Replacing Low Water Cut-off (float type)

EdwinD

@Fred Thank you! Yes I have a pressure relief valve. see attached. Appreciate you asking.

EdwinD

After a little more due diligence, I'm going with the Honeywell PA404A1033 Pressuretrol which I understand is the standard for residential steam boilers. I'll set it at .5 PSI cut-in and differential set to "1"

One final question, I have a 24VAC line powering the boiler, can I work off that line and wire the Vaportstat and Pressuretrol in a series?

Thanks

Fred

Yes, the Vaporstat, Pressuretrol and LWCO all need to be wired in series, otherwise any one of those safeties can see a problem and attempt to shut the boiler down but power from the others may allow the boiler to continue to run.

On a vapor system, like you have, a Vaporstat is the best option. You don't have a standard residential steam system, you have one of the best and it should maintain very low pressures to be most effectient (below 12 ounces). You can't get that with a Pressuretrol. Of course, a Pressuretrol is fine as a back-up to the vaporstat. I have a Vaporstat and back-up Pressuretrol on my system too. Been on the system for about four years now. Works great!

EdwinD

@Fred Sounds good! I think I've got all the info I need for now. Thank you and thank everyone for your knowledge and expertise and showing great patience in assisting this layman. It's very much appreciated! You've been great. Once I get setup, I'll circle back to share the final configuration with pics.

Thanks again!

Jamie Hall

As @Fred said, you have to have a vapourstat on that system. You can wire it in series with the pressuretrol, but the vapourstat, set as we've mentioned above, is required. Yours is not a standard residential steam system, it is a residential vapour system, and the are not the same thing!

EdwinD

@Jamie Hall Thank you! I need to know that! Appreciate it.

EdwinD

Hello folks,

I wanted to get your feed-back for this mock-up on my Vaporstat and Pressuretrol before taping and tightening. No settings have been completed nor electrical work, I'm still waiting for my probe LWCO.

Thanks

EdwinD

One other point, I'm replacing the 1st tee (on left) with a cross tee with a plug on the end. And the 2nd tee (on right) I'm switching around so the plugged end is horizontal.

Steamhead

That'll work fine. And, you can check the pigtails every year or so by simply removing the gauges and blowing into them. No need to take the whole thing apart to do that.

EdwinD

Awesome. Once, LWCO arrives, electrical begins. I understand I need to do a series wiring, yet I may have a few questions. Thanks Steelhead!

EdwinD

@Steamhead I meant to say! Been buying too much black "steel"

EdwinD

I have all my parts, Probe LWCO, Vaporstat, Pressuretrol, of which I'll be wiring in a series. I'll add a 4" box and route my 24volt hot and negative wires into it - I traced those wires from the transformer, then to the gas valve, and then to the old pressure trol (see attached)

To get your input and check my understanding on series wiring, I attached a series diagram which in principle should work for my control devices as well shouldn't it?

Thanks in advance

Fred

Yes, basically the same but you want to make sure the gas valve is the last connection in the series, after all of the safeties. You want any one of those safeties to break/interrupt power to the gas valve, should one of them trip.

EdwinD

@Fred
Thanks Fred. Great point. I get what you're saying - with the old setup the gas valve is the last connection in the series. I know that to be the case, b/c when testing the old low water cutoff, the gas cuts off immediately. I won't be touching any wiring to the gas valve. I'll be starting with the wiring at the old pressuretrol to be sure. Doe that make sense? Just trying to keep it simple and safe. I will test it for sure.

Fred

EdwinD said:

@Fred
Thanks Fred. Great point. I get what you're saying - with the old setup the gas valve is the last connection in the series. I know that to be the case, b/c when testing the old low water cutoff, the gas cuts off immediately. I won't be touching any wiring to the gas valve. I'll be starting with the wiring at the old pressuretrol to be sure. Doe that make sense? Just trying to keep it simple and safe. I will test it for sure.

Yes, Vaporstat, Pressuretrol, LWCO(s) and then on to the wire that goes to the gas valve. The safeties can be in any sequence in the series as any one of those (when tripped) will interrupt power to the gas valve and prevent the gas valve from opening (or staying open).

EdwinD

@Fred Great advice. I always learn something new each time I'm here. I'll keep you all informed as I proceed. Others will surely benefit.Thanks!

EdwinD

I had to delay my project (traveling for work) but I'm now in the final phase : series wiring - in the following order - 1) LWCO (Safegard 400), 2) Vaporostat, and 3) Pressuretrol. I understand how to wire in series the Vaporstat and Pressuretrol. Adding in the Vaportstat in series is where I got thrown off.

1) See attached - Diagram A2 - Safegard 400 Probe LWCO wiring diagram. I wired the boiler common (neutral) from burner circuit to Terminal 2. No problem.

2. Next I ran the hot wire from boiler circuit to Terminal P2.
This is where I stopped.

3. Question: I intend to run another wire from terminal P2 to terminal R on Vaporstat. Then run terminal B on Vaporstat to 1st Pressuretrol terminal. Then run 2nd Pressurerol terminal back to boiler common wire.

Is this correct? Thank you.

