 3 minute on cycles? I thought short-cycling was Not A Good Thing.
@ February 17, 2010 6:50 PM in Temperature-based cut-in for a Vaporstat?I installed a vaporstat on my steamer last weekend and have been datalogging the flue temperature to get cycle time data. When maintaining temperature, the system runs for 20-25 mins, and never cuts out on pressure. On recovery from setback (60 to 67 degF), the burner runs for about an hour, then there are 3 or 4 pressure cycles of 1 min off and 3 mins on, before the thermostat is satisfied.
Operating pressure is 2 oz, v-stat cut-out is 3 oz, diff is 3-1/2 oz (it cuts in at a bit of negative pressure).
Those pressure cycles at the end of the burn seem like wasted fuel to me. If it cuts out on pressure, then the system is (or should be) filled with steam. And if the system is filled with steam, then I should let the latent heat do its job and shouldn't re-fire the burner until its spent.
The Tekmar 279 steam control has a "lockout differential" feature where it waits for a measured temperature on a condensate return to drop below a setpoint before letting the burner re-fire.
I've been kicking around a couple of ideas for doing something similar, to add a temperature-based cut-in when the vaporstat cuts out on pressure.
So I was wondering if anyone has done this already, or if it's even worthwhile to try, or if I should just save up and buy the Tekmar. :-)
@ February 17, 2010 4:03 PM in searching the walljpf, the iGoogle link for #1 should be http://www.google.com/ig
@ February 13, 2010 9:57 PM in why do Honeywell vaporstats suck so badly?I ordered a new L408A1109 vaporstat from patriot-supply's ebay store (Great service from these guys btw - ordered it Thursday and received it late Friday afternoon). Having followed this thread, I figured I'd better bench check it before putting it in. I made a test rig with some fittings, the 0-30" inH2O low pressure gauge from the boiler, an ohmmeter, some plastic tubing and a bit of lung power. And sure enough, out of the box the v-stat would not break the RB circuit no matter what I did with the setpoint and diff screws. Finally had to adjust the screw in the back of the unit in order to get the microswitch to operate.
It's in service now, with the cutout set at 3.5 oz (the system fills with less than 2), and the diff set slightly higher so that it will cut in on a bit of negative pressure. I have a thermocouple data logger in the flue to track how the boiler cycles once it cuts out on pressure.
@ February 11, 2010 12:28 PM in Should I split this main?I created it using DIA - a free, open source counterpart to Visio, available here.
@ February 10, 2010 7:48 PM in Should I split this main?Thanks guys. Here's a bird's eye diagram of the mains. The earlier photo is shot from "B" looking towards "A" and "G".
Luv'nSteam: The water line bounces, which according to TLAOSH is a symptom, but I'm not getting any water hammer. Insulating the fittings is definitely on my to-do list, along with the rest of the near-boiler piping.
jpf321: Yep, that's the page! I was pretty sure about the first tee, but not so sure about the second.
Steamhead: Thanks for the advice. A 3" drop header is in my plans.
So in my diagram, would the tee at "B" be considered bullheaded, or is this OK because the steam only changes one direction? That tee points up, btw.
@ February 10, 2010 10:22 AM in Should I split this main?My one-pipe system has a single riser that connects to the main via a (bullheaded?) tee. One side of the tee heads off to the right (see pic) to serve the radiation in the rear of the house. The other side goes about a foot to the left, makes a 90, then goes 2-1/2 feet to another tee (not sure if this one qualifies as bullheaded or not), with the two sides of that tee serving the front of the house.
I want to re-do the near-boiler piping this spring. Would there be any benefits to splitting the main so that the front-of-house and rear-of-house mains are served by separate risers? I was thinking of capping the left side of the big tee, replacing the 2-1/2 foot section with something shorter and adding a 2nd riser to that.
