LWCO and LPCO question on Vitola

Constantin

... to install a LWCO on our Vitola in conjunction with fixing the two leaks on in the near-boiler piping. Naturally, I picked up the tab for installing the LWCO. However, when I returned from vacation, I found the install to deviate from the OEM install instructions.

Note the location of the LWCO on the exit piping on the Vitola instead of being mounted at the top of the boiler by the vent as shown in the Viessmann install manual. Is this something I should worry about?

A while back, we also discussed the merits of LWCO + LPCO's. Some professionals like Mark Eatherton put them in as a matter of course, others like UniR prefer flow sensors, it seems. I would like to install a LPCO as a canary to alert me to whether a flooring guy did staple a PEX tube accidentally and 4 months later the thing rusts out and sprouts a leak. Naturally, I'd be turning off the autofeeder...

So, what LPCO's have you installed that you liked?

Locationwise, should I have our contractor move the LWCO to its proper location (at least as per the installation instructions) and install the LPCO in the hole that the LWCO currently sits in?

jim lockard

LWCO

Constantin---I for one always install the low cut off above the height of the boiler. I like to place it between valves so that it can be serviced. Best Wishes J.Lockard

Mark Eatherton1

Square 'D'...

We get out LPCO's from WW Grainger. They have a bunch of them, and we use the lower range models that break at 10 PSI and make at 15 PSI (reverse acting). It is best to install them at the PONPC to avoid nuisance trip outs or false positives coming from the circulators. It is wired in series with the primary power supply, as should the LWCO be.

I know the manufacturers show it as being in series with the ignition circuits only, but personally, if I'm seeing a low water or low pressrue condition, I don't want any of my pumps running...

Watch the ampacity though...

ME

Constantin

Is this the model you were thinking of?

• Type F Pumptrol Water Pressure Switch, Class 9013
  
• Reverse Action: Contacts Open on Falling Pressure
  
• Cut in Range (psig): 6-14
  
• Approximate Adjustable Differential: 5 Non-adjustable
  
• Cut-out Range: 1-9psi
  
• Pressure Code: 8.5-5.5 psi: J17
  
• Part: #9013-FRG59-J17-T (1/4" NPT)

S Ebels

An LWCO...........

Won't do you any good unless it's installed above the water level of the boiler. It should be relocated to the correct place.

What Viessmann should do is provide a 3/4" tapping in their safety header for a LWCO. Nice convenient location for wiring too. Maybe someone from V will read this/maybe I'll get to Warwick or Waterloo and have a chance to bend the right ear.

Weezbo

i cant see how youd ever know if you had a low water fault

with it buried under the lowest water in the boiler...er..low water is located above the floodlevel of the boiler and some where near the supply wiring just to keep it looking professional...i like the idea of 6" above the flood level , that way it should alert you if the feed water isnt working or if there is a problem...really Constantine ,where it is currently located, it is all but a useless appendage...

Mark Eatherton1

I don't have a Grainger catalog here, but...

that looks right. 1/4" threaded tapping on back.

ME

Ernie

Tee at back....

of Vitola below the draft regulator, did that come with the unit or is it just a standard tee?

Constantin

Good Point...

... IIRC, the installation instructions show the LWCO being installed into a T ahead of the safety header. Hence my question above... I thought the present installation will do little to ensure that the boiler water levels don't drop too much or that the pumps will stay wet & happy.

So, I guess I'll ask them to move the LWCO to the Viessmann-specified location, then perhaps use the remaining hole as a location for the LPCO. Then set the LPCO to trip at 7psi (normal operating pressure is 12psi and up) so as to catch a low-water pressure situation before it gets out of hand.

Paul Pollets

Agreed

We always put the LWCO on the supply piping within 6" of the boiler. the existing LWCO is too low to be of any use. the boiler can easily dry fire, in that location.

Viessmann does not have any tappings for the LWCO on any of their boilers, which should be done...at least modify the safety header, which should not be cost prohibitive.

Relief valve tappings should also be modified on their water tanks, which currently force the installer to move the vertical tanks 12-16" from walls to allow their (relief valve) removal. Most mechanical rooms are way too small for that spacing. Bad design. The relief valve tapping should be on the side of the tank for convenience and space savings.



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Paul Pollets

No valves....

Isolation valves should not be placed between the boiler and the LWCO. If the valve is mistakenly closed, the boiler would have no protection.

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Mad Dog

Common sense dictates...........................................

that if that boiler sprang a leak, by the time the lwco broke the circuit, the boiler would be dry-firing away. Good discovery Constantin...maybe you should be doin the installations. Mad Dog

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Constantin

If you're referring to the drain under the flue...

... that is the standard location for the drain, auto-feed, and expansion tank (at least if you follow the install instructions). In our case, the installer decided to mount a separate Spirovent elsewhere, along with the expansion tank and autofeed.

Mark Eatherton1

Interestingly enough...

On large commercial boilers, the state boiler inspectors, along with private boiler insurers (That's right, the one that the loop is named after) WANT isolation valves around the LWCO. When they asked me to start installing them, I told them to take a hike. If thier guys can't figure out how to isolate a system without using valves directly around the LWCO, then they shouldn't be in the boiler room at all...

Their excuse is that they don't carry any tools or ladders around to access the big isolation valves...

NIMBY...

ME

Glenn Harrison_2

If that is a McDonnell Miller LWCO,

then M&M wants to see it in the main piping, not in an air vent pipe like Viessman wants. So now you have a predicament, Viesmann specs or M&M specs. Personally, I would go with M&M.

However, I will agree with everyone else that it should be much higher in the system than it is right now.

Ron Schroeder_3

location of LWCO

As the TSA for said manufacturer I can only reiterate the instructions found in the installation manuals regarding LWCO installation points. All boiler approvals were achieved together with their documentation.
Speaking for myself, I would personally prefer to see the incorporation of a Hydronic System Feeder as opposed to a hard piped auto feeder. System feeders make boiler fill valves and backflow preventers obsolete. Additionally, all fluids drained during service can be replaced into the heating system via the feeder pump.

Constantin

Which brand/model would you recommend?

I am intrigued by your description of a hydronic system feeder... I too am not a fan of auto-fill systems because they can make a bad situation (leak) worse by allowing the house to fill up with water.

Hence the LPCO and the LWCO. I want the boiler to be protected, but I also want to limit the possible damage from a errant flooring staple to be less than 100 gallons (the total system capacity). After the system ages and no leaks become apparent (i.e. within the next year or so), I'll be a bit more confident that the system integrity has not been breached.