EdwinD

EdwinD

Re #3 above - Or should I simply run a single wire FROM terminal P2 of the Safegard 400, then in series to Vaporstat , then Pressuretrol (in series) , and then go back to the boiler Hot.

Steamhead

EdwinD said:

Re #3 above - Or should I simply run a single wire FROM terminal P2 of the Safegard 400, then in series to Vaporstat , then Pressuretrol (in series) , and then go back to the boiler Hot.

You'd hook the other Pressuretrol terminal to the wire that feeds 24V power to the burner. The thermostat connection is probably located inside- make sure it does not cut power to the LWCO when it opens. It should interrupt the 24V coming back from the Pressuretrol before it gets to the burner.

zoom

Based upon my experience and the guidance elsewhere on this sight, mount the Vstat to a pressure snubber. This inexpensive device will protect your Vstat against pressure waves than can damage the Vstat (or they did mine at least).

EdwinD

@Steamhead

Steamhead said:

EdwinD said:

Re #3 above - Or should I simply run a single wire FROM terminal P2 of the Safegard 400, then in series to Vaporstat , then Pressuretrol (in series) , and then go back to the boiler Hot.

You'd hook the other Pressuretrol terminal to the wire that feeds 24V power to the burner. The thermostat connection is probably located inside- make sure it does not cut power to the LWCO when it opens. It should interrupt the 24V coming back from the Pressuretrol before it gets to the burner.

Got it about making last run to 24V power to the burner. Thank you.

Steamhead

You need to have 24V on P1 because that is the center terminal of the SPDT switch that feeds power either to the burner or the water feeder, depending on whether there is enough water in the boiler. Generally, a jumper is installed between terminals 1 and P1 to do this, as shown in diagram A1 above. When the LWCO is satisfied, it sends 24V to P2 and that feeds 24V through the pressure controls and thermostat to the burner.

EdwinD

@Steamhead Thanks for your help.

EdwinD

I wired up the LWCO (Safegard 400) - problem is the amber colored light stays on indiacting a low water condition - which it's not. I removed the probe and removed the dope off the threads. I didn't use teflon tape ro any sealant upon replacement - light continues to stay on. FYI, my boiler is an EG-55 gas fired steam/vapor boiler. See attached image of probe.



Any thoughts are appreciated.

Fred

- Are you 100% sure the boiler water level is correct? The lower gauge glass tapping may be clogged and the gauge may show a higher water level than is actually in the boiler.
- Make sure the probe lead wire is secure
- Make sure the probe is clean and doesn't have a coating of oil on it. Clean it with a fine steel wool.

EdwinD

@Fred

The sight glass shows water is at the correct level. One thought though, out of necessity I replaced the sight glass yesterday. It's all new hardware. Anything there I might have missed?

Probe is secure - checked it.

Probe is clean, used regular brush to clean the grooves, with solvent. I cleaned it with a brush - not steel wool. But I'll take it out and try again - I also cleaned the boiler tap the probe is installed into.

Is it possible the probe is too long? I know I need at least 1/4 " clearance between probe tip and boiler surface. I'll measure again. Just a thought.

Steamhead

Is the wire connected between the probe and circuit board?

BobC

make sure the ground connection is good and that it goes all the way back to the circuit breaker box.

Bob

EdwinD

@Steamhead Yes, the wire is connected between the probe and circuit board

Thanks

EdwinD

@Bob It's an old 24 volt transformer. To my knowledge there is no ground running back to the circuit breaker box.

Jamie Hall

oy. Is there a ground from the burner itself, or the boiler? I hope? And I will bet that the ground for the transformer is -- or should be -- that BX cable I see sticking out of the side of the on/off switch. Which may or may not be adequate. is the box the transformer is mounted on grounded?

EdwinD

@Jamie Hall

No, there doesn't appear to be a ground from the burner or bolier itself. The only wires from the boiiler come from the gas valve - thermostat and gas

The transformer box itself only has the two wires leading in from the switch, otheriwise it does not appear to be grounded.

JUGHNE

You must have a standing pilot with thermocouple?
Not any form of electronic ignition?

Steamhead

Is that LWCO being fed from 120-volt or 24-volt power?

If the former, the green (ground) wire is not connected to the control's chassis.

EdwinD

JUGHNE said:

You must have a standing pilot with thermocouple?
Not any form of electronic ignition?

That's correct. It has a standing pilot with thermocouple.

EdwinD

Steamhead said:

Is that LWCO being fed from 120-volt or 24-volt power?

If the former, the green (ground) wire is not connected to the control's chassis.

The LWCO is being fed from 24 volt power.

Jamie Hall

Anybody have access to a circuit diagram? Not just the attach this wire to that screw, but the actual internal circuit diagram? I have a dismaying suspicion that the Safeguard simply won't work unless there is a continuous ground and bonding, but I don't want to say for sure without the circuit diagram...

EBEBRATT-Ed

try running a ground wire between the low water cutoff and the box the transformer is mounted on. Even a temp jumppper wire and see what happens. You could also try reversing the 24 volt wires

Fred

Are you sure that probe isn't touching the back wall of the boiler when it is screwed in? They also make a short probe for that unit.