@ February 10, 2010 9:52 AM in Understanding working steam pressurefrom a setback (10 deg diff), where the t-stat won't be satisfied until 30-45 minutes after the rads are hot. In the meantime, the burner keeps firing, and the pressure builds slowly. The highest pressure I've observed prior to t-stat shutdown is 16 inH2O (abt 9 oz). I haven't found any leaking valves, so I have to believe that the reason the pressure builds so slowly is due to how closely matched the boiler is to the connected load. At any rate, the pressuretrol might just as well not be connected for all the good it does.
@ February 9, 2010 7:43 PM in Understanding working steam pressureMy new boiler, installed Dec 09, is sized about 4% larger than the connected load (633 sf boiler vs 607 sf load, net). After replacing all of the main and rad vents, the system consistently fills with just 3 inH2O on the low pressure gauge (about 1-3/4 oz.) and increases slowly after that (maybe 1 inH2O every 3-5 minutes).
My understanding from the previous threads is that once the rads are filled, it's a waste to keep the boiler firing after pressure gets above, say, 4 oz in my case. Correct?
There's a pressuretrol on the boiler that is doing nothing for me at these operating pressures. If I replace the p-trol with a vaporstat, can I set it to cut out at 4 oz? What about cut-in? The system goes to vacuum within a minute or so of shutdown. Is there a way to add a time delay to the cut-in? Having the boiler re-fire after just a minute or two doesn't seem to be the right thing to do, unless I've missed a point somewhere.
@ February 7, 2010 4:18 PM in King valve recommendation?Thanks for the links Rod. I wasn't sure if there was anything unique about a king valve.
I like what Alex Marx did with the equalizer in the first photo. I assume the Hartford loop ties in behind the boiler on the right side of the photo. I have a similar situation with my boiler, where the return is on the opposite side of the boiler than the main. Unfortunately, rather than innovate, the installer chose to run the equalizer and the header in opposite directions from the boiler risers. It's not causing any noticeable problems, but I still don't like it and want to re-do the near-boiler piping the right way after this heating season, with a 3" drop header, and a king valve (or two if I split up the main, but that's another subject).
@ February 6, 2010 7:53 PM in King valve recommendation?Does anyone have a source and/or recommendations for king valve to go on a 2-1/2" riser?
@ January 30, 2010 6:46 PM in A Collection of Retired VentsNow that my re-venting project is complete, I thought I'd share a photo of some of the old vents that were retired from service.
Top row, left to right: Vent-Rite No. 1, Flair No. 0, USAV 884, Jacobus self-adjustable
Middle row: Vent-Rite No. 1 (different version than the one in the top row), Dole Vari-Vent 1A, USAV No. 64, Hoffman 1A, Hoffman 75
Bottom Row: Dole Vari-Vent 1A, Cadwell No. 10, Air MACK Valve, Hoffman 4A
@ January 30, 2010 6:37 PM in Stubborn Hoffman #75thanks to some tapping and a couple of good whacks on the wrench with a small sledgehammer. The nipple came loose before the vent did.
The re-venting project is now complete, with Gorton's on all the mains and rads. Now for some more time trials with the data loggers to see how much (or if) the venting times have improved.
@ January 30, 2010 3:48 PM in Stubborn Hoffman #75So I'm down to the last stubborn vent on my re-venting project. It's an old Hoffman #75 on a six inch riser, and it leaks. The vent appears to be screwed into some kind of sleeve on the top of the riser. Everything is rusted solid, and to make matters worse, a takeoff to one of the radiators runs in front of it.
I've sprayed the base of the riser and the vent with PB Blaster a couple of times, let it soak in, then went at it with an 18" pipe wrench. So far the rust is winning.
I'm looking for suggestions for what to try next.
@ January 25, 2010 8:14 AM in Getting steam to the mainsHi Rod - I'm sure you're right about there being some counterflow in the header, though it's been quiet so I'm guessing there's no collision there. Unless I get some evidence to the contrary (like someone whose steam takes 30 seconds to get from the riser to the mains), I'll have to leave it be. Thanks for the source of insulation for the fittings, I'll be ordering those and insulating the rest of the near-boiler piping.